| Project/Area Number |
62430014
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属精錬・金属化学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
SAITO Yasutoshi TOKYO INSTITUTE OF TECHNOLOGY, RESEARCH LABORATORY OF ENGINEERING MATERIALS, PROFESSOR, 工業材料研究所, 教授 (40005236)
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| Co-Investigator(Kenkyū-buntansha) |
MARUYAMA Toshio TOKYO INSTITUTE OF TECHNOLOGY, FACULTY OF ENGINEERING, ASSOCIATE PROFESSOR, 工学部, 助教授 (20114895)
ATAKE Tooru TOKYO INSTITUTE OF TECHNOLOGY, RESEARCH LABORATORY OF ENGINEERING MATERIALS, ASS, 工業材料研究所, 助教授 (30028229)
伊藤 義孝 東京工業大学, 工業材料研究所, 助手 (70016822)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥29,000,000 (Direct Cost: ¥29,000,000)
Fiscal Year 1989: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1988: ¥8,500,000 (Direct Cost: ¥8,500,000)
Fiscal Year 1987: ¥18,200,000 (Direct Cost: ¥18,200,000)
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| Keywords | Heat-resisting alloys / High temperature oxidation / Oxide scales / Rare earth effect / Keying-on structure / High temperature corrosion / Pre-oxidation / 高温耐酸化性 / 酸化挙動 / 酸化速度 / 希土類元素添加効果 / 保護性皮膜 / 密着性 / ペロブスカイト型酸化物 |
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| Research Abstract |
In this research, high temperature corrosion of heat-resisting alloys was studied with an emphasis on the effect of rare earth elements.
Alloying additions of Y, Ce, La, Er, and superficial application of Y_2O_3, La_2O_3 and CeO_2 to Ni-20Cr-lSi alloys were found to decrease the mass gain of the alloy and increase Cr_2O_3 scale adherence during isothermal and cyclic oxidation, respectively. A mechanistic model based on the high oxygen diffusivities of the rare earth-oxides, was proposed to explain the effect of these additions on the growth mechanism and adherence of Cr_2O_3. A similar improvement in scale adherence was found in the case of Ni-20Cr-3Al alloys on which thin CeO_2 layers were deposited by vacuum evaporation. This superficial layer was observed to change the growth mechanism of the Cr_2O_3 scale and promote internal oxidation of aluminum.
High temperature corrosion of heat-resisting alloys such as SUS 310 and SUS 430 were studied in sulfur, bromine and water vapor-containing environments. In sulfur and bromine-containing gases, formation of a thick, compact oxide scale was found necessary to prevent extensive corrosion of the alloy by forming sulfates or gaseous bromides at the scale/alloy interface. A high concentration of water vapor in the environment was observed to increase the isothermal oxidation rate of SUS 430 at temperatures around 900 K.
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