| abstract |
According to the present invention, powder coating compositions comprise one or more than one thermoplastic or thermosetting polymer or resin and one or more than one finely divided magnetic material, such as a ferromagnetic material. Preferred magnetic materials include Ni 1−x Zn x Fe 2 O 4 compounds, wherein 0.4≦X≦0.75, piezoelectric compounds, ferrimagnetic δFeOOH, Fe—Ni—B, Cu 2 MnIn, transparent polymer-Cobalt oxide nanocomposites and soft ferrites. In addition, the present invention provides methods of making powder coatings on a substrate comprising applying to a substrate a resinous powder coating composition comprising one or more than one magnetic material to form a powder coating layer, followed by induction heating to melt the applied powder coating to form a coating film and, optionally, to cure the powder coating. The powder coatings remain at a pre-selected temperature equal to or less than the Curie temperature (T C ) of the one or more than one finely divided magnetic material during induction heating of the powder coating without directly heating the substrate. Powder coatings on metal parts may also be induction heat cured. |