Making particulates of controlled dimensions by electroplating

摘要

We make particulates, especially magnetic Fe—Co alloys having high magnetic permeability, of controlled dimensions, especially those having a narrow thickness size distribution centered around a median or target thickness in the range of about 0.1-1.0 &mgr;m, using electrodeposition typically on a smooth (polished) titanium cathode. Our preferred continuous process uses a rotating drum cathode inside a fixed anode to grow flakes and to produce them automatically by inherent instability in the deposited film. The drum preferably rotates about a substantially vertical axis. The particulates shed (slough off) into the electrolyte (because of mismatch between the cathode surface and the plated metal or alloy at the molecular level) where they are separated in a magnetic separator or other suitable device. If the flakes are soft iron or iron-cobalt alloys, the drum generally is titanium or titanium alloy.