# Fileset [proc-fgm-1995.xlsx](https://mdr.nims.go.jp/filesets/63d202db-e9c9-4cff-97a1-38df94ee075e/download) ## Creator National Institute for Materials Science ## Rights ## Other metadata [FY 1995 Proceedings of Functionally Gradient Materials (FGM'95) ](https://mdr.nims.go.jp/datasets/853cad5a-9ccb-4060-acd1-605b4559a053) ## Fulltext Sheet1 BookTitle_j BookTitle_e Volume/Issue Issueddate Page Title_j Title_e AuthorList_j AuthorList_e Abstract Language １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 1-6 FGMコーティングC/Cコンポジットの模擬実環境評価試験 Evaluation Test of C/C Composite Coated by FGM Method, under Simulated Condition for Aerospace Application 若松義男1)、斉藤俊仁1)、小野文衛1)、石田清道2)、松崎貴至2)、濱村修3)、早田喜穂4)、久手幸徳4)1)航空宇宙技術研究所角田研究センター2)航空宇宙技術研究所3)(株)エイ・イー・エス4)日本石油(株)中央技術研究所 Y.Wakamatsu l) , T.Saito1) , F.Ono1) K.Ishida2) , T.Matsuzaki2), O.Hamamura3) Y.Sohda4), Y.Kude4)1) Kakuda Research Center, National Aerospace Laboratory, Kakuda, Miyagi, 981-15, Japan 2) National Aerospace Laboratory, Chofu, Tokyo 182, Japan 3) Advanced Enigineering Service Company, Ltd., Tukuba, Ibaraki, 305, Japan 4) Central Technical Research Laboratory, Nippon Oil Company, Ltd. , Naka-ku, Yokohama, 231, Japan In the previous paper, the authers reported that they fabricated carbon/carbon composites coated with SiC/C functionally graded materials (FGM). This specimen had a hemispherical shape with a diameter of 50 mm and was fabricated using a 3D near net shape fabric of pitch-based carbon fibers. It was heated twice for 20 seconds in a high-temperature supersonic gas flow and showed excellent performance. This time, the specimens were fabricated in the same way as that described in the previous paper and heated in order to evaluate the durability. In the arc heated wind tunnel tests, the specimen was evaluated twice for 1,100 seconds. Damage was found after that. In the high-temperature gas flow tests, damage was found after the specimens was evaluated seven times for 30 seconds. Pin-holes were observed on the surface of all the specimens and pores were found in the carbon under the CVD-SiC coating layer by means of the X-ray CT. From those evaluation tests, it was found out that the FGM layer remained healthy but the CVD-SiC was damged due to the oxidation. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 7-12 C/C複合材の耐酸化コーティング技術のための熱応力緩和層の検討 Study of Thermal Stress Relaxation Layer for Oxidation Protection Coating Carbon=Carbon Composites 岸克宏、岡本久夫、山内宏、小坂勝明日産自動車(株)　宇宙航空事業部 K.Kishi, H.Okamoto, H.Yamauchi and K.KosakaNISSAN MOTOR CO., LTD. Aerospace Division, 2 1-1 Matobashinmachi, Kawagoe-City, 350- 11,1, Japan As a 2000deg.C class anti-oxidation system for C/C composites, following concept of surface coating has been examined. First, the mixture layer of Ir-C is formed on the surface of C/C substrate as a thermal stress relaxation layer, and dense Ir layer is formed on the Ir-C layer as a diffusion prevention of oxygen and carbon. Finally, high melting point oxide is coated on the Ir layer as anti-oxidation and low-sublimation layer. This report showed the results of preliminary experiments about the formation technology of thermal stress relaxation layer and the evaluation tests a 2000deg.C. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 13-18 繊維傾斜配列法によるC/Cコンポジットの熱物性制御 Thermal Management of Carbon-Carbon Composites by Functionally Graded Fiber Arrangement Technique 久手幸徳、早田喜穂日本石油株式会社中央技術研究所 Y.Kude and Y.SondaNippon Oil Company, Ltd. Yokohama 231, Japan Next to mechanical properties, the most important characteristics of a carbon-carbon composite are thermal conduction and thermal expansion. In this paper, several investigations have been made into carbon fiber arrangement relationship for different carbon-carbon composite materials. Pitch-derived carbon matrix-carbon fiber composites have been used, generally processed by means of the hot isostatic pressing (HIP) technique for converting of pitch into a dry carbon fiber preform. Repeated HIP cycles are required to build the composite matrix up to an acceptably high density/low porosity for deployment in severely ablative environments. The effect of heat treatment temperatures on thermal conductivity, thermal conductivity at high temperatures and thermal expansion behavior have been studied. At room temperature, the values of thermal couductivity for uni-directional (UD) carbon-carbon composites are 700W/m*K. In the case of three-dimensional (3D) carbon-carbon composites, those values are determined by the volume of fiber arrangements. On the other hand, the thermal expansion of carbon-carbon composites in the fiber axis direction is chiefly governed by the thermal expansion of the fiber. On the basis of these fundamental research, a functional graded fiber arrangement technique have been proposed which present the opportunity to 'tailor' thrmophysical properties into carbon materials. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 19-24 遮熱性傾斜機能材料の熱衝撃き裂伝播特性 Effect of Graded Compositional Profile on Thermal Shock Cracking of Functionally Graded Materials as Studied by Burner Heating Test 川崎亮1）、葉建宏2）、渡辺龍三1）1）東北大学工学部、2）東北大学大学院 A.Kawasaki1), C-H Yeh2) and R.Watanabe1)1)Dept. Materials Processing, Faculty of Engineering, Tohoku University 2)Graduate School, Tohoku niversity Effect of graded compositional profile on thermal shock cracking of functionally graded materials was studied by burner heating test. Discussions were made on the basis of fracture mechanics with special reference to the effect of compositional profile on crack extension be-havior. Three types of FGMs, having the same thickness of graded layer with different compo-sitional profiles, were fabricated by powder metallurgical process. The fracture toughness of each composition was determined by newly devised repeated vickers indentation method di-rectly on FGM specimens. The fracture toughness increased with increase in the metal phase content, owing to toughening mechanisms of thermal-strain-misfit and crack deflection. The FGMs were joined on cooling substrates and used for burner heating test. The crack formation was always observed on the ceramic surface during cooling due to large residual tensile stresses. By comparison between the fracture toughness and mode I stress intensity factor, ver-tical cracks in convex-profile FGMs were deflected toward the direction parallel to the surface. The depth of the parallel cracks beneath the surface may correspond well to a location of mode II stress intensity being equal to zero. On the other hand, initiated vertical cracks in concave-profile FGMs were considered to arrest without deflection Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 25-30 Al-Al3Ni FGM長柱の軸圧縮変形挙動 Deformation Behaviour under Axial Compression in Columns of Al-Al3Ni Functionally Graded Material 福井泰好1)、岸田一茂2〉1)鹿児島大学工学部、2)鹿児島大学大学院 Y. Fukui1) and K. Kishida2)1) Kagoshima University, Korimoto, Kagoshima 890, Japan 2) Kagoshima University, Graduate School Axial compression tests were carried out in columns of Al-Al3Ni functionally graded material (FGM) to observe the deformation behaviour. FGM bars having 6x6 mm square cross-section and 90 mm length were machined from thick-walled tube. They had composition gradient only toward thickness direction. In Al-Al3Ni FGM columns, the applied stress condition was seemed to be same as the buckling of a column under an offset loading. Euler buckling did not happen and plastic buckling was observed in case of present FGM. The buckling of an instability phenomenon arose as a superposition of bending where the stress states were compression at higher elastic modulus side and tension at lower elastic modulus side of the column. The average of the buckling load was 3.73 kN and the nominal buckling stress was 103.6 MPa. It was necessary to apply a plastic-elastic analysis for the evaluation of the collapse strength of Al-Al3Ni FGM columns under axial compression. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 31-36 SiC/C傾斜組成化におよぼす基材黒鉛の特性　一曲げおよび硬さ試験結果一 Influence of properties of graphite matrix on preparation of SiC/C compositionally graded materials ―bending and hardness tests results― ○中野純一、藤井貴美夫、山田禮司日本原子力研究所材料研究部 J. Nakano, K.Fujii and R.YamadaJapan Atomic Energy Research Institute, Tokai-mura, Ibaraki-ken 3 19-11 , Japan Influence of graphite matrix on SiC/C compositionally graded materials has been studied by bending and hardness tests carried out at room temperature in air. Two types of graphite, IG-110 and PGX, were used as matrixes. In forming a SiC/C graded layer, the penetration of Si atoms showed a difference between IG-110 and PGX. Their bending strengths were almost the same as those of each virgin graphite and independent of Si contents in the SiC/C layers. Micro Vickers hardness at the SiC/C layers increased with Si content for SiC/IG-110, but the scatter of the values was much larger than that of a CVD SiC coating layer as well as of the graphite matrix. For SiC/PGX, the average hardness values and their scatter were similar to those of the matrix. The present results reveal that the mechanical properties of the SiC/C compositionally graded materials are mainly dependent on those of graphite materials . Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 37-42 Al-Sn合金インサートを使用したアルミナとMoの拡散接合 Diffusion Bonding of Alumina to Mo using an Al-Sn Alloy as an Insert Metal 伊藤勲1)、山田英明2)、一場朋典2)、小島理規2)、乙黒靖男1)1)群馬大学、2)群馬大学(院) I.Itoh1) , H.Yamada2) , T.Ichiba2) , Y.Kozima2) , Y.Otoguro1)l) Gunma University, Kiryu-shi, Gunma Pref. 376, Japan 2) Graduate Student of Gunma niversity A diffusion bonding of Al2O3 to Mo using an Al-Sn alloy as an insert metal is investigated. The bonding is carried out at 873 K for 7.2 ks under the pressure of 2 MPa in the atmosphere in order to obtain the relation between the bonding strength of Al2O3/Mo couple and the thickness of the insert metal at the bonding interface. As the results, the shear fracture strength of the couple, which has the insert metal more than the thickness of 1 mm, shows about 50 MPa. This strength is neary equal to that of an Al-Sn alloy. In order to enable the above bonding couple to be used at higher temperatures than the melting point of Al, the insert metal at the interface has to be eliminated from the interface. The eliminating treatment at 873 K for the couples using the insert metal of 0.5mm in thickness requires the longer time than 21.2 ks under the pressure of 8 MPa in the atmosphere. After this treat-ment, the couples show the about 20 MPa in strength. These couples which are exposed at 1173 K for 600 s in the atmosphere have the about 10 MPa in srength. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 43-48 遮熱型傾斜機能材料の熱衝撃破壊：弾塑性解析とクラック・アレスト Fracture of Heat Shield Type FGM Structure Subjected to Thermal shock : Elasto-plastic Analysis and Crack Arrest 中垣通彦、呉亜東、柴田泰成、大河原孝一、萩原世也九州工業大学情報工学部 M. Nakagaki, Y.D.Wu, Y. Shibata, K. Ogawara, and S. HagiharaSchool of Information Science and Systems Engineering Kyushu Institute of Technology, Iizuka, Fkuoka-ken 820,JAPAN A thermoelastic-plastic material modeling of a functionally graded material is performed with the use of a micromechanics analysis and a hierarchical neural network algorithm. The material is composed of a zirconia and a titanium alloy, where the plastic flow is considered to occur in the titanium alloy phase. A thermal shock problem of the functionally graded material in the pipe geometry with an internal crack is studied. To detect the crack-tip fracture severity in the highly inhomogeneous media, T* integral parameter is employed. Also shown in the text is the analysis of crack running transverse to the FGM plate subjected to the thermal shock. A phenomenon of the possible crack arrest is detected as the crack propagates from the brittle ceramic area toward the metal rich region. Thus, the effect of the FGM with respect to the enhanced fracture resistibility is verified. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 49-54 竹の傾斜構造の発現機構に関する研究 Study on Formation of Functionally Graded Structure of Bamboos 天田重庚1)、○清水尚之2)1)群馬大学、2)群馬大学大学院 S.Amada1)　 N.Shimizu2)1) GUMMA UNIVERSITY　 2) GUMMA NIVERSITY Bamboo is a composite and functionally graded material. It has a hierarchical structure, both in macroscopic and microscopic regimes. The bamboos grown on the slanted ground must have an adaptive structure. One of the adaptive structures is presented based on the functionally graded and hierarchical structure. To adapt the environmental loads it was concluded that they change not only diameter and shape of the culm-cross section but also the pattern of the fiber disribution. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 55-60 TiC-Ni3Al系傾斜機能材料の繰り返し熱衝撃 Cycli Thermal Shock of TiC-Ni3Al FGMs ○熊川彰長1)、佐々木正樹1)、高橋守1)、Zhang Lianmeng2)、平井敏雄2)1)航技研角田研究センター、2)東北大学金研 A. Kumakawa1), M.Sasaki1), M.Takahashi1), Z.Lianmeng2) and T.Hirai2)1)Kakuda Research Center, NAL, Kakuda, Miyagi, Japan 2)Tohoku Univ., Sendai Miyagi, Japan TiC-Ni3Al FGMs were successfully fabricated by using a hot pressing process. After mixing two kinds of powder, TiC and Ni3Al, in desired compositions, eleven layers were stacked according to the designed constitution gradient. They were hot-pressed under a pressure of 30 MPa and a temperature of 1573 K for 2 hours in Argon gas atomosphere. Then four FGM specimens with a diameter of 30 mm were tested under large-temperature-difference conditions. It was observed that the effective thermal conductivity of the FGM specimens decreased with an increase in the number of thermal cycles. Based on these results compared with previous ones, it was confirmed that the thermal damage of FGMs can be expressed based on the change of effective thermal conductivity and that there are three degradation modes of the effective thermal conductivity of FGMs. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 61-64 焼結熱電材料の物性推定 II Theoretical Calculation of Thermoelectric Figure of Merit for Sintered Materials II 吉野淳二東京工業大学・理学部 Junji YoshinoTokyo Institute of Technology, Meguro-ku, Tokyo 152, Japan Thermoelectric figure of merit, Z, for sintered materials has been estimated theoretically taking into account of interface effects on Seebeck coefficient in addition to electric and thermal conductivity and based on Boltzmann equation and a heterojunction model of interfaces. However, it is found that the influence of interface on Seebeck coefficient is negligibly small. Furthermore, detailed study show that the optimum grain size depends on the operating temperature in the case of high interface state density. These results suggest that grain size gradient structures could be effective to improve the energy conversion efficiency of thermoelectric converters. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 65-70 BiSb系の熱電特性に対する粒界効果 On the Effect of Grain Boundaries for BiSb 西尾好正、平野徹ダイキン工業(株) Yoshimasa Nishio and Tohru HianoMEC Labotatory, Daikin Industries Co. Ltd., 3 Miyukigaoka, Tsukuba, Ibaraki, 305, Jaan Calculations of various transport properties have been performed for BiSb by solving the Boltzmann equation. Ionized impurity scattering, alloy scattering, acoustic phonon scattering and optical phonon scattering have been taken into account. In addition to these scatteing effects, the grain boundary scattering has been included by simple one dimensional model, i.e. scatteting by randomly distributed potentials in one-dimension. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 71-76 傾斜機能熱電変換材料の2次元デバイスシミュレータの開発 Two Dimensional Device Simulation of Functionally Gradient Thermoelectric Materials ○寺本潤一1)、平野徹1)1)ダイキン工業（株） J. Teraki1), T.Hiano1)1) DAIKIN INDUSTRIES, LTD. MEC Laboratory, 3 Miyukigaoka, Tsukuba, 305, JAPAN. For the design of FGM thermoelectric device, it is not only necessary to get optimum energy conversion efficiencies, but also essential to decrease thermal stress induced by the high temperature difference within the device. In this paper, a procedure of an elastic thermal stress analysis has been presented on a functionally graded thermoelectric device by two-dimensional finite element technique. First, temperature distributions are calculated by two-dimensional non-linear finite element method based on expressions of thermoelectric phenomenon. Next, using temperature distributions, thermal stress distributions are computed by two-dimensional elastic finite element analysis. Finally, the temperature distribution, the electric potential distribution and the thermal stress distribution for Bi2Te3 thermoelectric generator were calcuated. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 77-82 熱電変換用RI円筒熱源の複合機能傾斜構造の設計 Design of Composite Functionally Graded Structure of Cylindrical RI Heat Source for Thermoelectric Conversion System 天田重庚1)　○寺内淳一郎1〉千田哲也2)　金井康二2)1)群馬大学工学部　2)船舶技術研究所 S.Amada 1), J.Terauchi 1), T.Senda 2), K.Kanai 2)l) Gunma University, Kiryu, Gunma, Japan 2) Ship Research Institute,itaka, Tokyo, Japan The graded structure with the multiple functions is required to construct a radio-isotope(RI) heat source for a new energy generating system. This structure is a cylinder, composed of RI-SrTiO3 as a heat source and BN as a radiation shielding material. The composite RI-cylinder must be designed to maximize the surface temperature and to minimize the radiation intensity on the cylindrical surface. It is presented that an optimum distribution of RI-SrTiO3 exsists to satisfy two distinct requirements. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 82-88 Bi2Te2.85Se0.15の熱電特性に及ぼす超高圧焼結の影響 Influences on Thermoelectric Properties of Bi2Te2.85Se0.15 by Ultra- High- Pressure Sintering 大和田仁1)、三浦啓一1)、中村和史1)、仙波裕隆1)、西田勲夫2)1)秩父小野田株式会社、2)金属材料技術研究所 H.Owada1), K.Miura1), K.Nakamura1), H.Semba1) and I.A.Nishida2)1)Chichibu Onoda Cement Corporation, Sakura, Chiba 285, Japan 2)National Research Institute for Metals, Tsukuba, Ibaragi 305, Japan Influences on thermoelectric properties of Bi2Te2.85Se0.15 by sintering under the conditions of Ultra- High- Pressure (UHP) were studied. Although the temperature during UHP was 50K lower than that of hot- pressing, relative densities of UHP-sintered bodies were more than 99%. The calculation of a parameter for orientation- distribution(W) has clarified that UHP gave rise to the reorientation of crystal grains and that W's of UHP- sintered bodies were unity which corresponds to a case {if the single crystals. It was confirmed from the results of Hall measurements that carrier density increased with pressure during UHP-sintering. Thermal conductivity of UHP-sintered bodies decreased with increase of UHP- pressure. It was suggested from these results that lattice- distortions were introduced into the crystalline by UHP and that Bi2Te3 materials with high thermoelectric performances could be fabricated by UHP method. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 89-93 n型Bi2Te3焼結体の熱電特性に及ぼすドーパントの影響 Influence of Dopants in Thermoelectric Properties of the Sintered n-type Bi2Te3 安倍のぞみ1)、桑折仁1)、塩田一路2)、西田勲夫3)1)工学院大(工)、2)工学院大、3)金属材料技術研究所 N.Abe1), H.Kohri1), I.Shiota2), I.A.Nishida3)1)Kogakuin University Gra., Hachioji, Tokyo 192,Japan. 2)Kogakuin University, Hachioji, Tokyo 192, Japan 3)National Research Institute for Metals, Tsukuba, Ibaragi 305, Japan Electrical resistivities and Hall coefficients, thermoelectric powers and thermal conductivities have been measured on sintered n-type Bi2Te3 doped with HgBr2, HgI2, SbBr3 or SbI3. Electrical resistivity and Hall coefficient were in the temperature range from 80 to 500K, and thermoelectric powers and thermal conductivities were at room temperature. The resistivities of all specimens were increased with temperature. Hall coefficients of specimens doped with HgBr2 and HgI2 were almost constant in the temperature range from 80 to 300K and then decreased avobe 300K by the influence of intrinsic range. Hall coefficient of specimens doped with SbBr3 and SbI3 had the same tendency, while the effet of influence of intrinsic range was obsearbed at a high temperature. Hall mobilities of specimens doped with HgBr2 or HgI2 and with SbBr3 or SbI3 had the different temperature dependence below 230K. It is clear that the scattering mechanism of specimens doped with HgBr2 or HgI2 are different from SbBr3 or SbI3. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 95-99 傾斜構造を有するBi2Te3系焼結体の熱電特性 Thermoelectric Properties of Functionally Graded Sintered Bi2Te3 ○桑折仁1)、佐藤浩三1)、安倍のぞみ1)、鈴木敏之2)、塩田一路2)、西田勲夫3)1)工学院大学(院)、2)工学院大学、3)金属材料技術研究所 H.Kohri1), K.Sato1), N.Abe1), T.Suzuki2), I.Shiota2), I.A.Nishida3)l)Kogakuin University Gra. Shinjuku-ku, Tokyo 163, Japan 2)Kogakuin University Shinjuku-ku, Tokyo 163, Japan 3)National Research Institute for Metals, Tsukuba-City, Ibaraki 305, Japan Samples of n-type Bi2Te3 doped with 0.06, 0.09, or 0.15 wt.% of HgBr2 as the dopant were prepared by hot pressing. Two samples doped with 0.06 and 0.15 wt.% were soldered to form an FGM. The electrical resistivity rho, Hall coefficient RH, and thermoelectric power alpha were measured over the temperature range from 100 to 500 K. RH decreased with increasing of the amount of the dopant. The FGM showed a higer alpha than the monolithic samples at a higher temperature than approximately 450K. Power factor alpha 2/rho values were estimated by using alpha- and rho-data. It was found that the temperature at which the alpha 2/rho showed a maximum value shifted to a higher temperature with increasing carrier concentration. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 101-106 中温領域熱電材料の高性能化とキャリア濃度FGM High Efficient Program and Carrier Concentration FGM of Thermoelectric Materials in the Intermediate Temperature region 今井義雄1)、篠原嘉一1)、西田勲夫1)、海部宏昌2)、佐藤浩三3)、桑折仁3)、塩田一路4)1)金材技研、2)都立大、3)工学院大(院)、4)工学院大 Y.Imai 1) , Y.Shinohara 1) , I.A.Nishida 1) , K.T.kaibe 2) , K.Sato 3) , H.Kohri 3) and I.Shiota 3)1)National Research Institute for Metals, Ibaraki 305, Japan2)Tokyo Metropolitan University, Tokyo 192-03, Japan 3)Kogakuin University Tokyo 192, Japan As a part of the national project, the experimental examination and investigation have been carried out on PbTe compounds and their functionally graded material (FGM) with a view to an elevation of thermoelectric energy conversion efficiency. Unidirectional solidified PbTe doped with 0.2 and 0.5wt%PbI2 formed FGM structure whose electron concentration varied continuously along the growing direction in one order of magnitude. An electron concentration in the starting growth edge of PbTe doped with 0.2wt%PbI2 was of 0.82x10**(25)/m3, and this maximum figure of merit Zmax was estimated to be 2.0x10**(-3)/K at 410K. High eletrical figure of merits was confirmed to be obtained in the lower temperature range. A 3-stage FGM composed of each layer with different electron concentrations of 3.5,2.6 and 2.2x10**(25)/m**3 was prepared by the hot-pressing technique. It was found th at a larger figure of merit than ones of homogeneous materials composing FGM was obtained in the wide temperature range and that Zmax was 1.3x10**(-3)/K at 600K. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 107-112 PbSnTe系化合物の熱電特性 Thermoelectric Properties of Pb0.95Sn0.05Te 米田征司1)、海部宏昌1)、奥村次徳1)、今井義雄2)、西田勲夫2)、佐藤浩三3)、塩田一路3)1)東京都立大学工学部、2)金属材料技術研究所、3)工学院大学 S .Yoneda1), H.T.Kaibe1), T.Okumura1), Y.Imai2), I.A.Nishida2), K.Satoh3), I.Shiota3)1) Tokyo Metropolitan University, Hachioji-shi,Tokyo 192-03, Japan 2) National Research Institute for Metals, Tsukuba-shi, Ibaraki 305, Japan 3) Kogakuin University, Hachioji-shi Tokyo 192, Japan An n-type Pb0.95Sn0.05Te doped with 0.4wt% of PbI2 was prepared by means of unidirectional solidification. The major portion of the as-grown ingot was n-type and p-type region was formed in the vicinity of the growth end. The electron density decreased along the growth direction from 3.18x10**20cm**-3 to 2.60x10**17cm**-3, which confirms FGM stucture. The n-type sintered Pb0.95Sn0.05Te were also prepared by the hot-pressing technique using the melt-grown ingot. The thermal conductivity of the sintered specimens was 16.4 mW/(cmK), which was 12% lower than that of an n-type sintered PbTe. It is found that the carrier scattering mechanism of the sintered specimens is remarkably different from that of the solidified ones. The resistivity of an melt-grown n-type PbTe had a hysteretic temperature dependence up to 800K at ambient Ar pressure due to evaporation of Te ,which indicates that the changes of the thermoelectric properties occur during practical operation of the devices. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 113-116 p型PbTeの作製と熱電特性 Preparation and thermoelectric properties of p-type lead telluride 野田泰稔1)　折橋正樹2)　西田勲夫3)1)東北大学工学部　2)東北大学大学院　3)金属材材料技術研究所 Y.Noda 1), M.Orihashi 2), I.A.Nishida 3)1)Department of Materials Science, Faculty of Engineering, Tohoku University, Aoba-ku Sendai 980- 77, Japan 2)Department of Materials Science, Graduate school, Tohoku University, Aoba-ku Sendai 980-77, Japan 3)National Research Institute for Metals, Tsukuba-City, Ibargi 305, Japan Single crystals of p-type PbTe were prepared by Bridgman method, where Ag2Te was doped as the source material of Ag. The electrical conductivity and Hall mobility were measured from 77 to 300K. The hole concentration was controlled in the range from 2.0x10**(18) to 9.0x10**(18) cm -3 by doping 100 to 1000molppm Ag2Te. The Hall mobility indicated that the dominant scattering mechanism is phonon scattering at 77-300K. From the observed data of electrical conductivity and thermoelectric power measurements and the literature data of thermal conductivity, the maximum figure of merit at 300K reached 1.5x10**(-3) K -1 at 200molppm Ag2Te. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 117-122 n-PbTeの合成と熱電特性 Synthesis and Thermoelectric Properties of n-type PbTe 腰越美営1）、佐藤浩三1）、塩田一路2）、今井義雄3）、西田勲夫3）1)工学院大学大学院、2)工学院大学、3)金属材料技術研究所 M.Koshigoe1), K.Sato1), I.Shiota2), Y.Imai3) and, I.A.Nishida3)1)Kogakuin University (Gra.),Hachioji-City,Tokyo 192 Japan 2)Kogakuin University, Hachioji-City, Tokyo 192 Japan 3)National Research Institute for Metals, Tsukuba-City, Ibaragi 305 Japan The effect of dopant and grain size on thermoelectric properties has been investigated to develop n-type PbTe with FGM structure. Seebeck coefficient, thermal conductivity, resistivity and Hall coefficient were measured on PbTe doped with 0.1 at.% PbI2 or 0.1 at.% PbCl2. The solidified PbTe doped with PbI2 had a higher carrier concentration than PbTe with PbCl2. The sintered PbTe doped with PbI2 was n-type, while the solidified PbTe doped with PbCl2 was p-type. It was found that PbI2 was more effective as dopant than PbCl2. The n-PbTe ingot doped with PbI2 also had a change of carrier concentration in the direction of solidification. Therefore, the PbTe with FGM structure is expected to be synthesized from only one ingot doped with PbI2. The sintered PbTe had a lower thermal conductivity than solidified PbTe. Reducing the grain size was effective for PbTe to decrease the thermal conductivity due to scattering of phonon. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 123-127 SiGe熱電材料の傾斜機能化 Functionally Graded Si-Ge Thermoelectric Material 高橋一寿、増田忠、持丸敏昭、野口照夫真空冶金株式会社 K.Takahashi, T.Masuda, T.Mochimaru, T.NoguchiVacuum Metallurgical Co., Ltd. Sanbu-cho, Sanbu-gun, Chiba Pref. 289-12, Japan A functionally graded SiGe thermoelectric material composed of parts with three different Si/Ge compositions was succesfully obtained by using the so-called spark plasma sintering method. In boundary areas of the graded compositions having a width of about 0.5mm, the electrical resistivity at room temperatures was large compared with non-boundary areas of a uniform composition. This will suggest that the increase of layer number in FGM themoelectric materials might be resulted in an increse in the internal electrical resistance. It will be required to study the performance of this resistance increase in the boundary areas at high temperatures. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 129-132 SiC-Si FGMの熱電特性 Thermoelectric Properties of SiCSi FGM ○高木慶光1)、岡野一雄2)1)能開大(院)、2)能開大 Y.Takagi1), K.Okano2)l)Graduate School of The Polytechnic University, Sagamihara-City, Kanagawa, Japan 2)Department of Electrical Engineering, The Polytechnic University, Sagamihara-City, Kanagawa, Japan SiC ceramics are promising materials for high temperature operating devices such as the thermoelectric energy converters, because of the high chemical stability at high temperatures. However, the electrical conductivity of SiC ceramics is too low to apply to the thermoelectric energy converters at low temperatures. Therefore, we propose a SiC-Si FGM in order to improve the low electrical conductivity at low temperatures. A green SiC rod was sintered in the temperature gradient furnace. One edge of SiC rod was kept at 1973K and another edge was kept at 2373K for 0.5hr. After sintering, the SiC rod was dipped into molten Si with 3.0wt% of Al in order to impregnate porous SiC with Si. The electrical conductivity(sigma) and the Seebeck coefficient(alpha) for each part of SiC-Si FGM were measured at 300K to 1000K and power factor(alpha 2 sigma) was calculted. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 133-138 対称傾斜型MoSi2/Al2O3/Ni系高温電極の構造安定性 Structural Stability of Symmetric MoSi2/Al2O3/Ni High Temperature Electrode 康燕生、宮本欽生大阪大学・産研 Yan-Sheng Kang, Yoshinari MiyamotoISIR, Osaka Univrsity Thermal and structural stability of a high temperature electrode is of importance to ensure high efficiency and long life of the SiGe thermoelectric converter. In this work, the behavior of diffusion in the symmetrically graded electrode of the MoSi2/Al2O3/Ni/Al2O3/MoSi2 system between 900deg.C to 1400deg.C war investigated and the stress distribution was determined by x-ray analysis and calculated using FEM method. The Al2O3 phase acted as a diffusion barrier to Ni up to 1400deg.C and restrained the reaction of MoSi2 with Ni. The calculated residual stress exhibited that the surface has compressive stress which was introduced by the thermal expansion mismatch between the MoSi2 and the Al2O3O3-Ni layer. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 139-142 プラズマ処理による熱電セラミックスの構造制御 Microstructure control of thermoelectric ceramics by plasma treatment 岸本堅剛1)、長本泰征1)、小柳剛1)、松原覚衛2)1)山口大学、2)山口東京理科大学 K.Kishimoto1), Y.Nagamoto1), T.Koyanagi1), and K.Matsubara2)1) Yamaguchi University, 2557 Tokiwadai, Ube 755 2) Science University of Tokyo in Yamaguchi, 1-1-1 Daigaku-dori,Onoda 756 The microstructure control at grain boundaries for SiGe ceramics has been made by plasma treatment to improve their thermoelectric figure of merit. SiGe micrograins were exposed to rf plasma of GeH4 gas, and then were sintered. The plasma-processed ceramics had a higher electrical conductivity and lower thermal conductivity than non-processed one, so that their figure of merit values were about three times as high as non-processed one at room temperature. The increase in electrical conductivities may be explained by a reduction of a potential barrier height at grain boundaries. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 143-148 SiC/B4C熱電半導体の熱電特性・密度依存性及び温度依存性---II Effects of density and temperature on thermoelectric properties of SiC/B4C thermoelectric semiconductor - Part II 岡本庸一、宮川浹、守本純、有賀敦、藤本司郎防衛大学校　材料物性工学 Y.Okamoto, T.Miyakawa, J.Morimoto, A.Aruga, S.FujimotoNational Defense Academy Dept. of MSE, Yokosuka, Kanagawa 239 Japan We report the results of both experimental measurement and theoretical simulation on the temperature and density dependence of thermoelectric properties of p-type SiC(98 wt. %) doped with B4C(2.0 wt. %). The temperature and density dependence of electrical resistivity, thermoelectric power and thermal conductivity were measured over the range from room temperature up to 700deg.C and as a function of PSS (Poly-SilaStyrene) concentration over the range 0.5 wt.%～25 wt.%, where PSS acts as the controller of density. On the other hand, results of the theoretical simulation, using effective medium theory are fitted to the results of experimental measurements by adjusting the thermoelectrical parameters of grain and grain boundary. Comparing the experimental results and theoretical simulations, we found that effective medium theory can explain the actual thermoelectric properties qualitatively . The effects of pores on sigma and kappa tend to cancel in the expression for Z. Temperature dependence of Z is discussed. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 149-154 アーク溶解法により作製したW-B-C系複合セラミックスの微細組織と熱電特性 Microstructure and Thermoelectric Properties of W-B-C Composite Ceramics Prepared by Arc Melting ○後藤孝、李剣輝、平井敏雄東北大学金属材料研究所 T. Goto, J. Li and T. HiraiIMR, Tohoku University, Sendai, Miyagi 980-7, Japan W-B-C system composites were prepared by arc melting in an argon atmosphere using B4C, WC, WB, B and C powders. Lamella textures indicating eutectic reaction were observed at B4C contents of about 20mol% and 10mol% in the quasi-binary W2B5-B4C and WB4-B4C systems, respectively. Carbon phase in the W2B-B4C-C ternary system was needle-like. The Seebeck coefficient (alpha) generally decreased with increasing W2B5 and WB4 contents. However, the W2B5-B4C composites containing 2mol%W2B5 have slightly greater alpha values than those of B4C in the temperatures range between 200 and 1000K. The electrical (sigma) and thermal conductivities (kappa) increase with increasing W2B5 and WB4 contents. The figure of merit (Z) values increased with increasing temperature. The W2B5-B4C composites containing 2mol%W2B5 Showed slightly greater Z-values than those of B4C at temperatures between 200 and 1000K. The highest ZT value at T=1000 was about 0.1. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 155-160 (0001)配向Re層を有する傾斜構造エミッタの熱電子発電特性と熱安定性 Thermionic Properties and Thermal Stability of Emitter with a (0001) Oriented Rhenium Layer and Graded Structure 五十嵐廉1)　加藤昌宏1)　高岡重彦1)　林武彦1)　岡本謙一1)　福田隆三2)1)東京タングステン(株)　2)電子技術総合研究所 T. Igarashi1), M. Katoh1), S. Takaoka1), T. Hayashi1), K. Okamoto1), R. Fnkuda2)1) Tokyo Tungsten Co.. Ltd.. Toyama-shi. Toyama. 931. Japan 2) Electrotechnical Laboratory, Tsukuba-shi, Ibarai. 305, Japan The rhenium layer with a (0001) preferred orientation and ragged surface was prepared by chemical vapor deposition on molybdenum substrate coated with tungsten layer. Work function of the rhenium was 5.0eV. Maximum power of thermionic converter comprised of the rhenium emitter and molybdenum collector with a gap of 500 micro meter was 1.0W/cm2 , when the convertor was operated at 1600K of emitter, 1000K of collector and 567K of caesium reservoir. Rhenium/tungsten/molybdenum structure with graded-composition layers were formed by high temperature annealing. Tungsten layer inhibited interdiffusion between rhenium and molybdenum to obtain thermal stability of the rhenium layer at high operating temperature. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 161-166 熱電子発電器用高融点金属酸化物コレクタの開発 Development of Refractory Metal Oxide Materials for Thermionic Energy Converter Collector ○福田隆三、春日康弘、加藤健電子技術総合研究所 R. Fukuda, Y. Kasuga, K. KatohElectrotechnical Laboratory, 1-1-4, Umezono, Tsukuba-shi, Ibaraki305 Japan In order to improve efficiency of a thermionic converter, it is most effective to develop collector electrode materials with low work function (~1.0eV) and high temperature enduarance capability (to 1000K). Refactory metal oxides such as NbOx, WOx, TaOx, and Silver oxide (AgOx) have been studied for a high per formance collector. These metal oxide materials were deposited on the metal substrates by RF Sputtering under the atomoshere of Ar/O2 mixture and these metal oxide coated sample electrodes were fabricated for a collector of a thermionic converter. Work function of the sample electrodes was measured by cesium plasma immersion technique. As results , minimum work function values (phi)c (min) for each oxide materials were obtained as follows ; phi c (min) of AgOx= 1.25eV, NbOx=1.38eV, WOx=1.42eV, TaOx=1.43eV. NbOx and AgOx are considered most promising material for a collector. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 167-170 Mo/TiC傾斜組成皮膜の形成と皮膜の性質 Fomation and Properties of Mo/TiC Graded Coatings 福島孟、黒田聖治、北原繁金属材料技術研究所 T. Fukushima, S. Kuroda and S. KitaharaNational Research Institute for Metals, Tsukuba, Ibaraki, Japan Formation of graded coatings(FGM) was carried out with the plasma twin torch spraying method in air. Mo and TiC powder (particle size:10 to 44 micro meter) were sprayed onto Mo substrates to obtain coatings with high thermal absorption in order to improve the performance of the thermoelectric conversion materials. The laminated structure and the thermal stability of the obtained coatings were investigated. The results are summarized as follows. 1) Graded coatings are obtained by stepwise control of each powder feed rate. 2) The compositional gradient within the coating is nearly smooth and linear. 3) Even after the heat treatment of the sprayed coatings in vacuum(at 1473K, 16h, 10**(-4) Pa), there are no recognizable reaction products between Mo and TiC in the coatings. 4) There are no recognizable defects in the FGM coatings after the thermal cycle test (from R.T. to 1223K, 5 cycles) in comparison with the TiC single coating onto the Mo sustrate. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 172-176 高性能熱電子発電器の開発 Development of Efficient Thermionic Energy Converter 加藤寿仁、加藤裕一、森本清水、礒貝和博(三井造船株式会社) T.Kato, Y.Kato, K.Morimoto, K.IsogaiMitsui Engineering & Shipbuilding Co.Ltd., Ichihara-City, Chiba Pref., Japan This paper presents the development of efficient thermionic energy converter by applying functionally graded materials, shortly FGM. It can be heated up to 2000 K by concentrated solar light. The converter is a planar diode having a circular solar reciever of TiC/Mo graded layer, a emitter electrode of Re/W graded layer, and a collector electrode of refractory metal oxide layer. Each layer has an area of 3 cm2. These elements were prepared by other laboratories. Each electrode is connected to a heat-choke to reduce the heat loss of conduction, and kept at the distance of 0.2 mm by the insulator pins of single crystal sapphire. Both heat-chokes are united by ceramic sealing, where the electrodes are broken electrically. In addition, radiation seal is placed in the converter. The measuring apparatus for the converter was developed. The converter in it can be heated by electron bombardment heating method similar to concentrated solar light. In experiment, voltage-current characteristic; output power density, and efficiency can be measured at variable condition. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 177-182 プラズマ溶射法による固体電解質型燃料電池用FGM燃料電極の開発 Development of FGM Anode for Solid Oxide Fuel Cell by Plasma Spray Coating 永田雅克、岩澤力、清野謡子、小野幹幸株式会社フジクラ M.Nagata, C.Iwasawa, Y.Seino and M.OnoFujikura Ltd., Koto-ku, Tokyo 135, Japan Fujikura Ltd. are studying a cathode substrate-type Solid Oxide Fuel Cell(SOFC) using the spray coating method,etc. in order to develop a cell with high performance and long life. Major issues of SOFC are the sintering of Ni at the operating temperature(1273K) of Ni-YSZ(Yttria Stabilized Zirconia) cermets anode and mismatching the thermal expansion with YSZ electrolyte. Ni has the function of electrochemical activity and electric conductivity. And YSZ has the function of matching the thermal expansion with electrolyte. It is difficult for single composition Ni-YSZ cermets to be compatible with their function. Therefore we are developing of FGM anode, which consists of a YSZ rich layer at the electrode/electrolyte interface and a Ni rich layer at the surface, for SOFC by plasma spray coatng. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 183-188 積層型サブユニットを使用するキロワット級熱電発電システムの開発 Developement of Thermoelectric System Composed of Laminated Subunits Generating Kilowatt Power 丹治雍典1)、中川康昭2)、新野正之3)、増本健4)、鈴木謙爾4)、隅山兼治4)、佐藤利三郎5)、井門秀秋5)、須藤一5)1)（株）東北テクノプレインズ、2)東北工業大工学部、3)航技研、4)東北大金研、5)東北学院大工学部 Y.Tanji (1) , Y.Nakagawa (2) , M.Niino (3) , T.Masumoto (4), K.Suzuki (4), K.Sumiyama (4), R.Sato (5), H,Ido (5), H.Sudo (5)1) R&D Division,Tohoku Techno Brains CO.Ltd ,5-25-2; Kamo, Izumi, Sendai, 981-31,Japan. 2) Faculty of Engineering, Tohoku Institute of Technology, Sendai, 982, Japan. 3) Kakuta Research Center, National Aerospace haboratory, Kakuta, 989-15, Japan. 4) Institute of Materials Science,Tohoku Univefsity,Sendai, 98, Japan. 5) Faculty of Engineering, Tohoku Gakuin University, Tagajyo, 985, Japan. A thermoelectric system with a new heat-transfer method is proposed, which is composed of a thermoelectric generator and a pair of hot and cold heat-reservoirs. The thermoelectric generator is composed of 10 laminated subunits. It has been estimated that the electric power amounts to 1.57 kW at the temperature difference between both ends of thermoelectric elements of 50 K. After being collected in the hot heat-reservoir, reserved and kept constant temperature under control, some energies which generate from different energy sources such as solar energy, waste heat energy and low-price electric power at midnight are used as a composite energy source in the thermoelectric system. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 189-192 超高温太陽受熱器の開発と傾斜構造型エネルギー変換素子の特性評価 The development of the Solar Receiver for a High Efficient Energy Conversion System and the Characterization of the Functionally Graded Emitter Material 嵐治夫1)、内藤均1)、梅岡貴志2)1)東北大学、2)東北大学(院) H. Arashi1), H. Naito1), T. Umeoka2)l) Tohoku University, Aoba, Aramaki, Sendai 980-77, Japan 2) Graduate Student at Tohoku University, Aoba, Aramaki, Sendai 980-77,Japan Solar energy will be one of the most promising energy resources on earth or in space because it is clean and inexhaustible. We are studying a solar-powered high efficient thermionic/thermoelectric conversion system. This system combines a thermionic converter (TIC) with a thermoelectric converter (TEC) to use efficiently thermal energy and to obtain high conversion efficiency. The emitter of TIC can be heated uniformly up to the temperature range of 1700 K using thermal radiation from a solar receiver. A cylindrical cavity-type solar receiver made of graphite was designed and heated in vacuum by using the solar concentrator installed at Tohoku University. The maximum temperature of the solar receiver enclosed with a Mo cup attained to 1965 K which was sufficiently high to heat an emitter of TIC by thermal radiation from the receiver. The temperature distribution of the functionally graded emitter material was also meaured. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 193-198 傾斜構造複合熱電変換素子の性能評価装置 An Evaluation System For Thermoelectric Elements Over a Large Temperature Difference 須藤孝幸1)、陳立東1)、木皿且人1)、新野正之1)、岡村寛志2)、宮島雅史2)、渡辺龍三3)1)航空宇宙技術研究所　角田宇宙推進技術研究センター2)東北大学大学院3)東北大学工学部材料加工学科 T.Sudo1), L.Chen1), K.Kisara1), M.Niino1), H.Okamura2), M.Miyajima2, R.Watanabe3)1) Kakuda Research Center, National Aerospace Laboratory, STA, Kakuda, Miyagi, Japan 2) Department of Materials Processing, Faculty of Engineering, Tohoku University, Sendai, Japan 3) Department of Materials Processing, Faculty of Engineering, Tohoku University, Sendai, Japan A large-temperature-difference evaluation apparatus has been designed and built for thermoelectric performance evaluation of gradient thermoelectric composite elements. This apparatus can simultaneously measure thermoelectromotive force, electrical resistance, temperature profiles and heat flux through the specimen during the same thermal cycle. Measurement can be made up to 1500K with a temperature difference of 800K. Especially, efforts have been made on controlling axial heat flow pattern under high heat flux and large temperature difference conditions. Thermoelectric energy conversion measured for the non-FGM SiGe p-type module was less than that of the calculated value. The result indicates that the heat losses must be controlled in the further studies. Thermoelectric characterization was also made for n-SiGe/n-PbTe segment bonded FGM, which revealed an effect of thermal resistivity at the interface between the comosite layers. Japanese １９９７年度　傾斜機能材料論文集　＜ＦＧＭ’９５＞ FY 1995 Proceedings of Functionally Gradient Materials 15 1996-07-01 199-201 スピネル型蛍光体の多色化に伴う傾斜設計 Graded Design for full-colored spinel phosphors ○遠藤忠、滝澤博胤、上田恭太東北大・工 T.Endo, H.Takizawa and K.UedaFaculty of Engineering, Tohoku University, Aoba-ku, Sendai City, 90-77, Japan One of spinel phosphors, ZnGa2O4 had an intense emission under ultra violet-light and electron radiations without any dopants. Emission peak pofiles were remarkably governed by both substitutions of Cd2+ for Zn 2+ and Al3+ for Ga3+. The peak position was participated with the energy gap between conduction and valence bands. On the ther hand, Mn2+ and Cr3+ ions were responsed for dopants so that the emission disappeared completely as spinel phosphor. Co-existance of Mn2+ and Cr3+ was allowed to emit the both colors. Full-colored phosphor was newly realized in ZnGa2O4. Japanese