Production Process:
Sintered neodymium magnet: produced by powder metallurgy process, the smelted alloy is made into powder, pressed into a pressed embryo in a magnetic field, and then sintered in an inert gas or vacuum to achieve densification. Aging heat treatment is usually required to improve the coercive force of the magnet.
Bonded neodymium magnet: It is made by mixing rapidly quenched NdFeB magnetic powder and a binder, and is made by pressing or injection molding. It has high dimensional accuracy and can produce magnetic components with relatively complex shapes.
Physical Properties:
Sintered neodymium magnet: It has high magnetic properties, such as high remanence and maximum magnetic energy product, but relatively low mechanical strength, and is relatively brittle and susceptible to corrosion. It usually requires surface treatment such as electroplating or coating.
Bonded neodymium magnet: The magnetic properties are usually lower than those of sintered neodymium magnets, but it has higher mechanical strength and dimensional accuracy, better corrosion resistance, and is suitable for applications with complex shapes.
Application Areas:
Sintered neodymium magnet: It is widely used in high-performance magnetic applications such as high-performance permanent magnet motors, speakers, hard disk drives, power tools, etc.
Bonded neodymium magnets: commonly used in micro motors, sensors, magnetic fixtures, toys, packaging and other fields, especially for applications with complex shapes or high dimensional accuracy.
Cost And Price:
Sintered neodymium magnets: due to their high performance, they usually have higher costs and prices.
Bonded neodymium magnets: the production process is relatively simple, the cost is low, and the price is relatively cheap.
Corrosion Resistance:
Sintered neodymium magnets: easy to corrode, usually require surface plating to improve corrosion resistance.
Bonded neodymium magnets: usually have better corrosion resistance due to the presence of binders.
Appearance And Surface Treatment:
Sintered neodymium magnets: the surface is smooth and dense, usually silver-white, and no additional surface treatment is required.
Bonded neodymium magnets: the surface is relatively rough, with a certain porous structure, usually wet black or gray, and need to be coated with a layer of epoxy resin or polyparaxylene to prevent corrosion.
Density And Hardness:
Sintered neodymium magnets: the density is about 7.4-7.6 g/cm3, and the hardness is about 560-580Hv.
Bonded neodymium magnets: Density is usually lower than the theoretical value because they contain a binder. The hardness and density vary according to the specific binder and magnetic powder ratio.
Temperature Stability:
Sintered neodymium magnets: Depending on the performance level, the maximum operating temperature is between 80-250 degrees Celsius.
Bonded neodymium magnets: Poor heat resistance, the operating temperature usually does not exceed 150°C.
Both types of neodymium magnets have their own advantages and limitations, and the choice needs to be determined based on specific application requirements and cost budgets.