莫来石含量对钙长石/莫来石复相多孔陶瓷组织结构与性能的影响

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

以CaCO3、SiO2、α-Al2O3为原料,采用泡沫注凝法制备了不同莫来石含量的钙长石/莫来石复相多孔陶瓷,研究了莫来石含量对复相多孔陶瓷的体积密度、气孔率、抗压强度、热导率及微观组织和结构的影响.结果表明,莫来石含量对气孔率有很大的影响,烧结过程中液相出现引起的收缩是气孔率下降的主要原因;在气孔率相近的情况下,莫来石含量较高试样的抗压强度和热导率也较高,致密的孔壁、长柱状的莫来石晶粒使得复相多孔陶瓷的抗压强度提高.所制备的钙长石/莫来石复相多孔陶瓷的开口气孔率介于60.8%～75.2%,抗压强度为12.94～36.95 MPa,热导率为0.30～1.33 W/(m.K).

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）.