Method for producing permanent magnetic material

Method for producing permanent magnetic material

  • CN 107,068,380 B
  • Filed: 01/23/2017
  • Issued: 02/18/2020
  • Est. Priority Date: 01/23/2017
  • Status: Active Grant
First Claim
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1. A method for producing a permanent magnetic material, characterized in that the method comprises the following steps:

  • s2) electroplating process;

    plating a heavy rare earth metal on the surface of the sintered magnet in a plating solution to form a magnet with a plating layer;

    wherein the length, width and height of the sintered magnet are respectively 10-60 mm, 5-40 mm and 1-10 mm, and the density of the sintered magnet is 6.5g/cm3

    8.9g/cm3The oxygen content of the sintered magnet is lower than 2000 ppm;

    s3) diffusion step;

    heat-treating the magnet with the plating layer to diffuse heavy rare earth metals into the interior of the sintered magnet;

    wherein the electroplating solution is an aqueous solution containing soluble heavy rare earth salt, soluble group VIII metal salt and a complexing agent;

    the soluble heavy rare earth salt is terbium acetate;

    the soluble group VIII metal salt is ferrous sulfate; and

    the complexing agent is selected from lithium, sodium or potassium salts of citric acid;

    the aqueous solution is not an organic solvent or an ionic liquid;

    in the electroplating solution, the concentration of the soluble heavy rare earth salt is 0.3-0.6 mol/L;

    the concentration of the coordination agent is 0.3-0.6 mol/L; and

    the concentration of the soluble VIII group metal salt is 0.1-0.3 mol/L.

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