Structure and Thermal Conductivity of Flame Sprayed Polyamide 11 Coatings Filled With Al2O3, AIN and BN Ceramics

Abstract Polymer ceramic composite coatings were applied by flame spraying on preheated steel substrates. Polyamide (PA 11, nylon) powder was blended with alumina (Al2O3), aluminium nitride (AIN) or boron nitride (BN) powder with two different filler content to increase thermal conductivities of polymer coatings. Morphologies and particle sizes of polyamide and filler powders were examined by scanning electron microscope and laser scattering methods. Coating structures and thicknesses of composite coatings were studied by the polished cross sections. Thermal conductivities were measured by hot disc method. Thermal conductivities of polyamide coatings increased from 30 % up to few times by blending ceramic filler material on PA 11 powder. Structures of composite coatings were dense and filler materials were clearly observed in polyamide matrix.