Fire resistant permanent magnet alloy and manufacturing method thereof

A permanent magnet, high temperature resistant technology, applied in the direction of magnetic objects, magnetic materials, electrical components, etc., can solve the problem of uniform mixing of main phase alloy and grain boundary phase alloy, no clear improvement of magnet temperature resistance, no public sintering High temperature resistance of magnets and other problems, to improve the poor temperature resistance, make up for the low temperature of use, and reasonably control the effect of grain size

Active Publication Date: 2012-07-18
BEIJING ZHONG KE SAN HUAN HI TECH +1
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The third-generation rare earth permanent magnet material sintered NdFeB, because its Curie temperature is only about 320 ° C, and the temperature coefficient is relatively large, such as the temperature coefficient of remanence is -0.11 ~ -0.126%, and the temperature coefficient of coercive force is -0.6 ~-0.8%, usually its working temperature is low, with the continuous expansion of the application range of rare earth magnets, such as the expansion of the demand for sintered NdFeB for automobile starter motors, motor products and integrated CO-ROM, in the current miniaturization Under the equipment, a new topic has been raised about the performance of magnets at high temperatures. How to improve the temperature resistance of sintered NdFeB magnets is a new challenge to expand its market application range.
In the sintered magnet NdFeB, the minimum content of the main phase alloy composition is Nd25.6B0.94Fe (wt%), and the minimum composition of the grain boundary phase alloy is the Nd28B0.63Fe remainder. With this composition range, it is impossible to achieve a high Hcj magnet. No addition of Co to the material is a necessary component for magnet preparation. There is no clear description of improvement in the temperature resistance of the magnet, and there is no specific method disclosed to reflect that the sintered magnet NdFeB can withstand high temperature.
During the addition process, the patent needs to add gasoline and liquid lubricants, which will easily cause powder agglomeration during the powder mixing process and high residual C and other elements in the sintering process, which will easily cause deterioration of magnet performance. Method and sintering method From the perspective of industrial production, this addition method seriously pollutes the sintering vacuum system and it is difficult to ensure the uniform mixing of the main phase alloy and the grain boundary phase alloy. Once a deviation occurs, it is difficult to ensure that Hcj reaches the predetermined value. Sintered NdFeB has not been produced on a large scale by such methods

Method used

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  • Fire resistant permanent magnet alloy and manufacturing method thereof
  • Fire resistant permanent magnet alloy and manufacturing method thereof
  • Fire resistant permanent magnet alloy and manufacturing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] The composition and content of the high temperature resistant permanent magnet alloy prepared in this embodiment are:

[0073] B: 1.02; Co: 4.5;

[0074] Nd: 19.5; Dy: 12;

[0075] Nb: 0.3; Cu: 0.14;

[0076] Ga: 0.12; Zr: 0.029; the above are percentages by weight;

[0077] Fe: 62.391 and above are weight percentages.

[0078] Wherein, the Zr is added in the form of nano-zirconia during the mixing of fine powder in the following step (3).

[0079] The high temperature resistant permanent magnet alloy manufacturing method of the present embodiment comprises the following steps:

[0080] 1. Weigh the raw materials according to the above alloy composition and content;

[0081] 2. Melting in a vacuum induction furnace until it is completely melted, pouring the resulting solution into a water-cooled ingot mold for casting to obtain an alloy ingot, and performing a solid melting treatment on the alloy ingot in a vacuum sintering furnace at 1080°C for 5 hours; using the ...

Embodiment 2-3

[0102] The composition and weight percentage of the high-temperature-resistant permanent magnet alloy to be prepared are listed in Table 2, and the rest of the preparation process is the same as in Example 1; the difference lies in step 4: the sintering temperature in a vacuum sintering furnace is 1100° C., and the sintering time is 5.5 hours. Further tempering at 470°C for 5 hours, followed by rapid cooling. The characteristics of the sintered magnet were measured in the same manner as in Example 1, and the results are recorded in Table 2.

[0103] Table 2 Example 2, 3 Irreversible demagnetization rate and weight loss results

[0104]

[0105] From the results of Table 2, when Example 2 is at 200°C (Pc=1), the irreversible demagnetization rate is -31.2%, and at 150°C (Pc=2), the irreversible demagnetization rate is -4.5%; Example 3 At 200°C (Pc=1), the irreversible demagnetization rate is -21%, and at 150°C (Pc=2), the irreversible demagnetization rate is -0.15%, so the m...

Embodiment 4

[0107] Embodiment 4, 5? The irreversible demagnetization rate of conventional sintered iron boron magnets with the same performance is about -17% at 200°C (Pc=1). It can be seen that the irreversible demagnetization rate at high temperature is lower than that of sintered NdFeB magnets of the same grade. It can be greatly improved, and the effect of maintaining high magnetic properties can be achieved even at high temperatures.

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Abstract

The invention relates to a permanent magnet alloy with excellent heat resistance and a preparation method thereof, and the alloy consists of components according to the following formula: R29-32Al0-0.4Nb0-0.8(Ti+Sn)0-0.1Zr0.01-0.029Ga0-0.4B0.95-1.2Co4.5-10Cu0.05-0.2Fe remaining, wherein, R at least selects from one of Ce, Pr, Nd, Dy or Tb, Fe remaining is Fe and inevitable impurities. In the preparation method, Zr is added by a 10-30 nanometer zirconium oxide powder form when mixing fine powder; as the zirconium oxide disperses in crystal boundary phase of an NdFeB magnet and is of square crystal structure, oxygen content distribution of the magnet and microstructure are effectively improved. The permanent magnet alloy with excellent heat resistance optimizes the matching of elements, improves the shortcoming of bad heat resistance of sintered NdFeB material, expands the application range of the sinterable NdFeB, improves the performance of the sintered NdFeB in two aspects of ingredient and technique, and can make up the shortcoming of low use temperature of the sintered NdFeB.

Description

technical field [0001] The invention relates to a magnetic material and a preparation method thereof, in particular to a high-temperature-resistant sintered NdFeB material and a preparation method thereof. Background technique [0002] Rare earth NdFeB permanent magnet material is the third generation permanent magnet material developed in the early 1980s. It is commonly known as the "Permanent Magnet King" because of its extremely strong magnetism. It can pick up objects equivalent to 1000 times its own weight, and has excellent magnetic characteristics and energy-saving, material-saving, and environmental protection effects. It is a high-performance material that other permanent magnet materials cannot match. As an important functional material, rare earth permanent magnet materials have been widely used in the fields of energy, transportation, machinery, medical treatment, computers, and home appliances, and penetrated into all aspects of the national economy. Its output ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/057C22C1/04C22C38/00B22F3/10
Inventor 赵玉刚张瑾胡伯平
Owner BEIJING ZHONG KE SAN HUAN HI TECH
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