The Preparation Of The Ni-Fe-W Alloy Coating And Performance Research

The Ni-Fe-W ternary alloy coating is prepared by the method of electrode-position, this coating has numerous interests such as good integration with the substrate, high hardness and good wear resistance and good thermal conductivity. This coating when it applies to the crystallizer can effectively improve the service life of the crystallizer, save energy and cause no pollution to the environment, so it has very wide application prospect. Based on the studies of this coating which were carried out by scholars both at home and abroad, we focus our attention on the preparation technology of the Ni-Fe-W ternary alloy coating.In this paper, taking sodium tungstate, nickel amino sulfonate, ferrous chloride as the main salt of the solution with the use of sodium citrate which is completing agent of the solution, boric acid is buffer agent, scorbutic acid is stabilizers. It is also need to add some saccharin and laurel sodium sulfate to wipe off the stress and make the surface active. Through the orthogonal experiment and single factor experiment, we summary the conclusion is that the optimal formulation and process parameters of coating solution are: Fe Cl2?4H2O 2.9 g/L, laurel sodium sulfate 0.1 g/L, H3BO3 40 g/L, saccharin 0.5 g/L, Ni(NH2SO3)2?4H2O 280 g/L, C6H5Na3O7?2H2O 40 g/L, Na2WO4?2H2O 40 g/L, ascorbic acid 2 g/L; PH value is 3.5 to 4.5, the current density is 1~2 A/dm2, the temperature is 55~65 ℃. The performance test of coating solution: the coating solution of catholic current efficiency is 68.39%, the dispersion coating ability is 75% and the deep coating ability is 100%. The result shows that the coating solution has good performance. Then test the performance of the coating, such as coating surface morphology, phase structure and corrosion resistance. The results show that: the surface of the coating is uniform; the coating is amorphous structure and it is mainly composed of Fe Ni3 phase and Fe0.64Ni0.36 phase. Electroplating a Ni-Fe-W alloy coating on the copper substrate can effectively improves the corrosion resistance of the copper.Besides, the article also contains the influence of different Fe2+, WO42- in the solution and current density on the composition and properties of the coating. The results show that the higher concentration of Fe2+ in the solution, the lower hardness of the coating and the deposition rate is reducing. When the concentration of Fe2+ in the solution is 3.6 g/L, the current efficiency reaches maximum of 74.23%. Tungsten element content and microhardness of the coating are increasing when the concentration of WO42- in the solution is increasing. When the concentration of WO42- in the solution is 40 g/L, the deposition rate is 8.67 ?m/h. The current density increases, the coating micro-hardness, iron and tungsten content of the coating also increase. When the current density is 1.5 A/dm2, the highest current efficiency is 73.64%.