Method for producing Sm-Fe-N permanent magnet alloy powder by reduction diffusion

Abstract

The invention provides a method for manufacturing Sm-Fe-N permanent magnetic alloy powder by adopting a reduction diffusion method. The process flow is: selection of raw materials and pretreatment→ratio of reactants→mixing of reactants→metal thermal reduction and diffusion alloying→chemical separation of reaction products→dehydration and drying of metal powder→powder nitriding treatment→manufacture of anisotropic bonding Sm-Fe-N magnet; it is characterized in that: use rare earth chloride and selectively control the particle size of alloy element iron powder, and the reducing agent is metal Ca and CaH 2 , carry out reduction diffusion reaction in the lower temperature range of 760-860 ℃ to generate Sm-Fe alloy and by-products, and after chemical separation, Sm-Fe alloy is pulverized and nitrided to directly obtain Sm-Fe with required composition and particle size requirements -N magnetic alloy powder. The advantages are: low reaction temperature, small loss of Sm, easy control of composition, simplified process and good performance.

Description

Technical field:

[0001] The invention belongs to the field of magnetic materials, and in particular provides a method for manufacturing Sm-Fe-N permanent magnetic alloy powder. Background technique:

[0002] Sm-Fe-N series alloy is a kind of rare earth permanent magnet material with excellent performance. In terms of basic magnetic properties, its saturation magnetization is equivalent to that of R-Fe-B system, and the anisotropy field and Curie temperature ratio R- Fe-B should be high. Since Sm-Fe-N will decompose when it is higher than 600°C, it is mainly used to manufacture bonded magnets, and the magnetic properties of bonded magnets mainly depend on the magnetic properties of Sm-Fe-N magnetic powder. At present, the preparation methods of Sm-Fe-N magnetic powder include ingot mechanical crushing method, also known as conventional method (IEEE.Trans.Mag.1993(29):2815); HDDR method (Physical Statuas Solidi A 1995(147):229); Rapid quenching method (J.Appl.Phys.1991.70(6)...

Examples

Embodiment 1

[0019] The raw material adopts SmCl 3 , Fe powder (500 orders), calculate the chemical dose of each reactant required by formula (1), SmCl 3 The amount added is 103% of the stoichiometric dose, the metal Ca particle size is 3mm, and the added amount exceeds the stoichiometric dose by 15%, SmCl 3 After vacuum dehydration at 360°C. The reduction diffusion reaction was carried out under the protection of argon, and kept at 820°C for 2 hours. The reaction block was naturally pulverized in water, and the powder was filtered out and dried in vacuum. Alloy powder in NH with a pressure of 0.1Mpa 4 Treated at 450°C for 1 hour in the atmosphere, the magnetic properties of the prepared Sm-Fe-N alloy powder are: Br=9.8kGs, M Hc=8kOe, (BH)m=18MGOe.

Embodiment 2

[0021] The raw material adopts SmCl 3 , Fe powder (500 mesh) and Co powder (500 mesh), according to formula (1) calculate the stoichiometric dose of each reactant required, SmCl 3 The amount added is 105% of the stoichiometric amount, Co replaces 5% of the amount of Fe powder, the particle size of metal Ca is 3mm, and the added amount is 120% of the stoichiometric amount. SmCl 3 After vacuum dehydration at 360°C. The reduction diffusion reaction was carried out under the protection of argon, and kept at 850°C for 2 hours. The reaction block was naturally powdered in water, and the powder was filtered out and dried in vacuum. Alloy powder in NH with a pressure of 0.2Mpa 4 and H 2 (7.5:2.5) in a mixed atmosphere of 450 ° C for 1 hour, the magnetic properties of the prepared Sm-Fe-N alloy powder are: Br=11.2kGs, M Hc = 9.8kOe, (BH)m = 26MGOe.

Technical field:

[0001] The invention belongs to the field of magnetic materials, and in particular provides a method for manufacturing Sm-Fe-N permanent magnetic alloy powder. Background technique:

[0002] Sm-Fe-N series alloy is a kind of rare earth permanent magnet material with excellent performance. In terms of basic magnetic properties, its saturation magnetization is equivalent to that of R-Fe-B system, and the anisotropy field and Curie temperature ratio R- Fe-B should be high. Since Sm-Fe-N will decompose when it is higher than 600°C, it is mainly used to manufacture bonded magnets, and the magnetic properties of bonded magnets mainly depend on the magnetic properties of Sm-Fe-N magnetic powder. At present, the preparation methods of Sm-Fe-N magnetic powder include ingot mechanical crushing method, also known as conventional method (IEEE.Trans.Mag.1993(29):2815); HDDR method (Physical Statuas Solidi A 1995(147):229); Rapid quenching method (J.Appl.Phys.1991.70(6)...

Examples

Embodiment 1

[0019] The raw material adopts SmCl 3 , Fe powder (500 orders), calculate the chemical dose of each reactant required by formula (1), SmCl 3 The amount added is 103% of the stoichiometric dose, the metal Ca particle size is 3mm, and the added amount exceeds the stoichiometric dose by 15%, SmCl 3 After vacuum dehydration at 360°C. The reduction diffusion reaction was carried out under the protection of argon, and kept at 820°C for 2 hours. The reaction block was naturally pulverized in water, and the powder was filtered out and dried in vacuum. Alloy powder in NH with a pressure of 0.1Mpa 4 Treated at 450°C for 1 hour in the atmosphere, the magnetic properties of the prepared Sm-Fe-N alloy powder are: Br=9.8kGs, M Hc=8kOe, (BH)m=18MGOe.

Embodiment 2

[0021] The raw material adopts SmCl 3 , Fe powder (500 mesh) and Co powder (500 mesh), according to formula (1) calculate the stoichiometric dose of each reactant required, SmCl 3 The amount added is 105% of the stoichiometric amount, Co replaces 5% of the amount of Fe powder, the particle size of metal Ca is 3mm, and the added amount is 120% of the stoichiometric amount. SmCl 3 After vacuum dehydration at 360°C. The reduction diffusion reaction was carried out under the protection of argon, and kept at 850°C for 2 hours. The reaction block was naturally powdered in water, and the powder was filtered out and dried in vacuum. Alloy powder in NH with a pressure of 0.2Mpa 4 and H 2 (7.5:2.5) in a mixed atmosphere of 450 ° C for 1 hour, the magnetic properties of the prepared Sm-Fe-N alloy powder are: Br=11.2kGs, M Hc = 9.8kOe, (BH)m = 26MGOe.