ENVIRONMENTAL DURABILITY OF SILICON NITRIDE-BORON NITRIDE COMPOSITES

氮化硅-氮化硼复合材料的环境耐久性

基本信息

批准号：
06650972
负责人：
ODA Kohei
金额：
$ 0.32万
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 General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

It is well known that Si_3N_4-BN composite materials are attracting considerable interest for a range of diverse applications such as components for automobiles to refractory nozzles, tubes, sliding gates, and break rings for the horizontal continuous casting of steel. It is important to investigate the high-temperature oxidation and the high-temperature high-pressure water corrosion of these composites because these materials are subject to corrosive attack in severe environments such as chemical engineering. The purpose of this project is to investigate the corrosion behavior of pressureless-sintered and reaction-bonded Si_3N_4-BN composite in pure oxygen and pure water at elevated temperatures. The results are discussed with respect to the microstructure of these materials. The high-temperature oxidation tests were conducted in pure oxygen at 900-1200ﾟC.The hydrothermal corrosion tests were conducted in an autoclave at 120-300ﾟC.The following results were obtained.(1) The high-temperature oxidation resistance and the hydrothermal corrosion resistance were mainly dependent on BN content, and the material with higher amount of BN had more poor oxidation and corrosion resistance.(2) The depression of further oxidation and corrosion due to the stable passive film which were made from silica and additives such as Y_2O_3 and Al_2O_3 was recognized in pressureless-sintered Si_3N_4-BN composite.(3) The high-temperature oxidation resistance and the hydrothermal corrosion resistance for reaction-bonded Si_3N_4-BN composite were superior to those for pressureless-sintered Si_3N_4-BN composite.

众所周知，Si_3N_4-BN 复合材料在一系列不同的应用中引起了人们的极大兴趣，例如汽车部件、水平连铸钢的耐火喷嘴、管道、滑动浇口和制动环，因此研究非常重要。由于这些材料在化学工程等恶劣环境中受到腐蚀，因此这些复合材料的高温氧化和高温高压水腐蚀的问题。研究了无压烧结反应粘结Si_3N_4-BN复合材料在纯氧和纯水中的高温腐蚀行为，并对这些材料在900℃的纯氧中进行了高温氧化试验。 -1200℃。在120-300℃高压釜中进行水热腐蚀试验，得到以下结果。(1)耐高温氧化性和耐水热腐蚀性主要取决于BN含量，BN含量越高，材料的抗氧化和耐腐蚀性越差。(2)由于钝化膜稳定，抑制了进一步的氧化和腐蚀。以二氧化硅为原料,添加Y_2O_3、Al_2O_3等添加剂,在无压烧结Si_3N_4-BN复合材料中得到了应用。(3)高温烧结反应烧结Si_3N_4-BN复合材料的抗氧化性和耐水热腐蚀性能均优于常压烧结Si_3N_4-BN复合材料。