ZrB2-SiC composites for sliding wear contacts: Influence of SiC content and counterbody

In recent times, significant efforts have been put to develop wear-resistant ZrB2-SiC composites for aerospace and automotive applications. The present study details friction and wear of spark plasma sintered ZrB2-(10, 20, 30 vol %) SiC composites in dry unlubricated conditions of sliding against different counterbodies: SiC (120 W/m-K, 22 GPa), WC-Co (100 W/m-K, 15 GPa), Al2O3 (30 W/m-K, 18 GPa), ZrO2 (25 W/m-K, 12.5 GPa). The coefficient of friction (COF) varied in the range of 0.49-0.69 and wear volume in the range of 0.006-0.152 mm(3) with varying SiC content in ZrB2-SiC composites and counterbody. Against a given counterbody, less friction and wear are found for the composites with large SiC content, owing to the high fracture toughness and hardness. Friction and wear of the composites are influenced by thermal conductivity of the counterbody. Worn surface analysis of the composites reveals mechanical aspects of fracture, pull-out, deformation as well as tribo-oxidation, while fracture and pull-out decreased with increased SiC content in the composites or thermal conductivity of the counterbody. Results from the present study recommend ZrB2-30 vol % SiC composites for the use in sliding contacts against SiC counterbody.

Automated summary

This study investigates the friction and wear of spark plasma sintered ZrB2-SiC composites in dry unlubricated conditions against different counterbodies. It is found that composites with higher SiC content exhibit lower friction and wear, and the thermal conductivity of the counterbody influences the friction and wear of the composites.