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  1. drmagnet

    Identifying a Magnet

    There are a few ways to tell the difference between magnetic materials. One is density: Neo is 7.5 g/cc, SmCo is 8.4 g/cc, Alnico is 7.3 g/cc. Ferrite is much lower density (4.9 g/cc) and also has the color and feel of a ceramic rather than a metallic gray color. The magnet in the photo was...
  2. drmagnet

    transformer residual flux remanis forever or decays with time?

    Herivelto, That is correct. It also helps to remember that magnetic flux does not "flow". It is an energy state. So once the field is established, it takes no additional energy to stay that way. Steve (drmagnet)
  3. drmagnet

    Sm2Co17 in water

    The several commercially available permanent magnets can be ranked in order of their corrosion resistance (to moisture) as follows: 1) Ferrite, 2) Alnico, 3) FeCrCo, 4) SmCo, 5) NdFeB Corrosion in water is due to: 1) galvanic couple between dissimular phases (as pointed out by EdStainless) and...
  4. drmagnet

    transformer residual flux remanis forever or decays with time?

    Let me start by saying I am NOT a transformer expert. But I suspect the issue is related to the material from which the transformer is made. That a transformer becomes warm (or even hot) is an indication that there is conversion of electrical energy into heat from hysteresis loss. The...
  5. drmagnet

    Neo Magnet Manufacturers

    About 75% of NdFeB magnets are manufactured and supplied from China. The five licensed companies are: BJMT (Beijing Jingci Magnetism Technology), Yunsheng, San Huan, Thinova, AM&T. About 22% come from Japan: Shin-Etsu, Hitachi, and TDK. About 3% come from Western Europe: Vacuumschmelze. As...
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