Electronickelling method for neodymium iron boron sheet magnetic steel product

Abstract

The invention discloses an electronickelling method for a neodymium iron boron sheet magnetic steel product. Nickel preplating, semi-bright nickel plating and bright nickel plating are sequentially conducted, a double-pulse power supply is adopted in the nickel preplating process, high current density is used by the double-pulse power supply, and therefore a nickel preplated coating large in density, high in hardness, low in porosity and high in uniformity is formed on the surface of the neodymium iron boron sheet magnetic steel product where nickel preplating is conducted. In the subsequent semi-bright nickel plating process, a semi-bright nickel solution is composed of nickel sulfate, nickel chloride, boric acid, sodium potassium tartrate tetrahydrate, triethanolamine, ammonium sulfate, ammonium hydroxide and water according to a specific ratio, sodium potassium tartrate tetrahydrate serves as a coordination agent in the semi-bright nickel solution, ammonium sulfate serves as conducting salt, uniformity of a semi-bright nickel coating is improved, and finally a bright nickel layer high in uniformity is generated on the semi-bright nickel coating. The electronickelling method has the beneficial effects that a nickel-plated layer is composed of the nickel preplated layer, the semi-bright nickel layer and the bright nickel layer which are high in uniformity, and the coating distribution uniformity of the neodymium iron boron sheet magnetic steel product is greatly improved.

Description

technical field [0001] The invention relates to a nickel electroplating method, in particular to a nickel electroplating method for neodymium-iron-boron thin-slice magnetic steel products. Background technique [0002] NdFeB permanent magnet material is a powder material with strong chemical activity. Its characteristics are hard and brittle, and it is easy to be oxidized and corroded. The corrosion resistance of NdFeB magnet products made of NdFeB permanent magnet materials poor. At present, the most effective anti-corrosion method adopted by NdFeB magnet products is to use surface treatment methods to form a protective layer on the surface of NdFeB magnet products. Since the surface of NdFeB magnet products has a deteriorated layer produced during grinding, voids and oxidation caused by incomplete densification, the surface treatment process usually includes necessary pre-treatment and appropriate electroplating process. Electroplated nickel crystals are extremely small ...

AI Technical Summary

Problems solved by technology

However, the existing electroplating nickel method is applied to the treatment of neodymium with the characteristics of thin thickness (thickness ≤ 1mm), small chamfering angle (chamfering radius R ≤ 0.2) and narrow dimensional tolerance band (positive and negative tolerance ≤ 0.010mm). When using iron-boron thin-film magnet products, the power lines will be too concentrated on the edge and tip of the NdFeB thin-film magnet product, and "edge effect" and "tip effect" often appear, making the coating at this place thicker than other parts, resulting in product failure. The thickness difference between the end size and the center point size is too large, resulting in poor uniformity of coating distribution, which directly affects the overall assembly of the product

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