Study on friction behavior of SiC-B4C composite ceramics after annealing

Abstract

Purpose This study aims to investigate the friction behavior of SiC-B4C composite ceramics treated by annealing in air sliding against SiC balls. Design/methodology/approach 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. Findings 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. Originality/value 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.