To improve the mechanical properties and tribological characteristics of boron carbide (SiC) ceramic, silicon carbide as incorporation phase was added into boron carbide (B4C) matrix. The results showed that the incorporation of SiC phase led to denser microstructure and lower porosity. When the content of SiC was 20 wt.%, the composite presented higher bending strength of 447.6MPa and fracture toughness of 7.21 MPa·m1/2. Meanwhile, when the composite slid against PEEK in seawater, lower friction coefficient of 0.052 and wear rate were obtained. The excellent tribological performance would be attributed to the denser ceramic structure, weakened abrasive wear and tribo-chemical removal.

In this paper, the tribological behaviors of B 4 C-SiC composites self-mated pairs in seawater and pure water were investigated, respectively. The results showed that the B 4 C-SiC composite with the content of 20%SiC has good mechanical properties. For the B 4 C-20%SiC self-mated pair in seawater, the abrasive wear is greatly weakened, and the tribo-chemical reactions between the composite surface and water molecules occurred. The tribo-chemical polishing causes very smooth wear surfaces, and the sliding pairs enter to the status of liquid lubrication. An extremely low friction coefficient (0.038) and wear rate (both below the order of magnitude 10 −5 mm 3 /N m) were obtained in this study. Due to the lower viscosity of pure water, the load carrying capacity of the liquid film reduces. So, in pure water, the sliding pair shows slightly higher friction coefficient and wear rate than that in seawater.

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