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National Institute for Materials Science

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[FY 1998  Proceedings of Functionally Gradient Materials (FGM'98) ](https://mdr.nims.go.jp/datasets/05d5c5f7-e5ac-4074-9cbc-aedadcda7983)

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Sheet1 BookTitle_j BookTitle_e Volume/Issue Issueddate Page Title_j Title_e AuthorList_j AuthorList_e Abstract Language 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 1-5 傾斜熱電材料の設計・性能評価の現状 Present status of material-design and performance-analysis on FGM thermoelectric materials 吉野淳二1), 林原光男2), 小島勇夫3), 渡辺龍三4), 小柳剛5), 平野徹6), 新野正之7)1)東京工業大学　物理学科　152-8551　東京都目黒区大岡山2)株式会社　日立製作所　319　日立市3)物質工学工業技術研究所　305　茨城県つくば市4)東北大学　大学院　981　宮城県仙台市5)山口大学　755　山口県宇部市6)ダイキン工業(株)　MEC研究所305　茨城県つくば市7)航空宇宙技術研究所　角田宇宙推進技術研究センター　981　宮城県角田市 J. Yoshino, M. Hayashibara, I. Kojima, R. Watanabe, T. Koyanagi, T. Hirano, and M. Niino1) Tokyo Institute of Technology, Department of Physics, Meguro-ku, Tokyo 152-8551, Japan 2) Hitachi Ltd, Hitachi Research Laboratory, Hitachi-shi, 319, Japan 3) National Institute of Materials and Chemical Research, Tsukuba-shi, Ibaraki 305, Japan. 4)Tohoku University, Graduate School, Sendai-shi, Miyagi 981, Japan 5)Yamaguchi University, Graduate School, Ube-shi, Yamaguchi 755, Japan 6)Daikin Industries Ltd., MEC Laboratory, Tsukuba-shi, Ibaraki 305, Japan 7)National Aerospace Laboratory, Kakuda Research Center, Kakuda-shi, Miyagi 981, Japan  The results obtained in material-design and performance-analysis group of FGM II projects have been reviewed with special emphasis on thermoelectric properties of low dimensional systems, microscopic analysis of FGM structures, and percolation effects on thermoelectric materials. Remarkable results obtained are as follows: Theoretical study reveals that second subband in two dimensional systems could be effective to improve dimensionless figure of merit, contrary to previous reports. Thermal diffusivity measurement system based on the micro-photothermal radiation method was developed and spatial resolution less than 100 micro meter has been confirmed by analyzing n-BiTe/Ni heterojunction. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 7-11 傾斜構造による熱電材料と高温電極の現状 The State of Thermoelectric Materials and High Temperature Electrodes with the FGM Structure. 西田勲夫科学技術庁　金属材料技術研究所　305-0047　茨城県つくば市 Isao A. NISHIDANational Research Institute for Metals, STA, Tsukuba, Ibaraki 305-0047, Japan  The development of the efficient thermoelectric (TE) material with high efficiency and the high temperature electrode with high reliability had been promoted in the national project of functionally graded material (FGM) for energy conversion since 1993 to the fiscal year 1997. For the TE materials, the relationship between the physical properties and fabrication processes was investigated fundamentally on three kinds of systems; Bi-Te, Pb-Te and Si-Ge. The stepwise FGM with different carrier concentrations or compositions was prepared and was clarified to have higher thermoelectric performance than the homogeneous materials composed of the FGM. For the high temperature electrode, the joining technique and the thermal stability of electrical, thermal and mechanical properties were investigated. The SHS process formed the high temperature electrode in good contact with the TE materials, successfully. Thermal stress at the electrode was relaxed by applying FGM structure. The thermally stable electrode was developed for high temperature use. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 13-23 傾斜構造による熱電子発電素子の高性能化 Development of Thermionic Energy Conversion with FGMs ○福田隆三1)、平井慶彦2)、五十嵐廉3)、加藤昌宏3)、加藤寿仁4)、福島孟5)、黒田聖治5)、久手幸徳6)、曽我部浩一7)1)電子技術総合研究所　茨城県つくば市2)東海大学　神奈川県平塚市3)東京タングステン(株)　富山県富山市4)三井造船(株)　千葉県市原市5)金属材料技術研究所茨城県つくば市6)日本石油(株)　神奈川県横浜市7)住友電気工業株式会社　兵庫県伊丹市 R.Fukuda1), Y.Hirai2), T.Igarashi3), M.kato3), T.Kato4) T.Fukusima5), S.Kuroda5),Y.Kude6), K.Sogabe7)1)Electrotechnical Laboratory, Tsukuba-shi, Ibaraki, 2)Tokai University, Hiratuka-shi, Kanagawa, 3)Tokyo Tungsten Co., Ltd.. Toyama-shi, Toyama, 4)Mitsui Engineering & Shipbuilding Co. Ltd.. Ichihara-City, Chiba, 5)National Resarch Institute for Metals, Tsukuba-shi, Ibaraki, 6)Nippon Oil Company, Ltd., Yokohama-shi, Kanagawa, 7)Sumitomo Electric Industries, Ltd., Itami-shi, Hyogo.  Fruitful results of research and development of the Thermionic Energy Conversion and High Temperature Environment Materials Team in FY 1996-97 are briefly presented. The results are: 1) Ir/W/Ta emitter and a NbOx collector with FGMs for a thermionic converter, 2) A TiC/Mo plasma sprayed FGM layer for thermal absorption, 3) Carbon-carbon filter composite materials by HIP, 4) High emissivity AlN/W material with graded structure. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 25-31 未利用熱エネルギーの有効利用について－総括－ Research Project on the Effective Use of Untapped Thermal Energy from Waste Incineration etc. 新野正之,木皿且人航空宇宙技術研究所　角田宇宙推進技術研究センター　981-1525　宮城県角田市 Masayuki Niino,Katsuto KisaraNational Aerospace Laboratory, Kakuda Research Center, Kakuda-shi , Miyagi 981-1525, Japan  The objective of this project is to develop thermoelectric generation systems that convert untapped energy from close-at-hand sources, such as waste incineration, industrial exhaust, etc. into electricity. The project began in December 1995, supported by the Science and Technology Agency of the Japanese government. Four electric power generation systems have been produced and successfully evaluated with respect to their reliability and advantages. Two of these systems (500W-class power generation ) were linked to a conventional waste incineration plant with a capacity of 80 tons/day. Another system was tested in conjunction with a gas cogenerator. In the fourth system, solar thermal energy was combined with a photovoltaic cell to demonstrate the capability of hybrid generation from a thermoelectric and photovoltaic system. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 33-38 アモルファスシリコン系傾斜超格子を用いたアバランシェ増倍型フォトダイオード膜 Avalanche Multiplication Type Photodetectors using a-Si:H Functionally Graded Superlattice Structure ○澤田和明, 石田誠豊橋技術科学大学 電気・電子工学系 Kazuaki SAWADA, Makoto ISHIDAToyohashi University of Technology  The photocurrent multiplication due to impact ionization was observed in the a-Si:H/a-SiC:H staircase photodiode. On the staircase photodiode with one band offset, the photocurrent was multiplied double and was saturated. It was confirmed that almost all electrons were multiplied after they crossed the band offset. On the staircase photodiode with 3 band offsets, the saturated multiplication gain of about 6 was also obtained. The gamma values of the photocurrent characteristics were 1.0 indicating that there were no excess carriers entering from the electrode and no interband tunneling affected on photo-induced current. These results suggested that the impact-ionization at each conduction band step due to the conduction-band discontinuity may be the dominant mechanism of the photocurrent multiplication. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 39-44 n型PbTe接合材の長さ比と出力特性 Length Ratio of Segments and Thermoelectric Generation Properties in 2-Segmented n-PbTe 田口健二1)、今井義雄2)、篠原嘉一2)、磯田幸宏2)、西田勲夫2)1)(株)ミツバ、2)金属材料技術研究所　茨城県つくば市 K.Taguchi 1) , Y.Imai 2) , Y.Shinohara 2) , Y.Isoda 2) , I.A.Nishida 2)1) Mitsuba Corporation 2) National Research Institute for Metals, Tsukuba, Ibaraki, Japan  The n-type PbTe, which consists of two segments with carrier concentration ne of 1x10**(25) and 3x10**(25)/m3, have been fabricated by hot pressing. The effective maximum power Pmax has been evaluated in relation to the length ratio X of the segment (ne = 1x10**(25)/m3) to the total length. The X was changed to be 44, 50 and 62%. The Pmax of the joined compacts was between the Pmax curves of the two segments at delta Thc is equal to or less than 420 - 480 K, while it was larger at delta Thc is more than 480 K. Delta Thc is the temperature difference between the hot and the cool side temperatures. The optimum interface temperature Ti of the joined compact was 640 K. When delta Thc= 500K and also X=75%, temperature Ti was 640 K. It is estimated that the joined compact with X=75% is about 10% higher in Pmax at deltaThc= 500 K than the homogeneous compacts. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 45-50 PbTe-SnTe固溶体とそのFGMの熱電特性 Thermoelectric Properties of PbTe-SnTe Solid Solution and its FGM 西田勲夫1), 今井義雄1), 篠原嘉一1), 橋本政靖2), 海部宏昌3), 塩田一路4)1)金属材料技術研究所　305-0047　茨城県つくば市2)新潟大学　大学院生　950-2181　新潟県新潟市3)東京都立大学　192-0397　東京都八王子市4)工学院大学　192-0015　東京都八王子市 I.A.Nishida 1), Y.Imai 1), Y.Shinohara 1), M.Hashimoto 2), H.T.Kaibe 3) and I.Shiota 4)1) National Research Institute for Metals, Tsukuba, Ibaraki, 305-0047, Japan 2) Niigata University, Grad., Niigata, Niigata, 950-2181, Japan 3) Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan 4) Kogakuin University, Hachioji, Tokyo, 192-0015, Japan  The stoichiometric lead and tin tellurides, and their solid solution were prepared by a rocking-freezing furnace with rocking cycle of 0.2Hz. The lead and tin tellurides were n- and p-type semiconductors, respectively. For Pb1-xSnxTe solid solution, it was found to be a p-type conduction in the range of x is greater than 0.10, and the temperature having a maximum figure-of-merit shifted to higher side with increasing x. A segmented thermoelectric material of Pb1-xSnxTe with different x was prepared by liquid phase diffusion bonding under 2.0MPa at 700K for 1800s in an Ar atmosphere. The segmented material was the most primitive FGM structure. The bonding was strong enough and the electrical resistance at the interface was very low. The segmented material showed a higher effective maximum power Pmax than each monolithic material above the temperature difference delta T of 260K. The Pmax for the segmented material agreed with the theoretically expected result from the properties of monolithic materials and is 28Wm-1 at delta T=330 K. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 51-56 傾斜SiGe熱電素子の性能評価 Performance Evaluation of Graded SiGe Thermoelectric Conversion Units ○宮本欽生1)、林君山1)、郭麗斌1)、柴田賢朗2)、山口修2)、康燕生3)、新野正之3)1)大阪大学　接合科学研究所　567-0047　大阪府茨木市美穂ケ丘2)同志社大学　工学部　610-0321　京都府京田辺市多々羅3)航空宇宙技術研究所　981- 1525　宮城県角田市 Y.Miyamoto 1), J.S.Lin 1), L.Guo 1), K.Shibata 2), O.Yamaguchi 2), J.S.Kang 3), N.Niino 3)1)Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047, Japan 2)Faculty of Engineering, Doshisha University, Kyoutanabe, Kyoto 610-0321, Japan 3)National Aerospace Laboratory, Kakuda Researeh Center, Kakuda-shi, Miyagi 981- 1525, Japan  Dense SiGe thermoelectric conversion units with graded electrodes and dopants of n-type phosphorus and p-type boron were prepared in one step by glass encapsulation HIP. The graded n-type SiGe showed the higher power factor than the homogeneously doped ones. The highest output power of the graded n-type SiGe unit reached to at least two times higher than the homogeneously doped units. However, no such high performance was observed for the graded p-type SiGe unit. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 57-62 PbTe系熱電素子の出力特性 Power Output Characterization of Pb-Te thermoelectric device 折橋正樹1)、野田泰稔2)、陳立東1)、康燕生3)、新野正之3)、平井敏雄1)1)東北大学　金属材料研究所　980-8577　宮城県仙台市青葉区片平２丁目１－１2)島根大学　総合理工学部　690-8504島根県松江市3)航空宇宙技術研究所　角田宇宙推進技術研究センター　981-1525　宮城県角田市君萱小金沢１ Masaki Orihashi(1), Yasutoshi Noda(2), Lidong Chen(1), Yan-sheng Kang(3), Masayuki Niino(3) and Toshio Hirai(1)(1)Institute for Materials Research, Tohoku University, 2-1-1 , Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan (2)Faculty of Science and Engineering, Shimane University, Matsue, Shimane 690-8504, Japan (3)National Aerospace Laboratory, Kakuda Research Center, Koganezawa 1 , Kimigaya, Kakuda, Miyagi 981-1525, Japan  In order to fabricate PbTe thermoelectric element, Ni electrodes were joined with n-PbTe and p-Pb0.5Sn0.5Te by plasma activated sintering (PAS). The characterization of the Ni/n-PbTe and Ni/p-Pb0.5Sn0.5Te junctions was carried out by measuring voltage distribution around the joint boundary. No potential voltage gap was found at the interface of Ni/n-PbTe joint, while a large potential gap was found at the interface of Ni/p-Pb0.5Sn0.5Te joint. A buffer layer of p-SnTe was introduced into the Ni/p-Pb0.5Sn0.5Te joint to reduce the interface resistivity between Ni and p-Pb0.5Sn0.5Te. Low resistivity joint of metal/semiconductor was obtained by insertion of p-SnTe between Ni and p-Pb0.5Sn0.5Te. Thermoelectric (TE) device of pi shape was fabricated. Power output of the TE device was estimated at 85mW under the large temperature span delta T =240 K. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 63-69 SiGe熱電半導体/炭素電極接合体の高温長時間暴露による寿命評価 SiGe/Electrode Response to Long-Term High-Temperature Exposure 長谷崎和洋1)、佃洋1)、山田明1)、中島昭二2)、康燕生3)、新野正之3)1)三菱重工業(株)長崎研究所2)三菱重工業(株)長崎造船所3)科学技術庁　航空宇宙技術研究所　角田宇宙推進技術研究開発センター K. Hasezaki 1) H. Tsukuda 1) A.Yamada S. Nakajima 2) Yangsheng Kang 3) M. Niino 3)1) Nagasaki Research & Development Center, Mitsubishi Heavy Industries, Ltd 2) Nagasaki Shipyard & Machinery Works, Mitsubishi Heavy Industries, Ltd 3) Kakuda Reserch Center, National Aerospace Laboratory, Japan  Joints between a n-type Si0.8Ge0.2 (P 0.3atomic%) thermoelectric semiconductor and carbon electrodes were prepared by hot-pressing with thin sheets of titanium foil inserted between them at 1523K in vacuum. The content of phosphorus, measured using an ICP ( Inductively Coupled Argon Plasma Emission Spectro-photometer), decreased from 0.20% to 0.11% after joined.       To evaluate the upper limit of heating dependence, the SiGe / carbon electrode was exposed in an argon atmosphere at 1273K and 1373K for 300 hours, after which the electrical resistance and Seebeck coefficient were measured. These results showed that the power factor ( alpha 2 sigma) could be effectively evaluated using the Larson-Miller Parameter ( C = 13.3 ).       SEM and EPMA observations showed the presence of many voids in the junction layer of the SiGe/ electrode after exposure. The titanium atoms were enriched in the junction layer, and started diffusing at over 1273K. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 71-76 ツインバーガー型熱電素子で構成される新型熱電モジュールの試作 Trial manufacture of a new-type thermoelectric module composed of thermoelectric elements of the 'twin-burger' type 丹治雍典1)、中川康昭2)、木皿且人1)、安岡督敏2)、森谷信一1)、熊谷達夫1)、新野正之1)、佐藤利三郎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）東北工業大学　工学部　982-0831　仙台市３）東北学院大学　工学部　985-8537　多賀城市 Yasunori Tanji 1),  Yasuaki Nakagawa 2), Katuto Kisara 1),  Masatoshi Yasuoka 2),  Shinichi Moriya 1), Tatuo Kumagai 1), Masayuki Niino 1) and Risaburo Sato 3)1) National Aerospace Laboratory, Kakuda Research Center, Japan, 981-1525. 2) Faculty of Engineering, Tohoku Institute of Technology, Sendai, Japan, 982-0831. 3) Faculty of Engineering, Tohoku Gakuin University, Tagajo, Japan, 985-8537.  Previously, we proposed a new-type thermoelectric module composed of the hamburger type elements and tried to realize the practical modules. In the present work, the new type module composed of the elements of 'twin-burger' type, one of the hamburger type, is assembled using a sealing wax sheet as the heat transmission medium. The generating properties of this module are measured and compared with those of the two kinds of the HZ-14 type modules using silicone grease or a sealing wax sheet as the heat transmission medium. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 77-83 FGM酸素添加金属コレクタの酸素供給能 Development of the Oxygenated Thermionic Energy Converters Utilizing the Sputtered FGM Metal Oxides as a Collector ○福田隆三、春日康弘、加藤健、清水定明電子技術総合研究所　305-8568茨城県つくば市梅園1-1-4 R. Fukuda, Y. Kasuga, K. Kato, S. SimizuElectrotechnical Laboratory, 1-1-4, Umezono, Tsukuba-City, Ibaraki 305-8568 Japan  Refractory metal oxides such as NbOx, WOx, MoOx, TaOx, PtOx and Silver oxide (AgOx) have been studied for an oxygenated thermionic converter and a low work function collector. A research thermionic energy converter with a plane parallel type of a polycrystalline W emitter and the metal oxide collectors (AgOx, NbOx and PtOx), was set up and the power generation experiments were conducted. In the case of the W-AgOx thermionic converter, the barrier index VB was 2.05V. Similarly VB=2.15V for the W-NbOx converter, VB=2.25V for the W-PtOx converter. The oxygen supply ability of the AgOx, NbOx, PtOx collectors were evaluated by the bare work function values phi o of the W emitter, for instance, phi o=5.4V for the W-PtOx converter. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 85-90 太陽エネルギー総合活用システムの検討 The examination of the solar energy total system 木皿且人1)、熊谷達夫1)、新野正之1)、湯上浩雄2)、多田保夫3)、中島昭二4)、長山博幸5)1)航空宇宙技術研究所　角田宇宙推進技術研究センター 981-1526 宮城県角田市2)東北大学　工学部　980-8579宮城県仙台市,　3)財団法人　航空宇宙技術振興財団　981-3133　宮城県仙台市4)三菱重工業株式会社　長崎造船所　851-0301　長崎市,5)株式会社　三菱総合研究所　100-8141　東京都千代田区 Katsuto KISARA 1) , Tatsuo KUMAGAI 1) , Masayuki NIINO 1) , Hiroo YUGAMI 2) Ysasuo TADA 3) , Shoji NAKAJIMA 4) , Hiroyuki NAGAYAMA 5)1) National Aerospace Laboratory, Kakuda Research center, Kakuda-shi, Miyagi 981-1526, Japan 2) Tohhoku University, School of Engineering, Sendai-shi, Miyagi 980-8579,Japan 3) Foundation for Promotion of Japanese Aerospace Technology, Sendai-shi. Miyagi 981-3133, Japan 4) Mitsubishi Heavy Industries. LTD. Nagasaki Shipyard & Machinery Works, Nagasaki-shi, 851-0301 ,Japan 5) Mitsubishi Research Institute,Inc. Chiyoda-ku,Tokyo 100-8141, Japan  Now, the problem of the whole world of the earth warming happens. Then, new saving energy technology became necessary to cope with that problem. Therefore, it is hoping for the development of the energy system such as solar power generator. We have done research about the new energy conversion material and that application system since 1992 until 1998. This report is the new concept that solar energy is changed into the light, the heat and the electric power and used efficiently. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 91-96 傾斜機能熱電変換材料及び素子の最適設計 Optimal design of functionally graded thermoelectric materials and modules 平野徹、寺木潤一、○西尾好正ダイキン工業(株)　MEC研究所　305-0841　茨城県つくば市 J. Teraki, Y. Nishio and T. HiranoDaikin Industries Ltd., MEC Laboratory, Tsnkuba, Ibaraki 305-0841, Japan  Based on the simulations of the thermoelectric materials and their devices, we have established the design procedure of the thermoelectric generator consisted of functionally graded materials (FGM generator). By using this design procedure the optimal efficiency of the ideal 3-stage cascaded FGM generator, whose working temperature range is from 300K to 1100K, is estimated to be 18%. At the same tine the optimal distribution of graded impurities and the optimal device dimension of the cascaded FGM generator has been calculated explicitly. We also develop a new FGM design of the highly efficient thermoelectric material by utilizing the multilayered structure with graded barrier layers. The transport propeties of the multilayered material is roughly estimated and the maximum ratio of the dimensionless figure of merit between bulk and multilayered material is expected to be 1.8. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 97-103 熱電子発電器エミッタとしてのRe/W/MoおよびIr/W/Ta傾斜構造における熱応力 Thermal stress in graded Re/W/Mo and lr/W/Ta structures for emitters of thermionic converter 加藤昌宏, 堀田秀和, 五十嵐廉東京タングステン(株)　931-8543　富山県富山市 Masahiro Katoh, Hidekazu Horita and Tadashi IgarashiTokyo Tungsten Co. Ltd., Toyama-shi, Toyama 931-8543, Japan  Elastic thermal stresses of Re/W/Mo and Ir/W/Ta graded structures in emitters for thermionic converters were analyzed by the axisymmetric finite element method. axisymmetric axial principal stress and shear stress in the graded structures were simulated by raising the temperature from 300 K to 1800 K. Young's modulus and the shear modulus, and the thermal expansion coefficient of Re-W alloys and Ir-W alloys were measured by the natural frequency method from 300 K to 1270 K and the differential detection method at 1120 K, respectively. The maximum axial tensile stress periphery at the interface of the 50-micro meter-thick Re layer and W, which has direct effect on peeling of the Re layer, decreased to 274 MPa from 671 MPa upon inserting the 40-micro meter-thick Re/W graded layer. The tensile stress periphery at the interface of the 2.5-mm-thick Ir layer and W decreased to 319 MPa from 406 MPa upon inserting the 250-micro meter-thick Ir/W graded layer. It was revealed that the micro graded structure with comparable thickness of the coated layer can decrease the thermal stresses. The maximum axial principal stresses around the W/Mo and W/Ta interfaces with and without graded structure were both small. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 105-110 Bi2Te3/PbTe FGM熱電材料の特性 Properties of Bi2Te3/PbTe FGM Thermoelectric Materials ○工藤康全1)、橋本政靖2)、腰越美営3)、塩田一路3)、西田勲夫4)1)工学院大学　大学院　163-8677　東京都新宿区2)新潟大学　大学院　950-2102　新潟県新潟市3)工学院大学　192-0015　東京都八王子市4)金属材料技術研究所　305-0047　茨城県つくば市 Y.Kudo 1), M.Hashimoto 2), M.Koshigoe 3), I.Shiota 3), I.A.Nishida 4)1)Kogakuin University Grad., Shinjuku, Tokyo 163-8677, Japan 2)Niigata University Grad., Niigata, Niigata 950-2102, Japan 3)Kogakuin University, Hachioji, Tokyo 192-0015, Japan 4)National Research Institute for Metals, Tsukuba, Ibaraki 305-0047, Japan  The objective of this paper is expanding the high performance temperature range of thermoelectric materials by forming an FGM structure. As is known, a thermoelectric material shows a high efficiency at a specific temperature range, and the area below the ZT curve means the capability to generate electricity. Then the capability can be improved when the area below the ZT curve is expanded.      In this experiment, n-type Bi2Te3 for low temperature range and n-type PbTe for middle temperature range were soldered with Te-67Ag eutectic alloy (m.p.624K) to form an FGM structure. Two kinds of FGM with different ratio of Bi2Te3 to PbTe length were prepared. One was the ratio of Bi2Te3: PbTe of 1:1 and the other was 2:3. It was found that each FGM showed larger power factor values, alpha 2/rho , than both homogeneous materials at the hot side temperature range between 400K and 650K. The hot side temperature was gradually raised at the rate of 10K/min. and was controlled not to excess 520K at the joined part, Tm, which was 100K lower than the melting point of the solder.      After the joined part reached to 520K, the FGM sample was cooled down to R.T.. When the sample was heated again at the same heating rate, the thermoelectromotive force E0 was not recognized, which was completely different from the first time heating. It was found that PbTe side of FGM changed from n-type to p-type. This phenomenon was not caused when Tm=500K. When Tm was kept at 520K for over 180min., thermoelectromotive force E0 did not change so much. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 111-114 PbTe薄膜の作製とその熱電気的特性 Preparation of PbTe films and their thermoelectric properties 岸本堅剛、塚本昌義、小柳剛山口大学　工学部　755-8611　山口県宇部市 K. Kishimoto, M. Tsukamoto, and T. KoyanagiFaculty of Engineering, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan  Films of n-type PbTe doped with PbI2 were prepared on fused quartz substrates by rf sputtering. They have larger Seebeck coefficients than bulk alloys with the same carrier concentration. The temperature dependence of the Seebeck coefficient for sputtered films and bulk alloys also exhibit significant differences. The difference in Seebeck coefficient between films and bulk is explained by the potential barrier scattering at grain boundaries of the films. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 115-118 気相成長法によるn型PbTe単結晶の結晶成長と熱電特性 Crystal growth and thermoelectric properties of an n-type PbTe single crystal grown by gas phase transport 大杉功1), 米田征司2), 太田英二3), 海部宏昌4), 宮元克徳5), 塩田一路6), 西田勲夫7)1)育英工業高等専門学校　167-0021　東京都杉並区2)慶応義塾大学　大学院理工学研究科　神奈川県横浜市3)慶応義塾大学　理工学部　神奈川県横浜市 4)東京都立大学　工学部　東京都八王子市5)工学院大学　大学院工学研究科　東京都八王子市6)工学院大学　工学部　東京都八王子市, 7)金属材料技術研究所　305-0047茨城県つくば市 I.J. Ohsugi 1), S. Yoneda 2), E. Ohta 3). H.T. Kaibe 4), K. Miyamoto 5), I. Shiota 6), I.A. Nishida 7)1)Salesian Polytechnic, Suginami-ku, Tokyo 167-0021 , Japan 2)Keio University. Graduate School, Yokohama-shi, Kanagawa , Japan 3)Keio University, Yokohama-shi, Kanagawa, Japan 4)Tokyo Metropolitan University. Hachioji-shi. Tokyo, Japan 5)Kogakuin University, Graduate School. Hachioji-shi, Tokyo. Japan 6)Kogakuin University. Hachioji-shi. Tokyo. Japan 7)National Research Institute for Metals, Tsukuba-shi, Ibaraki 305-0047, Japan  An attempt was made to grow a single crystal of n-type PbTe heavily doped with PbI2 in order to establish a standard of thermoelectric properties for thermoelectric materials in FGM structure. A crystal of about 20 mm in diameter was grown by gas phase transport. X-ray diffraction experiments and thermoelectric measurements were made to evaluate the crystal grown in this work. It was found that the grown crystal is a high quality single crystal of PbTe with a carrier concentration useful for practical applications. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 119-126 傾斜機能材料による熱電子発電器の開発 Development of Thermionic Energy Converter with Functionally Graded Materials 加藤寿仁 1), 森本清水 2), 礒貝和博 1)1) 三井造船（株）　290-8601　千葉県市原市 2) （株）三造試験センター　290-8601　千葉県市原市 1) Mitsui Engineering & Shipbuilding Co. Ltd., Chiba Technology Center, lchihara-shi, Chiba 290-8601, Japan 2) MES Testing & Research Center Co. Ltd., Tobu Works, lchihara-shi, Chiba 290-8601, Japan  Thermionic energy conversion is a method for generating electricity directly from heat energy. It does not require any mechanical rotary motion or fluid circuit.      A solar heated thermionic energy converter used as the power source of space investigation purposes has been developed by applying functionally graded materials, FGM, in order to improve both high temperature endurance capability and energy conversion performance. The converter is mainly composed of a TiC/Mo-FGM solar receiver, a Re/W/Mo-FGM emitter electrode, and an Oxygen-containing Nb collector electrode. Another type of converter with Ir/W/Mo-FGM emitter electrode is also developed for further improvement of energy conversion efficiency.       The converters are tested in an experimental measuring apparatus which has an electron bombardment heating system, then the designed value of output power density 8W/cm2 is obtained at the emitter temperature of 1840K. The tested converters prove to have sufficient endurance capability in its various aspects, such as heat resistance, vacuum sealing, and electrical insulation. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 127-131 フェライト/金属傾斜機能材料の作製および電磁気特性 Fabrication of Ferrite/Metal Functionally Graded Materials and their Electromagnetic Properties 平塚信之、○山崎武志、柿崎浩一、小林秀彦埼玉大学　大学院理工学研究科　338-8570　埼玉県浦和市 Nobuyuki Hiratsuka, Takeshi Yamazaki, Kouichi Kakizaki and Hidehiko KobayashiSaitama University, Graduate School of Science and Engineering, Urawa, Saitama 338-8570 Japan  Ferrite/Metal functionally graded materials were fabricated by sintering at 600-900deg.C for 5hours under N2 gas flow. NiFe2O4 was selected as ferrite and Fe-Ni alloy was selected as metal. These powders were synthesized by coprecipitation of FeCl2, NiCl2 and (NH4)2C2O4, and thermal decomposition. Green bodies were provided by grading the composition of ferrite and metal. Two phases of NiFe2O4 and Fe-Ni were produced in bulk sintered below 800deg.C. The samples sintered at 900deg.C however contained non-magnetic FeO besides these two phases. The bulk density depended on Fe-Ni alloy content. Sintering behavior of bulks was nearly similar, in spite of gradient of composition of ferrite and metal. Magnetic characteristics of Ferrite/Metal functionally graded materials were moderate between these of ferrite and metal. In comparison with the sample mixed ferrite and metal, it had higher initial permeability and gradual decline of that above frequency of 10kHz. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 133-138 放電プラズマ焼結法によるCu/Al2O3/Cu対称型コンプライアントパッドの作製 Fabrication of Cu/Al2O3/Cu Symmetric Functionally Graded Material 尾関健 1), 大塚愛子 1), 川崎亮 2), 渡辺龍三 2)1)東北大学　大学院　980-8579　宮城県仙台市、2)東北大学　大学院工学研究科　980-8579　宮城県仙台市 Takeshi Ozeki 1), Aiko Ohtuka 1), Akira Kawasaki 2), Ryuzo Watanabe 2)1) Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan  2) Tohoku University, Department of Materials Processing, Sendai, Miyagi 980-8579,Japan  Thermoelectric (TE) power conversion system has been focused as a candidate of direct energy conversion systems from nuclear energy source to meet the various power requirements next century. To achieve high thermal energy density in TE power convention systems, conductivity coupling the TE module to the hot and cold heat exchangers is the most effective configuration. This is accomplished by FGM compliant pad. This pad demands (1) a high flux, direct conduction path to heat source and heat sink, (2) the structural flexibility to protect the cell from high stress due to thermal expansion, (3) electrical insulation, (4) an extended durability by a simple FGM structure. In this paper, densification of Copper-Alumina powder mixture by SPS, thermal conductivity data for a series of Cu-Al2O3, optimization of thickness of FGM layer by one dimensional analysis and the process of manufacturing copper/alumina/copper symmetry FGM was discussed. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 139-142 結晶性高分子/非晶性高分子系傾斜機能ブレンドの作成とその特性 Preparation and Properties of Crystalline Polymer/Non-Crystalline Polymer Functionally Graded Blend ○上利泰幸1)、島田雅之1)、野村良紀2)、川崎吉包2)1)大阪市立工業研究所　536-0025　大阪府2)大阪工業大学　535　大阪府大阪市旭区大宮 ○ Y. Agari 1), M. Shimada 1),  R. Nomura 2),  Y. Kawasaki 2)1) Osaka Municipal Technical Research Institute, Osaka 536-0025, Japan 2) Osaka Institute of Technology,Ohmiya, Asahi-ku, Osaka535, Japan  We prepared and characterized crystalline polymer/non-crystalline polymer functionally graded blends, that is, polycaprolactone(PCL) /polyvinyl chloride(PVC) and polyethylene oxide(PEO)/polymethyl methacrylate(PMMA) functionally graded blends and found that the PEO/PMMA graded structure decreased the dissolution rate in water and suppressed perfectly the warp in comparison with 2 layers system. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 143-148 微視力学アプローチによるFGM平板の熱応力解析法(クリープ,界面拡散を考慮) Analysis of thermal stresses in a FGM plate based on a micromechanical approach (Consideration of creep and interfacial diffusion) 塚本英明東京工業大学　精密工学研究所　横浜市 Hideaki TsukamotoTokyo Institute of Technology, Precision and Intelligence Lab., Yokohama-shi  In this paper, an analytical method of thermal stresses in functionally graded materials (FGMs) is developed. To begin with, a constitutive equation describing the thermomechanical behavior of a two-phase composite system under multiaxial loadings is formulated on the basis of a mean-field micromechanics theory, taking account of time-dependent inelastic deformation, that is creep. This equation, expressed in a piecewise-linear form, can be linked to structual analysis without difficulty. Next, by way of example an analytical procedure for predicting transient thermal stresses in a ceramic-metal FGM plate with spherical particles subjected to a unidirectional heat flow through the thickness is presented in consideration of not only creep but also interfacial diffusion between ceramic phase and metal one, to which the constitutive relation above and the classical laminated plate theory are applied. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 149-154 FGM用CVD-SiCのIS法による非破壊評価 Non-destructive Evaluation of CVD-SiC for FGM by Impedance Spectroscopy 若松義男1), 庄子哲雄2), 小川和洋3), 小野文衛1)1)航空宇宙技術研究所　981 -1525　宮城県角田市, 2)東北大学　大学院工学研究科 980-8579　宮城県仙台市　3)東北大学　大学院工学研究科博士課程　980-8579　宮城県仙台市 1) National Aerospace Laboratory, Kakuda Research Center, Kakuda-shi, Miyagi 981 -1525, Japan 2) Tohoku University, Graduate School, Sendai-shi, Miyagi 980-8579, Japan 3) Tohoku University, Graduate School, Doctoral Course, Sendai-shi, Miyagi 980-8579, Japan  Non-destructive Evaluation by an impedance spectroscopy method was studied to apply it to the inspection of CVD-SiC for FGM C/C composites. It was made clear that the contact pressure of more than 40 kg/cm2 was recommended to obtain good reappearance data. A high compliance material such as rubber was proved suitable for electrodes of a probe. The linear relationship between the thickness of the SiC and the impedance was confirmed. It was found that the impedance should be measured at fixed point because the SiC plate had a non-uniform distribution of specific resistance and that the specific resistance of the SiC decreased after heating. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 155-160 TiC/Mo系溶射皮膜の高温特性 High Temperature Properties of TiC/Mo Thermal Sprayed Coatings 福島孟、黒田聖冶金属材料技術研究所　茨城県 T.Fukushima, S.KurodaNational Research Institute for Metals, Tsukuba, Ibaraki, Japan  Formation of graded coatings (FGM) was carried out with the thermal spraying method in air. TiC and Mo powder (particle size: 10 to 44 micro meter) were sprayed on to Mo substrate to obtain coatings with high thermal absorptive in order to improve the performance of the thermionic conversion materials.      The thermal stabillity and wavelength absorptiveness and so on by heat treatment in a vacuum up to 2000K of obtained coatings were investigated.      The results are summarized as follows.      1) Even after the heat treatment of the sprayed coatings in vacuum ( up to 2000K, 100h, 10**(-4)Pa). There are recognizable reaction products (Ti2O3) between TiC and Mo in the coatings.      2) Energy absorption rate of each coatings are indicated above 75%.      3) FGM coating maintain sound for thermal cycle test in vacuum up to 2000K. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 161-166 傾斜機能化耐酸化膜の検討 Study on the Coating of Oxidation Resistant Layer with FGM 山田康雄、下島康嗣名古屋工業技術研究所　462-8510愛知県名古屋市北区平手町 Y.Yamada, K ShimojimaNational Industrial Research Institute of Nagoya(NIRlN)  Hirate-cho, Kita-ku, Nagoya 462-8510, Japan  Molybdenum is one of refractory metals and is a good material at high temperatures. However, it is difficult to use over 700K because of its poor resistance to oxidation. Thus, it is inevitable to introduce a protective surface layer with an oxidation-resistant material such as silicides or aluminides of refractory metals when it is used in oxidizable surroundings at high temperature. MoSi2 is expected to be used as the protection layer since it shows excellent resistance to against oxidation in hot air at temperatures above 2000K. When MoSi2 is used as the surface layer, cracks would form between the metal matrix and surface layer because of the difference of coefficients of thermal expansion between MoSi2(8.56 x 10**(-6)/K) and Mo(5.6 x 10**(-6)/K).      In this paper, the protection layer, which consists of multiple layers with gradient compositional rate, was prepared and tested. A Mo/MoSi2 material with multiple layers was fabricated by Plasma Activated Sintering (PAS) and Self-propagating High-temperature Synthesis (SHS). As a result, samples that have good relaxation of thermal stress can be obtained by this method. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 167-172 Fly ashを用いた厚手傾斜機能材料の製作 Manufacturing of large-thickness functionally graded materials using fly ash 山本孝生、田口広宣、渡辺茂男、内田悦行、林二一愛知工業大学 T. Yamamoto,H. Taguchi,S. Watanabe,Y. Uchida,N. HayashiAichi Institute of Technology  This paper presents an attempt to manufacture large-thickness functionally graded materials (FGMs) by means of a solid-liquid separation technique using a vacuum filtration method. The two base materials used ferric oxide and fly ash. It sintered this material which was manufactured with this new technique at the electric furnace or gas furnace. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 173-178 圧縮処理を施した防・耐火木質材料の傾斜機能性 The fire retardance and endurance of functionally graded wood after heat compressed treatment ○月東秀夫1), 石原茂久2)1)アイカ工業（株）研究開発部門　490-1112　愛知県海部郡2)京都大学　617-0824　京都府長岡京市 ○ H. Getto,S. Ishihara1)Aica Kogyo Co.,Ltd., R&D Division, Ama-gun, Aichi, 490-1112, Japan 2)Kyoto University, Nagaokakyo-shi, Kyoto, 617-0824, Japan  The behavior of the wood after heat-compressed treatment was evaluated. Fire retardance and endurance of wood treated with basic nitrogen compounds and phosphoric acid were much improved by a compressing with a hot press. By this way, the concentration of chemicals content and the density of wood were increased at the surface of the treated wood and the total specific gravity of the wood was also increased. It was recognized that increase of specific gravity improved fire retardance and endurance, especially increase of specific gravity of wood surface. Wood treated with chemicals showed a high limiting oxygen index in proportion to increase of loading of chemicals regardless of treatment method, and high fire endurance was not always accompanied by high limiting oxygen index. High concentration of chemicals at the surface and high density due to compression are essential for high fire endurance. Then graded concentration of chemicals is effective to improve the fire endurance without increasing the cost for the treatment. Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 179-184 三角形断面を有するシュロ枝の力学的特性 Bending and Torsion of Hemp Palm-Branch with Triangular Section and Functionally Graded Structure 天田重庚1)　寺内奏2)1)天田重庚、群馬大学　群馬県桐生市天神1-5-12)寺内奏、群馬大学大学院 1)Sigeyasu AMADA,2)Yasusi TERAUCHI1)Sigeyasu AMADA,Gunma University, 1-5-1 , Tenjin, Kiryu, Gunma 2)Yasusi TERAUCHl, Gunma University; Graduate School  Hemp palm branch with a triangular cross-section is discussed in this report based on a functionally graded structure and a composite material. Assuming that hemp palm branch consists of a bi-components (fiber and parencyma) structure, the Young's modulus and tensile strength were evaluated on each components by tensile tests, and the fiber distribution in cross-section was evaluated by using image analysis.      A very high Young's modulus and tensile strength of the fiber were obtained as compared with parenchyma. It was concluded that the triangular cross-section of the hemp palm branch could reduce the maximum bending stress and the fiber distribution corresponds to stress distribution under bending or tortional loadings.       Japanese 1998年度　傾斜機能材料論文集＜ＦＧＭ’98＞ FY 1998  Proceedings of Functionally Gradient Materials <FGM'98>  13 1999-06-25 185-188 FGMデータベースの有効活用手法について The way of useful use for the FGM database 木皿且人、康燕生、新野正之、毛呂明夫航空宇宙技術研究所　角田宇宙推進技術研究センター 981-1525　宮城県角田市 Katsuto Kisara. Kang yangsheng, Masayuki Niino, Akio MoroNational Aerospace Lab., Kakuda Research Center, Kakudashi,Miyagi 981-1525, Japan  The FGM project was enforced for 10 years from 1987, and, many FGM data were collected with that project. We should use FGM-data effectively. National project for the FGM was finished, then FGM-data is managed in the FGM forum which has supported a project. That forum construct the imaginary data base center on the Internet and, that center is managed with that forum, and, that promotes the internationalization of FGM proposed in Japan. And it is the center of the overall information of FGM, and, the center exchanges information of the FGM research database at the other countries and each other. Like this, we make the most of intellectual property by the international cooperation effectively. Japanese