Effects of Content of Al2O3 Particles and Heat Treatment on Corrosion Resistance of Ni-P-Al2O3 Composite Coatings

摘要

Ni-P-Al2O3 composite coatings with the uniform distribution of Al2O3 particles were prepared by adding Al2O3 particles into Ni-P plating solution and adopting optimum plating process.The morphology and microstructure of the coatings were investigated by using SEM,EDS and XRD.Being immersed in 10 vol.％ H2SO4 solutions,the corrosion resistance of Ni-P-Al2O3 composite coatings was tested.The results show that when the solubility of Al2O3 particles in plating solution is 8 g/l,the corrosion resistance is best.Comparing with as-plated Ni-P-Al2O3 composite coatings,the corrosion resistance of heat-treated Ni-P-Al2O3 composite coatings decreases by raising the temperature to 300 °C and then increases by raising the temperature to 450 °C.