| abstract |
According to the present invention, powder coatingncompositions comprise one or more than one thermoplastic ornthermosetting polymer or resin and one or more than onenfinely divided magnetic material, such as a ferromagneticnmaterial. Preferred magnetic materials include Ni 1-x Zn x Fe 2 O 4 ncompounds, wherein 0.4 ≤ X ≤ 0.75, piezoelectric compounds,nferrimagnetic δFeOOH, Fe-Ni-B, Cu 2 MnIn, transparent polymer-Cobaltnoxide nanocomposites and soft ferrites. In addition,nthe present invention provides methods of making powderncoatings on a substrate comprising applying to a substrate anresinous powder coating composition comprising one or morenthan one magnetic material to form a powder coating layer,nfollowed by induction heating to melt the applied powderncoating to form a coating film and, optionally, to cure thenpowder coating. The powder coatings remain at a pre-selectedntemperature equal to or less than the Curie temperature (T c )nof the one or more than one finely divided magnetic materialnduring induction heating of the powder coating withoutndirectly heating the substrate. Powder coatings on metalnparts may also be induction heat cured. |