Modeling the Interfacial Bonding Strength of Al-Zn-Si Alloy between Substrates with Linear Surface Roughness and Its Coating

Interfacial bonding strength between the substrate and its coating is one of the important indexes affecting the service life of parts. To reduce the manufacturing cost, a mathematical model can be established to quantitatively describe the microscopic surface roughness and its anti-corrosion coating adhesion strength. Anti-corrosion life could be improved by controlling the surface roughness of the substrate. In this study, a model of interfacial bond strength and roughness, which was calibrated using the substrate surface and closely related to the cell spacing and length of the support, was established. Under the same condition as the coating, component materials and the coating thickness, results were obtained that the coating strength changed along with the substrate roughness. When roughness changed between 37.1 & mu;m and 48.4 & mu;m, the bonding strength showed a decreasing trend. The larger the value of the roughness, the more conducive it was to the bonding between the arc spraying layer and the substrate. The adhesion between the coating and substrate was not always increased with the higher roughness on the same surface. It should be evaluated based on the surface roughness and its evaluation parameters, and there was an optimal roughness evaluation and selection range. The experimental results were consistent with the theoretical predictions.