SiC platelet and SiC platelet-alumina reinforced TZP matrix composites

摘要

SiC platelet-TZP and SiC platelet-Al_2O_3-TZP composites were fabricated from dispersions of SiC platelets in solutions containing salts of zirconium, yttrium, and aluminium. After coprecipitation and drying, the resulting powders were hot pressed at 1550℃ using a pressure of 25 MPa in an argon atmosphere. The resulting microstructure consisted of a uniform distribution of SiC platelets in a TZP matrix. Addition of SiC platelets resulted in a loss of both strength and toughness at all temperatures compared with the monolithic material. Additions of Al_2O_3 to the SiC platelet-TZP composite was useful in enhancing the strength and toughness at room temperature, and also the elevated temperature strength compared with equivalent alumina free materials. Phase analysis measurements showed that additions of Al_2O_3 promoted increasing amounts of tetragonal→monoclinic zirconia transformation during fracture.