Effect of Surface Roughness of Cold-rolled Steel Sheet on Phosphate Performance

Cold-rolled steel sheets with different surface roughness were phosphatized. The surface roughness was tested by T1000 roughness tester, the weight of the phosphate coating was measured by removing the coating by chemical method. Scanning electron microscopy(SEM) and friction testing were used to characterize the performance of the phosphate coating, including the surface morphology, the friction coefficient and wear resistance. The results show that the substrate surface roughness has little effect on the weight of the phosphate coating. The smaller the surface roughness of the substrate is, the more uniform the phosphate coating is and the smaller the size of the particles is, however, the friction coefficient is relatively larger and the wear resistance is relatively poorer, and vice versa.