Effect of In-situ Self-generated SiC Whiskers on Microstructure and Properties of Preoxidized SiC Wear Resistant Materials

In-situ self-generated SiC whisker reinforced SiC wear-resistant composite materials were prepared by using Si powder and activated carbon as SiC whisker precursor and pre-oxidized SiC particles as raw materials, which were sintered under charcoal-buried conditions at 1500 ℃ for 3 h. Effect of the SiC whiskers on properties of the pre-oxidized SiC wear resistant materials was studied, while the relationship between properties and microstructure was analyzed. With the incorporation of the in-situ self-generated SiC whiskers, densification and mechanical properties of the SiC wear resistant materials were improved. It is found that the improvement effect is maximized when the addition of Si powder and activated carbon is 12 wt.%. Correspondingly, impact strength, hardness and wear ratio of the sample are 29.91 kJ·m^-2, 98 (HRB) and 4.49, respectively. The in-situ self-generated SiC whiskers fill the pores between SiC particles, forming a uniform and dense network structure. SiO₂ from the associated and pre-oxidized SiC raw materials reacted with α-Al₂O₃ to produce mullite, which enhanced the binding force between the whiskers and matrixes. When the SiC wear-resistant materials were subjected to external forces, SiC whiskers with good bonding with the matrix resulted in enhanced mechanical properties through extraction, crack deflection and bridging connection.