MoO_(3)含量对钙钛锆石基硼硅酸盐玻璃陶瓷的影响

Effect of MoO_(3)Content on the Zirconolite-based Borosilicate Glass-Ceramics

采用原位热处理制备了钙钛锆石基硼硅酸盐玻璃陶瓷,研究了不同MoO 3含量对钙钛锆石基硼硅酸盐玻璃陶瓷晶相、微结构和化学稳定性的影响。结果表明,随着MoO 3含量的增加,玻璃化转变温度略有升高。在不产生黄色第二相的条件下,所有样品的主晶相均为钙钛锆石。当MoO 3含量增加到4.88%(质量分数,下同)时,样品中出现了球状的钼钙矿晶相。然而,当MoO 3含量增加到7.14%时,玻璃陶瓷样品中出现了黄相。SEM结果说明MoO 3含量的增加使钙钛锆石晶粒尺寸减小、晶体数量增加,对钙钛锆石形貌和分布无明显影响。Mo元素主要分布在钼钙矿晶体中。在不产生黄相的情况下,所有玻璃陶瓷样品分布均匀,并且表现出良好的化学稳定性。对于CM0、CM2和CM4样品,Si、Ca、Mo元素的归一化浸出率在14 d时稳定在10^(-3)g·m^(-2)·d^(-1)量级,Ce元素的归一化浸出率在3 d时急剧下降并低至10^(-6)g·m^(-2)·d^(-1)量级。

A series of zirconolite-based borosilicate glass-ceramics were synthesized by in-situ heat treatment.The effects of MoO 3 content on crystalline phase,microstructure and chemical durability of the zirconolite-based borosilicate glass-ceramics were investigated.The results show that glass transition temperature increases slightly with increasing content of MoO 3.In the absence of the yellow phase,the main crystalline phase is zirconolite for all of the samples.When the content of MoO 3 up to 4.88wt%,spherical powellite crystals appear in the bulk of glass-ceramics.However,the glass-ceramic containing 7.14wt%of MoO 3 produced yellow phase.The SEM results show that the increase of MoO 3 content has effects on the grain size and the number,but has no significant effect on the morphology and distribution of zirconolite crystals.In the case of no yellow phase,all the glass-ceramic samples are evenly distributed with excellent chemical stability.For the CM0,CM2 and CM4 samples,the normalized leaching rates of Si,Ca and Mo of these samples stabilize at 14 days and is of the order of 10^(-3)g·m^(-2)·d^(-1)and the leaching rates of Ce stabilize after a sharp drop on the third day,and fell as low as 10^(-6)g·m^(-2)·d^(-1).