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National Institute for Materials Science

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[Functionally Graded Materials VII (FGM2002) (pp.213-415)](https://mdr.nims.go.jp/datasets/cf881774-e7ec-4579-9ea0-56d6ab94e8ff)

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Sheet1 BookTitle_j BookTitle_e Volume/Issue Issueddate Page Title_j Title_e AuthorList_j AuthorList_e Abstract Language Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 213-218 放電プラズマ焼結法によるTiCN傾斜機能サーメットの作製 The Fabrication of TiCN-Based Functionally Graded Cermets by Spark Plasma Sintering. Wei Wang, Longhao Qi, Wei Pan, Dapeng Liu, Hezhuo Miao, Wei Wang, Longhao Qi, Wei Pan, Dapeng Liu, Hezhuo Miao,  TiCN-based functionally graded cermets were fabricated by spark plasma sintering (SPS) technology. The-sandwich specimens containing different metal binder from 10 mass% to 40mass% were sintered in varied temperature from 1450 deg.C to 1600 deg.C. The Transmission Electron Microscope (TEM) and the scanning electron microscope (SEM) with EDX equipment were used to observe the powders and the sample microstructure. The graded distribution of cermets was attained at 1550 deg.C for 0.5 min. The typical core-rim structure of cermets appeared in the layer TiCN-(Mo. Ni)0.4. The results also show that, the layer containing 25 mass% metal binder phase in graded cermets is a transition location of grain size. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 219-222 SHS生成物の高温変形による傾斜および微粒構造の形成 Formation of Graded and Fine-Grained Structures upon Hot Deformation of SHS Products. Yury A.Gordopolov, . Nail G.Zaripov, Yury A.Gordopolov, . Nail G.Zaripov,  We investigated evolution in the microstructure of off-stoichiometric titanium carbide (TiC0.47) for the following two limiting cases: (1) rapid hot deformation at a low strain epsilon (shock compression) and (2) slow deformation to high epsilon (superplastic deformation). Hot deformation of TiC0.47 was found to give rise to two parallel processes: dynamic recrystallization and phase transformation. These processes lead to refining the material structure and to a change in the chemical composition of carbide grains. The process of dynamic recrystallization can be utilized to prepare graded and fine-grained ceramic composites. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 223-226 スラリーコーティングと後熱処理プロセスによってSi3N4-Si/MoSi2-SiC多層を被覆した炭素／炭素複合材料の微細構造と耐酸化性 Microstructure and Oxidation Resistance of Carbon/Carbon Composites Coated with Si3N4-Si/MoSi2-SiC multi-layers by Slurry Coating and Post Heat-treatment Process. Jae-Ho Jeon, Zhong-Hong Lai, Jin-Chuan Zhu, Zhong-Da Yin, Jae-Ho Jeon, Zhong-Hong Lai, Jin-Chuan Zhu, Zhong-Da Yin,  Si3N4-Si/MoSi2-SiC multi-coating layer was fabricated on the surface of two dimensional carbon-carbon (C/C) composites in order to improve their oxidation resistance at high temperatures. Si-6wt%Al inner layer and Si-Mo outer layer was pre-coated to C/C composites by a slurry dipping process, and then they were heat-treated at 1500 deg.C for 1 hour in a vacuum and then heat-treated 1 hour in nitrogen atmosphere. Dispersed MoSi2 phase in the Si matrix and SiC interface layer between C/C composite substrate and Si/MoSi2 layer was formed by the reaction between Mo and Si and between Si and C, respectively, during heat-treatment in a vacuum. On the other hand, Si3N4 layer was formed by the reaction between liquid Si and nitrogen gas during heat-treatment in nitrogen atmosphere. The oxidation resistance of C/C composites coated with a Si3N4-Si/MoSi2-SiC multi-layer was excellent during a cyclic oxidation test at 1400 deg. C up to 5 hours. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 227-230 Al柱状化モンモリロナイトの吸着特性の研究 Study on the Adsorption Properties of Al-Pillared Montmorillonites. Lizhen Fan, Ce-Wen Nan, Libing Liao, Lizhen Fan, Ce-Wen Nan, Libing Liao,  Al-pillared montmorillonites were prepared by ion exchange reaction and characterized by X-ray diffraction and traditional chemical elemental analysis. The optimum conditions for fluoride adsorption such as vibrating time, sample dosage, pH value and original concentration of fluoride were studied by orthogonal experiments. The stabilities of pillars on pillared montmorillonites were also investigated. The results showed that Al-pillared montmorillonites have high adsorption capacity and adsorption percent. Their adsorption isotherms belong to the Freundlich type. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 231-234 重力分離テルミットSHS 法によるセラミックライニングパイプに及ぼすプロセス条件の影響 Influence of Processing Condition on the Ceramics-Lined Pipes by Gravitational Thermit SHS Method. Li Shuhua, Wang Shen, Li Jie, Tan Huimin, Li Shuhua, Wang Shen, Li Jie, Tan Huimin,  The ceramic lined pipes with high qualities had been produce by gravitational-thermit SHS method. The influence of coating density and heat preservation method on the SHS reaction and mechanical properties of ceramic lined pipes was investigated. It was found that the quality of composite pipe was closely related to the density and heating preservation method. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 235-238 Al2O3-PSZ~Fe-Ni傾斜機能パイプの作製 Fabrication of Al2O3-PSZ~Fe-Ni Functionally Graded Pipes. 小林弘旺　 H.Kobayashi,  The fabrication of Al2O3-PSZ~Fe-Ni functionally graded pipes has been investigated by slurry coating and pressureless sintering process. Each slurry of Al2O3-PSZ~Fe-Ni mixture and Fe-Ni was coated in order on the Al2O3-PSZ pipes formed by slip casting or planetary slip casting with those slurries. The laminar green pipes were sintered in vacuum at 1350 deg.C. The structure of pipes fabricated by this method was microscopically examined and the graded distribution was examined by an X-ray line analysis of Al and Fe. The pipes with 2 layers of Al2O3-PSZ and Fe-Ni had crevices in those bonding interface. Some functionally graded pipes with 3 layers or multiplayer were free from cracks and warps, and had the bonding interfaces bonded completely each other. These pipes had the graded distribution without smoothness of Al and Fe in the middle layers. These functionally graded pipes with 3 layers had better resistance to thermal shock than that of ceramics alone pipes. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 239-244 燃焼合成法による傾斜機能材料のモデル化と作製 Modeling and Fabrication of Functionally Graded Materials by the Combustion Synthesis Technique. H.C Yi, J.Y.Guigne, A.R.Manerbino, L.A.Robinson, J.Ma, J.J.Moore, H.C Yi, J.Y.Guigne, A.R.Manerbino, L.A.Robinson, J.Ma, J.J.Moore,  The combustion characteristics of hypothetical four-layer FGMs (Functionally Graded Materials) were studied using a one-dimensional model. Modeling covered cases of ignition from either the most reactive side, or the least reactive side. It was found that the overall combustion rate was higher when ignited from the least reactive side. Although the combustion wave reached the end of the pellet in relatively short time, it took much longer time to complete the reaction at the end of pellet due to the high rate of heat losses. It was also found that, when ignition was initiated from the least reactive side, the reaction continued even after the combustion wave had passed. Examples of both porous and fully dense FGMs are given. Porous FGMs were fabricated to exhibit a porosity gradient, as well as exhibit both porosity and composition gradients. Fully dense FGMs containing four composition layers were fabricated by in-situ densification immediately following the completion of the combustion synthesis reactions. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 245-248 TiB2-Cu傾斜機能材料の熱応力のシミュレーション Thermal Stress Simulation in TiB2-Cu Functionally Graded Materials. Xuebing Wang, Xinghong Zhang, Shanyi Du, Xuebing Wang, Xinghong Zhang, Shanyi Du,  A model for designing TiB2-Cu Functionally Graded Materials (FGM) was presented. The thermal stress in the steady-state was calculated with finite element method. To simulate the transient real using condition of FGM, a continuous stable heat flux is applied to the ceramic side of the model. By analyzing the thermal stress distribution along the gradient direction and the maximum stress distribution in both steady-state and transient temperature fields, the thermal stress relaxation in FGM, layered non-Functionally Graded Materials (nFGM) and homogeneous cermets were compared. The result showed that the optimized FGM has much better ability of anti-distortion and thermal stress relaxation than the nFGM. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 249-252 被覆法とSPS焼結によるCu/SiC FGMの合成 Preparation of Cu/SiC FGM by coating method and SPS sintering. Rui Zhang, Lian Gao, Yubai Pan, 陳立東, Jingkun Guo, Rui Zhang, Lian Gao, Yubai Pan, Lidong Chen, Jingkun Guo,  Cu/SiC functionally graded materials (FGMs) were prepared using coated Cu/SiC composite powder and spark plasma sintering (SPS). Characterization was carried out with XRD, EDS, TEM, and optical microscope. It was found that a graded structure was formed in the sintered cylindrical compacts. The Cu content was higher near the cylindrical surface and dropped gradually within the bulk. The hardness increased versus the distance from the cylindrical surface. Such a structure was beneficial to the low surface electrical contact resistance and good surface thermal-releasing properties. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 253-256 短炭素繊維／SiC傾斜機能材料の作製 Fabrication of Short-Cf/SiC Functionally Graded Materials. Ran Li, Qiang Shen, Lianmeng Zhang Ran Li, Qiang Shen, Lianmeng Zhang  By using Spark Plasma Sintering (SPS), homogeneous SiC composites reinforced with unidirectional short carbon fibers were sintered. And (Al2O3+graphite), (AlN+graphite) and (B4C+graphite) are added respectively as additives in order to achieving high densification. The effects of these additives on the densification of short-Cf/SiC composites are investigated, and their influences on carbon fibers are also analyzed. Then by adjusting the additive amount of suitable additives, homogeneous short-Cf/SiC composites with different bulk ratio are densified at the same sintering conditions. Finally, these homogeneous composites are stacked layer by layer and formed FGM. And as a result, short-Cf/SiC functionally graded materials, in which the volume distribution of short Cf changes gradually along the thickness orientation, were successfully fabricated. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 257-262 遠心鋳造法で合成したAl/SiCp傾斜機能金属マトリックス複合材料：強化材分布に及ぼす粒子結晶粒径の効果 Al/SiCp Functionally Graded Metal-matrix Composites Produced by Centrifugal Casting: Effect of Particle Grain Size on Reinforcement Distribution. A.Velhinho, P.D.Sequeira, F.Braz Fernandes, J.D.Botas, L.A.Rocha, A.Velhinho, P.D.Sequeira, F.Braz Fernandes, J.D.Botas, L.A.Rocha,  Functionally graded materials (FGMs), particularly in the form of Al-Si metal matrix composites (MMCs) selectively reinforced at the surface with SiC particles, are advanced materials, combining high wear resistance with high bulk toughness or even a thermal barrier at the surface. Centrifugal casting is one of the most effective methods for processing this type of MMC, but accurate control of the ceramic particles distribution/gradient in the metallic matrix has not yet been completely attained. In this work, precursor Al/SiC composites were prepared by rheocasting, using SiC particles and an Al-10Si-2.2 Mg alloy. Morphology of the SiC particles was previously characterized by laser interpherometry and SEM. Differing grain sizes were selected as reinforcing elements. The MMCs were then molten and centrifugally cast in order to produce the FGM composites, whose structure and properties were investigated by XRD, quantitative image analysis of optical micrographs and longitudinal hardness profiles. Therefore, it was possible to evaluate the influence of the particle grain size on the structure and properties of the FGM. Apart from the evaluation of the effects of particle grain size per se, its influence when combined with differing casting conditions are reported as well. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 263-268 シンクロトロン放射マイクロトモグラフィーによる傾斜機能金属‐マトリックス複合材料Al/SiCの濡れ特性の評価 Evaluation of Al/SiC Wetting Characteristics in Functionally Graded Metal-Matrix Composites by Synchrotron Radiation Microtomography. A.Velhinho, P.D.Sequeira, Rui Martins, G.Vignoles, F.Braz Fernandes, J.D.Botas, L.A.Rocha, A.Velhinho, P.D.Sequeira, Rui Martins, G.Vignoles, F.Braz Fernandes, J.D.Botas, L.A.Rocha,  The concept of functionally graded material (FGM), may be considered as a model particularly interesting to be applied in components for the automotive industry, if reliability and cost can be controlled in an advantageous way. In fact, coupling superior superficial wear resistance with a significant bulk toughness, without compromising important weight savings, by using Al-Si metal matrix composites (MMC's) selectively reinforced at the surface with SiC particles, is likely to be considered as a innovative advance to that industrial field, if adequate production techniques are developed. Casting under a centrifugal force may well be considered as one of the most effective methods for processing Al-based FGMs. A primary problem to be faced when producing MMC's reinforced with ceramic particles is related with the imperfect wetting of the ceramic particles by the molten matrix alloy. A first consequence of defective wetting may be the formation of ceramic-ceramic, ceramic-gas and/or metal-gas interfaces, instead of the desired metal-ceramic interface. Secondly, wetting phenomena play an essential role regarding the physical, chemical and mechanical characteristics of the metal/ceramic interface. A general consequence of these aspects may be related with the degradation of the material properties, be it mechanical, chemical, or thermal in nature. The present work refers to an X-ray microtomography experiment aiming at the elucidation of some aspects regarding particle distribution in SiC**p-reinforced functionally graded aluminium composites. Precursor composites were produced by rheocasting. These were then molten and centrifugally cast in order to produce the FGM composites. From these, small cylindrical samples were extracted and observed by X-ray microtomography at the European Synchrotron Radiation Facility (ESRF). The 3D tomographic images were obtained in edge-detection mode (phase-contrast mode), and an adequate segmentation procedure was employed to isolate the pores and SiC particles from the Al matrix. This has allowed a study of the relations between the matrix, the SiC particles, and locally intervening porosities of varying shapes, aiming at a better understanding of the mechanisms involved. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 269-274 Al/Al2O3傾斜機能材料のR‐カーブ挙動の実験および理論的研究 Experimental and Theoretical Investigation of R-curve Behavior in Al/Al2O3 Functionally Graded Materials. Achim Neubrand, Tai-Joo Chung, Juergen Roedel, Achim Neubrand, Tai-Joo Chung, Juergen Roedel,  The effects of composition gradients on the crack propagation in metal/ceramic composites are investigated. Compact tension specimens with different gradation profiles in the direction of crack propagation were prepared. It is demonstrated that crack propagation is affected in three different ways by the gradient: (1) The gradient in elastic properties modifies the driving force for crack propagation. (2) The gradient in thermal expansion behavior leads to residual stresses which change the effective stress intensity factor acting on the crack tip. (3) The composition gradient leads to a position dependent crack tip fracture toughness and bridging stress relation. A model based on the weight function method taking into account all these effects could describe the R-curve of graded composites quantitatively. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 275-282 ステンレス鋼と部分安定化ジルコニアから成る多層複合材パイプのマルチビレット押出成形 Multi-Billet Extrusion of Multi-Layer Composite Pipes Composed of Stainless Steel and Partially Stabilized Zirconia. W.Q.Zhang, J.X.Xie, Z.G.Yang, S.Chen , Y.Q.Liu, C.Z.Wang, W.Q.Zhang, J.X.Xie, Z.G.Yang, S.Chen , Y.Q.Liu, C.Z.Wang,  In order to investigate extrusion characteristics for multi-layer pipes, multi-layer metal-ceramics gradient composite pipes were extruded through simultaneous extrusion of different pastes composed of different proportions of 316L to PSZ with binder by means of subpresses for two-layer and four-layer pipe extrusion, then were fabricated utilizing gas pressure sintering in this paper. The characteristics of extrusion pressure-stroke curves are discussed. Sectional microstructure of sintered multi-layer pipes shows that transitional interfaces between different compositional layers are continuous and unitary. Thermal shock resistance of multi-layer pipes was measured utilizing thermal shock test of soak and water quench. In summary, multi-layer metal-ceramics gradient composite pipe can be fabricated utilizing the multi-billet extrusion forming and sintering solidification. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 283-286 放電プラズマ焼結法で合成したナノ構造FGMsの引張特性 Tensile Properties of Nanostructured FGMs Produced by Spark Plasma Sintering. 市川洌, Takashi Murakami, Shin-ichi Miyamoto, Yukihiro Nakayama, 鴇田正雄 Kiyoshi Ichikawa, Takashi Murakami, Shin-ichi Miyamoto, Yukihiro Nakayama, Masao Tokita,   The nanostructured functionally graded material (Nano-FGM) is one of the most promising materials for engine components. Nanocrystalline functionally graded material was composed of 3 weight percent yttria stabilized zirconia (YSZ) powder layer, mixed powder layers of the zirconia and SUS410L (similarly to AISI410) stainless steel and the stainless steel powder layer. It was consolidated by spark plasma sintering process that makes possible sintering at a low temperature because on-off pulse electric current causes melting and evaporation on an oxidized and contaminated surface of powder particles without ordinary heating the particle interior during the consolidation of the powders. Tensile tests were made at room temperature in the composition-graded direction of the multi-layer bulk FGMs 50 mm in diameter and 17 mm in thickness. In the FGMs composed of the stainless steel powders 9 micrometers in diameter including 63 nm size crystal grains and the YSZ powders 50 micrometers in size including 35 nm size crystal grains, the tensile strength was increased from 61.9 to 110 MPa and from 30.5 to 109 MPa with increasing from 19.6 to 39.2 N/mm2 at a sintering die temperature of 1243 and 1293 K. In the FGMs composed of the stainless steel powders 60 micrometers in size including 52 nm size crystal grains and YSZ powders 50 micrometers in diameter including 35 nm size crystal grains, the tensile strength was increased from 37.5 to 71.9 MPa and from 53.4 to 76.1 MPa with increasing from 19.6 to 39.2 N/mm2 at a sintering die temperature of 1243 and 1293 K. It was found that the tensile strength must depend on the size of powders. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 287-292 チタン鉄鉱からその場炭素還元による炭化チタン‐鉄金属‐セラミックの機構、特性および微細構造 Mechanism, Properties and Microstructure of Titanium Carbide-Iron Metal-Ceramic from Ilmenite by in-situ Carbothermic Reduction. Zhengguang Zou, Hanyuan Chen, Zhengguang Zou, Hanyuan Chen,  The fabrication of titanium carbide-iron metal ceramic was reported in this paper. The mainly starting materials are ilmenite (FeTiO3) and graphite. Synthesis and sintering were accomplished unanimously in the vacuum resistance furnace. The reaction forming mechanism was studied through various analytical methods including DTA, XRD and SEM. It is showed that the mechanism of the carbothermic reduction process is complicated and multistage. The reaction process was found as following: an initial, rapid reduction of ilmenite to elemental iron and a series of lower titanium oxides; the gradual removing of oxygen from the TixOy phases step by step until the formation of TiC apparently in subsequent heating; TiC crystallite growth occurs with the increasing temperature. The investigation of microstructure and properties of titanium carbide-iron composites found that additives Mo and Ni have a beneficial effect on the microstructure and properties of titanium carbide-iron composite. Product with 8wt% Mo additive had high density of 5.848 g/cm3, Rockwell hardness of 88.3 and good microstructure. Adding Mo and Ni (1:1) together also has a marked beneficial effect on titanium carbide-iron composites. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 293-296 窒化アルミニウムセラムックの銅への結合に及ぼすFGM中間層の効果 Effects of FGM Interlayer on Joining Aluminum Nitride Ceramics to Copper. Sheng Zhu, Wladyslaw Wlosinski, Binshi Xu, Sheng Zhu, Wladyslaw Wlosinski, Binshi Xu,  The mismatch of coefficient of thermal expansion (CTE) between AlN ceramic and metal is one of the main challenges to join AlN ceramic to metal successfully. Joining of AlN ceramics to metals was investigated by using diffusing bonding with various surface modification interlayer to satisfy its bonding challenges in this paper. Radio frequency (r.f.) sputtering was first applied to deposited titanium film on AlN surface to improve its wetting. Plasma spraying and brush plating were utilized to obtain FGM interlayer to reduce residual stresses caused by mismatch of CTE in AlN-to-Cu joint. On the basis of study of the effects of joining process conditions on the mechanical strength of joint as well as microstructures and residual stresses at the interfaces of AlN/interlayer/Cu, it can be deduced that the joinability of AlN ceramics to metals is in directly proportion to the values of the diffusion coefficients of metal atoms inside AlN, but in inversely proportion to the mismatch values of CTE between AlN and metals, and both of the values could be improved by using proper FGM interlayer. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 297-300 AlNセラミックの多層膜金属化とその金属に対するシーリング Multi-Layer Film Metallization of AlN Ceramic and Its Sealing to Metal. Yanping Lu Yanping Lu  Aiming to the application of AlN ceramic in microwave tube, this report presents the brazing technology of AlN ceramic to metal, in which multi-layer metal films with different functions were formed on the surface of AlN ceramic through magnetron-controlled sputtering and electroplating to ensure high vacuum tightness and high tensile strength of the joints. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 301-304 活性合金中間層を用いた基質窒化アルミニウムへの銅の結合 Bonding of Copper to Aluminum Nitride Substrate Using Active Alloy Interlayer. S.Q.Bai, 陳立東, A.Yamamura, Q.Bai, L.D.Chen, A.Yamamura,  Bonding AlN substrate with copper plate was performed in a N2 atmosphere and under pressure by introducing an Ag-Cu-Ti based alloy interlayer. The microstructure of the interface was examined by means of SEM and EPMA. (Ti,Al)N thin layer formed in the interfacial between AlN and interlayer alloy. The chemical bonding between AlN and (Ti,Al)N corresponds to provide adhesion of metallization. A maximum adhesion strength of 1.8kg/mm**2 was achieved. The effects of the interlayer composition on the adhesion strength of the joints were investigated. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 305-310 複合パイプにおけるセラミックスと金属間のSHS過渡液相結合の機構に関する研究 Study on Mechanisms of SHS Transient Liquid Phase Bonding between Ceramics and Metal in the Composite Pipes. Z.M.Zhao, J.J.Wang, L. Zhang, M.H.Ye, J.Yan, S.Q.Li Z.M.Zhao, J.J.Wang, L. Zhang, M.H.Ye, J.Yan, S.Q.Li  Ceramic-lined composite pipes could be fabricated with three-layer structures of steel substrate, intermediate alloy and ceramics through SHS gravitational separation process. Intermediate alloy is composed of Fe-Cr-Ni-Al-Ti base with gradient distribution of carbide of Ti enrichment. This kind of carbides are obtained through chemical reaction between carbon black and Ti powder, re-melting and dissolving of solid carbide into alloy liquid of Fe-Cr-Ni-Al-Ti, and precipitation of the carbide from alloy liquid. Bonding mechanisms between ceramics and the intermediate come into effect by bridging of the carbide with Ti enrichment between two sides. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 311-314 LTCCの熱伝導率 Thermal Conductivity of LTCC. Z.T.Geng, H.L.Ning, J.S.Ma, Y.G.Wang, G.N.Zhang, Z.T.Geng, H.L.Ning, J.S.Ma, Y.G.Wang, G.N.Zhang,  Low temperature ceramics co-fired with copper (LTCC/Cu) was one of the important technologies in ceramic packaging. Due to the low thermal conductivity of LTCC substrates and the low sinter temperature, selecting an appropriate ingredient for LTCC substrates was important. This paper contrasted the influence of several ingredients for LTCC substrates. Protective atmosphere such as nitrogen and hydrogen ambience were used. The thermal conductivity of BSG-AlN system surpasses that of BSG-Al2O3 system in some degree, but sintering temperature of BSG-AlN system is higher than that of BSG-Al2O3 system. The result also shows that the air hole of LTCC substrates could decrease the thermal conductivity, but the introduction of more glass phases and the higher sintering temperature could reduce the number of air holes. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 315-320 遠心固体粒子法により作製した傾斜機能モデル材料における三次元小板配向の直接評価 Direct Evaluation of Three-Dimensional Platelet Orientation in Functionally Graded Model-Material Fabricated by a Centrifugal Solid-Particle Method. 江竜寛之, Tetsuya Yamamoto, 渡辺義見, Hiroyuki Eryu, Tetsuya Yamamoto, Yoshimi Watanabe,  An aluminum-platelet / plaster is used as a model system to investigate the orientation effects in the platelet reinforced FGM fabricated by the centrifugal solid-particle method. Every aluminum-platelets are bared from the plaster matrix, and three-dimensional (3-D) orientation for the platelets is directly observed using a 3-D orientation observation system. The effects of G number, platelet size and mean volume fraction of platelets on graded distributions of volume fraction and orientation parameter are studied. The results of the present study are compared with the previous results, and the validity of the proposed 3-D orientation observation system is discussed. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 321-326 生物医学向けの傾斜機能インプラントおよび歯柱の開発 Development of Functionally Graded Implant and Dental Post for Bio-Medical Application. 亘理文夫, Hideomi Kondo, Shingo Matsuo, Rika Miyao, 横山敦郎, 大森守, 平井敏雄, Yutaka Tamura, 宇尾基弘, Noboru Ohara, 川崎貴生 Fumio Watari, Hideomi Kondo, Shingo Matsuo, Rika Miyao, Atsuro Yokoyama, Mamoru Omori, Toshio Hirai, Yutaka Tamura, Motohiro Uo, Noboru Ohara, Takao Kawasaki  The polymer-ceramics (1) and metal-ceramics (2) FGMs were fabricated for bio-medical application and the effect of gradient structure was evaluated. (1) Dental post, which is inserted in root canal after endodontic treatment to restore mastication function by setting a crown on the core part, often causes the fracture in dentin around the apex of post by imposition of impact force. Functionally graded post made of composite resin was fabricated by laser lithography, one of the photo-curing type CAD/CAM systems. The elastic modulus changed gradually from 10.6GPa in core part to 2.9GPa at the apex of post by decreasing the filler content of ceramic powders from 64% to 0% in polymer matrix. Stress analysis using finite element method showed the stress relaxation by further 30 % in FGM, compared with the uniform composite resin. (2) Functionally graded implant with the gradience from titanium to hydroxyapatite (Ti/HAP) in longitudinal direction was made by spark plasma sintering (SPS) to optimize the mechanical properties and biocompatibility. The Brinel hardness decreased from 61 in Ti to 15 in HAP, which contributes for stress relaxation in the implanted region of bone. The new bone formed in bone marrow of femora of rats after 8 weeks showed the thin and smooth external form, directly contact to the implant surface, in HAP rich region and the thick, wavy form, less contact to implant, in Ti rich region. Maturation of bone is more advanced in HAP rich region. The gradient functions in both mechanical properties and biochemical affinity to osteogenesis contribute to the efficient biocompatibility. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 327-330 亜音速溶射によって生成したヒドロキシアパタイト傾斜被覆 Hydroxyapatite Graded Coatings Made through Subsonic Thermal Spraying. Muqin Li, Chen Ma, Dashan Shang Muqin Li, Chen Ma, Dashan Shang  Bioactive graded coating of hydroxyapatite (HA) on Ti6Al4V substrate made through subsonic thermal spraying was investigated in the present study. Pure Ti powder was selected as material of bottom layer, Ti70%+HA30% powder as transitional layer and HA powder as working layer. To be compared, another coating (non-graded coating) was prepared by spraying HA on pure Ti bottom layer directly. The tensile test shows that the bond strength between bottom layer and substrate is higher than that between transitional layer and working layer, and the bond strength between bottom layer and working layer of the non-graded coatings is the lowest. This indicates that the graded structure leading to the changes of coefficient of thermal expansion (CTE) from bottom layer to working layer is beneficial to the bond strength. The cross-section and surface morphology of the coatings were observed using optical microscope (OM), and SEM. The phases were determined using XRD. The results show that the bottom layer is composed of TiN, TiO2, Ti2O3, the working layer is composed of HA, Ca4P2O9 and Ca3(PO4)2, and the transitional layer is composed of the composite of above two layers. From the implant point of view, micro-cracks and porosities formed in working layer surface are helpful to the growth of green bone and the bond strength between implant and bone. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 331-334 疑似体液中でのプラズマ溶射けい灰石被覆の生体活性 Bioactivity of Plasma Sprayed Wollastonite Coatings in Simulated Body Fluid. Xuanyong Liu, Lianfu Deng, Chuanxian Ding,  Xuanyong Liu, Lianfu Deng, Chuanxian Ding,   Wollastonite coatings were deposited by plasma spraying and incubated in simulated body fluids to investigate the nucleation and growth of apatite on their surface. Surface structural of the coatings were analyzed by XRD and IR technologies. SEM and EDS were used to observe surface and cross-section morphologies and determine the composition of wollastonite coatings before and after immersion in simulated body fluid. The changes in the concentrations of calcium, silicon and phosphorus in the simulated body fluids due to the immersion of the coatings were measured by inductively coupled plasma atomic emission spectroscopy. The cytocompatibility of wollastonite coatings was examined by osteoblasts culturing test. The carbonate-containing hydroxyapatite (CHA) layer was formed on the surface of plasma sprayed wollastonite coating soaked in SBF solution. Prior to the formation of the CHA layer, silica-rich layer appeared on the surface of plasma sprayed wollastonite coating soaked in SBF solution. The formation of CHA layer on coating surface indicates wollastonite coating had a good bioactivity. Osteoblasts survive and proliferate on the surface of wollastonite coating, which showed plasma sprayed wollastonite coatings possess good cytocompatibility. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 335-340 DCグロープラズマ酸化によるTi6Al4VへのTi-O傾斜医用膜の作製 Fabrication of Ti-O Gradient Biomedical Film on Ti6Al4V by DC Glow Plasma Oxidizing. C.L.Zheng, F.Z.Cui, Z.Xu C.L.Zheng, F.Z.Cui, Z.Xu  Ti-O film is a kind of biocompatible surface materials. In this paper, a new method, DC glow discharge plasma oxidizing, has been used in synthesizing Ti-O gradient films on Ti6Al4V substrates. The effects of ion bombardment and process parameters on the structures of titanium oxide layers have been investigated. It can be concluded that DC glow plasma oxidizing is more efficient in preparation of dens, hard, and high adhesive Ti-O graded biomedical films on titanium alloys. In the condition of hollow cathode discharge, the ion bombardment enhances ionization of oxygen, promotes the oxygen permeation and facilitates the formation of the oxide of low valence states of titanium. In addition, blood compatibility of the Ti-O films was evaluated by measuring the dynamic clotting time as well as the platelet consumption rate. The results indicate that the Ti-O films possess better blood compatibility than that of Ti6Al4V, 316L stainless steel and NiTi alloy. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 341-346 細胞培養用としてのチトサンによる生分解性PLGA足場の表面の改良 Surface Modification of Biodegradable PLGA Scaffold With Chitosan for Cell Culture. X.H.Wang, W.J.Wang, D.P.Li, Q.L.Feng, F.Z.Cui, Y.X.Xu, X.H.Song, X.H.Wang, W.J.Wang, D.P.Li, Q.L.Feng, F.Z.Cui, Y.X.Xu, X.H.Song,  Chitosan is a good biocompatible polysaccharide obtained from deacetylation of chitin and has been widely used in biomedical fields. In the present study, chitosan immobilization to a biodegradable poly(lactic-co-glycolic acid) (PLGA) for hepatocyte seeding was investigated. The immobilization agent was N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) in N-hydroxy-succinimide (NHS) and 2-morpholinoethane sulfonic acid MES buffer. Scanning electron microscopy (SEM) observation displayed little difference in surface morphology between the chitosan-modified film and the control. But water contact angles decreased with an increase of chitosan concentration in cross-linking solvent and the reaction time. Electron spectroscopy for chemical analysis (ESCA) showed an obvious additional peak in the chitosan-modified PLGA film due to nitrogen atoms, based on the considerable amount of amino groups in chitosan molecules. Hepatocyte culture indicated that chitosan could improve the biocompatibility of PLGA scaffold. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 347-350 ポリ‐L‐乳酸膜表面への新しい蛋白質固定化法 A New Method for Protein Immobilization on the Surface of Poly-l-Lactic Acid Film. D.P.Li, X.H.Wang, B.Meng, Q.L.Feng, F.Z.Cui D.P.Li, X.H.Wang, B.Meng, Q.L.Feng, F.Z.Cui  In the present study, a new method to immobilize type I collagen on the surface of poly-l-lactic acid (PLLA) film was invented. The film treated by Sodium hydroxide was immersed alternately in 2-(N-morpholino)ethanesulfonic acid (MES) buffer containing N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS), and MES buffer containing type I collagen. Consequently, a kind of hybrid biodegradable film with a transition from PLLA to crosslinked collagen was synthesized. Laser scanning confocal microscopy (LSCM) was used to investigate the treated films. Grafting of proteins on the PLLA surface was observed. The result was further confirmed using X-ray photoelectron spectroscopy (XPS). English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 351-354 ヘパリン化PLLA膜の合成と生物化学的評価 Preparation and Biological Evaluation of Heparinized PLLA Films. X.H.Wang, Q.L.Feng, F.Z.Cui, X.H.Wang, Q.L.Feng, F.Z.Cui,  Heparin is a well-known anti-thrombogenic polymer which is widely used in surgery. In this study, heparin sodium was used to modify the surface of poly(L-lactic acid) (PLLA) in order to enhance its biocompatibility. The properties of a modified PLLA surface and the control sample were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). The former indicated that the hydrophilicity of the modified PLLA film was improved with the immersion time and the concentration of heparin sodium in the solution. The latter suggested that the modified PLLA film is enriched with nitrogen atoms. The biocompatibility of PLLA film is altered and in turn affects the anticoagulant activity. The number of platelets deposited on the modified film was greatly decreased. These data suggest that heparin can improve the in vitro blood compatibility of the PLLA film. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 355-358 SiC熱電気デバイスのスパークプラズマ焼結による調製 Preparation of SiC-based Thermoelectric Device by Spark Plasma Sintering 野田泰稔, 北川裕之，角直美, 植田優, 金山信幸 Yasutoshi Noda, Hiroyuki Kitagawa，Naomi Kado, Yu Ueda, Nobuyuki Kanayama  The preparation of SiC-based thermoelectric materials and joining the electrodes were made by Spark Plasma Sintering (SPS). The n- and p-type SiC materials were prepared by the addition of Si3N4 and Al4C3 as the source materials of N and Al dopants, respectively. The power factor takes the maximum value at the each content of 7wt% Si3N4 or Al4C3. The SiC-thermoelectric material was tentatively joined to MoSi2. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 359-365 フラーライトとカーボンナノチューブを含有n-型SixGe(1-x) 傾斜材料に関する熱電気性質 Thermoelectric Properties on n-Type SixGe(1-x) Graded Materials Containing Fullerite and Nanometer Carbon Tube Gui-Ying Xu, Ting-Jie Chen Gui-Ying Xu, Ting-Jie Chen  SixGe1-x is typical thermoelectric materials used for higher temperature as thermoelectric generator. Their property is dependent on their composition. Here different amount of fullerite or nanometer carbon tube as hollow quantum dot and hollow quantum wire were added into SixGe1-x. Their samples with different composition and the graded materials were fabricated by Hot Pressing method. The relations about thermoelectric property and the addition of fullerite or nanometer carbon tube and the microstructure were investigated in detail by normal measurement or analytical method. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 367-371 スパークプラズマ焼結で調製した傾斜機能性（FGM）擬似二元系合金(PbTe)(1-x)-(SnTe)x の最適化と性質 Optimization and Properties of Graded Pseudo-Binary Alloys (PbTe)(1-x)-(SnTe)x Prepared by Spark Plasma Sintering   J. L Cui, X. Qian J. L Cui, X. Qian  The pseudo-binary alloys (PbTe)1-x-(SnTe)x (0 =< x=<  0.4) doped with 0.02 mol% Ag concentration were prepared by spark plasma sintering (SPS). It was observed that the temperature at which the figures of merit Z reach the maximal increases with the mole fraction x, the materials with this temperature dependence of Z values can be used to prepare functionally graded thermoelectric material (FGM). The property of the FGM prepared by SPS is significantly improved as compared with those of any monolithic materials (PbTe)1-x-(SnTe)x concerned, the maximal power output 12.0 (mW.g-1) from calculation and 9.2(mW.g-1) from measurement for the FGM are all approximate twice as much as those of the monolithic alloy (PbTe)0.8-(SnTe)0.2, and about 5 times those of (PbTe)0.6-(SnTe)0.4 at the same applied circumstances. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 373-376 セグメント化CoSb3/Bi2Te3 熱電気材料の調製と界面分析 Preparation and Interface Analysis of the Segmented CoSb3/Bi2Te3 Thermoelectric Materials Jiangying Peng, Tongjun Zhang, Junyou Yang, Kun Cui Jiangying Peng, Tongjun Zhang, Junyou Yang, Kun Cui  FGM structure is promising to enhance thermoelectric conversion efficiency. Excellent bonding of different materials is important. In this study, three types of CoSb3/Bi2Te3 FGM were fabricated, and interfaces were analyzed. Results for powder co-sintering samples showed that a transition section about 110 micrometers was formed. Strong bonding was acquired in samples with Bi0.5Sb1.5Te3 powder as interface layer, and width for diffusion area was about 30 micrometers. While in samples using Sn foil as interface layer, two new phases were formed in transition section. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 377-379 テルル化ビスマスの熱電気冷却性質に及ぼす傾斜機能性材料（FGMs）の影響 Effect of FGMs on Thermoelectric Cooling Properties of Bismuth Telluride Asako Iwama, 桑折仁,塩田一路 Asako Iwama, Hitoshi Kohri,Ichiro Shiota  Every thermoelectric materials shows high performance at a specific narrow temperature range. The temperature range with high performance can be expanded by joining the materials with different peak temperature. This is the concept of an FGM. The FGMs for Peltier cooling materials have never been reported though the FGMs for thermoelectric power generation were reported to enhance conversion efficiency. Bismuth telluride is the best material for cooling devices at around room temperature. Then we investigated the thermoelectric cooling properties for bismuth telluride with two steps graded structure FGM. Two kinds of melt-grown materials of p-type bismuth telluride (hereafter, sample 1 and sample 2) were used. The samples 1 and 2 of 3 mm**2x2.5 mm were joined to form an FGM of 3 mm**2x5 mm in length by soldering with ultrasonic vibration. Thermoelectric cooling properties were evaluated by observing the maximum temperature drop to electric current when the high temperature side was kept constant. When the high temperature side is kept at 370 K, the temperature drop of the monolithic sample 1 was 34.6 K, and 39.7 K for sample 2, because of the difference of the carrier density. In the case of the FGM, the temperature drop was 45.2 K when the sample 1 was placed at the high temperature side. On the other hand, the temperature drop was only 27.6 K when the sample 2 was placed at the high temperature side. From these results, it is clear that high performance can be obtained by forming an FGM when the proper material arrangement is performed along the temperature gradient. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 381-384 Ge添加によるn-型PbTeの熱電気性質の改良 Improvement of Thermoelectric Properties for n-type PbTe by Adding Ge 桑折仁, 西田勲夫, 塩田一路 Hitoshi Kohri, Isao A. Nishida, Ichiro Shiota  Thermoelectric materials can directly convert thermal energy into electrical power. The thermoelectric property of every thermoelectric material has temperature dependence and a high performance appears at a specific temperature. If the proper materials with different carrier concentrations and/or compositions are placed and joined along the temperature gradient, the performance should be higher than a monolithic material. Pb-Te is generally used for thermoelectric power generation at the medium temperature range between 500 and 800 K. The performance of PbTe with different carrier concentration, however, is not high enough at the high temperature range. Then, it is also insufficient as a component for an FGM, as it is necessary for every part of an FGM to show high performance. In order to improve the thermoelectric properties, we investigated the effects of Ge on thermoelectric properties for PbTe added with GeTe as a component of an FGM. The melt grown materials of PbTe added with GeTe were prepared by vertical Bridgeman method. The GeTe content range was from 0 to 15 mol%. Crystal structure of each part of the ingot was identified by means of XRD. The microstructure of each ingot was observed by scanning electron microscopy. The temperature dependence of electrical resistivity, Hall coefficient, Seebeck coefficient and thermal conductivity were measured over the temperature range from 300 to 700K. From the results of XRD, the ingots with above 10 mol%GeTe consisted of two phases of PbTe and GeTe. Dimensionless figure of merit, ZT, was calculated from results of thermoelectric properties. The PbTe with 10 mol%GeTe showed a largest ZT of 1.19 at 500K, which is rather promising for a component of an FGM. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 385-389 熱処理によるPbTe中のキャリヤ濃度傾斜の設計 Graded Design of Carrier Concentration in PbTe by Heat-Treatment 篠原嘉一, 今井義雄, 磯田幸宏, Hachiro Nakanishi Yoshikazu Shinohara, Yoshio Imai, Yukihiro Isoda, Hachiro Nakanishi  In order to develop a new process of forming a carrier concentration gradient in lead telluride PbTe only by using heat-treatment, the effect of heat-treatment on a carrier concentration n of the p-type PbTe has been investigated, and the p-type PbTe has been heat-treated using a temperature gradient. The as-grown stoichiometric PbTe was p-type with an n of 1.0 x 10**24m－3. Vacuum thermal exposure with Te-rich PbTe at 900K for 1h increased the n of the stoichiometric PbTe to 5.1 x 10**24m-3, which indicates that hole formation was achieved by thermal exposure at this temperature and duration. The thermally exposed stoichiometric PbTe was heat-treated in the temperature range of 400 to 900K for a period of 24h. The n decreased with an increasing heat-treatment temperature of between 300 and 500K, while the n increased with an increasing heat-treatment temperature of between 500 and 900K. A minimum n was measured at 500K, above which the formation energy of holes was determined to be 16.4kJ/mol. On the basis of these results, a 19mm long thermally exposed stoichiometric PbTe was heat-treated using a temperature gradient of 340-900K for a period of 24h. A continuous change in n was formed in the PbTe, and a minimum value of n was determined to be at a position corresponding to the heat-treatment temperature of 500K. A continuous gradient of hole production was successfully achieved in the p-type PbTe only by heat-treatment using a temperature gradient. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 391-398 Bi2Te3とFeSi2間の機械的／化学的安定な関係付けの開発 Developing Mechanically and Chemically Stable Contacts between Bi2Te3 and FeSi2 Cestmir Drasar, Antje Mrotzek, Christian Stiewe, Eckhard Mueller, Wolfgang A. Kaysser Cestmir Drasar, Antje Mrotzek, Christian Stiewe, Eckhard Mueller, Wolfgang A. Kaysser  Recently, there is a strong interest in developing superior thermoelectric devices and materials. The performance of a thermocouple can be considerably improved by applying a gradient of composition along the temperature gradient inside the thermocouple causing that at each position the respective material achieves its maximum thermoelectric efficiency (TE FGM principle). Combining the thermoelectric materials Bi2Te3 (used at low temperatures) and FeSi2 (applied up to high temperatures) will result in a thermoelectric device operating at a wide temperature range. The challenge is to contact these dissimilar materials without any negative impact on the thermoelectric properties. Besides providing good electrical and thermal contact of Bi2Te3 and FeSi2 the junctions have to be mechanically and chemically stable. In order to maintain mechanical stability an interlayer adjusting the different coefficient of thermal expansion alpha of FeSi2 (10*10-6K-1) and Bi2Te3 (19*10-6K-1) is essential. Various composites of Bi2Te3-SiO2 approximating alpha of FeSi2 have been employed as connecting layer. The contacts between those and Bi2Te3 and FeSi2, respectively, were prepared by uniaxial hot pressing. While the mechanical stability is enhanced significantly by a Bi2Te3-SiO2 composite, the thermoelectric conversion efficiency of the FGM decreases. Therefore the thermoelectric properties of the FGM material were studied regarding the ratio of SiO2 in the composite. In addition the diffusion of FeSi2 and Bi2Te3 near the interface of the Bi2Te3-SiO2 composite, the mechanical stability, and the microstructure of the FGM were studied. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 399-403 傾斜機能性微細構造（FGM）を有する圧電セラミック／金属曲げアクチュエータ Piezoelectric Ceramic/Metal Bending Actuators with Functionally Graded Microstructures  Jing-Feng Li, Kenta Takagi, Shohei Yokoyama, 渡辺龍三, Abdulhakim Almajid, 田谷稔 Jing-Feng Li, Kenta Takagi, Shohei Yokoyama, Ryuzo Watanabe, Abdulhakim Almajid, Minoru Taya  As a model study for bending actuators with functionally graded microstructures (FGM), platinum (Pt)-dispersed lead zirconate titanate (PZT) piezoelectric ceramic composites and laminated PZT/Pt bimorph actuators were fabricated by powder processing. The electrically induced deflections of the graded bimorph actuators were evaluated and compared with theoretically predicted values. The present study demonstrated that the FGM actuators suffer from low stress concentrations during electric actuation, while exhibiting bending displacements equal to that of the conventional non-FGM actuators. It was also found that the actuation property of an FGM actuator is dependent on its compositional distribution through the thickness, suggesting that design is valid and important for the development of FGM piezoelectric actuators. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 405-410 傾斜気孔率を持つ圧電セラミックアクチュエータの開発 Development of Piezoelectric Ceramic Actuators with Graded Porosity Kenta Takagi, Jing-Feng Li, 渡辺龍三, Abdulhakim Almajid, 田谷稔 Kenta Takagi, Jing-Feng Li, Ryuzo Watanabe, Abdulhakim Almajid, Minoru Taya   The objective of this study was to develop bending-type piezoelectric ceramic actuators having functionally graded microstructures (FGM). Porosity-graded lead zirconate titanate (PZT) ceramics were selected as a model material. Miniature porosity-graded actuator samples with three layers of different porosities (0,10,20%) were fabricated by sintering layer-stacked powder compacts that consist of PZT and pore-forming agent (PFA) powders in air atmosphere, whereby stearic acid was added as a pore-forming agent. In order to fabricate PZT/Metal or PZT/Polymer FGM actuators using porosity-graded PZT ceramics as a preform, another pore-forming agent, polymethylmethacrylate (PMMA) powder was also used to increase open porosity. The electric-field-induced deflection characteristic of the beam-shaped actuator samples was measured with electric strain gages, and compared with the values calculated from the modified classical laminate theory using the elastic and piezoelectric constants of the non-FGM porous PZT ceramics. It was found that the experimentally measured deflection values of the obtained actuator samples well agreed with the calculated data. An optimum porosity profile that gives the largest deflection was also determined by the modified classical lamination theory. English Functionally Graded Materials VII (FGM 2002) Functionally Graded Materials VII (FGM 2002) 23 2002-10-15 411-415 (Sr,Pb)TiO3 傾斜機能性セラミックスの調製と誘電性 Preparation and Dielectric Property of Strontium-Lead Titanate Functionally Graded Ceramics  Huarong Cheng, Jingchuan Zhu, Zhongda Yin, Jaeho Jeon Huarong Cheng, Jingchuan Zhu, Zhongda Yin, Jaeho Jeon  A new type of functionally graded dielectric ceramics of (Sr, Pb)TiO3 system were fabricated by means of powder metallurgy from chemical coprecipitated (Sr1-xPbx)TiO3 particles. The microstructure and dielectric property were characterized via X-ray diffractometer, electron probe microanalyser, transmission electron microscope and impedance/grain-phase analyzer. It is shown that, the (Sr1-xPbx)TiO3 powders exhibit nano grain and particle structure. After sintering at 1150 deg.C, the ceramics were nearly full densified, in which ferroelectric domains were observed in the coarsened grains. No sharp peak appears in the permittivity-temperature curve of (Sr, Pb)TiO3 FGM as that in homogeneous (Sr1-xPbx)TiO3 ceramics. It reveals that the graded constitution effectively optimized the dielectric property of (Sr, Pb)TiO3 ceramics; the work temperature zone was broadened and the dielectric-temperature stability was improved. English