Role of spray processes on microstructural evolution, and physical and mechanical properties of multi-walled carbon nanotube reinforced cu composite coatings

•The MWCNT/Cu composite coatings were successfully fabricated kinetic spraying, atmospheric plasma spraying, and HVOF spraying.•Kinetic and thermal energy transferred to deposited particles by three different spraying processes critically influenced microstructure features and MWCNT states.•MWCNT states resulted from KS, APS, and HVOF processes affect their coating properties.•Electrical and mechanical properties of each coating layer were measured, and the values were analyzed based on quantitative data of microstructural analysis.•Relationship among spraying processes, microstructural features, and coating properties was investigated. Kinetic and thermal spray processes were used to fabricate the multi-walled carbon nanotube (MWCNT) reinforced Cu composite coatings with 0–1.0wt% MWCNTs. The microstructures of the composite coatings were analyzed and electrical and mechanical properties such as the electrical resistivity, micro-hardness, wear rate, and friction coefficient were evaluated. Since the deposition and microstructural evolution mechanisms of kinetic and thermal spraying are entirely different, the characteristics of the spray processes dominated the microstructure and interface of the Cu matrix, MWCNT structure, and the nature of the interface between MWCNTs and the Cu matrix, which are correlated with the properties. In this study, the relationship among electrical and mechanical properties with (MWCNT) state and the microstructural factors of the MWCNT/Cu composite coatings were investigated via microstructural and physical metallurgical analyses.