Electrodeposition Of Al-Ni And Al-Mn Alloys In Molten Salt

Aluminum alloy has great corrosion resistance, strength and processing, etc., other elements are adding to inhibit effectively the crystal growth of aluminum. The plating process has small thermal stress, well binding force, and almost no damage to the substrate material. Coating thickness can be controlled as need, the plating has no restrictions to the base material, can be widely used on the surface of various of materials and shapes such as steel, copper, nickel, plates, rods, etc., has broad application prospects.The technology of electroplating aluminum-nickel alloy layers from low temperature chloride molten salts was studied in this paper. The process parameters' effects on the deposit-ion rate, the coating composition and the current efficiency of Al-Ni alloy coating were discussed. The surface morphology and microcosmic phase composition were characterized and analyzed by scanning electron microscopy (SEM), X-ray thermal field energy dispersive spectrometer (EDS), X-ray fluorescence spectrometer (XRF) and polycrystalline X-ray diff-raction (XRD). The properties such as corrosion resistance and hardness of the Al-Ni alloy and Al-Mn alloy were detected using electrochemical anodic polarization curve and HV-1000 type Vickers hardness tester. The parper also studied the mechanism of deposition process of the Al-Ni alloy on steel electrode.The experiment results have show that the addition of NiCl2 in the molten salt has a direct impact on the performance of the alloy coatings. It can perfect the coating morphology, help the formation of Al, Ni alloy phase, greatly improve the corrosion resistance and hardness, and the maximum hardness value can reach 7200Mpa when the Ni content in the coating was 6.19%. The cyclic voltammetry curves show that the Al-Ni alloy coating on steel electrode was deposited in three stages. The Al-Mn alloy coating had the best corrosion resistance and hardness when the Mn content was about 32.21%. Al-Mn alloy coating have the better corrosion resistance than Al-Ni alloy coating, but the hardness of Al-Ni alloy coating is large, almost is two times higher than the Al-Mn alloy coating.