Effects of Surface Roughness on Performance of Drive Shaft Electrostatic Powder Coating

The surface of automobile drive shaft was sandblasted under different sandblasting conditions, so that the surface of the workpiece had different surface roughness. Phosphating and electrostatic powder spraying were performed on workpieces with different surface roughness, and the state of the phosphate film on the surface of the workpiece was observed by scanning electron microscopy. The effect of surface roughness of the substrate on the corrosion resistance of the coating samples was investigated by a -40 ℃ freezing impact test and a 6-week cyclic salt spray corrosion test. The results show that when the surface roughness of the substrate was Ra 3.0-4.0 μm, the corrosion resistance of the coating sample was the best.