摘要
Al4SiC4/Al4O4C composites were synthesized based on m （ sintered clay） ： m （ active carbon ） ： m （ aluminum powder） =39： 27. 6： 33. 4, adding TiO2 powder （ anatase type, 0. 3%, 6%, 9%, respectively）, adding 〈 10% phenolic resin as binder, mixing well, pressing, drying, firing in a corundum tubular furnace in flowing argon at 1 300, 1 400, 1 500, 1 600 and 1 700℃ for 2 h, respectively. Effect of TiO2 addition on phase composition and microstructure of Al4SiC4/Al4O4C composites was investigated by TGA, chemical analysis, XRD and SEM. The results show that ： （ 1 ） Ti in the specimens loses a little in the process of firing, all residual TiO2 transforms into TiC when the firing temperature is below 1 300℃, and the formed TiC exists stably at 1 300 - 1 700 ℃; （2） the TiO2 addition has little effect on phase composition of composites ; however, when more than 3% of TiO2 is added, the formation temperature of Al4SiC4 and Al4O4C increases from 1 500 ℃ to 1 600℃ ; （ 3 ） with the concentration of Ti^4＋ increasing, Ti^4＋ may react easily with Al4SiC4 and Al4O4C forrning the finite substitution solid solution resulting in lattice defect, which leads to the decomposition of Al4SiC4 at 1 700℃, the formation of more Al4O4C short fiber, and the formation of flake Al2O3 layer on suorface of the specimen.
Al4SiC4/Al4O4C composites were synthesized based on m （ sintered clay） ： m （ active carbon ） ： m （ aluminum powder） =39： 27. 6： 33. 4, adding TiO2 powder （ anatase type, 0. 3%, 6%, 9%, respectively）, adding 〈 10% phenolic resin as binder, mixing well, pressing, drying, firing in a corundum tubular furnace in flowing argon at 1 300, 1 400, 1 500, 1 600 and 1 700℃ for 2 h, respectively. Effect of TiO2 addition on phase composition and microstructure of Al4SiC4/Al4O4C composites was investigated by TGA, chemical analysis, XRD and SEM. The results show that ： （ 1 ） Ti in the specimens loses a little in the process of firing, all residual TiO2 transforms into TiC when the firing temperature is below 1 300℃, and the formed TiC exists stably at 1 300 - 1 700 ℃; （2） the TiO2 addition has little effect on phase composition of composites ; however, when more than 3% of TiO2 is added, the formation temperature of Al4SiC4 and Al4O4C increases from 1 500 ℃ to 1 600℃ ; （ 3 ） with the concentration of Ti^4＋ increasing, Ti^4＋ may react easily with Al4SiC4 and Al4O4C forrning the finite substitution solid solution resulting in lattice defect, which leads to the decomposition of Al4SiC4 at 1 700℃, the formation of more Al4O4C short fiber, and the formation of flake Al2O3 layer on suorface of the specimen.
基金
supported by the National Science Foundation of China (NSFC) under Grant No.50772079
the National Basic Research Program of China Earmarked Research Grant No.2009CB626605
