Design and enhanced high temperature wear performance of laser clad Co matrix coatings containing NiCrAlY and TiC over a wide temperature

This research aims to design a high-temperature wear resistance cobalt-based coating of hot-end parts as protective coating. The cobalt-based matrix coatings were reinforced by NiCrAlY and different contents of TiC (6.0, 8.0 and 10.0 wt%) using laser cladding technology. Some efforts were made to explore the influence of TiC on the microstructure, hardness and wear behavior of prepared coatings. The wear behavior of coatings was done via a ball-on-disk wear machine under room temperature -800 °C. The results showed that NiCrAlY decomposed and formed γ-Co(fcc) and β-NiAl phases. The hardness of coatings with TiC was reinforced due to the fine-grain strengthening and dispersion strengthening. The friction coefficients of reinforced coatings were destroyed due to the TiC particle and in-situ synthetized ceramic particles, whereas the wear resistance of coatings with TiC was enhanced. There existed an optimal content of TiC for the wear resistance of Co-NiCrAlY-TiC coatings. The coating with 8.0 wt% TiC had a satisfactory tribologcial performance at test temperatures. It was ascribed to the moderate hardness and in-situ synthetized solid lubricants, as well as the tribo-layer.