1) Cobalt alloy 
Permendur is a cobalt-iron soft magnetic alloy with equal parts of cobalt and iron . The alloy was invented in the United States around 1920 . Standard permendur compositions coined Fe-Co 50/50 or 50Fe-50Co may contain carbon up to 1% while a composition patented in 1932 named Vanadium Permendur, Permendur 2V and recently offered by Goodfellow Cor...