Pressureless sintering of multilayer graphene reinforced silicon carbide ceramics for mechanical seals

The silicon carbide (SiC) ceramics containing multilayer graphene derived from graphite exfoliation were successfully prepared by pressureless sintering, and the effect of graphene content on the sintering behaviours, microstructure, mechanical, tribological, electrical and thermal properties was investigated in detail. The bulk density, bending strength and hardness of the composite ceramics gradually decrease with the increase of graphene content, but the friction, conductance and thermal conductance properties are improved obviously. When the graphene content reaches 5 wt-%, the dry friction coefficient of 0.22, electrical conductivity of 2724.14 S−1 m−1 and thermal conductivity of 8.5 W (m−1 K−1) can be obtained, indicating good comprehensive mechanical, tribological, electrical and thermal properties. This multilayer graphene reinforced silicon carbide ceramic is a promising seal material instead of SiC seal materials containing graphite to be applied in next-generation mechanical seals.