Effect Of Substrate Preparation On The Adhesion Strength Of Aluminum Alloy Sprayed Using Cold Spray Process

To improve the adhesion properties of aluminum alloy coating, substrate preparations were investigated. Two methods of preparation were tested: sandblasting and surface texturing. This new approach allows surface roughness control. Self organizing textures can be fabricated on different materials which consist of a pattern of laser drilled dimples. Thus, size holes on substrates surface match to the mean size of powder using cold spray. 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, the microstructure and the adhesion strength of aluminum coating were characterized by optical microscopy, scanning electron microscopy and adhesion test. Coating adhesion depends on different parameters such as the surface substrate morphology and the in-flight velocity of particles from cinematic parameters.