Effect of light burnt MgO powder on properties of porous MgAl2O4 ceramics by gel-casting route
In order to reduce the raw materials cost,simplify the process,and improve the performance of porous MgAl2O4 ceramics,MgAl2O4 powders were synthesized using Al2O3 powder and MgO powder at 1 500 ℃ for 2 h,and then light burnt MgO powders(0.5%,1.0%,1.5%and 2.0%,by mass)were extrally added to prepare porous MgAl2O4 ceramics using the gel-casting route at 1 500 ℃ for 2 h.Effect of the light burnt MgO powder addition on the structure and performance of porous MgAl2O4 ceramics were in-vestigated.The results show that:(1)the porous MgAl2O4 ceramics prepared using light burnt MgO pow-der as a hardener have small linear shrinkage and good volume stability,whose pore size is mainly in the range of 0.5-2.0 μm;(2)as the light burnt MgO powder addition increases,the apparent porosity and the gas flux increase,and the microstructure is uniform;(3)when the light burnt MgO powder addition is 2.0%,porous MgAl2O4 ceramics show the optimal comprehensive performance.