Role of the laser surface preparation on the adhesion of Ni−5%Al coatings deposited using the PROTAL process

The thermal spraying assisted by laser (PROTAL) process combines a laser surface preparation followed by a thermal spray process. This type of surface preparation avoids some drawbacks of the degreasing and sand blasting processes. Previous studies showed that the adhesion of the deposits obtained with the help of the PROTAL process is similar to that achieved by traditional surface preparation. To obtain better insight into the effects of the laser treatment, a Ni−5%Al coating was plasma sprayed using the PROTAL process under different surface conditions. The morphology of the impinging splats and adhesion of the deposits were examined. Removal of contaminants, adsorbates, and oxides at substrate surface is confirmed. The role of the laser irradiation on the coating adhesion is discussed. The original version of this paper was published in the CD ROM Thermal Spray Connects: Explore Its Surfacing Potential, International Thermal Spray Conference, sponsored by DVS, ASM International, and IIW International Institute of Welding, Basel, Switzerland, May 2–4, 2005, DVS-Verlag GmbH, Düsseldorf, Germany.