Magnetic materials in the third millenium

✍ Scribed by D Hadfield

• Publisher: Elsevier Science
• Year: 1989
• Weight: 857 KB
• Volume: 10
• Category: Article
• ISSN: 0261-3069
• DOI: 10.1016/s0261-3069(89)80058-5

✦ Synopsis

Until the middle 50's, both nnagnetically soft and hard metals were produced mostly by melting, casting and hot manipulation. During the last two decades, powder techniques have become dominant to the extent that in the future almost all permanent magnets will be produced by this route andapartfrom 4% silicon iron for electrical machines andpower transformers, most of the soft electromagnetic materials such as ferrites, cobalt and nickel irons, and chromium dioxide used for magnetic recording media also.

The paper describes briefly the particle theory of magnetism which embrace the main concepts of molecular fields and magnetic domains. The magnetic attributes of recording media ferrofluids and permanent magnets are discussed in relation to this theoretical context The development, manufacture and applications of magnetically soft products such as powder metal cores, ceramic ferrites and giant magnetostriction are dealt with in depth as are permanently magnetised materials, such as permanent magnets in alloys and ferrite form, precious and rare earth-transition metals and recording media. The latest innovations, trends and forecasts complete the survey.