A method for adjusting the size of an NdFeB magnet and a size adjusting agent
A technology of neodymium iron boron and regulator, applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve problems such as increasing production costs, delaying product delivery, and failing to meet requirements in size
Active Publication Date: 2015-12-23
DONGYANG ZHONGYUAN MAGNETIC MATERIAL
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Problems solved by technology
However, sintered NdFeB magnets shrink during the sintering process, and there are many factors that will affect the size of the product (radial and longitudinal shrinkage)
However, this uncertain factor of radial and longitudinal shrinkage brings inconvenience to NdFeB manufacturers to ensure product specifications.
Many manufacturers have encountered this situation, and the performance of the products they make is good in all aspects, but they cannot be shipped because the size does not meet the requirements.
Instead, the mold can only be replaced to re-produce in order to ensure the specification and size of the product, thus increasing the production cost and delaying the delivery date of the product
Method used
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[0010] In order to determine the effect of the addition of the size regulator on the size of the sintered blank, the experiment adopted is as follows: the NdFeB powder was added with 0.2‰, 0.3‰, and 0.5‰ size regulator for uniform mixing and without adding the regulator. For comparison, the dimensions of the sintered blanks obtained after molding and pressing into blanks, sintering and heat treatment are shown in the table below. The dimensions in the height direction in the table can be controlled by adjusting the weighing powder quality. Experiments show that with the increase of regulator content, the shrinkage in the direction of sintering orientation decreases. Adjusting the sintering shrinkage rate is conducive to obtaining NdFeB blanks of different sizes with the same pressing die, and the size difference can reach 10%, which brings great convenience to the production of NdFeB products. The size yield of NdFeB products has been greatly improved, and the achievement rat...
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Abstract
The invention provides a method for adjusting the size of a neodymium iron boron magnet. The method is characterized in that neodymium iron boron powder is subjected to airflow mill, then a size adjustment agent is added into the powder to perform full mixing, a mixture is formed in a magnetic field pressing machine, a formed blank is put into a sintering furnace and heated to be at 300 DEG C constant temperature through a vacuum furnace, and then the adjustment agent is discharged out of the blank. The size adjustment agent used in the pressing process of the neodymium iron boron powder can further reduce powder fiction and has the effect of a lubricating agent. Due to the fact that zinc stearate contained in the size adjustment agent can reduce friction force of magnetic powder particles in the neodymium iron boron forming process, the powder liquidity is enhanced, and the orientation degree of the magnet is improved. In the forming and pressing process, the powder gradually becomes the blank with certain density from a loose state with increasing pressure, and when the magnetic powder has high density, the added lubricating agent has not obvious effect on overcoming of magnetic flocculation, but has very remarkable effects on reduction of the friction force and improvement of orientation degree of the powder in the blank with certain density.
Description
technical field [0001] The invention belongs to a magnetic auxiliary material and a preparation method thereof, in particular to a method for adjusting the size of an NdFeB magnet and a size adjusting agent. Background technique [0002] As the third generation of rare earth permanent magnets, NdFeB permanent magnets have excellent magnetic properties, good processing characteristics and relatively low prices. They are widely used in industrial automation, computers, home appliances, communications and many other fields. Since 1984, after more than 20 years of development, the magnet industry has made great progress and achieved world-renowned achievements. The sintered NdFeB and bonded NdFeB produced in my country are all in the forefront of the world. It has reached a relatively high level in raw material supply, production volume, variety quality, process technology, domestic application volume and market sales. Among them, the output, application volume and market sale...
Claims
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IPC IPC(8): H01F41/02H01F1/057H01F1/08B22F3/16C10M169/04C10N30/06C10N40/14
Inventor 金向阳赵冶卢燎花
Owner DONGYANG ZHONGYUAN MAGNETIC MATERIAL