Method of supersonic chemical plating nickel phosphorus of powder metallurgy material

Abstract

In the invention, the sodium hypopphosphite 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 is adopted that utilizes the mechanical energy of the ultrasonic vibration, making the bath deposit nickel and phosphor under the catalysis of the metal surface and the chemical reduction method controlled. The plating procedure includes the steps of 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 a method for ultrasonically electroless nickel-phosphorous plating of powder metallurgy materials. Background technique [0002] In recent years, the application and development of powder metallurgy materials are very rapid, and most of the materials are synthesized from a variety of powders, and there are many micropores on the surface of the materials due to technological reasons. For example, neodymium-iron-boron (NdFeB) permanent magnet materials are prepared by powder metallurgy, and NdFeB permanent magnets are made after SmCo 5 and Sm 2 co 17 The third generation of rare earth permanent magnet materials after that has become an important functional material in the modern high-tech field due to its high saturation magnetization, coercive force and magnetic energy product, but because NdFeB permanent magnets are easy to oxidize and rust, corrosion resi...

AI Technical Summary

Problems solved by technology

For example, neodymium-iron-boron (NdFeB) permanent magnet materials are prepared by powder metallurgy, and NdFeB permanent magnets are made after SmCo 5 and Sm 2 co 17 The third generation of rare earth permanent magnet materials after that has become an important functional material in the modern high-tech field due to its high saturation magnetization, coercive force and magnetic energy product, but because NdFeB permanent magnets are easy to oxidize and rust, corrosion resistance Poor performance limits its wide application

[0003] In the prior art, the methods of electroless plating and electroplating are mostly used for materials with similar surface treatment. Among the electroless plating technologies, neutral electroless plating, acidic electroless plating and alkaline electroless plating have been developed. These electroless plating methods have been developed several times. Ten years, according to incomplete statistics, there are at least two hundred kinds of mature electroless nickel plating formulas in the world (page 6 of "Electroless Plating Theory and Practice", National Defense Industry Press), and ultrasonic electroless plating is used for powder metallurgy materials. The method has not been reported yet

For NdFeB powder metallurgy materials, electroless nickel plating or electroplating copper-nickel composite coating is generally used as the protective layer in the world. In February 2001, the first issue of volume 32 of "Magnetic Materials and Devices" introduced the analysis of defects in the coating of sintered NdFeB magnets. After electroplating treatment, irregular pits or pits often appear in some parts of the Ni coating or Zn coating of the magnet, which affects the quality of the coating and the use of the magnet; Nickel composite coating is used as a protective layer. Among them, the electroless nickel coating has a large porosity and poor corrosion resistance, while electroplating has problems such as uneven thickness and unstable coating quality.