Ningbo Longjian Magnetsy Industry Co., Ltd. is a company engaged in various types of magnetic materials and
manufacturing technology development company , The company has
advanced production technology and rich experience in engineering
and technical personnel , these are our customer service Guarantee
The company adopts advanced technology , excellent equipment, can
be customized according to different need of customers personalied
production programs, to save costs for customers , to provide
quality stablity of magnetic products.
Now our products have been widely used in various types of motors,
speakers, VCM, display equipment, door and window hardware,
refrigerator stickers, nuclear magnetic resonance, magnetic
separator, magnetic drive, magnetic suspension, iron remover, high
temperature spray, hardware tools, leather goods bags, glasses
Boxes, instruments, medical equipment, communication equipment,
computers, packaging boxes, electronics, handicrafts and many other
industries and fields.
Ningbo Longjian Magnetsy Industry Co., Ltd. is willing to excellent quality,reasonable price , excellent
service of Magnetic products with various specifications of various
characteristics to customers , Mutual benefit and win-win is our
pursuit of dragon !
Sintered NdFeB magnets, as one of the important substances to
promote contemporary technology and social progress, are widely
used in the following fields: computer hard disk, magnetic
resonance imaging, electric vehicles, wind power, industrial
permanent magnet motors, consumer electronics (CD, DVD) , mobile
phones, audio, copiers, scanners, cameras, cameras, refrigerators,
televisions, air conditioners, etc.) and magnetic machinery,
magnetic suspension technology, magnetic transmission and other
Since 1985, industrialization has begun in Japan, China and Europe
and the United States. In the past 30 years, the global permanent
magnet materials industry has flourished, and its magnetic
properties have been continuously recorded. The variety of
materials and grades has been increasing. With the expansion of the
market, its manufacturers are also increasing, and many customers
are inevitably caught in such confusion, how to judge the pros and
cons of the product?
The most comprehensive judgment method: one, magnet performance;
two, magnet size; three, magnet plating.
First of all, the guarantee of the performance of the magnet comes
from the control of the raw material production process.
1. According to the requirements of the company to manufacture
high-grade or medium-grade or low-grade sintered NdFeB, the raw
materials are selected according to the national standard.
2. The advanced production process directly determines the
performance quality of the magnet.
3. In terms of magnetic field orientation, China is the only
country in the world that adopts two-step press molding. It is
vertically molded with small pressure during orientation, and
finally adopts quasi-isostatic pressing. This is one of the most
important characteristics of China's sintered NdFeB industry. .
4. Moreover, the monitoring of the quality of the production
process is very important, and can be controlled by the thickness
measurement of the SC piece and the particle size distribution of
the JM powder. High-quality products are all dependent on the
control of the production process, but customers will be very
confused, how to judge the performance of the products I purchased?
China Institute of Metrology has developed a variety of magnetic
material measuring instruments for permanent magnet materials.
Pulsed Magnetic Field Magnetometer (PFM) is a test instrument for
testing ultra-high-coercive permanent magnets, mainly for the
high-coercive permanent magnets required in the electric vehicle
field and large permanent magnet motors.
Second, the guarantee of the size of the magnet depends on the
processing strength of the factory.
The practical application of sintered NdFeB magnets is various in
shape, such as wafer, cylinder, cylindrical (with inner hole);
square, square, square column; tile, fan, trapezoid, polygon and
various Irregular shapes, etc. Each shape of the permanent magnets
has different sizes, and it is difficult to make one molding in the
production process. The general production process is: the
production of large (large size) billets, after sintering and
tempering, and then through mechanical processing (including
cutting, drilling) and grinding, surface coating (coating)
treatment, and then Magnet performance, surface quality and
dimensional accuracy are measured and then magnetized, packaged and
Again, the quality of the magnet coating directly determines the
service life of the product.
It has been experimentally found that a 1 cm3 sintered NdFeB magnet
is placed in air at 150 ° C for 51 days and will be completely
oxidized and etched away. It is more susceptible to corrosion in
weak acid solutions. In order to make the NdFeB permanent magnet
durable, it is required to have a service life of 20-30 years, and
it must be subjected to surface anti-corrosion treatment to resist
the corrosion of the magnet by the corrosive medium. At present,
the sintered NdFeB magnet manufacturing industry generally adopts
electroplating metal, electroplating + electroless metal plating,
electrophoretic coating and phosphating treatment, and an
additional spacer is plated on the surface of the magnet to isolate
the surface of the magnet from the corrosive medium. To prevent the
media from invading the magnet.
In summary, customers can only correctly judge the eligibility of
products if they understand their production processes and
understand the requirements of the products. In a nutshell, it is
performance control, dimensional tolerance control, coating
inspection and appearance evaluation.
In terms of performance, it can be tested for Br (remanence), Hcb
(coercivity), Hcj (intrinsic coercivity), (BH)max (maximum energy
product) and demagnetization curve; dimensional tolerance can be
performed by vernier caliper Measure the accuracy; on the coating,
the brightness of the coating can be observed by the naked eye and
the detection method by bonding force, salt spray experiment, etc.;
the overall appearance, mainly with the naked eye or magnifying
glass, or optical microscope (for products with linearity less than
0.2mm), The sintered NdFeB magnet has a smooth surface, no visible
particles and foreign matter, no spots, no falling edges, and the
appearance is acceptable.