Microstructure and fracture toughness of in-situ nanocomposite coating by thermal spraying of Ti3AlC2/Cu powder

The low fracture toughness of ceramic coatings has always hindered their wide application. In this study, an in-situ nanocomposite coating was prepared by the atmospheric plasma spraying of a 50 wt% Ti3AlC2-50 wt% Cu mixed powder. The in-situ nanocomposite coating was found to have an unusual microstructure with a nano-micrometre phase synergistic enhancement, which consisted of submicrometre-thick layers of Cu and nanoparticles of Cu(Al), Ti4O5, TiO2, and Al2TiO5. Thus, in the spraying process, Al was delinked out of Ti3AlC2, forming a large amount of plastic Cu(Al) with Cu. The delinked channel provided a path for Cu to diffuse into Ti3AlC2, which a spatial Cu network structure was formed in the coating. The in-situ nanocomposite coating has high fracture toughness and crack growth resistance by a three-point bending test. This paper reports a new method to prepare a high-fracture-toughness composite ceramic coating.