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NdFeB Sintered Magnets Boast Industry's Best^* Characteristics among High Volume Products

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NdFeB Sintered Magnets Boast Industry's Best^* Characteristics among High Volume Products

http://www.global.tdk.com/news_center/pressTDK Press Release

NEOREC55 Series of NdFeB Sintered Magnets

April 11, 2007

TDK Corporation announced today development of the NEOREC55 series of NdFeB sintered magnets,¹ which boast the industry's highest^* energy products using existing production methods. Mass production is scheduled to begin in April 2007.

NdFeB sintered magnets have the best characteristics among numerous magnet materials, contributing to the miniaturization and higher performance of electronic devices. As a result, there are calls in the market for NdFeB sintered magnets with even better characteristics.

In the past, TDK has developed and marketed a number of different NdFeB sintered magnets as the NEOREC series. These magnets are used for numerous applications including hard disc drive (HDD) head driving voice coil motors (VCM),² hybrid vehicle drive and generator motors, motors in household appliances such as air conditioners, and optical heads of DVD and CD players, and for generating magnetic fields in various types of magnetic sensors.

TDK has now developed and will soon start mass production of the NEOREC55 series, which features a maximum energy product³ that is 5% higher than the earlier NEOREC53 series of products and boasts the best characteristics of any mass production NdFeB sintered magnets.

TDK employs an original low-oxygen process⁴ to minimize oxidation during manufacturing process and improve saturation magnetization. Powder control technology is used to raise magnetic orientation of compressed body⁵ and to substantially improve magnetic characteristics without modification of the existing dry method⁶ used for compression process. In addition, magnetization⁷ in small magnetizing fields has been improved, facilitating adequate magnetization.

These enhanced characteristics make it possible to raise magnetic flux in VCM magnetic circuits and the resulting torque⁸ while maintaining the same configuration as earlier products. This raises head movement speeds, which results in faster HDD seek speeds.⁹ In addition, the magnetizing ratio is high even among compact optical head magnets that form complex magnetization patterns, contributing to the miniaturization of magnets.

The NEOREC55 series of high-performance magnets was created using TDK's outstanding development technologies and will contribute to new advances in electronic devices such as HDDs.

The new products will be on display at the TDK booth at Techno-Frontier 2007, which will open at the Makuhari Messe International Exhibition Halls on April 18.

* As of April 2007, according to TDK investigations.

Glossary

NdFeB sintered magnets :
Magnets made from neodymium, iron, and boron materials that are alloyed, powdered, formed into shape, and sintered.
Head driving voice coil motor (VCM) :
A motor used to determine the position of the magnetic heads on a HDD.
Maximum energy product :
The maximum magnetic energy that a magnet can store; represented as (BH) max in units of kilojoules per cubic meter.
Low-oxygen process :
A technology used to limit oxidation of alloy powders by reducing oxygen in the process atmosphere from powdering of the materials to formation.
Magnetic orientation of compressed body :
The crystal direction of each powder particle lines up when a magnetic field is applied during compression process, and the magnetic orientation of compressed body is the degree to which the crystal directions of the compressed body are lined up.
Dry method :
A method of forming compressed body that applies high pressure to powdered material alone that has been placed in a mold. The dry method is contrasted with the wet method, which adds liquid to the powder to form slurry.
Magnetization :
Following the sintering process, the un-magnetized body is magnetized by applying a magnetic field. Residual magnetization persists even after the magnetic field is removed, and the magnet acts as a permanent magnet that can apply magnetic flux externally.
Torque :
The moment of force around an axis of rotation when an object is rotated around a fixed axis of rotation expressed as the product of force times distance.
HDD seek speed:
The average time that it takes to move to the next track when the magnetic head is reading or writing HDD data.

NEOREC55 Series Product Lineup

NEOREC55A
NEOREC53B
NEOREC50H

Example of Main Characteristics

NEOREC50H
Br = 1420 mT ± 20 mT
HcJ ≥ 1353 kA/m
(BH) max = 390 kJ/m³ ± 16 kJ/m³

Main Features

Maximum energy product is 5% higher than existing TDK products, reaching the industry's highest levels.
Manufactured using the existing dry method.
Improved magnetization in weak magnetizing fields facilitates magnetization.

Applications