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为了解决氧化铝基陶瓷型芯不易脱芯的难题,加入一定量的淀粉作为成孔剂。以白刚玉粉为基体材料、石蜡和蜂蜡为增塑剂、二氧化硅粉和氧化镁粉为矿化剂,采用热压注法制备氧化铝基陶瓷型芯;制备工艺参数如下:浆料温度为90℃、热压注压力为0.5 MPa、保压时间为25 s;研究不同淀粉加入量对氧化铝基陶瓷型芯性能的影响。结果表明:在烧结过程中,样品中淀粉的烧失,增大了氧化铝基陶瓷型芯内部的孔隙率;随着淀粉加入量的增加,氧化铝基陶瓷型芯的室温抗弯强度降低、显气孔率增大、溶失性增大、体积密度减小;经1560℃烧结2.5 h后,淀粉加入量为8%的氧化铝基陶瓷型芯综合性能最好,其室温抗弯强度为24.8 MPa、显气孔率为47.98%、溶失性为1.92g/h、体积密度为1.88 g/cm~3。
In order to solve the problem that the alumina-based ceramic core is not easy to be taken off the core, a certain amount of starch is added as a pore-forming agent. The alumina-based ceramic core was prepared by hot pressing injection with the white corundum powder as the matrix material, the paraffin wax and the beeswax as the plasticizer, the silica powder and the magnesia powder as the mineralizer, the preparation process parameters are as follows: the temperature of the slurry Of 90 ℃, hot pressure injection pressure of 0.5 MPa, dwell time of 25 s; study the different amount of starch on the performance of alumina-based ceramic core. The results show that the loss of starch in the sample during sintering increases the porosity of the alumina-based ceramic core; as the amount of starch added, the room temperature bending strength of the alumina-based ceramic core decreases, The apparent porosity increases, the dissolution increases and the bulk density decreases. After sintered at 1560 ℃ for 2.5 h, the alumina-based ceramic core with 8% starch added has the best comprehensive performance with a room temperature bending strength of 24.8 MPa, the apparent porosity was 47.98%, the dissolubility was 1.92g / h and the bulk density was 1.88 g / cm ~ 3.