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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 Ti4+ increasing, Ti4+ may react easily with Al4SiC4 and Al4O4C forming 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 surface of the specimen.
Al4SiC4 / Al4O4C composites were synthesized based on m (sintered clay): m (active carbon): m (aluminum powder) = 39:27.6:33.4, and 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 ° C 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 ° C, and the formed TiC exists stably at 1 300-1 700 ° C .; (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 Ti4 + increasing, Ti4 + may react easily with Al4SiC4 and Al4O4C forming the finite substitution solid solution resulting in lattice defect, which leads to the decomposition of Al4SiC4 at 1 700 ° C, the formation of more Al4O4C short fiber, and the formation of flake Al2O3 layer on surface of the specimen.