SiC_W对反应烧结多孔Al_2TiO_5-SiC_W复合材料的影响

Effects of SiC_W on porous Al_2TiO_5-SiC_W composites by reaction sintering

以γ-AlOOH、TiO2和SiCw为原料,通过反应烧结制备了多孔Al2TiO5-SiCw复合材料,研究了SiCw对Al2TiO5-SiCw复合材料物相、微观组织结构、孔隙率和抗压强度的影响。结果表明:反应产物中主要物相有Al2TiO5、Al6Si2O13、TiC和SiO2。由于晶须分解速度快,SiCw可全部与TiO2反应生成TiC和SiO2。添加SiCw,一方面显著细化了Al2TiO5基复合材料的微观组织,生成的细小规则的TiC晶粒和存在于Al2TiO5晶界处的Al6Si2O13有利于抑制Al2TiO5晶粒长大,提高其抗压强度。另一方面,因为SiCw改变了原料中颗粒之间的堆积方式,使孔径增大、孔隙率显著提高。生成的一定量的SiO2对晶粒产生黏结,使得Al2TiO5基复合材料的孔洞骨架密实,提高了抗压强度,但当SiCw加入量多时,由于出现较多的玻璃相,会降低抗压强度。

Porous Al2TiO5-SiCwcomposites were prepared by reaction sintering withγ-AlOOH,TiO2 and SiCwas raw materials.The effects of SiCwon phases,microstructures,porosity and compressive strength of Al2TiO5-SiCw composites were investigated.The results show that the main phases of the reaction products are Al2TiO5,Al6Si2O13,TiC and SiO2.SiCwreacts completely with TiO2 to form TiC and SiO2 because of the fast decomposition of slender SiCw.With the addition of SiCw,the microstructures of Al2TiO5 composites are significantly refined.The fine regular TiC grains and Al6Si2O13 grains which distribute between the grain boundaries of Al2TiO5 can impede the growth of Al2TiO5 grains and improve the compressive strength of the porous Al2TiO5 composites.Moreover,because SiCwchanges the packing form of the raw materials and increases the pore size,its porosity increases notably.In addition,some SiO2 existing among the crystalline grains makes the walls of pores denser and increases the compressive strength of Al2TiO5 composites,but the compressive strength will decrease when the content of SiCwis excessive for the appearance of more glass phase.