Effects of Mullite Content on the Properties and Microstructure of Porous Anorthite/Mullite Composite Ceramics

Porous anorthite/mullite composite ceramics with different mullite contents were fabricated by foam-gelcasting method,using CaCO3,SiO2,α-Al2O3 as raw materials.Effects of mullite content on bulk density,po-rosity,compressive strength,thermal conductivity and microstructure of the porous composite ceramics were re-searched.Mullite content has great effect on the apparent porosity of the porous anorthite/mullite composite ceramics.As a result of the appearance of liquid phase in the sintering,the sample shrunk,which is the main reason for the po-rosity decrease.Compressive strength and thermal conductivity increase with the mullite content under the condition of the similar porosity.Dense pore wall and rod-like mullite grain are benefit for compressive strength of porous anorthite/mullite composite ceramics.The apparent porosity of the prepared porous anorthite/mullite composite ce-ramics is in the range of 60.8%?75.2%,the compressive strength is between 12.94 MPa and 36.95 MPa,and the ther-mal conductivity is in the range of 0.30?1.33 W/(m?K).