Influence of substrate roughness on bonding mechanism in cold spray

In this study, optimization of substrate roughness for enhancing interface bonding state in cold spray for different material combinations is performed. Material combinations are classified into four different particle/substrate impact pairs (i.e., soft/soft, soft/hard, hard/soft and hard/hard) based on their thermo mechanical and physical properties. Finite Element Analysis (FEA) was employed to simulate the models in relation with constant powder size (25 μm), for estimating impact interface parameters. Experimentally, particles were deposited on different roughened substrates in order to compare the simulation results. Microstructures, deposition efficiency and bond strengths were observed for the coatings. On the basis of simulation and experimental results, optimum substrate roughnesses for different cases are suggested for better bonding. The optimum roughness for different materials combination has been figured out to be the fraction of particle size (0.5-1) based on the thermo-mechanical behavior of materials upon impact.376