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复合材料吸引了一系列潜水应用的考虑，例如汽车的组件，用于耐火喷嘴，管，滑动门和钢的水平连续铸件的断裂环。重要的是研究这些成分的高温氧化和高温高压水腐蚀，因为这些材料在化学工程等严重环境中受到腐蚀性攻击。该项目的目的是研究纯氧气和纯净温度下的纯氧气和纯净水中的无压力和反应键合的SI_3N_4-BN复合的腐蚀行为。讨论了这些材料的微观结构的结果。在900-1200 ﾟC中在纯氧气中进行了高温氧化物测试。在120-300 ﾟC中，在高压群体中进行了热热腐蚀测试。（1）获得以下结果。（1）高温氧化的耐药性和更高的抗热抗性均具有较高的抗性BN，并且具有较高的抗性BN含量，并具有较高的BN含量。（2）在无效的si_3n_4-bn复合材料中识别出由二氧化硅和Y_2O_3和Al_2O_3稳定的稳定膜和添加剂造成的进一步氧化和腐蚀的抑制。无压接的SI_3N_4-BN复合材料。