摘要
将Al_2O_3-SiC-C系铁沟浇注料及分别添加 8% (质量分数)氮化硅、氮化硅铁的浇注料试样在空气中进行 1500℃ 3h热处理后,分别对氧化层进行形貌(SEM)及能谱分析(EDS),并结合热力学分析了氮化硅铁的防氧化行为:高温氧化气氛下,表面氮化硅铁中的Si3N4首先氧化生成SiO2,构成氧化层的主体;随着铁相材料的氧化,形成的氧化铁不但降低了氧化层的熔点,而且降低了熔体的粘度,增进熔体在材料表面上的润湿性及流动性,形成覆盖于材料表面的氧化层而阻止碳素氧化,使其具有比纯氮化硅更好的防氧化性能;另外,由于氮化硅铁在Al2O3 -SiC-C系材料中加入量少,而且试样内部的铁不是以氧化铁形式存在的,故对材料高温使用性能的影响不大。
Al2O3-SiC-C castables with 8% Si3N4 and 8% ferro-Si3N4 respectively were prepared for specimens and then were heated to 1500°C and held at this temperature for 3 h. The oxidation layer of the specimen after heat treatment was analyzed by XRD, SEM and EDS, and the anti-oxidation behavior of ferro-Si3N4 was analyzed with thermodynamics. The result shows that in high oxygen pressure, ferro-Si3N4 will be oxidized forming SiO2 as the mainly oxide film. And with the oxidation of Fe, the ferric oxide can not only lower the melting point of the oxidation film of the castable, but also reduce its viscosity, which improve the wetting property and flowability of the film composites and prevent carbon materials from oxidizing. So adding ferro-Si3N4 to the castable can improve the oxidation resistance of Al2O3-SiC-C castable more remarkedly than adding Si3N4, and the ferro-Si3N4 has not much bad effect on the high temperature properties of the Al2O3-SiC-C castable because of its low addition and the existing form of ferro being not ferric oxide.
出处
《耐火材料》
EI
CAS
北大核心
2005年第1期50-53,共4页
Refractories
基金
国家自然科学基金资助项目(50172007 )
国家自然科学基金重点基金资助项目(50332010)
