CaSiO_3复合添加剂对CaZrO_3~-Al_2O_3接触层抗Al_2O_3附着性能影响

骨料部分采用锆酸钙颗粒(粒度≤0.374 mm和≤0.147 mm),基质部分采用6%的α-Al_2O_3微粉,在基质部分分别加入2%、4%、6%、8%的CaSiO_3以及3% CaSiO_3-3% SiO_2、3% CaSiO_3-3% ZrSiO_4,经冷等静压成型、干燥后于1550 ℃,3 h烧成制得复合了CaSiO_3的CaZrO_3-Al_2O_3接触层,对接触层检测其显气孔率及体积密度,同时进行XRD及SEM分析,并建立抗附着模型对比了CaSiO_3复合添加剂对接触层抗Al_2O_3附着性能的影响.结果表明,随着CaSiO_3含量的增加,接触层的致密化程度先增加后减小,其促进CaZrO_3分解的程度变大,抗Al_2O_3附着的性能增强.在添加剂量相同的情况下,CaSiO_3复合添加剂抗Al_2O_3附着堵塞的效果要比单独加入CaSiO_3的好,其中CaSiO_3-SiO_2复合添加剂抗Al_2O_3附着堵塞的效果最佳.此外,CaSiO_3复合添加剂不仅可以细化CaZrO_3颗粒,而且使颗粒间结合更为紧密;颗粒越小,其晶界面积越大,CaZrO_3分解出的CaO沿晶界扩散就越快,从而与Al_2O_3反应的程度越大.

Influence of CaSiO_3 Composite Addition on Al_2O_3 Adhesion of CaZrO_3~-Al_2O_3 Contacting Layer

The contacting layers with CaZrO_3 as aggregate, 6% α-Al_2O_3 as matrix, and adding 2%, 4%, 6%, 8% CaSiO_3 and 3% CaSiO_3- 3%SiO2, 3%CaSiO_3-3%ZrSiO_4 into matrix respectively, were prepared under the process of cold isostatic compaction, and 1500 ℃sintering for 3 h in turn. The apparent porosity and bulk density of contacting layers were examined, and contacting layers were analysed by XRD and SEM; the effect of CaSiO_3 and its composite on the Al_2O_3 adhesion were studied by building adhesion model. The results show that with the content of CaSiO_3 increasing, the density increase first and then decrease, the degree of CaZrO_3 decomposition increase and the property of Al_2O_3 anti-clogging is enhanced. Under the condition of the same content of additive, CaSiO_3 composite are more effective than CaSiO_3 to prevent Al_2O_3 adhesion, and the effect of CaSiO_3-SiO_2 composite is most obvious. Besides, CaSiO_3 composite can not only refine CaZrO_3 aggregate, but also make the aggregate bind more dense. The smaller the aggregate is, the bigger the square of grain boundary is, which promote CaO decomposed by CaZrO_3 to diffuse along the grain boundary more quickly, resulting in increasing of the degree of reaction between CaO and Al_2O_3.