添加MgO对不同SiO2含量的ZrO2-Al2O3-SiO2陶瓷烧结的影响

Influences of MgO addition on sintering properties of ZrO_2-Al_2O_3-SiO_2 ceramics with different SiO2 contents

以高纯石英砂、α-Al2O3、ZrO2为原料,MgO为添加剂(添加质量分数分别为0、1%、2%、3%),经研磨、造粒、成型,并在1 600℃烧结2 h后获得了SiO2含量(w)分别为4%、8%、12%的ZrO2-Al2O3-SiO2系陶瓷试样。采用XRD、SEM对试样进行物相和显微结构的分析。结果表明:1)所制备的ZrO2-Al2O3-SiO2陶瓷的主要物相是单斜氧化锆、莫来石和刚玉,随着SiO2含量(w)由4%增加到12%,SiO2与Al2O3反应生成的莫来石量增加,体积膨胀效应越发明显,导致烧结试样的致密度降低;2)添加MgO促进了ZrO2-Al2O3-SiO2陶瓷的烧结,在SiO2含量为4%(w)的陶瓷中加入1%(w)的MgO时,烧结试样的致密度最大,其相对密度达到90.49%,体积密度为3.90 g·cm-3。

The ZrO2-Al2O3-SiO2 ceramics specimens （SiO2 contents are 4% ,8% and 12% in mass, similar hereinafter） were prepared using high purity quartz sand,α-Al2O3 and ZrO2 as starting materials,MgO as additive （0,1% ,2% and 3% ） ,milling ,pelletizing,shaping ,and firing at 1 600 ℃ for 2 h. The phase compo- sitions and microstructure of the specimens were investigated by XRD and SEM. The results show that. （ 1 ） the main phases of the ZrO2-Al2O3-SiO2 ceramics are monoclinic zirconia, mullite and corundum ;with SiO2 content increasing from 4% to 12% ,the quantity of mullite produced from the reaction of SiO2 and AIEQ in- creases gradually and the volume expansion is more and more obvious, leading to gradual reducing of the density; （2）MgO promotes the sintering of the ZrO2-Al2O3-SiO2 ceramics;the density of the fired speci- mens containing 4% SiO2 and 1% MgO is the highest,the relative density reaches 90.49% ,and the bulk density is 3.90 g·cm^-3.