NdFeB permanent magnet materials have high energy density, high coercivity, and good temperature characteristics, and are widely used in the electronics industry.
With the increasing demand for high-performance NdFeB permanent magnets and the continuous advancement of technology, their prices are also declining. There are two types of high temperature resistant NdFeB permanent magnets currently on the market: sintered and non-sintered. This paper mainly compares and analyzes the characteristics and performance of two types of high-temperature NdFeB permanent magnets.
Sintered high temperature rare earth permanent magnet:
The working temperature of high-temperature rare earth permanent magnets is generally above 600°C (such as hc-mn series). Due to the high working temperature of this type of product, it is required to have high performance indicators such as high temperature resistance strength and oxidation resistance; at the same time, it must have better performance and lower cost advantages.
Types of sintered high temperature rare earth permanent magnets:
According to different preparation methods, it can be divided into:
(1) Powder metallurgy method:
It is formed by adding high-alumina powder or binder with a certain particle size into the molten metal and rapidly cooling and solidifying.
(2) Hot pressing method:
The sintered material is made into thin slices and then heat-treated to obtain the finished product.
(3) Direct casting method:
It is directly formed by heating the alloy ingot below the melting point.
(4) Preparation by casting method:
It is directly cast from liquid alloy.
(5) Preparation by extrusion method:
It is obtained by machining the blank into the required shape by mechanical pressure in a vacuum state and then annealing it.
(6) Preparation by induction heating:
It is obtained by sintering the alloy elements in the billet into the desired shape by induction heating and then annealing.
(7) Preparation by electroslag remelting method:
The metal material to be processed is melted and evaporated to form a dense oxide film by means of an electric arc generated by a resistance furnace or a high-frequency power supply to form a blank of the desired shape, and then heat-treated to obtain a finished product.