摘要
采用X射线衍射、扫描电镜、差热分析和热膨胀仪等手段研究了由氧化物粉末(MgO,Al_2O_3和siO_2)制备堇青石陶瓷时,添加Bi_2O_3对堇青石陶瓷相变、相组成和性能的影响。Bi_2O_3在烧结过程中的作用机理是低温产生液相促进烧结。试验表明,在1350℃烧结3h,该陶瓷由堇青石和孤立分布的玻璃相组成。随Bi_2O_3含量增加,陶瓷的致密度、弯曲强度和热膨胀系数逐渐升高。Bi_2O_3的添加量(质量分数)大于4％时,原料相石英消失。硅氧网络骨架结合力减小和一定量的玻璃相是引起堇青石陶瓷热膨胀系数升高的主要原因。
Bi2O3 is used as an additive in the sintering of cordierite ceramic in order to obtain ceramics with high amount of cordierite and to decrease the sintering temperature. The cordierite ceramics were prepared by the powder sintering method. The effects of Bi2O3 on the transformation, the phase components and properties of cordierite ceramics were studied using XRD, SEM, DTA and thermal dilatometer. The function of Bi2O3 additive is to produce liquid phase in lower temperature period in the sintering process. The results show that the sintering temperature is obviously decreased by adding Bi2O3. When sintered at 1350°C for 3 h, the ceramics are composed of α-cordierite and isolated glass phase. The density, the bending strength and the thermal expansion coefficient increase with the increase of Bi2O3 content. The optimum content of Bi2O3 is 4% (in mass fraction). The decrease of the binding power of Si-O network and the existence of some glass phase are the main causes to increase the thermal expansion coefficient of the cordierite ceramics.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2003年第9期888-891,共4页
Journal of The Chinese Ceramic Society
关键词
堇青石陶瓷
氧化铋
微观结构
烧结
性能
Additives
Bismuth compounds
Microstructure
Phase composition
Sintering
