The effect of MgO addition on the properties of alumina-based ceramic cores prepared via sol–gel process

Abstract

Alumina-based ceramic cores with MgO addition were prepared using sol–gel process. Prior to magnesia addition, the suitable amount of titania content was determined in the previous research, where it was found that the body with 15 wt% titania had the most suitable properties. The effect of magnesia addition on mechanical, physical, thermal, chemical, and microstructural properties of the cores was investigated through adding MgTi2O5 and sintering the bodies at two temperatures (1400 and 1500 °C) for two different soaking times (1 and 2 h). According to the results of flexural strength test, apparent porosity measurement, leaching test, and microstructural properties of the sintered bodies, the body which contained 15 wt% titania and 4 wt% magnesia had the least sintering shrinkage (~2%), suitable apparent porosity (~30%), acceptable flexural strength (40 MPa), good thermal expansion coefficient (~4.3 × 10−6 °C−1), and also exhibited a suitable leaching behavior.