| Project/Area Number |
05555237
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学
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| Research Institution | YONAGO NATIONAL COLLEGE OF TECHNOLOGY |
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Principal Investigator |
HATTORI Makoto YONAGO NAT'l COLL.TECH,PRESIDENT, 校長 (30034416)
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| Co-Investigator(Kenkyū-buntansha) |
ODA Kohei YONAGO NAT'l COLL.TECH., DEPT IND.CHEM., ASSOCI.PROF., 工業化学科, 助教授 (90043611)
SAWA Hiroyuki YONAGO NAT'l COLL.TECH,DEPT IND.CHEM., PROF., 工業化学科, 教授 (60043593)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥7,300,000 (Direct Cost: ¥7,300,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Keywords | CERAMICS / GRADIENT INTERFACE / SURFACE MODIFICATION / AUTOCLAVE / NON-OXIDE / CORROSION RESISTANCE / STRUCTURAL MATERIAL / COMPOSITE |
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| Research Abstract |
It is well known that Si_3N_4 ceramics are readily susceptible to high-temperature oxidation and hydrothermal corrosion. Mullite and Si_3N_4 have very close coefficients of thermal expansion, suggesting a durable coating/substrate system can be made. In general, mullite shows better corrosion resistance to high-temperature oxidation and hydrothermal corrosion. The purpose of this project is to fabricate mullite coated Si_3N_4 ceramics and to characterize the oxide/nitride gradient nano-interface of the materials. Mullite coatings by using the hydrolysis of mixed alkoxides were applied to Si_3N_4 coupons and hydrothermally corroded Si_3N_4 coupons. The following resuls were obtained.
1.X-ray diffraction indicated mullite powders to be a single phase, which were prepared by the hydrolysis of mixed alkoxides route and heated at above 900ﾟC.
2.Mullite coatings on Si_3N_4 substrates can be successfully made by dipping in the mixed alkoxides solution. Coatings were approximately 30 to 80 mum thick on Si_3N_4 substrates after heating at 1300ﾟC.These materials have a oxide/nitride gradient interface at coating/substrate system.
3.Coatings showed good adherence to the Si_3N_4 substrates, but poor density. Because of these features, the fracture strength and vickers hardness were relatively low compared to Si_3N_4 ceramics.
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