热处理气氛对SiBON陶瓷材料析晶行为的影响

熔融石英陶瓷在使用过程中的析晶现象一直备受关注。采用XRD、SEM、FT-IR、XPS分析手段研究了SiBON陶瓷物相结构、表面形貌、化学键存在形式对其析晶行为的影响。结果表明,SiBON陶瓷在氮气保护条件下经1 550 ℃烧结后仍可有效抑制方石英的析出,同一温度在真空气氛下烧结制成的样品抑制析晶效果不佳。SiBON陶瓷的物相组成为非晶SiBON、Si₃N₄、BN,抑制析晶机理为B、N元素的掺杂使SiO₂中的Si—O—Si键转变为B—O—Si、Si—O—N键,由此生成的Si—B—O—N非晶结构提高了SiO₂的析晶活化能。

Effect of Heat Treatment Atmosphere on the Crystallization Behavior of SiBON Ceramic Materials

The crystallization phenomenon of fused silica ceramics in use has received much attention. In this paper, XRD, SEM, FT-IR and XPS were used to study the effects of phase structure, surface morphology and chemical bond on the crystallization behavior of SiBON ceramics. The results show that the precipitation of cristobalite can be effectively inhibited by sintering SiBON ceramics at 1 550 ℃ under the protection of nitrogen. In contrast, the crystallization inhibition effect of samples sintered at the same temperature in vacuum atmosphere is not significant. The phase composition of SiBON ceramics is amorphous SiBON, Si₃N₄, and BN. The mechanism of suppressing crystallization of SiBON ceramics is that the doping of B and N elements converts the Si—O—Si bonds in SiO₂ into B—O—Si and Si—O—N bonds, and the resulting Si—B—O—N amorphous structure improves the SiO₂ crystallization activation energy.