Tribological behavior of CrCoNiAlTiY coating synthesized by double-glow plasma surface alloying technique

A dense CrCoNiAlTiY coating was deposited onto the γ-TiAl alloy by double-glow plasma surface alloying technique to improve its wear resistance. Microstructure analysis showed that the coating consisted of AlCr2, σ-NiCoCr, γ-TiAl and γ׳-Ni3Al phase, and was well diffusion bonded to the substrate. In terms of the H/E and H3/E2 ratios, the CrCoNiAlTiY coating was nearly 3.5 times better than the γ-TiAl substrate. Dry wear test results indicated that the specific wear rate of γ-TiAl substrate was 3.8×10−4 mm3N−1 m−1, which was about 4 times greater than that of the CrCoNiAlTiY coating. The improvement in wear resistance of the CrCoNiAlTiY coating may be attributed to the increased H/E and H3/E2 ratios and to good adhesion strength between CrCoNiAlTiY coating and γ-TiAl substrate.