摘要
研究了Si-B4 C复合抗氧化剂对MgAlON材料高温氧化行为的影响。通过对氧化后试样脱色层的厚度、相组成、氧化产物中尖晶石相的晶格常数及显微结构的研究发现 ,该复合抗氧化剂能显著改善MgAlON材料的高温抗氧化性能。抗氧化机理在于 :在相对较低的温度 (1 1 0 0℃以下 )下 ,SiO2 和B2 O3作用形成低粘度、低挥发性、低氧扩散系数的硼硅酸盐玻璃而有效地封闭气孔和裂纹 ;在较高温度下 ,硼硅酸盐玻璃中的SiO2 和B2 O3又能和MgAlON氧化产物中的α Al2 O3作用 ,形成由莫来石和Al18B4 O33构成的致密氧化物层 。
The effect of Si-B 4 C composite antioxidant on high temperature oxidation behavior of MgAlON was investigated. The results which obtained from the study of thickness of the discolor layer phase composition, lattice parameters of spinel in the oxidation products and microstructure of oxidized specimens show that the composite antioxidant can remarkably improve oxidation resistance of MgAlON at high temperature.It might be ascribe to two facts: one is the formation of borosilicate glass from oxidation products(SiO 2 and B 2 O 3 ) of antioxidants during oxidation at relative low temperature(below 1100 ℃),the glass, featured by low viscocity,low volatility and oxygen diffusion coefficient,can seal pores and cracks efficiently. Another fact is the formation of dense oxide layer mainly composed of mullite and Al 18 B 4 O 33 at higher temperature which acts as a barrier for oxygen diffusion.
出处
《耐火材料》
CAS
北大核心
2004年第3期145-147,共3页
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