NdFeB permanent magnet material electroplating solution

Features

(1) The 4f electron of rare earth neodymium is not tightly closed to the nucleus, and its shielding coefficient is smaller than other internal electrons with the same principal quantum number, so it has a larger effective nuclear charge and shows a strong adsorption capacity . When they are added to the plating solution in an appropriate amount, they can gather on the surface of the magnet, inhibit the corrosion of the neodymium-rich phase, and obtain a dense and uniform initial deposition layer on the surface of the magnet. At the same time, it is adsorbed on the crystal defects (such as vacancies, dislocation outcrops, grain boundaries, etc.) on the surface of the substrate, thereby reducing the surface energy, increasing the nucleation rate of the alloy coating, and accelerating the deposition.

(2) The structure of the electric double layer at the electrode interface is changed through the adsorption of rare earth elements, which affects the electrodeposition and interface diffusion process of nickel and phosphorus, so that the nickel atoms cannot reach the normal lattice junctions, which can change the coating The microstructure promotes the formation of amorphous state. At the same time, it improves the deep plating ability, dispersion ability and current efficiency of the plating solution.

(3) Rare earth has good complexing properties, so its ions can easily form a series of complexes with inorganic and organic ligands in aqueous solution, which promotes the equilibrium dissociation of metal ions in the plating solution and reduces The tendency of the plating solution to decompose spontaneously, so that the plating solution is more stable, not easy to decompose, and the stability of the plating solution is improved.

(4) After adding a proper amount of rare earth elements to the plating solution, the metal cell particles are smaller and denser, the surface of the coating layer is relatively flat, the gap between the center and the edge of the cell bulge is small, the metal content distribution in the layer is relatively uniform, and the composition is relatively uniform. Small, thus reducing the tendency of electrochemical corrosion, effectively improving the corrosion resistance of the coating.

Usage and usage: This product is mainly used in the electroplating of neodymium iron boron permanent magnet materials.

The method of using the electroplating solution is: adjust the pH to 3.0-5.0 with 5%-10% sodium hydroxide during plating, heat to 50-75℃, cathode current density 2-8A/dm2, anode nickel Metal, the cathode is a magnet.

Recipe:

Production method: (1) Dissolve nickel sulfate, nickel chloride, boric acid, sorbitol, and neodymium sulfate in water and mix them evenly;

(2) Dissolve sodium hypophosphite in water;

(3) Under stirring conditions, slowly pour the sodium hypophosphite solution into the solution of (1) and stir evenly;

(4) Add distilled water or deionized water to the specified volume, and stir evenly.