论文部分内容阅读
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-SiCw composites were prepared by reactive sintering using γ-AlOOH, TiO2 and SiCw as raw materials. The effects of SiCw on the phase, microstructure, porosity and compressive strength of Al2TiO5-SiCw composites were studied. The results show that the main products of the reaction products are Al2TiO5, Al6Si2O13, TiC and SiO2. Due to the rapid whisker decomposition, SiCw can react with TiO2 to form TiC and SiO2. Addition of SiCw, on the one hand, significantly refined the microstructure of Al2TiO5-based composites. The generated fine regular TiC grains and Al6Si2O13 existing at the grain boundaries of Al2TiO5 are favorable for inhibiting the grain growth of Al2TiO5 and increasing the compressive strength. On the other hand, since SiCw changes the way of accumulation between the particles in the raw material and increases the pore size, the porosity is significantly increased. A certain amount of SiO2 is generated on the crystal grains to make the hole skeleton of the Al2TiO5-based composite dense and improve the compressive strength. However, when the amount of SiCw is large, the compressive strength will be lowered due to the appearance of more glass phases.