Fabrication of porous MgAl2O4 ceramics using V2O5 as sintering additive

• Published in: Ceramics international Vol. 46; no. 14; pp. 22819 - 22825
• Main Authors: Han, Lei, Li, Faliang, Yao, Xingyu, Dong, Longhao, Luo, Mengting, Zhang, Haijun, Jia, Quanli, Zhang, Shaowei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2020
• Subjects: Mechanical properties; Porous MgAl2O4 ceramic; Thermal conductivity; V2O5; Mechanical properties; Thermal conductivity; Porous MgAl2O4 ceramic; V2O5
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2020.06.049

MgAl2O4 ceramics with high porosity and performance were fabricated via foam gel casting at 1673–1823 K using MgAl2O4 as the raw material and a small amount of V2O5 (0.25 wt%) as a sintering additive. The variations in the physical properties of the final porous MgAl2O4 samples at ambient temperature demonstrated that their flexural, compressive, and specific strength increased with the addition of a small amount of V2O5 as a sintering aid. However, the thermal insulation properties of the as-fabricated MgAl2O4 ceramics exhibited an inverse tendency. A porous MgAl2O4 ceramic containing 0.25 wt% of V2O5 and fired at 1823 K had flexural and specific strength values of 4.2 MPa and 14.0 (MPa cm3)/g, respectively, representing improvements over those reported in the literature at a similar porosity (72.0%). Moreover, a low thermal conductivity of approximately 0.24 W/(m·K) was measured at 473 K, which may be attributed to the relatively high porosity and high proportion of small pores with diameters less than 50 μm.