Sintering, adhesion, hot pressing ndfeb strong magnet properties and advantages and disadvantages of contrast _ ndfeb strong magnet manufacturers
Ndfeb permanent magnets with high magnetic energy product and coercive force, and has the advantages of high energy density, in the modern industry and has been widely used in electronics, instruments and meters, electronic motor, magnetization of the magnetic separation equipment such as lightweight, miniaturization, thin.
Ndfeb permanent magnet products according to the different production process can be divided into sintered ndfeb, ndfeb bonded ndfeb and hot pressing, etc. , because of the different production process, they after magnetic products, processing and application has great different.
Among them, the hot-pressing ndfeb has high density and high orientation degree and good corrosion resistance and high coercive force and close to the end, but the mechanical can not good and due to the patent monopoly, tooling cost is higher, general, Japanese datong (only on the market at present
And Europe delta three companies have production technology, and only Japan tatung company for mass production, so the output is far less than a hot-pressing ndfeb sintered and adhesive ndfeb magnets, domestic hot-pressing ndfeb magnet production is still blank in our country.
Therefore, this article focuses on analysis of sintered ndfeb and adhesive ndfeb.
Sintered ndfeb powder metallurgy process, smelting of metal powder in the magnetic medium pressure after pressing, the specific production process is: the ingredients & rarr;
Vacuum melting & rarr;
Broken flour & rarr;
The magnetic field orientation & rarr;
Sintering & rarr;
Heat treatment & rarr;
Machining & rarr;
Ndfeb magnet products.
Its advantage mainly magnetic is extremely high, is the largest current magnetic magnetic materials, widely used in electronics, electrical machinery, new energy vehicles, medical equipment, aerospace and other fields.
Its main shortcoming includes: first, you need to add heavy rare earths in dysprosium/Cheng in order to improve the intrinsic coercive force of magnets and the working temperature, and in order to adapt to the high temperature working environment, part of the sintered ndfeb containing heavy rare earths in large scale high value (
Unit cost is higher, making the product;
The second is the manufacturing process is the first sintering for blank and then to machining, the machining process loss is higher.
Bonded ndfeb is made from ndfeb magnetic powder adding glue, and adopt the molding method of preparation of magnet, the technological process consists of milling process, bonding process and molding process three steps, the specific process is as follows: magnetic powder and binder mixing one injection/compression molding & rarr;
Curing grinding & rarr;
Surface treatment of a plastic injection assembly & rarr;
The magnetization & rarr;
Bonded ndfeb magnets, finished products.
Among them, the magnetic powder and can be divided into isotropic and anisotropic two kinds, magnetic powder manufacturing method mainly has rapid quenching method, H DDR method (
Hydrogenated a disproportionation, dehydrogenation restructuring process)
, gas atomization method, etc.
Bonded ndfeb main advantages: one is the product easy to shape, has a very high dimensional accuracy, in the production of hard disk, CD has considerable advantages such as high precision;
Second, in the product does not contain heavy rare earths, make the product unit raw material cost is relatively low;
Three is due to use direct molding process, therefore, lower processing loss.
Its main drawback is that compared with sintered ndfeb, bonded ndfeb magnetic low intrinsic coercive force and low operating temperature (
See table 1)