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ENVIRONMENTAL DURABILITY OF STRUCTURAL CERAMICS IN HIGH-PRESSURE AND HIGH-TEMPERATURE WATER VAPOR

结构陶瓷在高压高温水蒸气中的环境耐久性

基本信息

批准号：
08650998
负责人：
ODA Kohei
金额：
$ 1.54万
依托单位：
YONAGO NATIONAL COLLEGE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

The corrosion behavior and strength degradation of structural ceramics in high-temperature and high-pressure water vapor, which coexists with the high-temprtature and high-pressure water, have been studied. The porpose of this study is to clarify the corrosion reaction and the forms of corrosion for typical non-oxide and oxide ceramics in such environments, to evaluate the corrosion resistance and the environmental strength for these ceramics, and to present the suggestions for the material design and the material improvement.Silica glass and silicon carbide ceramics were used as the test samples.Corrosion tests were conducted hydrothermally in saturated water vapor at 300ﾟC for 1-10 d. The weight change before and after corrosion of the sample, XRD analysis of the surface for the corroded sample, the solution analysis by ICP-AES,SEM observation and EDX analysis of the corroded sample, and the fracture strength of the sample before and after corrosion by 3-point bending test, were measured.The following results were obtained.(1) Corrosion rates of silica glass and sic ceramics in saturated water vapor at 300ﾟC is higher than those in water.(2) Intergranular corrosion proceeded in the SiC ceramics by preferential attack at the grain boundaries.(3) The fracture strength of silica glass agter corrosion rised up with increasing duration time, because the viscosity of silica glass was reduced due to the permeation of water. The fracture strength of SiC ceramics after corrosion was reduced by about 80% of the initial strength.

研究了结构陶瓷在高温高压水蒸气中的腐蚀行为和强度退化。本研究的目的是阐明典型的非氧化物和氧化物陶瓷在这种环境中的腐蚀反应和腐蚀形式，评价这些陶瓷的耐腐蚀性和环境强度，以石英玻璃和碳化硅陶瓷为试验材料，在饱和水中进行了水热腐蚀试验在300 ℃下蒸发1-10 d。对腐蚀前后试样的重量变化、腐蚀后试样表面的XRD分析、ICP-AES溶液分析、腐蚀后试样的SEM观察和EDX分析以及腐蚀前后试样的三点弯曲断裂强度进行了测试。(1)石英玻璃和SiC陶瓷在300 ℃饱和水蒸气中的腐蚀速率高于在水中的腐蚀速率。(2)晶间腐蚀在SiC陶瓷中通过优先侵蚀晶界进行。(3)由于水的渗透使石英玻璃的粘度降低，腐蚀后石英玻璃的断裂强度随着腐蚀时间的增加而升高。腐蚀后SiC陶瓷的断裂强度降低了约80%的初始强度。