Effects of substrate pre-treatment on metal coating fabricated by low pressure cold spray

Low pressure cold spray is an attractive method for on-site metal coating fabrication due to its compactness and portability. However, low deposition efficiency and limited available material inhibit further applications in engineering and industrial field. To resolve and improve these issues, we investigated the effects of substrate pre-treatment including heating, laser cleaning, and low-temperature plasma treatment on metal coating process. The results showed the deposition efficiency and coating thickness increased significantly with higher initial substrate temperature. We especially focused on the applicability of the substrate pre-treatment to removal of native oxide layer on the substrate which facilitates the direct contact of the metal material surface. To remove the oxide layer effectively without no damage on the substrate, use of atmospheric low temperature plasma, which is known to have a potential of quick oxidation reduction and less thermal damage, was suggested and the result was compared with that of laser cleaning.