Search results

This study aims to investigate the friction behavior of SiC-B₄C composite ceramics treated by annealing in air sliding against SiC balls.

The dry sliding tests were performed with a ball-on-disk tribometer in ambient air condition. Analysis of friction coefficient, phase compositions of the surfaces, morphologies of worn surfaces of disks and wear scars of balls and surface profiles of wear tracks for disks were carried out using Raman spectroscope, microscope and surface profilometer.

The results show that a self-lubricating layer with the main composition of H₃BO₃ was successfully fabricated on the surface of SiC-B₄C composite ceramics by the annealing treatment in air. When the mass fraction of SiC is more than that of B₄C, SiC-B₄C composite ceramics show higher friction coefficients, the values of which are 0.38 for 80 Wt.%SiC-20 Wt.%B₄C and 0.72 for 60 Wt.%SiC-40 Wt.%B₄C, respectively. SiC-B₄C composite ceramics show lower friction coefficients when the mass fraction of B₄C is more than that of SiC. The low friction coefficients of 40 Wt.%SiC-60 Wt.% B₄C composite ceramics (0.16) and 20 Wt.%SiC-80 Wt.% B₄C composite ceramics (0.20) are attributed to the formation of a sufficient amount of H₃BO₃ layer, rather than the layer of silicon oxides.

This study will help to understand the friction behavior of SiC-B₄C composite ceramics with different ratios of SiC to B₄C treated by annealing in air.