Effect Of Substrate Roughness On The Cratering Phenomenon In Surface Coating Using Cold Spray Process

The effect of substrate roughness on coating adhesion but also on the cratering phenomenon has been investigated. In order to understand and explain crater formation, surface texturing was used. This innovative process allows to control the substrate surface roughness. Self organizing textures can be fabricated on different materials which consist of a pattern of laser drilled dimples. Five size holes from 20 to 100 µm with an angle of 45° were made in order to obtain different surface roughnesses. The aluminum powder was accelerated by nitrogen gas through a De Laval nozzle. The gas temperature and pressure were respectively 500°C and 3 MPa. Surface substrate was also preheated. The morphology and the microstructure of aluminum coating were characterized by optical microscopy and scanning electron microscopy.