高铝瓷组成、结构与力学性能随烧成温度的演变

Evolution of Composition,Structure and Mechanical Properties of High Alumina Porcelain with Sintering Temperature

在配方和原料一定的情况下,高铝瓷的组成、结构与性能在很大程度上取决于烧成制度。本文系统研究了高铝瓷物相组成、微观结构和力学性能随烧成温度的变化,并分析了原因。结果表明,随着烧成温度从1160℃升高到1310℃,瓷件中发生熔解的刚玉和石英颗粒增加,内部刚玉相含量从37.85%(质量分数,下同)下降到35.02%,石英相含量从7.60%下降到1.94%,熔解的刚玉和部分石英以莫来石形式析出,瓷件内部莫来石含量从7.49%升高到11.41%。随着烧成温度从1160℃升高到1280℃,瓷件内部玻璃相含量从47.06%提高到51.63%,瓷件真气孔率从12.50%下降到5.59%,但是当烧成温度达到1310℃时,瓷件过烧,内部真气孔率增加到6.99%。当烧成温度为1160℃时,瓷件生烧,存在开口气孔,瓷件弯曲强度仅151 MPa;当烧成温度增加到1190℃,弯曲强度达最大值181 MPa;随着烧成温度继续升高到1310℃,瓷件内部总晶相含量从52.94%下降到48.37%,瓷件内部起弥散增强作用的晶相颗粒减少,瓷件强度从181 MPa逐渐降至158 MPa。这些研究结果对优化高铝瓷的配方、烧成制度及材料性能都有重要的参考意义。

When the formula and raw materials are fixed,the composition,structure and properties of high alumina porcelain largely depend on the firing system.Changes of phase composition,microstructure and mechanical properties of high alumina porcelain with sintering temperature were systematically studied,and the reasons were analyzed.The results show that with the increase of sintering temperature from 1160℃ to 1310℃,the amount of fused corundum and quartz particles in porcelain increases,the content of corundum phase decreases from 37.85%(mass fraction,the same below)to 35.02%,and the content of quartz phase decreases from 7.60% to 1.94%.The fused corundum and some quartz precipitate in the form of mullite,and the content of mullite phase in porcelain increases from 7.49% to 11.41%.As sintering temperature increases from 1160℃ to 1280℃,the content of glass phase in porcelain increases from 47.06% to 51.63%,while the true porosity of porcelain decreases from 12.50% to 5.59%.However,when sintering temperature reaches 1310℃,the porcelain are overburning,therefore the true porosity increases to 6.99%.When sintering temperature is 1160℃,the porcelain is undersintering with open pores,and the bending strength is only 151 MPa.When sintering temperature increases to 1190℃,the bending strength reaches a maximum value of 181 MPa.As sintering temperature continues to rise to 1310℃,the total content of crystalline phases in pocelain decreases from 52.94% to 48.37%,indicating that the crystalline particles which play a dispersion enhancing role in porcelain decrease,thus the strength of porcelain gradually decreases from 181 MPa to 158 MPa.These research results have important reference significance for optimizing the formulation,firing system and material properties of high alumina porcelain.