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[FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274 Physics and Chemistry of Functionally Graded Materials Research Report (pp.1-140)](https://mdr.nims.go.jp/datasets/8f8e28cc-c697-48fd-9a16-b485337f0d8f)

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Sheet1 BookTitle_j BookTitle_e Volume/Issue Issueddate Page Title_j Title_e AuthorList_j AuthorList_e Abstract Language 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 1-4 放電プラズマシステムによる傾斜機能材料の合成－高熱伝導性ポリイミド(AlN)/Cu 傾斜機能材料－ Synthesis of Functionally Graded Materials by Spark Plasma System -Thermal Conductive Polyimide (AlN)/Cu FGMs- 大森守、大久保昭、平井敏雄東北大学　金属材料研究所 Mamoru Omori, Akira Okubo and Toshio HiraiInstitute for Materials Research, Tohoku University  Today's IC's (integrated circuits) are so compact that such Microelectronic packaging requires high thermal conductivity. AlN ceramic can be one of the answers to this recent demand for such packaging materials because AlN ceramic is a high performance material with high　thermal conductivity. However, the fabrication process is complex because such Ceramics need high temperatures for sintering, and the cost of shaping hard, brittle polyimides is high.  Polymers are commonly used in electronic packaging, because of their high electric resistivity, low dielectric constant and ease of processing.  Polyimides have been used as insulation film for electrical and electronic applications, because of their thermal stability and toughness. However, the thermal conductivity of polyimides is low. To improve the shortcomings of the foregoing materials thermoplastic polyimide, SiC, and AlN have been mixed using slurry of the dissolved polyimide, and then hot-pressed at 11.5 MPa. The filler content of the composite is 50 vol.%, and its thermal conductivity is not high.  It is expected, though, that by applying the concept of functionally graded materials, the material with high thermal conductivity can be fabricated and used as package materials.      This paper is concerned with the formation of thermal conductive insulation consisting of polyimide composites and functionally graded materials (FGMs). FGM is prepared from a combination of thermosetting polyimide and Cu powder. The thermal conductivity of the FGM is about 6 W/m*K, insufficient for use in electronics. This low thermal conductivity is due to the polyimide layer. It is difficult to change a polymer structure from a thermal conductive one into a high one. Instead of changing the structure of the polyimide to make it highly thermally conductive, composites were prepared from AlN and thermoplastic polyimide powders using a spark plasma system. Furthermore, FGMs were fabricated from the composites and Cu powder to increase thermal conductivity.     Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 5-8 傾斜機能材料の知的機能発現のための粒子配列プロセス設計－単分散粒子の作製と制御配列－ Design Of Intelligent Particle Configuration Process for Functionally Graded Materials -Preparation and Controlled Arrangement of Monodisperse Particles- 渡辺龍三　市来浩一　（院）葉山知徳　（学生）川崎亮東北大学　工学部　材料加工学科 R. Watanabe, K. Ichiki (Graduate School), T. Hayama (Student), A. KawasakiDepartment of Materials Processing, Faculty of Engineering, Tohoku University  The Powder metallurgical process has been widely used for the fabrication of functionally graded materials as it is an effective way of controlling the gradient and developing the intended performance with respect to thermal and mechanical properties. Admitting its viability for tailoring various graded structures and shape forming freedom for the practical parts fabrication, the minimum size of the microstructural control is limited to several hundreds or thousands of primary particles in diameter and the formed microstructure is generally random in a micro scale, which restricts purely artificial control of the materials functions. To realize a more precise control of the particles to form a systematic gradient we have proposed a particle configuration process in which individual single particles will be positioned at the allotted sites according to the theoretical design with a goal to break free from the current limitation.     The main purpose of this investigation is to establish particle arrangement technique in two and three dimensions and to construct three dimensionally composition-graded compacts. This process will provide a determinate control of the concentration gradient, as well as phase dispersion and connectivity in FGMs. The following four task items have been carried out:     [1]Preparation of monodisperse particles for controlled particle arrangement.     [2]Development of the construction technique of particle arrays of two and three dimension by stacking the formed sheets.     [3]Sintering of the particle arrays with particular interest in sintering neck formation and the phase reaction at the neck regions.      [4]Property evaluation of the sintered particle arrays.      As to the last item the thermal and electrical properties have been discussed on the basis of percolation theory.  Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 9-12 MA複合粉末のプラズマ溶射による傾斜機能熱電皮膜の作製 Fabrication of Functionally Graded Thermoelectric Coatings by Plasma Spraying of Mechanically-alloyed Composite Powders 福本昌宏　時本雄次　三河克明　田中康徳（豊橋技術科学大学生産システム工学系） M. Fukumoto, Y. Tokimoto, H. Mikawa and Y. TanakaDepartment of Production Systems Engineering, Toyohashi University ofTechnology  The usual fabrication methods of thermoelectric conversion materials (TEC) are successfully applied in the laminating or joining of several elements, in order to effectively multiply the output as a single element is limited in its generation power. Moreover a functionally graded structure of several TEC is regarded as the most effective conversion system. In many configurations of TEC, thick coating may be advantageous in laminating or joining. Therefore, thermal spraying is worthy of consideration among several processing methods as the thick coatings of hard -forming materials can be easily made. However, the conventional method of simultaneous spraying of blended elemental metals followed by post heat treatment, is hard to apply because a strict control of elemental composition by delicate heat treatment is required to produce high performance TEC.     In this study, homogeneously mixed metal/metal composite powders, which were made by mechanical alloying (MA), were applied by plasma spraying in order to obtain the intermetallic TEC coatings, and the processing for getting the functionally graded TEC coatings was fundamentally investigated.  The great merit of MA process is the possibility of controlling the additional dopant fraction and creating the fine and homogeneous structured composite powders. In this way it is hoped that plasma spraying will simplify the laminating and joining process to form a Functionally Graded TEC coating.  By spraying of several kinds of composite powders, the functionally graded TEC thick coatings are expected to be made as a laminating or joining form.  Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 13-16 ゾル－ゲル法による傾斜機能光半導体薄膜電極の作製と光電極特性の評価 Preparation and Photoelectrochemical Properties of Semi-conductor Thin Film Photoelectrodes with Graded Bandgaps by Sol-Gel Method 趙高凌　幸塚広光　横尾俊信京都大学化学研究所 G. Zhao, H. Kozuka and T. YokoInstitute for Chemical Research, Kyoto University  Solar Energy conversion cells are hoped to be the means by which energy can be produced cleanly for the next generation. Because of the high chemical and photoelectrochemical durability, TiO2 has long been believed to be one of the promising candidates for photoanode materials that split water in solar energy conversion cells and because it is corrosion free. However, TiO2 has low solar energy conversion efficiencies due to its large band gap of about 3.0eV. On the other hand, any narrow gap semiconductors studied so far are known to have poor photoelectrochemical stability.     When the band gap of the electrode is graded and the electrode surface is of pure TiO2 composition as schematically illustrated in Fig. I, such an electrode would be expected to have:      (1) excellent photoelectrochemical stability and      (2) photoresponse over a wide range of wavelengths.      In addition to these,      (3) efficient charge separation due to graded bands would     also be possible.      In order to design such graded band gap semiconductor photoelectrodes, we have prepared TiO2-VO2 (bandgap 0.62eV) solid solution thin films with composition gradient across the film thickness direction utilizing the sol-gel method, and the photoanode properties have been investigated.  Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 17-20 加圧燃焼合成法による傾斜機能材料の合成プロセス Processing of FGM by SHS/Compaction 大柳満之　辻上哲也　小泉光恵龍谷大学理工学部 M. Ohyanagi, T. Tsujikami, M. KoizumiFaculty of Science and Technology, Ryukoku University  The product of SHS usually comes in the form of powder or porous material.  However, dense and consolidated material can be synthesized using a combination technique of this SHS and an external pressure applied by HP (hot pressing) HIP (hot isostatic pressing), explosive consolidation technique, high velocity forging, and/or centrifugal force. This study aimed to investigate the process of FGM fabrication by means of SHS compaction.  Until last year, our research program focused on the FGM fabrication process using the technique that simultaneously synthesizes and densities the material(SHS/Dynamic Pseudo Isostatic Compaction). This technique of graded dispersion allowed up to 70 vol.% diamond to be fixed in the TiB2-Si without much problem caused by the residual stress.  This year we tried the same process to form the material with graded dispersion of diamond in the matrix which includes the layer with a higher concentration of diamond, i.e. up to 90 vol.%, fixed on the surface of the outer layer.    However, if the diamond dispersion layer is attached to the matrix layer, cracks occur at the interface because of the difference in thermal coefficients. Therefore, we needed to introduce graded dispersion of Diamond in the Matrix reactant in order to fabricate diamond-containing materials.  We used the TiB2-Si composite as the matrix in this program in the trial of fabricating the material comprised of two to five dispersed layers of several different diamond concentration. We first calculated the residual stress by FEM, and then tried the fabrication process. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 21-24 高温用セラミックフィルター作製のための組成およびポア構造傾斜プロセス The Process to Form Graded Composition and Pore Structure for the Fabrication of High Temperature Resistant Ceramic Filter 小平紘平　高橋順一北海道大学　大学院工学研究科 K. Kodaira and J. TakahashiGraduate School of Engineering, Hokkaido University  In advanced coal-fuelled power generation systems, high temperature resistant filter elements must be placed at the front of rotating turbines to eliminate fine particles in gas streams. The severe environment of the hot gas streams in the system requires the filter elements to have excellent properties in thermal shock resistance and mechanical strength under working conditions. Among the candidate materials made from a single component for high temperature filter applications, cordierite ceramics are considered to be the best material, mainly because of its superior thermal shock resistance property. In this study, the fabrication of cordierite/mullite(C/M) composites with graded composition has been attempted to improve the mechanical strength of the cordierite-based filter material and to enable the filter to be used at much higher temperatures. The Thermal shock resistance of the graded C/M filters seemed to be lowered with an increasing content of mullite component in the filters. The required property of excellent thermal shock resistance, however, is expected to be maintained by grading the pore structure of the filters. The purpose of the present study is to establish the processing of the graded composition and corresponding pore structure gradient to produce a C/M filter with excellent thermal and mechanical properties that will have high thermal shock resistance. The double spray method was employed to fabricate graded C/M porous materials, in order to take advantage of the difference in behavior of the two materials during sintering. In this method, two different suspensions were simultaneously sprayed from separate nozzles into polymer foam. Changes in the composition and microstructure with graded composition were examined for the filters. Thermal shock resistance was also estimated. These results were related to the spray processing characteristics. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 25-28 有機高分子からの非晶質傾斜セラミックスの合成 Synthesis of Amorphous Ceramics from Organic Polymer 佐々木眞室蘭工業大学 Makoto SasakiMuroran Institute of Technology  Polymer-derived ceramics from polysilazane (Si-C-N-H) are suited for high-oxidation resistant materials because of their structural and compositional ease and it is hoped that these ceramics can be utilized for that purpose.      Author and the co-workers have already reported a degradation of carbon contents of Si-C-N amorphous ceramics by the introduction of ammonia gas during ceramization of the polymers. On the other hand, compositional graded coating is of interest to reduce thermal stresses between coated layer and substrate that occurs at interfaces when dissimilar materials are simply attached to each other, caused by the difference in thermal expansion coefficients of the materials.      This work details the results of the effect of different ceramization atmospheres, as well as the temperature and retention time of heat treatment, on the composition of ceramics derived from polysilazanes. Soluble Mo-Si-C-N-H polymers were fabricated by reaction of polysilazane with molybdenum-ammonium complex synthesized from molybdenum chloride and ammonia gas in chloroform. Mo-Si-C-N-H polymers were coated on two dimensional (2D)-C/C composite by dipping into the chloroform solution, and the oxidation resistance of the Mo-Si-C-N ceramic-coated 2D-C/C was evaluated. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 29-32 紫外線照射による傾斜機能ゾル／ゲル皮膜の新コーティングプロセスの開発 Development of New Coating Process for Functionally Graded Sol-Gel Film by Ultraviolet Irradiation 平井伸治　嶋影和宜室蘭工業大学　工学部　材料物性工学科 Shinji Hirai and Kazuyoshi ShimakageDepartment of Materials Science and Engineering, Muroran Institute of Technology  A report has been published on sol-gel coating for semi-conductor thin film photoelectrode 1). This coating was processed by the dip-coating technique, utilizing a sol solution of different composition at each dipping to form laminated layers of graded composition. With a view to developing a new technique, we tried ultraviolet (UV) irradiation in room temperature, instead of the conventional heat treatment, to consolidate the gel layers after the coating process. The density of each layer was changed by varying the irradiation parameters at each repetition of coating process to form a density gradient in the stacked thin layers.      The purpose of the oxidation treatment of the aluminum anode is to make the surface of the electrode corrosion and wear resistant, and to insulate it. The outer layer has a particular structure with hexagonal prism-shaped narrow holes (cells) lined up perpendicular to the material. We have previously fabricated composite coating on the aluminum anodic oxide film in order to improve its alkaline corrosion resistance using the sol-gel technique. This coating is made of two layers: the porous layer modified by zirconium oxide at the walls of narrow holes lined up in it, and ca. 0.1 micrometer thick zirconium oxide coating on top of the porous layer. This composite coating film was found to have much improved alkaline corrosion resistance after giving the gel film a heat treatment in the O2 atmosphere at 573K, because the treatment consolidates the gel film by eliminating water and organic substances in the film. This report shows that, when the gel film absorbs the UV light, organic substances and water are disintegrated because of the excitation and the film is consolidated, which can result in improving not only alkali resistance but also the adherence of the film to the matrix. The method of fabrication of this thick composite layer of the graded density is discussed. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 33-36 ナノスケールで変化した傾斜構造の物理的・力学的挙動の原子レベルシミュレーション Atomistic Simulation for Physical and Mechanical Properties of Nano-scale Graded Structure 相原智康　川添良幸東北大学金属材料研究所 Tomoyasu AIHARA and Yoshiyuki KAWAZOEInstitute for Materials Research, Tohoku University  The basic concept of the functionally graded material is active control of the material structure and the optimization of its functions in use. The application of this concept for the nano meter level structure of the materials, for example, atom level controlled interface, will develop their performance. Then, the nano meter level technology is important to evaluate the local physical and mechanical quantities in the material and to design the atom level structure.      We have been performing molecular dynamics simulation for the coherent interface between the Ni3Al L12 intermetallic compound ((gamma)' phase) and Ni ((gamma) Phase) with nano-scale graded structure. We simulated the elastic deformation last year. The microscopic distributions of the physical and mechanical properties were analyzed. We have clarified that the atom level graded structure relaxes the atom level stresses at the interface. In case of plastic deformation, however, the microscopic deviation does not coincide with the macroscopic one, because microscopic mechanism of plastic deformation involves dislocation and crossover of atoms, and those atomic motions interact with the interface. This year, we simulated the plastic deformation of nano-scale graded structure. The purpose of present research is to evaluate the micro mechanism and dynamics of the plastic deformation in the nano-scale graded structure material. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 37-40 SiO2とAl融体との置換反応により得られたAl/Al2O3複合材料の傾斜機能化 Functional Gradation of Al/Al2O3 Composites by Substitutional Reaction between SiO2 and molten Al 吉川昇、谷口尚司東北大学大学院工学研究科金属工学専攻〒980－8579仙台市青葉区荒巻字青葉 Noboru Yoshikawa and Shoji TaniguchiDepartment of Metallurgy, Graduate School of Engineering, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8579  It has been pointed out that fabrication cost of composite materials is generally high, because many processes are involved, such as mixing, dispersing of raw materials followed by heat treatments and processing into the desired shapes. Recently, In-situ Composites have attracted attention in the fabrication of these materials as it is possible to obtain the desired composite microstructures during the processes and it is expected to help reduce some of the other fabrication processes.       In the field of Al/Al2O3 in-situ composites, two methods have been known. The first method is by direct oxidation of the molten aluminum known as the DIMOX process and the second method is to make use of the substitutional reaction between SiO2 and molten Al. In both composites, microstructures consisting of Al and Al2O3 are obtained as the reaction products, having larger volume fraction of Al2O3, so they have been classified as the ceramics matrix composites.      In this study, composites by the latter methods are investigated, which have the characteristics that arbitrary shaped SiO2 can be transformed into the composites having the same shape and scale.      The application of these materials for machine elements has been taken into consideration. The researches conducted so far have been rather stressed for these practical aspects but there are still remaining fundamental problems concerning on the reaction mechanisms and the microstructure formation. The authors have investigated the relationship between the reaction kinetics, microstructure formation and the mechanical properties of the composites. It was found that the mechanical properties are dependent on the reaction temperature: the lower the temperature, the harder and more brittle the material.      This study is intended to fabricate the Al/Al2O3 composites with graded mechanical properties by means of controlling the reaction temperature. In this report, results on the microstructure observations and measurement of mechanical properties of the ungraded composites are shown first, and the results on the hardness gradation are presented. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 41-44 傾斜機能層への波動エネルギーの閉じ込め Trapped Wave Energy In Functionally Graded Layers 渡辺一美山形大学工学部 Kazumi WatanabeFaculty of Engineering, Yamagata University  In FGMs, a wave ray forms a curve due to the spatial variation of acoustic parameters such as elastic modulus and density, and thus a layer of the FGM may work as a wave channel. If the source of vibration exists in the low velocity layer, the layer may trap the energy of the waves, causing fracture and/or damages. Investigating works about the wave propagation character for FGMs may not only reveal the fracture mechanism but also establish a nondestructive evaluation technique by utilizing the waves. In the present paper, a basic wave character and SH wave energy trapped in the FGM Layer is discussed on the theory of elastic waves. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 45-48 共晶接合による金属／金属間化合物傾斜機能材料の開発 Development of Metal/Intermetallic Compound FGM Made by Eutectic Bonding 辻本得蔵、友田陽、鈴木徹也茨城大学工学部 T. Tsujimoto, Y. Tomota, and T. SuzukiFaculty of Engineering, Ibaraki University  An excellent idea for materials design is included in the concept of structural FGM. However, application of structural FGM has scarcely progressed up to date . The cause is in complexities of fabrication process for FGM, which charges high prices for manufactured FGM . In order to eliminate this hindrance, a simple fabrication process for FGM, which was based on eutectic bonding and on use of intermetallic compound, was invented by the authors . This new method simplifies the fabrication process considerably as it only involves selecting the right combination of metal and intermetallic compound that will have the eutectic reaction when heated up above the eutectic point. The FGM is formed as the result of the heating these two materials stacked on top of each other.       In this paper, the principle of the new method and the examples of IMC FGM fabricated by this method have been described. In parallel with the study of IMC FGM, further development of techniques for making use of eutectic melt is being attempted, which are named " eutectic coating method" and " eutectic melt infiltrating method" . Some explanations have been given for these methods. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 49-52 pH制御による電気泳動電着法によるセラミックス材料の傾斜機能化プロセス FGM Process for Ceramics with Electrophoretic Deposition Method by Controlling pH of Suspension 宇都野太東京大学　生産技術研究所 Futoshi UTSUNOInstitute of Industrial Science, University of Tokyo  A controlled continuous variation of composition, and thus of physical properties, such as thermal expansion and thermal conductivity with a view to optimizing the material under the working conditions, is characteristic of a functionally graded material (FGM). Such composites find applications in ceramic coating, the joining of ceramics to metals, and various other materials.       This is very fast and economic process of the green forming of functionally graded materials. Electrophoretic deposition is a colloidal process wherein particles of ceramics are suspended and then placed in a dc electric field to shape ceramics films on the substrate board. This is a very fast and economic process of the green forming of functionally graded materials compared to various methods for FGM processing, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma spraying, and powder stacking.  Particles in suspension move toward electrodes by (Seta) potential, which is generated at interface between solid and solute in suspension. The magnitude of (seta) potential is changed by various factors, such as kinds of particles or solute, pH of suspension, and so on. In this work, in order to establish one of techniques for preparing FGM ceramic films using EPD, EPD by controlling pH of suspension was carried out using the suspension that had a certain constant concentration ratio of two component ceramics particles. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 53-56 ソフト溶液プロセスによる傾斜機能材料の直接作製：水熱電気化学法によるATiO3（A＝Ba、Sr）複層膜 In situ Fabrication of Functionally Graded Materials by Soft Solution Processing: ATiO3 (A=Ba,Sr) Multilayered Films by Hydrothermal-Electrochemical Method 吉村昌弘、ヴォイチェク・スハネク東京工業大学・応用セラミックス研究所 Masahiro Yoshimura and Wojciech SuchanekMaterials and Structures Laboratory, Tokyo Institute of Technology  Recently, attention of the researchers has been focused on the multilayered films in the BaTiO3-SrTiO3 system. Demands to miniaturize and/or upgrade the DRAM capacitors necessitate fabrication of multilayered microstructures in order to reduce the leakage current several orders of magnitude, while keeping the high dielectric constant. Perfect multilayer, i.e. BaTiO3/SrTiO3 superlattice is one of the ideal candidates for the DRAM capacitors. Another interesting application of the multilayered films in the BaTiO3-SrTiO3 system are functionally graded materials having different chemical composition across the film thickness, resulting in a desired gradient of the dielectric constant across the material. Such FGMs can find applications as tunable multilayer capacitors, waveguide phase shifters, filters etc.      The previously prepared BaTiO3-SrTiO3 multilayered structures were fabricated by tape-casting, dip-coating or RF magnetron sputtering. The RF magnetron sputtering required high vacuum, and temperatures in the range of 500-700deg.C. Both tape casting and dip-coating required heating of the films above 600deg.C. Such heat treatments often result in cracking and/or peeling of the deposited layers, reaction of the film with the substrate, moreover are energy-consuming. However, it is possible to prepare the BaTiO3, SrTiO3, or (Ba, Sr)TiO3 thin films by hydrothermal-electrochemical method under mild conditions and temperatures around 100-150deg.C. In our earlier work, these thin films have been prepared in the newly constructed flow-system equipment by the hydrothermal-electrochemical method, and the effect of the synthesis parameters (temperature of 100-200deg.C, flow rate of 1-5 ml/min) on the film properties have been discussed.  The purpose of the research presented in this paper is demonstration of applicability of the flow cell for hydrothermal-electrochemical synthesis for preparation of functionally graded materials in the BaTiO3-SrTiO3 system. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 57-60 無機－有機傾斜複合体の合成と多孔体への応用 Preparation and Application of Porous Inorganic-organic Functionally Graded Complexes 熊田伸弘　木野村陽一山梨大学　工学部 N. Kumada and N. KinomuraFaculty of Engineering, Yamanashi University  We had attempted to prepare inorganic-organic functionally graded complexes, zirconium phenylphosphonate phosphates cointercalated with aniline and to convert the complexes to porous materials by removing aniline. However, the specific surface area for the inorganic-organic complexes was unexpectedly small, and the low surface area was attributed to incomplete removal of aniline. Then preparation of zirconium phenylphosphonate phosphates was attempted without aniline, and similar porous materials were pursued by using a silane compound instead of phenylphosphonic acid.      In addition to above inorganic-organic complexes, new functionally graded materials were prepared with sintered BaBiO3 under hydrothermal condition by using KOH solution to yield pyrochlore type (K, Bi)1.5Bi2O6-(delta)*nH2O Potassium ion in the pyrochlore type phase on the sintered BaBiO3 was ion-(K,Bi)1.5Bi2O6-(delta)*nH2O. Potassium ion in the pyrochlore type phase on the sintered BaBiO3 was ion-exchanged with proton. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 61-64 傾斜高分子膜の調製と膜透過・分離機構 Preparation of Graded Polymeric Membranes and Its Permeation-separation Mechanism 辻田義治名古屋工業大学　工学部 Y. TsujitaFaculty of Engineering, Nagoya Institute of Technology  When molecules permeate, or go through, a homogeneous membrane, they form a linear concentration gradient across the membrane. However, if the composition of the membrane is not uniform, the concentration gradient will not be linear. Its permeation behavior is also affected if the dispersion of the molecules depends upon their concentration. For example, the membrane with two graded components in the thickness direction that have different solubility for the permeating molecules has the flow reversal effects; i.e. number of molecules that permeate the membrane through its thickness depends upon the direction.      In this study, we try to prepare the graded polymeric membrane utilizing the miscible polymer blend system, and estimate its gas permeation properties. Polymethyl methacrylate/poly(styrene-co-acrylonitrile) (PMMA/SAN) blend system is chosen here. It had been reported that PMMA/SAN blend is miscible over a limited range of SAN comonomer compositions whereas PMMA is immiscible for the both polystyrene and polyacrylonitrile. It is therefore expected that the interaction between PMMA and SAN is weak. If the interaction between two polymers in the blend system is such, the permeability coefficient of the graded membrane can be easily calculated using some simple assumption.      Specifically, we first examined the gas permeation properties of this PMMA/SAN blend system, and then predicted the permeability coefficient of an ideally graded membrane using the series model. We also measured the permeability coefficient of different membranes we processed by casting and giving post heat-treatment to the above polymers to see if the graded structure exists. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 65-68 液相析出法による機能性セラミックスの傾斜化 Synthesis of Functionally Graded Ceramics from Aqueous solutions 岡興志男　八尾健　内本喜晴　梶原浩一京都大学　総合人間学部　京都大学大学院エネルギー科学研究科 Y. Oka, T. Yao* Y. Uchimoto*, K. Kajihara*Faculty of Integrated Human Studies, Kyoto University* Graduate School of Energy Science, Kyoto University  Ceramic thin films, either dense or porous, are desirable because of the high surface area, the reduction of both the ion-diffusion path length and electrical resistance, the light and compact system construction, and so on. A method for forming films from an aqueous solution is expected to be advantageous because no vacuum, no high temperature and no expensive apparatus will be required, and substrates, even those with wide areas and/or complicated shapes, are available. we believed it possible to synthesize ceramics from aqueous solutions, and we have shown that it is possible to synthesize various functional ceramics such as zirconium oxide and rare earth-transition metal perovskite oxides from aqueous solutions.      Solid oxide fuel cells (SOFCs) have a structure where anode layer, electrolyte layer and cathode layer are piled in sequence like sandwiches. Yttria-stabilized zirconia (YSZ) is used as the electrolyte material, nickel-zirconia cermet is used as the anode material, and rare earth-transition metal perovskite oxides having both electronic conductivity and oxide ion conductive property as the cathode material.  In order to make SOFCs fit for practical use, construction of highly efficient, highly accumulated and light system is necessary, then it is requested to use the materials in the form of thin films.       The objective of this study is to investigate the precise reaction mechanism for synthesizing functionally graded ceramics thin films from aqueous solutions, and then to apply the reaction to the production of SOFCs. In order to relax the strain in the layer boundaries caused by the difference in the thermal expansions, we have considered it useful to make the layer boundary where the electrolyte material is gradually replaced by the cathode material by changing the compositions of the aqueous solutions during the synthesizing reaction. The result would be called a graded SOFC.      In this report, we will describe the synthesis of lanthanum-transition metal perovskite oxides such as LaCrO3, LaMnO3, LaFeO3, and LaCoO3 from aqueous solution and the deposition of LaMnO3 on YSZ solid state electrolyte. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 69-72 傾斜機能材料の組成設計のための基礎研究 Fundamental Study on Compositional Design for Functionally Graded Materials 太田陸夫　福永二郎　若杉隆京都工芸繊維大学　物質工学科 R. Ota, J. Fukunaga and T. WakasugiDepartment of Chemistry and Materials Technology, Kyoto Institute of Technology  In order to design a functionally graded material, it is essential to develop a theoretical technique that enables one to compute multi-component glass compositions, which meet the desired properties (functions). In the present study a technique is proposed which determines the glass compositions giving desired values of molar volume and thermal expansion coefficient. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 73-76 ゴム系傾斜機能複合材料の作製とその物性 Preparation and Properties of Functionally Graded Rubber Materials 池田裕子、　*掬谷信三京都工芸繊維大学　工芸学部、*京都大学　化学研究所 Y. Ikeda, S. Kohjiya*Faculty of Engineering and Design, Kyoto Institute of Technology *Institute for Chemical Research, Kyoto University  Generally, elastomeric materials in the industrial fields are the composites consisting of three-dimensional network structure and fillers. In the processing of the rubber vulcanizates, the mixing and the curing are very important because the homogeneity of mixing and curing much influenced the mechanical properties of the vulcanizates. In this study, however, the cross-linking density of the vulcanizates were graded and the mechanical properties of the vulcanizates were evaluated in order to obtain the fundamental information for the development of new functional materials. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 77-80 無機－有機傾斜組成複合光学マトリックスの設計と創製 Design and Preparation for Optical Matrix with the Graded Composition between Inorganic and Organic Components 町田憲一大阪大学大学院工学研究科 Ken-ichi MachidaGraduate School of Engineering, Osaka University  The composite materials consisting of inorganic glass forming units such as silica and various organic oligomers possess a possibility to form optical matrix with excellent thermal or mechanical resistivity and molding or shaping characteristics. Furthermore, physical properties of the matrix can be continuously changed by controlling the composition of inorganic and organic components, possibly resulting in a graded function.       Bearing the foregoing and aiming to establish the design principle and fabrication technique for the excellent optical functional materials with high transparency as well as good molding or shaping characteristics, a series ORMOSIL (ORganically MOdified SILicates) composite glasses consisting of silica and organosilane units are synthesized at the various components of inorganic and organic components. Their glass forming regions and luminescence property when rare-earth ions or complexes are incorporated into this matrix are also investigated. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 81-84 多核錯体の逐次吸着を利用する傾斜機能材料の作成 Preparation of Functionally-Graded Materials by Means of Stepwise Adsorption of Multinuclear Complexes 一ノ瀬泉　安藤玲子　国武豊喜九州大学　工学部 I. Ichinose, R. Ando, T. KunitakeFaculty of Engineering, Kyushu University  Fabrication of functionally graded materials with molecular precision is an important field of current materials research. It is essential for chemical application of these materials. Based on this concept, we have developed several preparative techniques for ultra thin nano-graded films by means of stepwise adsorption from solution. Alternate adsorption of oppositely-charged polymers has been extended to a wide range of charged materials such as multinuclear complexes, clay, metal oxide particles, proteins, dye molecules, conductive polymers, etc. We have also developed a stepwise adsorption of metal alkoxides as a novel preparative technique for metal oxide thin films. In the current study we focus on the application of the surface sol-gel process to forming organic-inorganic nano-graded materials and to molecular imprinting on the surface of Quartz-crystal Microbalance as a molecular recognition devise. We also report here polymerization-induced adsorption as a novel technique for layer-by-layer deposition of organic polymers at nanometer scale. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 85-88 ミクロ結晶構造と架橋点濃度の制御による傾斜機能ポリウレタンの合成と特性 Synthesis and Properties of Functionally Graded Polyurethane Elastomers by Controlling Crystal Microstructure and Concentration at Cross-linking Point 古川睦久・椎葉哲朗長崎大学　工学部　材料工学科 Mutsuhisa Furukawa and Tetsuro ShiibaDepartment of Materials Science and Engineering, Faculty of Engineering, Nagasaki University  Functionally graded polymer materials are prepared by controlling a diffusion of a reactive monomer into a polymer sheet and by use of different compatibility or miscibility of two or more components of macromolecular chains. We have studied how the structures of polyurethane elastomers (PUEs) are related to their properties, taking advantage of easy molecular design using this particular component. It has been found that size and the number of the produced spherulites, glass transition temperature depend upon the curing temperature. This result showed the possibility of a preparation method of graded PUEs using a mold with temperature gradient, in which spherulite size and superstructure gradually change. This study first aimed to synthesize the graded PUE sheets and to evaluate its graded property, such as modulus of elasticity. Dependence of spherulite growth behavior on curing reaction temperatures was also studied in situ observation by a polarizing microscopy to gain a fundamental insight into the graded structure control. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 89-92 TiAl合金に対する耐酸化性皮膜の傾斜化 Functionally Grading of Oxidation-resistant Coatings on TiAl Alloys 間渕博 津田大大阪府立大学　工学部 H. Mabuchi and H. TsudaCollege of Engineering, Osaka Prefecture University  Gamma titanium aluminides ((gamma)-TiAl alloys), having an L10-type structure, are candidate materials for use in future gas turbine aero-engines and automotive engines because of their low density, high specific strength and high stiffness. However, coatings is essential for the use of this material in air at a high temperature (perhaps above 800deg.C) because of its poor oxidation resistance under the condition. On the other hand, L12-type Al3Ti based alloy seen in Ti-Al-X(X=Cr,Mn et al.) system indicates significant oxidation resistance and may be usable up to about 1000deg.C. It has been recently found that adding large amount of Cr or Mn (up to 13 - 16 at%) into the L12-type alloy results in improved morphology and ductility. Moreover, he Al-Ti-Cr ternary phase diagram indicates that the L12 phase field is in equilibrium with the L10-type phase field. Furthermore, the both alloys resemble each other very closely in crystal structure and lattice parameter, as shown. Therefore, the L12- type alloy can be considered applicable to L10-TiAl alloys as an optimum material of coatings. However, TiAl alloy and L12-Al3Ti alloy are dissimilar in their thermal expansion coefficient and other functions (mechanical properties), making it necessary to further grading these two phases.     In the previous studies the authors have investigated the phase equilibrium of L10- and L12-type alloys in the Ti-Al-Cr system and prepared the diffusion couple of both phases. The resulted diffusion layer showed a fine gradient of composition and structure. In the present study, we have tried various coating processes to form a graded coating in assumption that L12- type alloy is the optimum material for oxidation resistant coatings of L10-TiAl alloys. We report here the preparation method of the diffused coating using the very simple pack cementation technique. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 93-96 傾斜化プロセスを用いたミスト冷却素子の開発 Development of Mist Cooling Elements by Functionally Graded Processing 西山勝廣　高橋秀史　島崎益男　阿部正彦　立崎陽介　大森守＊東京理科大学理工学部、＊東北大学金属材料研究所 K. Nishiyama, H. Takahashi, M. Shimazaki, M. Abe, Y. Tatsuzaki and M. Omori*Faculty of Science and Technology, Science University of Tokyo*Institute for Materials Research, Tohoku University  Conventional air conditioner is comprised basically of a heat pump system and refrigerant gas having large vapor enthalpy such as flon gas. The flon-gas causes the destruction of ozone-layer. Because the environmental problem such as the destruction of ozone-layer and energy-saving have become major issues in recent years, the use of the alternative gas for normal flon has been tried. But even the alternatives have some serious adverse effects on the environment when it is quasi-flon.      In search of a new heat exchanging system, we have developed a novel concept of using a water mist as a medium material and a heat pump cooler with fractal dimension surface. When applied, the method should be utilize the water mist in an air current to enhance the heat transfer from the heating surface by making the air current collide the surface material. In theory, the heat transfer enhancement is about five times more efficient than the method using single-phase flow. However, we must overcome two technical difficulties to realize this new application. One is to create a technique to make the mist particles diameter below 0.1 micrometer. The other is to establish the technique to make a heat pump with fractal surface, i.e. and extremely wide surface area.     The present study purposes to develop the mist generation device and to apply a functionally graded structure to the fabrication of the cooling element for the formation of mist cooling device with novel cooling mechanism. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 97-100 傾斜機能材料のコンピュータシミュレーション Computer Simulation of Functionary Graded Materials 木暮嘉明　堂山昌男帝京科学大学 Y. Kogure and M. DoyamaTeikyo University of Science & Technology  The functionary graded materials are widely used in the fields of space, aeronautical, energy science and technology. Development of more functionally graded materials are under way. A computer simulation to design the FGM have been made in this study. The finite element method combined with the Monte Carlo method are used in the calculation. Using this method, the components distribution can be determined from arbitrary initial values in the way that a wanted temperature and stress distribution can be achieved once the physical parameters of the material is known as a function of each component. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 101-104 湿式濾過法による厚肉傾斜機能材料の創製 Creation of a Thick Functionally Graded Material by Use of Wet Filtration Method 岩田政司　下野晃鈴鹿工業高等専門学校　工業化学科 M. Iwata and A. ShimonoDepartment of Industrial Chemistry, Suzuka National College of Technology  A porous brick and other products are produced by firing green bodies consisting of double components: carbonaceous particles and inorganic particles. We here propose a new process of fabricating process of a functionally graded porous material by the "filtration method". The different components are layered so that the green body has a smoothly graded composition profile. Sintering of this body results in a porosity gradient in the direction of cake thickness. This porous material seems to be suitable for use in artificial bones, artificial tooth-roots, supports for cultured cells in biotechnology, asymmetric ceramic filters and thermal insulators etc. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 105-108 傾斜機能誘電体基板 A Functionally Graded Substrate for Dielectrics 西田俊彦、Giuseppe PEZZOTTI、塩野剛司京都工芸繊維大学 Toshihiko Nishida, Giuseppe Pezzotti, Takeshi ShionoKyoto Institute of Technology  The field of electrical resistant substrates for high-frequency application has been recently the object of intensive efforts given the goal of applying the dielectrics technology to industrial applications. The development of substrates capable of transmitting high-band frequency waves as, for example, in portable small-sized telephones is of particular interest as more advanced forms of mobile communication technology is utilized. In order to connect the very small substrates used in such application to external circuits, a constant impedance (typically 50 (ohm)) must be maintained. The width within which the printed circuits are contained on the substrate is somewhat limited by both the thickness of the substrate and its relative electrical conductivity. Thus, to realize the small size of both the substrate and the circuits, a high value of electrical conductivity in the substrate is necessary. However, this makes connecting the substrates to external circuits difficult. To solve this problem, the external part of the substrate has been designed with a low conductivity, while the central part is conceived as a high conductivity area. These two regions of the substrate have been interconnected with a functionally graded structure, which allows the minimization of the high-frequency signal loss and, at the same time, ensures the availability of a larger substrate width for circuit print at the outer part of the substrate. Last year we attempted to fabricate the functionally graded structure by successive superpositions of layers with different compositions in the system CaTiO3-MgTiO3 and confirmed the above approach is possible. However, when this system forms eutectic structure at the sintering temperature leading to discontinuous interfaces between adjacent layers. In our recent studies, the different system of BaTiO3-SrTiO3 which should form a solid-solution over the whole composition range to investigate the possibility of forming a smooth compositional gradient without he layered discontinuity within the substrate during sintering processes. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 109-112 傾斜圧電機能ドーム型アクチュエータ Functionally Graded Piezoelectric Dome Actuators 谷順二　菱進浩　D．J. Warkentin　曽我拓一朗東北大学流体科学研究所外国人研究員東北大学大学院 J. Tani, J. Qiu D. J. Warkentin T. SogaInstitute of Fluid Science, Tohoku University JSPS Postdoctoral Fellow, Tohoku University Graduate School, Tohoku University  Many studies have been carried out on the development and application of piezoelectric/electrostrictive actuators. The actuators have mainly been applied to high precision devices in which the required displacement is in micrometer or sub-micrometer order so that the piezoelectric or electrostrictive effects can be directly used. However, the applications of piezoelectric and electrostrictive actuators are being extended in recent years to linear motors, pumps, switches, noise reduction devices, adjustable lenses and laser reflectors, in which displacements of 100 micrometer order or larger are necessary. The typical piezoelectric actuators with large displacement include unimorph actuators and bimorph actuators. These actuators are manufactured by bonding a piezoelectric layer and a metal shim layer. Due to the stress concentration and physical weakness on the bonding interface of the two layers, cracks and delamination can easily be induced during actuation. Hence these actuators are not suitable for applications requiring high reliability, such as measuring equipments. To solve this problem, a new type of actuator called RAINBOW has been proposed. RAINBOW actuators have the same structure as unimorph actuators except that the shim layer is obtained by chemically reducing the piezoelectric material on one side of an actuator instead of bonding a metal layer. Since the reduced layer and the unreduced piezoelectric layer are chemically integrated, the interface has higher strength and delamination on the interface can be avoided. However the chemical reduction process is performed at high temperature and the reduced layer and unreduced layer have different heat expansion factors. Therefore thermal stress are induced in the actuator after cooling down. The thermal stress becomes the main factor of fracture of RAINBOW actuators since in some region of the piezoelectric layer the thermal stress is extensional. In this paper a new type bending actuator with functionally graded composition of a piezoelectric material and a dielectric material in the thickness direction is proposed and numerical simulation is performed on the performance analysis of the actuators. The spark plasma sintering process was used in the sample fabrication of the new actuators. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 113-116 高周波用異方性傾斜Ni－Znフェライト Ni-Zn Ferrite with Graded Magnetic Anisotropy for High Frequency Applications 平塚信之、中村陽平、柿崎浩一、小林秀彦埼玉大学　工学部 N. Hiratsuka, Y. Nakamura, K. Kakizaki and H. KobayashiFaculty of Engineering, Saitama University  Magnetic materials for high frequency are required to apply at giga-hertz order in the high speed informative communication and the diversity of correspondence ways of multi media. To meet these demands, the magnetic materials require high and constant initial permeability in high frequency. However, ferrites including W- and Z- type with hexagonal crystal structure, which have already been put into practice as high frequency applications are inferior in, lower initial permeability.HA1 and HA2 are anisotropic magnetic fields. When HA1 and HA2 are not equal, the ferrite will have higher resonance frequency than isotropic ferrites that have the same values of Ms and (mu)i. The spinel-type ferrites, which are isotropic and their magnetic anisotropy are small, can't keep the same value of initial permeability up to high frequency because of Snoek's theory. However, endowing a spinel-type ferrite with magnetic anisotropy might result in a spinel-type ferrites with higher resonance frequency. Thus we decided to try that approach using a sample of new soft spinel-type ferrites, and investigate its frequency dependence of initial permeability after giving it magnetic anisotropy.      In this study, we examined the magnetic and electric properties of this sample, namely, the spinel-type Ni-Zn ferrites doped with CoO to make them anisotropic. We subsequently double-layered Ni-Zn ferrites and CoO-doped Ni-Zn ferrites to form a ring-shaped sample with Co2+ ion gradient, i.e. graded magnetic anisotropy. The purpose was to discuss the dependence of initial permeability on frequency of the graded magnetic property of this sample. This graded material has both high initial permeability of the Ni-Zn ferrites and the high frequency of CoO-doped Ni-Zn ferrites. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 117-120 傾斜構造を有するFeSix系化合物の熱電特性に及ぼす微細構造の影響 Effect of Microstructure on Thermoelectric Properties in the FeSix Compound 一ノ瀬昇　中島晃　小田巻誠早稲田大学理工学部 N. Ichinose, A. Nakajima and M. OdamakiSchool of Science and Engineering, Waseda University  Thermoelectric power generator has become a subject of great interest to meet the recent requirements for a reliable source of electric power. A number of materials have been tested for utilization in a thermoelectric generator. The FeSix compounds (x=1.90 - 2.20) transforms from semi-conductor phase  to metal phase at 986deg.C . beta-FeSi2 is one of the promising materials useful for energy conversion because of its good oxidation resistance in high temperature and large thermoelectric power. The raw materials, Fe and Si, exist in abundance making this material even more attractive for the use in high temperature and in air. We have prepared the FeSix compound with the composition range x=1.90-2.20, applying new technologies such as mechanical alloying and spark plasma sintering, to be investigated as to the microstructure and thermoelectric properties. Also, functionally graded thermoelectric materials with varying X values was also considered. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 121-124 傾斜機能磁性薄膜 Functionally Graded Magnetic Thin Films 逢坂哲彌、本間敬之、鈴木充早稲田大学　理工学部 T. Osaka, T. Homma, M. SuzukiSchool of Science and Engineering, Waseda University  With the development of information superhighway, a higher density recording media is required. We previously developed various perpendicular magnetic recording media suitable for high density recording using electroless deposition techniques. The results of previous studies on their recording characteristics in combination with recording heads revealed that "double-layered" media consisting of the films with different magnetic properties could exhibited better recording characteristics than "single-layered" ones. These results suggest that it is important to control the microstructure and magnetic properties precisely in the direction of film thickness, in accordance with the head field distribution. Thus, it is expected that further improved recording characteristics can be achieved by grading the media properties along the head field distribution. We intend to fabricate such a functionally graded magnetic recording media by an electrochemical process and verify the effectiveness of graded function in a magnetic recording media by evaluating its recording characteristics. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 125-128 溶融塩反応で作製した組成傾斜BaTiO3－PbTiO3系複合粒子の誘電特性 Dielectric properties of graded BaTiO3-PbTiO3 composite particles fabricated by molten salt reaction 嶋田志郎北大院工 Shiro ShimadaGraduate school of Engineering, Hokkaido University  We have previously reported the first successful case of the molten reaction in BaTiO3-PbCl2 system to produce Ba1-xPbxTiO3 solid solutions and BaTiO3-Ba1-xPbxTiO3 composite particles with controlled compositions. Compared to the conventional solid-phase reaction process, this solid solution can be synthesized at lower temperature of 600deg.C. A so-called core-shell structured bulk of BaTiO3 (core)-Ba1-xPbxTiO3 (shell) was also obtained from a sintered BaTiO3 compact by the molten reaction by optimizing the condition of reaction.  The average composition of the outer Ba1-xPbxTiO3-shell of the particles was changed by changing the PbCl2/BaTiO3 ratio and particle size of BaTiO3. Also, using sintered BaTiO3 in the molten salt reaction with PbCl2 resulted in the core-shell sintered structure in which the core is BaTiO3 and the shell has graded Pb concentration, higher toward the surface.      In 1996, the tetragonal(t)<=>cubic(c) phase transitions of Ba0.13Pb0.87TiO3 solid solution and two kinds of BaTiO3-Ba1-xPbxTiO3 composite particles (0.7 and 0.3 micromters in average size) were monitored by high temperature XRD (HTXRD) and differential scanning calorimetry (DSC) measurements.       Dielectric temperature characteristics (epsilon(T) curve) of the Ba1-xPbxTiO3 solid solution are changed according to the x-value.  On the other hand, a wide compositional distribution or gradient exists in the composite particles, the resulting (epsilon)(T) curve is expected to consist of a number of overlapping epsilon(T) curves of Ba1-xPbxTiO3 with varied x-values. It is proposed that a sintered compact made of the composite particles with such a wide range of the x values can show a flattened dielectric characteristic in a wide temperature range. In this study, the four types of sintered compacts were obtained from the solid solution Ba1-xPbxTiO3 particles, the BaTiO3-Ba1-xPbxTiO3 composite particles (0.7micrometers and 0.3micrometer), the core-shell BaTiO3-Ba1-xPbxTiO3 bulk, and the mixed powders of BaTiO3 and PbTiO3. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 129-132 広帯域超音波トランスジューサ実現のための圧電傾斜機能材料の基礎的研究 Basic Research of piezoelectrically Graded Materials for Broadband Ultrasound Transducers 中村僖良　山田顕　本郷哲東北大学　大学院工学研究科 K. Nakamura, K. Yamada and S. HongoGraduate School of Engineering, Tohoku University  Ultrasound transducers have been widely used in various fields of ultrasonic measurements and/or imaging such as nondestructive evaluation and medical diagnosis. In these fields, broadband transducers with high-resolution capability are required. However, conventional plane transducers having a uniform polarization generate ultrasonic waves at both surfaces, and this results in a narrowband frequency characteristic of the transducer. If the piezoelectric parameter in a plane transducer could be faded out between one face and the other, there would be only one acoustic pulse corresponding to the larger gradient of the piezoelectric stress at one surface.      The authors' group has been studying on piezoelectric materials with effectively graded piezoelectric parameters and their application to broadband ultrasound transducers. This academic year a new broadband transducer is proposed that has a graded electric field applied across the piezoelectric material. A broadband transducer of planar structure is also proposed that utilizes a domain inversion phenomenon in a ferroelectric crystal. Relationship between the frequency characteristic and the piezoelectric stress distribution in space is also studied theoretically. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 133-136 傾斜機能化電極／固体電解質一体型燃料電池の作製と電気特性評価 Fabrication and Characterization of Functionally Graded Electrode for Solid Oxide Fuel cells 湯上浩雄　内藤均東北大学大学院工学研究科 Hiroo Yugami, and Hitoshi NaitoGraduate School of Engineering, Tohoku University  Using Solid Oxide Fuel Cell (SOFC) in the conversion system can enhance the power generating efficiency because it can convert the chemical energy of fuels directly to power supply. Mixed electronic and ionic conductor is preferred for an electrode material for SOFCs, and if YSZ is used as electrolyte for SOFC, good adherence can be achieved by using a zirconia-based mixed conductor as an electrode. From this point, the use of a single component solid oxide fuel cell has been proposed. To improve electronic conductivity in zirconia-based mixed conductor, higher concentration of dopant, which promotes electronic conduction, is required. However, when the dopant concentration increases, a large difference in mechanical properties, such as thermal expansion coefficient, occurs between electrolyte and electrode. To overcome this problem, we applied functionally graded materials (FGMs) to the electrode in which the dopant concentration in the electrode is gradually changed from gas/electrode interface (high dopant concentration) to electrode/electrolyte interface (low concentration). Our idea is to use the mixed conductor so as to keep its crystal structure while grading the function and also to keep fine commensurate structure in terms of physical and electrochemical properties. We investigated CeO2 doped YSZ (Ce- YSZ) mixed conducting films, in which Ce concentration was varied. The higher the concentration of Ce, the higher Ce-YSZ shows high electronic conductivity of Ce-YSZ at low oxygen partial pressure, so graded concentration of Ce can result in graded ion and electron transports leading to improved electrical properties.       In this paper, the fabrication of functionally graded Ce-YSZ thin film by laser ablation method is discussed, and its structure and electrical properties are evaluated in order to optimize the fabrication process. The over potential was also evaluated with the use of functionally graded electrode. Japanese 平成９年度科学研究費補助金重点領域研究領域番号　２７４「傾斜機能材料物理・科学」研究成果報告書平成１０年３月 FY 1997 Grant-in-Aid for Scientific Research on Priority Area, No. 274Physics and Chemistry of Functionally Graded MaterialsResearch Report March 1998  1 1998-03-01 137-140 組成傾斜 K(Nb,Ta)O3単結晶の合成および組織観察と誘電特性 Preparation, Texture, and Dielectric Properties of Composition-Graded K(Nb,Ta)O3 Single Crystals 山根久典、島田昌彦東北大学素材工学研究所 H. Yamane and M. ShimadaInstitute for Advanced Materials Processing, Tohoku University  High-capacity ceramic condensers are manufactured with perovskite-type ferroelectrics, which have high dielectric constant around the Curie temperatures. Two kinds of additives are added homogeneously to the oxides for practical applications. One is called shifter, which moves the Curie temperature to the operation temperature of capacitance (normally, room temperature). The additives of the other kind (depressor) moderate the temperature dependence of dielectric constant. Most perovskite-type compounds form continuous solid solutions. The Curie temperatures can be shifted by the substitution of elements in the solid solutions. We have attempted to fabricate high-dielectric materials with the temperature dependence of dielectric constant controlled by changing composition of solid solutions gradually.      In the previous study, we adopted an alternative fabrication process using non-equilibrium cooling of the melts. In the solid solution system, the homogeneous solids with compositions identical with the melts are obtained by cooling under near-equilibrium conditions. However, if the melts are cooled rapidly, the solidification proceeds before homogenization of the composition by diffusion in the solid phase and the composition gradient is formed in the solids from the core part having high melting point to that of outer part crystallized at lower temperature.      We chose the KNbO3 - KTaO3 system as a case study of a perovskite-type ferroelectric solid solution. In this system, the liquidus temperature reported is from 1312 to 1630 K. The curie temperature at the transition of K(TaxNb1-x)O3 solid solutions from the cubic phase to tetragonal phase varies from 100 K at x = 0.9 to 707 K at x = 0.0. In the present study, we tried to prepare the samples from the melts with various cooling conditions, and then characterized the texture, composition distribution and temperature dependence of dielectric constant to compare with the properties of homogeneous KNbO3 single crystal. Japanese