Design Guide 1 - Magnetic Head Core Material Selection | Brush Industries

Design Guide 1 - Magnetic Head Core Material Selection

Effects of materials selection on HiCo/LoCo recording and magnetic head life

The wide range of media available for high and low coercivity recording 300 to 3500 oersted makes magnetic head core material selection important. When environmental (life) considerations are also added into the equation, material selection becomes even more critical.

For the record, ISO identifies LoCo media as up to 600 oersted, above 600 oersted is identified as HiCo media. This Design Guide will aid in selecting the correct material or combinations of materials to meet your magnetic head requirements. These requirements may vary from, low use ATM's ,100 or less transactions per day to high use turnstiles, several thousand transactions per day. Media requirements can range from 300 to 5000 oersted with the possibility that the head will need to work with several different media's in the same system 300 to 2750 oersted.

The design guide will aid in core material selection to meet your Magnetic Head requirements with the most cost effective material or combination of materials available.

Life comparisons of the various core materials have been derived from brush research and independent studies conducted by the Pennsylvania State University and Bucknell University and experience with specific high traffic turnpike transit data site locations, actual results can vary under different operating conditions.

Magnetic Core Materials Definitions
used in this guide

Hypermium™ I

  • Hardness Rc 25
  • Annealed to brush proprietary specifications

Hypermium™ II

  • Hardness Rb 62
  • Annealed to brush proprietary specifications

Mumetal

  • Hardness Rb 58

Supermium®

  • Hardness Rc 50
  • Processed for enhanced magnetic characteristics, increased hardness and reduced grain size

Supermium® 2.75

  • Hardness Rc 50
  • Material specially processed to produce core laminations for high coercivity, 2750 Oersted media and high frequency applications

CC (Ceramic Coat)

  • Hardness Rc 60
  • Plasma sprayed coating of AlO2 and TiO2 producing a hard wear surface

Comparison of Magnetic Head Materials*

Core Material Specifications Capabilities Life Expectancy
Mumetal* Used to encode up to 600 Oersted. To be used for LoCo encoding only. May be used as a read head material for both HiCo and LoCo applications 0 to 600 Oersted 1X
Mumetal/CC* Mumetal with the addition of ceramic coating for extended life 0 to 600 Oersted 12X
Supermium®* Long life material used to encode up to 600 Oersted. To be used for LoCo encoding only. Suitable for use as a read head material for both HiCo and LoCo applications 0 to 600 Oersted 20X
Supermium®/CC* Supermium® with the addition of ceramic coating for extended life 0 to 600 Oersted 102X
Supermium® 2.75* Used for both LoCo and HiCo applications. Long life material used to encode media up to 2750 Oersted. Will not self-erase LoCo media Up to 2750 Oersted 20X
Supermium® 2.75/CC* Supermium® 2.75 with the addition of ceramic coating for extended life Up to 2750 Oersted 102X
Hypermium II* Used to encode LoCo and HiCo media up to 3500 Oersted. Under certain circumstances, these materials may not exhibit optimum overwrite capabilities on media above 2750 Oersted. Will not self-erase LoCo media Up to 3500 Oersted 1X
Hypermium II/CC* Hypermium II with the addition of ceramic coating for extended life Up to 3500 Oersted 12X
Hypermium I* Used to encode media up to 5000 Oersted. Cannot be used in systems that have both HiCo and LoCo tickets. Residual magnetism causes erasure of LoCo media Up to 5000 Oersted 2X
Hypermium I/CC* Hypermium I with the addition of ceramic coating for extended life Up to 5000 Oersted 20X

* This is only a guide to core material selection. Many factors will affect the choice of core material, such as high speed encoding, combined read and write requirements and many more. Please talk to a Brush Industries engineer to help you specify the correct material for your specific application.

Brush Industries can help you. Call 570-286-5611.