Characterization of infrared absorption by powder coatings on steel panels

Interest in faster curing systems has led to infrared (IR) curing of powder coatings. The efficiency of IR heating depends on both the coating spectral absorption characteristics and the spectral emissions of the infrared source. Coating spectral absorptivities were measured with an FTIR spectrometer with an integrating sphere. Using the spectral absorptivities and normalized blackbody emissions, integrated average absorptivities and overall radiant efficiencies were calculated for blackbody emitter temperatures ranging from 500 to 3000 K (440 to 4940 deg F). The effects of several powder coating parameters on spectral absorptivities, integrated average absorptivities, and overall radiant efficiencies were studied.