Preparation and Performance of Al₂O₃ Strengthened Ni-P-W Composite Coatings

The α-Al2O3 strengthened Ni-P-W composite coatings were prepared.The effects of the diameter of Al2O3 particles,mixing manner,current density,content of Al2O3 and Na2WO4,and pH of the electrolyte on the content of Al2O3 in coating,deposition rate and appearance quality of coating were studied.The hardness,wear properties,resistance to oxidation,corrosion resistance,appearance,phase structure and chemical composition of the plating layer were tested.The best conditions of the electrodeposition technology were obtained using supersonic mixing with current density of 2 A·cm-2,pH of 5,nano-Al2O3 concentration of 50 g·L-1 and Na2WO4 concentration of 6 g·L-1.The performance of micro-Al2O3 strengthed Ni-P-W composite coatings and nano-Al2O3 strengthed Ni-P-W composite coating are both better than that of Ni-P-W coating.