In situ generated SiC_w-ZrO₂ collaborative enhancing Al₂O₃-based composites and their mechanical properties

In this work, a four-step process was developed to fabricate Al₂O₃-based composites synergistically reinforced with in situ generated ZrO₂ and SiC_w. First, a homogeneous Al₂O₃/SiO₂/ZrO₂+C precursor was prepared by SCS method. Second, the precursor was converted into Al₂O₃/SiC_w/ZrO₂ composite powder through carbothermal reduction, water washing, and air calcination. Third, the composite powder was first mixed with a PVA solution by ball milling, and the resulting mixtures were then pressed into form a green compact of Al₂O₃/SiC_w/ZrO₂. Finally, the green compact were sintered by the APS method to obtain five Al₂O₃/SiC_w/ZrO₂ composites (denoted as ASxZy). The mechanical properties and wear resistance of the five ASxZy samples were investigated. The results indicate that the friction coefficients of the five ASxZy samples range from 0.6 to 0.7. Among them, the AS10Z20 sample exhibits the lowest wear rate and the best overall mechanical properties. In these ASxZy samples, SiC_w mainly inhibits crack propagation and dissipates fracture energy through whisker bridging, whisker pull-out, and crack deflection, whereas ZrO₂ mainly contributes to toughening through crack deflection and microcrack toughening. The dominant wear mechanism of four SiC_w-containing ASxZy samples is fatigue wear, whereas that of the AZ30 sample without SiC_w is adhesive wear.

Keywords:
Al₂O₃/SiC_w/ZrO₂ composites; Mechanical properties; Wear resistance; SiC_w/ZrO₂ collaborative enhancement; Solution combustion synthesis