Study On Ceramic Materials Applied For Melting Magnesium Alloy

Magnesium alloys have many excellent properties such asspecific strength, specific stiffness, thermal conductivity, shieldingelectromagnetic wave, recoverability and so on, but they have not beapplied widely due to their poor corrosion resistance. In order toprevent iron, copper and chromium and other harmful elements fromgoing into alloys to the greatest extent during melting process,ceramics inner liner and ceramic parts can be used for melting andcasting equipment which can boost our country magnesium industrydevelopment greatly. The background and meaning of the study on ceramic materialsapplied for magnesium alloys melting were clarified in this paperfirstly. Then the properties of magnesium alloys melting and demandsfor employed material and destruction mechanism were analyzed.Magnesium oxide ceramics were considered as desired materials formelting magnesium alloy. Sinterability, fabrication and applicationof magnesium oxide ceramics were introduced. MgO-Al2O3-ZrO2system composite ceramic had been prepared successfully at 1550℃by solid state sintering with light-weight magnesium oxide as mainraw material and certain content Al2O3, nanometer ZrO2 asadditives and a little sintering aid. Effects of Al2O3 and ZrO2 onSinterability and mechanical property of magnesia ceramic wereresearched. Phases and microstructure mechanical property andthermal stability and chemical stability of this kind of materials werestudied. Optimal preparing technology of MgO-Al2O3-ZrO2 ceramicmaterial was investigated. Performances of this kind of ceramicmaterial were measured for its industry application. It was shown that Al2O3 and ZrO2 improved sinterability of -II-magnesium oxide greatly, and MgO-Al2O3-ZrO2 formed perfectmicrostructure, as a result MgO-Al2O3-ZrO2 displayed excelentmechanical behavior and thermal shock resistance and chemicalstability. MgO-Al2O3-ZrO2 sintered at 1550℃ had high performanceas follows: ρ /ρ ≥ 90%,σ ≥ 220MPa,KⅠ ≥ 3MPa.m1 ,wetting/ 2 t h Cangleθ =116°, residual strengthσ ≥ 140 MPa after thermal shock 100 rtimes (Δ T=700℃ ) which satisfied demands for melting magnesiumalloys completely。...