Effect of solid solution reaction on the structure and properties of MA-Al2O3 materials

Two groups of MA-Al2O3 materials were prepared by using fused magnesia-aluminum spinel as the main raw material and adding a small amount of sintered corundum fine powder instead of spinel fine powder, or white corundum as the main raw material and adding a small amount of fused magnesia-aluminum spinel fine powder instead of white corundum fine powder. The effect of solution reaction between corundum and MG-Al spinel on the material properties and microstructure was studied. The results show that :1) the solid solution reaction occurs in both groups of materials, which increases the aluminum-rich degree of MG-Al spinel and increases the content of alumina (w) from about 76% to more than 80%, thus strengthening the bonding between the sample aggregate and the matrix, reducing the structural defects, and improving the high temperature performance of the material; 2) Adding sintered corundum to MA-Al2O3 material with magnesia-aluminum spinel as the main raw material can increase its compressive strength at room temperature and improve its high temperature creep resistance and thermal shock resistance; 3) In the white corundum as the main raw material of MA-Al2O3 material, adding magnesium aluminum spinel fine powder, its room temperature compressive strength, high temperature creep resistance and high temperature bending strength are greatly improved.

Key words: solid solution reaction, magnesium aluminate spinel, corundum, physical properties