The Preparation Of Ni–Based Alloy Coating By Spray Electrodeposition And Performance Research

Nickel-based alloys are mainly alloys that exhibit good overall performance at a certain temperature?650°C to 1000°C?.Different kinds of trace elements are added to the nickel-base alloy coating,which will produce different properties for nickel-based alloy coatings.Impact.In the past,the slower deposition rate using conventional methods caused coarse grains and affected the performance of the coating.In order to overcome the shortcomings of the traditional technology,this article uses spray electrodeposition method to prepare pure nickel coating,nickel-iron alloy coating,nickel-tungsten alloy coating and nickel-iron-tungsten alloy coating.The electrolyte formulations for the four nickel-base alloy coatings areThe reasonable formulation of nickel alloy coating prepared by spray electrodeposition is as follows:Pure nickel coating:Ni?NH₂SO₃?2·4H₂O 250g/L,NiCl₂·4H₂O 10 g/L,H₃BO₃ 40 g/L;based on this formula,add FeCl₂·4H₂O 1.2 g/L,ascorbic acid 2 g/L,Sodium saccharin 8.0g/L to form a nickel-iron alloy coating;Na₂WO₄·2H₂O 80 g/L,sodium citrate 40 g/L,saccharine 8.0 g/L to form a nickel-tungsten alloy coating;and finally FeCl₂·4H₂O 1.2 g/L,ascorbic acid 2 g/L is added to the nickel-tungsten alloy coating to form a nickel-tungsten-iron alloy coating.The optimum process parameters are:current density 60 A/dm2,jet speed 3.5 m/s,electrolyte solution temperature 60?,pH value 4.0.The results show that the addition of iron and tungsten can improve the performance of nickel-base alloy coatings to a certain extent.After adding iron and tungsten,the hardness of the nickel-iron alloy coating is greatly improved compared with the pure nickel coating.However,if the content of tungsten and iron exceeds a certain limit,it will also have a bad influence on the coating.The nickel-tungsten-iron ternary alloy coating The surface is smooth,the grains are small,and the hardness is high.As the nickel-tungsten-iron ternary alloy coating is oxidized at a high temperature,various oxides are formed and the oxide film is dense,so that the high-temperature oxidation resistance is significantly improved.In addition,the wear resistance of the nickel-tungsten-iron ternary alloy coating is superior to that of other nickel-base coatings.The main reason is that the wear rate of the oxide film during wear of the nickel-tungsten-iron alloy coating is faster than that of the coating wear.