氧化铋对低温燃烧合成堇青石粉相变和烧结性能的影响

Effect of Bismuth Oxide on Phase Transformation and Sintering Characteristics of Cordierite Powder by Low-Temperature Combustion

为研究Bi2O3在堇青石基微晶玻璃烧结过程中的作用及其添加量对微晶玻璃相转变和烧结性能的影响,以硅酸、硝酸铝、硝酸镁为原料,尿素为燃料,用低温燃烧法制备了具有不同Bi2O3含量的堇青石基微晶玻璃,并对其进行了X射线衍射分析、显微分析和能谱分析.结果表明:添加Bi2O3能明显促进μ-堇青石向α-堇青石的相转变或促进α-堇青石相直接析晶,降低α-堇青石相的析出温度(由1 050℃降至900℃),有效促进微晶玻璃的烧结致密化;Bi2O3的添加量以质量分数5%左右为宜.此外,介绍了一种简便快捷地制备堇青石基微晶玻璃的新方法.

Cordierite-based glass ceramics containing different amounts of Bi2O3 were prepared by low-temperature combustion technique, where silicic acid, magnesium nitrate and aluminium nitrate served as materials, and urea as fuel. The effect of Bi203 on the phase transformation and sintering characteristics of the cordierite-based glass ceramics was analyzed with XRD, SEM and EDS. The results show that Bi2O3 obviously improves the formation of α-cordierite phase from μ- cordierite or glass. Bi203 lowers the crystallization temperature of α-cordierite phase from about 1 050 ℃ to 900 ℃, and enhances the densification of cordierite-based glass ceramics. The optimum amount of Bi2o3 gets about mass fraction of 5 %. This study also provides a simple and rapid method for preparing eordierite-based glass ceramics.