A sintering method for reducing cracks in NdFeB products

Abstract

The invention belongs to the technical field of rare-earth magnetic materials, and particularly discloses a sintering method capable of reducing cracks of neodymium iron boron products. The sintering method includes the following steps: cast sheet broken materials and cast sheet hydrogen broken materials are mixed in proportion, and then the mixture is grinded through an air-current mill to prepare alloy powder with the size ranging from 2.8 micrometers to 3.5 micrometers; then sieving is carried out; the powder is finally oriented in a 1280-1440-KA / m magnetic field pressing machine, forming is carried out in a vertical-steel-mold-pressing and isostatic-cool-pressing mode, green bodies are sintered for three hours to five hours at 1323 K to 1383 K under the 10<-2>-10<-3>-Pa vacuum condition, then gas quenching and cooling are carried out, tempering is carried out for three hours at 1073 k to 1173 k, tempering is carried out for two hours to three hours at 733 k to 873 k, and the neodymium iron boron products are obtained. By means of the sintering method, the cracks of the high-performance large products are reduced, scrapping, caused by the cracks, of magnets is reduced, and the production cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of rare earth magnetic materials, and specifically relates to a sintering method for reducing cracks in NdFeB products. Background technique [0002] Since the invention of sintered Nd-Fe-B permanent magnet material in 1983, it has received extensive attention all over the world, applied in many high-tech fields, and rapidly developed into an important industry. Extensive research efforts have led to the commercial production of high energy product magnets. However, there is little research on the production process of large-scale products. For large-scale products, if the sintering and cooling are too fast, the internal stress of the product will not be released in time, which will cause the product to crack. The pass rate of the product is low. At present, the production of large-scale products is to reduce the cooling speed of the product during sintering, but the slow cooling of the sintering aging is n...

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Problems solved by technology

However, there is little research on the production process of large-scale products. For large-scale products, if the sintering cooling is too fast, the internal stress of the product will not be released in time, which will cause the product to crack

The pass rate of the product is low. At present, the production of large-scale products is to reduce the cooling speed of the product during sintering, but the slow cooling of the sintering aging is not conducive to the performance of the product, and the squareness is not good; Cracks of about 5-50% are inevitable, which increases the production cost of large-scale products and the risk of poor quality

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