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

Abstract

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 nextgeneration mechanical seals.

Layered 2D Nanomaterials to Tailor Friction and Wear in Machine Elements—A Review

“…Guo et al fabricated silicon carbide composites reinforced by different amounts of multi-layer graphene using pressureless sintering. [164] With increasing graphene content, friction and wear tended to improve, reaching the best performance for composites containing 10 wt% graphene. The resulting COF and wear rate were reduced by ≈50%.…”

“…2D materials have been considered for improving the sealing properties of mechanical seals made of different base materials including fluoroelastomer (FKM), [158][159][160][161] nitrile butadiene rubber (NBR), [158] hydrogenated nitrile butadiene rubber (HNBR), [158] thermoplastic polyurethane (TPU), [158] silicone rubber [162] as well as glass [163] and silicon carbide ceramics. [164] In this context, graphene, GO, and thermally reduced graphene oxide (TrGO) [159,[160][161][162]164] as well as MoS 2 [158] and vacuum conditions (V). [139] b) Schematic illustration of different options to apply coatings to different components as well as c) load-velocity relationship in rolling bearing contacts following.…”

“…[137] h-BN [163] have been either applied as coatings and hybrid coatings [158] or incorporated as a reinforcement phase for composite materials. [158][159][160][162][163][164] To probe the improvement in the sealing properties, Wang et al deposited coatings of pure MoS 2 and diamond-like carbon, as well as hybrid hard-soft MoS 2 /DLC films (thicknesses of 150 and 300 nm), by PVD onto FKM, NBR, HNBR, and TPU for sealing purposes. [158] For the DLC/MoS 2 hybrid films, the relative ratio of the components was further varied.…”

“…Together with an enhanced electrical and thermal conductivity, these 10 wt% graphene composite materials were regarded as promising alternatives for sealing applications. [164] In addition, to show the improved performance of 2D materials-reinforced mechanical seals for tribological purposes, glass/h-BN composites were applied as compressive seals in high-temperature solid oxide fuel cells. [163] Figure 7.…”

Decreasing Resistivity of Silicon Carbide Ceramics by Incorporation of Graphene

“…However, reports on graphene decreasing resistivity of SiC composite are relatively few. Guo et al [22] investigated the effect of graphene on the microstructure, mechanical, and tribological properties of SiC ceramic, but their mechanisms were not discussed.…”