Pack cementation processing parameters for SiC coatings on C/C for optimum tribological properties

SiC coating was synthesized on carbon/carbon composites to improve wear resistance by pack cementation. The effects of cementation temperatures and times on the microstructure, surface morphology, and tribological behavior of the composites were analyzed. Coatings formed at 1200 °C were found to be the most compact, whereas as-formed coatings were loose and had large pores at lower cementation temperatures (1000 and 1100 °C). Meanwhile, the coating structures were dense and contained pores and cracks at high cementation temperatures (1300 and 1400 °C). Specimens formed at 1200 °C had lower, more stable friction coefficients and lower weight loss values. The surface morphologies of these specimens were more compact, and the coating surfaces formed a lubrication film with a certain amount of graphite. The reaction temperatures and times influenced the tribological properties. Specimens produced at 1200 °C for 16 h exhibited the lowest weight loss and the most stable friction coefficient.