ASTM Int'l Approves First in Series of Permanent Magnet Materials Standards - ASTM A 1054

October 18, 2007 // Published as a news service by IHS

The standard, ASTM A 1054 - Specification for Sintered Ceramic Ferrite Permanent Magnets helps users of ceramic ferrite magnets identify widely recognized grades of permanent magnet material for use in their device designs.

While ASTM International has standards covering soft magnetic materials such as oriented and non-oriented sheet steels, relay steels, nickel-iron alloys and powder metal materials, it has not addressed permanent magnet materials until recently, said Reinhold Strnat, chair of Subcommittee A06.01 on Test Methods and technical manager, KJS Associates.

"It is important to design around a magnet that actually exists so a list of commercially recognized and available magnet grades with defined properties, as is included in [ASTM] A 1054, gives a designer a solid starting point to develop the rest of his machine and predict its performance," said Strnat.

Strnat said that once a design has been proven out, it must be manufacturable and ASTM A 1054 can provide guidance in this area as well.

"By specifying a grade of material that is listed in [ASTM] 1054, any manufacturer knows, by reference to the standard, what the properties of the magnet must be in order to satisfy the design requirements," said Strnat. "Without such a standard, each product would have its own customized list of magnetic requirements that magnet producers may or may not be able to meet. Standardization in this context also offers opportunities for significant cost savings."

According to Strnat, ASTM A 1054 will be used by designers and manufacturers of loudspeakers, electric motors (especially in the automotive area - seat adjust motors, remote mirror adjusters and other devices using electric motors), magnetic sensors and even simple holding magnets like magnetic door latches and refrigerator seal magnets.

"Ultimately the producers of the magnets will also be users of the standard as they strive to meet the requirements of their end-user customers," said Strnat.

ASTM A 1054 and the other proposed standards are under the jurisdiction of Subcommittee A06.02 on Material Specifications. Subcommittee A06.02 is working on the next in the series of proposed permanent magnet material standards.

According to Strnat, there will be individual standards for each of the commercially important classes of permanent magnets such as Alnico, samarium cobalt and neodymium-iron-boron.

Strnat said that the proposed standards would benefit from as much input as possible about real-world applications and the types of magnetic properties that need to be specified in order to assure reliable product function.

Case studies that include a description of the magnetic design process for specific products and a review of how the magnets are being specified would be valuable, said Strnat.

In addition, Strnat said that ASTM A 1054 would benefit from participation from magnet producers so that the subcommittee can make sure that all commercially relevant grades of magnets are appropriately referenced.

"Since there is a constant influx of magnets with unique, new property sets, it is difficult to keep up with the innovation that is taking place without active input from the magnet producers," said Strnat.

Source: ASTM International.