Nickel phosphorus chemical plating method of neodymium iron boron permanent magnet material

Abstract

In the invention, the sodium hypophosphite is as the reducing agent of the bath, nickel sulfate as the main salt, with the complexing agent, accelerating agent and stabilizing agent being added. The ultrasonic chemical plating and second chemical plating method are adopted that utilizes the mechanical energy of the ultrasonic vibration, making the bath deposit nickel and phosphor under the catalysis of the metal surafce and the chemical reduction method controlled. The plating procedure includes the steps of edge rounding, oil removal, rust removal, activation, chemical plating and post treatment. The multiple complexing, accelerating and stabilizing agents raises the stability of the bath. The plating speed is adjustable. The even, compact nickel and phosphor plating layer covers the surface of the base body of powder metallurgical material so as to increase the service life of the material and provide wide application area.

Description

technical field [0001] The invention relates to the field of surface chemical treatment of materials, in particular to an electroless nickel-phosphorus plating method for NdFeB permanent magnet materials. Background technique [0002] In recent years, the application and development of NdFeB permanent magnet materials is very rapid, and the success of the protection of NdFeB permanent magnet materials is the key to whether the material can be popularized and applied. NdFeB permanent magnet is following SmCo 5 and Sm 2 co 17 The third generation of rare earth permanent magnet materials has become an important functional material in the modern high-tech field due to its high saturation magnetization, coercive force and magnetic energy product. However, due to technological reasons, there are many micropores on the surface of the material. The surface of NdFeB permanent magnet is porous and the existence of Nd-rich phase makes it easy to oxidize and rust, and its poor corros...

AI Technical Summary

Problems solved by technology

NdFeB permanent magnet is following SmCo 5 and Sm 2 co 17 The third generation of rare-earth permanent magnet materials has become an important functional material in the modern high-tech field due to its high saturation magnetization, coercive force and magnetic energy product. However, due to technological reasons, there are many micropores on the surface of the material. The surface of NdFeB permanent magnet is porous and the existence of Nd-rich phase makes it easy to oxidize and rust, and its poor corrosion resistance limits its wide application

[0003] In the existing technology, Al-Cr acid passivation method, organic coating method, vacuum coating method, electroplating and chemical plating are often used for surface treatment of NdFeB materials, and some effects have been achieved, but there are still problems of poor corrosion resistance. , such as: "Magnetic Materials and Devices" Volume 32, Issue 1, February 2001, introduced the analysis of coating defects of sintered NdFeB magnets. After electroplating, some parts of the Ni coating or Zn coating of the magnet often have irregular shapes Points or pits, which affect the quality of the coating and the use of magnets; in addition, currently the world generally uses electroless nickel coating or electroplating copper-nickel composite coating as the protective layer, of which the electroless nickel coating has a large porosity and poor corrosion resistance, while There are problems such as uneven thickness and unstable plating quality in electroplating