Preparation and properties of MgAl2O4 spinel ceramics by double-doped Sm2O3-(Y2O3, Nb2O5 and La2O3)

Magnesium aluminate (MgAl2O4) spinet ceramics have gained widely using in some crucial industries by right of superior properties. However, their further applications have been restricted by the complicated preparing technology and high processing cost. In the present work, a series of MgAl2O4 spinet ceramics with high-density have been fabricated by solid-state reaction sintering. Role of different composite oxide additives including Sm2O3-Y2O3, Sm2O3-Nb2O5, and Sm2O3-La2O3 respectively, on phase compositions, morphologies, sintering characteristics, mechanical properties, and thermal stability of as-prepared MgAl2O4 spinet ceramics was investigated. Some secondary phases such as Y3Al5O12, SmAlO3, and MgAl11LaO19 were formed. Due to the synergistic effect of the secondary phases and consequent solid solutions, the densification and properties of MgAl2O4 spinet ceramics were obviously promoted. Simultaneously, the positive effects were also intuitively manifested in the decrease of apparent porosity and increase of the cold compressive strength and thermal shock resistance.