半水基石英陶瓷浆料性能的影响因素

Factors affecting properties of semi-hydrate-based silica ceramic paste

为制备出尺寸更精确、密度更均匀,纯度更高、成型周期更短的石英陶瓷材料,采用实验研究的方法,对半水基石英陶瓷浆料性能的主要影响因素进行了研究。实验中,在水基浆料中部分引入了与水互溶的低黏度有机溶剂,采用凝胶注模成型工艺制备出了固相体积分数高达φ(Solid)=80%,流变性能满足凝胶注模工艺要求的半水基英陶瓷浆料。对浆料抽空时间对坯体显气孔率的影响研究表明:真空抽气15 min左右得到的坯体气孔率较低;通过改变有机溶剂、引发剂量和环境温度,可控制凝胶固化时长。对烧结体的性能研究结果表明:坯体在1250℃烧成温度下,保温2 h,制备坯体体积密度为1.97 g/cm^(3),弯曲强度58.1 MPa;熔融石英颗粒在最佳级配条件下,制备的石英陶瓷的体积密度为1.95 g/cm^(3),弯曲强度达到65.7 MPa。XRD分析表明:当烧结温度低于1220℃时,烧结体中均为石英玻璃相;进一步提高烧结温度,会有α-磷石英和α-方石英析出。

In order to prepare quartz ceramic materials with more accurate size,more uniform density,higher purity and shorter molding cycle,the main factors affecting the properties of semi-aqueous quartz ceramic slurry were studied by experimental method.In the experiment,a low viscosity organic solvent mixed with water was introduced into the water-based slurry.A semi-aqueous ceramic slurry with a solid volume fraction up toφ(solid)=80%and a rheological property satisfying the gelcasting process was prepared by gel casting process.The influence of slurry evacuation time on the apparent porosity of the green body is examined.The results show that the porosity of the billet obtained by vacuum pumping is comparatively lower within around 15 min,and the curing time can be controlled by changing the organic solvent,the initiating dose and the ambient temperature.An examination of the performance of the sintered body shows that the bulk density of the sintered body is 1.97 g/cm^(3) and the bending strength is 58.1 MPa when the sintered body is sintered at 1250℃for 2 h;the bulk density of the fused quartz ceramic is 1.95 g/cm^(3) and the bending strength is 65.7 MPa when the fused quartz particle is in the best grading condition.XRD analysis shows that when the sintering temperature is lower than 1220℃,the sintered body is composed of quartz glass phase;when the sintering temperature is further increased,α-phosphorous quartz andα-cristobalite will precipitate.