Effect of laser-textured substrate on adhesion and microstructure of deposited Mo–NiCrBSiCFe coating

Abstract

The novel application of laser surface texture as a method for enhancing the deposition of coatings on substrates has garnered significant interest. This study focuses on the use of atmospheric plasma-sprayed Mo–NiCrBSiCFe coating, which was applied to both laser surface textured and grit-blasted AISI 304 substrates. The coating powder was created by mechanically milling a mixture of 25 % molybdenum and 75 % NiCrBSiCFe powders, providing a unique combination of materials for the deposition coating. The analysis zeroed in on examining the effects of laser texture grooves on the microstructure, porosity, microhardness, and adhesion strength of the composite coating. The findings revealed that the composite coating primarily comprises MoO2, Mo, and Ni phases. In comparison to the grit-blasted substrate, the coating applied on the laser-textured groove substrate exhibited a porosity increase of 15.15 %, a pore size rise of 17.45 %, a notable 45.62 % improvement in adhesion strength, and a significant 23.57 % enhancement in scratch resistance. Furthermore, the coating on the laser-textured substrate exhibited fewer closed pores. The microhardness of the coating surface was higher than that of the coating cross-section within the grooves. Notably, the laser surface texture had a significant impact on the adhesion strength, microstructure, and hardness of the composite coating, surpassing the results achieved through traditional grit blasting. One novel observation from this study is that laser surface texturing can have a significant impact on the porosity of Mo–NiCrBSiCFe coatings. Another noteworthy finding is that laser surface texturing can enhance the hardness of Mo–NiCrBSiCFe coatings.

Keywords

• Atmospheric plasma spray
• Laser surface texture
• Mo–NiCrBSiCFe coating
• Microstructure
• Adhesion strength