干压成型-固相反应法制备MgAl_(2)O_(4)多孔陶瓷

Preparation of porous MgAl_(2)O_(4) ceramics by dry pressing-solid phase reaction route

为了解决固相烧结法制备MgAl_(2)O_(4)多孔陶瓷过程中体积膨胀导致性能下降的问题,以d_(50)=1.1μm的Al_(2)O_(3)和d_(50)=1.5μm的MgO为主要原料,d_(50)=1.5μm的TiO_(2)为外加剂,用干压成型-固相反应法制备MgAl_(2)O_(4)多孔陶瓷。研究了热处理温度(1300、1350、1400、1450、1500℃)和TiO_(2)外加量(质量分数分别为0、0.5%、1.0%、1.5%、2.0%)对多孔陶瓷烧后线变化率、显气孔率、体积密度、物相组成和显微结构的影响。结果表明:1)随着热处理温度的升高,MgAl_(2)O_(4)多孔陶瓷的致密化程度提高,体积密度增大,显气孔率降低;2)随着TiO_(2)外加量的增加,MgAl_(2)O_(4)多孔陶瓷的烧后线收缩率增大,显气孔率显著降低,平均晶粒尺寸增大。

To solve the problem of property decline caused by the volume expansion during the preparation of porous MgAl_(2)O_(4) ceramics by solid phase sintering method,porous MgAl_(2)O_(4)ceramics were prepared via the dry pressing-solid phase reaction route using Al_(2)O_(3)(d_(50)=1.1μm)and MgO(d_(50)=1.5μm)as the main raw materials and TiO_(2)(d_(50)=1.5μm)as the additive.Influences of hot treatment temperatures(1300,1350,1400,1450,and 1500℃)and TiO_(2)additions(0,0.5%,1.0%,1.5%,and 2.0%,by mass)on the linear change rate on heating,apparent porosity,bulk density,phase composition and microstructure of the porous MgAl_(2)O_(4)ceramics were investigated.The experimental results show that:(1)as the hot treatment temperature increases,the densification of the porous ceramics increases,the bulk density increases but the apparent porosity decreases;(2)as the TiO_(2)addition increases,the linear shrinkage rate on heating of the porous ceramics increases,the apparent porosity decreases remarkably,while the average grain size increases.