SiCW对反应烧结多孔Al2TiO5-SiCW 复合材料的影响

以γ-AlOOH、TiO₂和SiC_w为原料,通过反应烧结制备了多孔Al₂TiO₅-SiC_w复合材料,研究了SiC_w对Al₂TiO₅-SiC_w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,SiC_w可全部与TiO₂反应生成TiC和SiO₂。添加SiC_w,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SiC_w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SiC_w加入量多时,由于出现较多的玻璃相,会降低抗压强度。

Effects of SiCW on porous Al2TiO5 SiCW composites by reaction sintering

Porous Al₂TiO₅-SiC_w composites were prepared by reaction sintering with γ-AlOOH, TiO₂ and SiC_w as raw materials.The effects of SiC_w on phases, microstructures, porosity and compressive strength of Al₂TiO₅-SiC_w composites were investigated.The results show that the main phases of the reaction products are Al₂TiO₅, Al₆Si₂O₁₃, TiC and SiO₂.SiC_w reacts completely with TiO₂ to form TiC and SiO₂ because of the fast decomposition of slender SiC_w.With the addition of SiC_w, 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 SiC_w changes 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 SiC_w is excessive for the appearance of more glass phase.