Zirconium iron: It is an alloy synthesized by smelting zirconium and iron. As deoxidizer and alloy additive, ferrozirconium is used in special purpose superalloys, low-alloy high-strength steel, ultra-high-strength steel and cast iron, and then used in atomic technology, aviation manufacturing, radio technology and other fields. Zirconium iron alloy coarse particles are also widely used in neodymium iron boron industry and rare earth permanent magnet industry, which can better alloy with magnetic materials and improve product performance. Adding Nb, Zr, Ti and other metals to the Nd-Fe-B fast quenched permanent magnet alloy will change its microstructure, refine the crystal grain size evenly, improve the coercivity of the magnet and improve the temperature stability. China is rich in zirconium resources, and the price of zirconium is much lower than that of rare metals. Therefore, by replacing expensive rare metals with low-price metals, we can prepare products with the same magnetic properties to reduce production costs and improve market competitiveness.

Application: ingredients: according to the weight proportion of the following ingredients: 30.2% of the weight of praseodymium neodymium alloy, 2.0% of the weight of gadolinium, 1.03% of the weight of boron element, 0.64% of the weight of aluminum, 0.3% of the weight of zirconium, 0.02% of the weight of copper, and the rest is iron and other impurities. Among praseodymium neodymium alloy, praseodymium accounts for 25% of the weight, neodymium accounts for 75% of the weight, and boron is added as BFe alloy, with boron content of 19% and iron content of 81%; The gadolinium element is added as GdFe alloy, with gadolinium content of 75% and iron content of 25%;



Take smelting 100 kg NdFeB alloy as an example:

The metal raw materials described in the above table are loaded into the vacuum induction furnace.



Melting and casting: after being loaded into the vacuum induction furnace, vacuum the air in the vacuum induction furnace to less than 1 Pa, start heating and melting, close the vacuum valve when the ingredients in the furnace turn red, fill with argon, and after the materials are melted, refine and cast into spindles, then turn off the power supply, and then leave the furnace when the spindle temperature is lower than 60 ℃; Milling: Crush the spindle to 90~110mm blocks, and then treat the discharged particles of the blocks into less than 20 meshes after passing through the jaw crusher and the intermediate crusher, and then put the discharged particles into the air mill for milling, so that the powder particles are controlled within 2.7~5.5 μ M, put the powder into the mixer, add gasoline according to the proportion and mix for 30~60 minutes;



Forming: after weighing the mixed powder, put it into the mold of the forming press, apply magnetic field orientation, press it into shape, demagnetize it to take the green blank, quickly vacuumize it for packaging, and then put the packaged blank into the isostatic press to pressurize 150-200Mpa, hold the pressure for 1~3 minutes, and then take out the green blank made;



Sintering: put the green body into the material box, put it into the vacuum sintering furnace for sintering, sintering at the sintering temperature of 1080-1115 ℃ for 3.5-4.5 hours, and then take it out of the sintering furnace to make NdFeB magnets.



According to the above process steps, the sintered neodymium iron boron alloy is made by replacing 1% Nb with 0.3% Zr, and the other components remain unchanged. The test method is in accordance with the provisions of GB/T 3217 Magnetic Test Method for Permanent Magnet (Hard Magnetic) Materials. After testing, the magnetic properties reach:



Residual magnetic energy Br: 12 6KGs



Intrinsic coercivity Hcj: 13 5KOe



Magnetically induced coercivity Hcb: 11.9KOe



Magnetic energy product BH (max): 38. 4MGOe



Compared with the data of performance test, it can be seen that the value of the above four parameters of magnetic properties has been improved after using 0.3% zirconium element to replace 1% niobium element. It can be seen that using the replacement element zirconium and using the above process to manufacture sintered NdFeB alloy has achieved the goal of cost saving.