Corrosion and mechanical properties of epoxy-polyurethane/bronze composite coatings with low infrared emissivity

Low infrared emissivity coatings were prepared by using epoxy-polyurethane (EPU) and bronze as adhesives and fillers, respectively. Due to the increasing electrical conductivity with increasing bronze content, the infrared emissivity is decreasing obviously. Mechanical properties of EPU/bronze composite coatings were studied by using adhesion test and impact strength test. We found that EPU/bronze composite coating had good adherence and impact strength at bronze content below 50 wt.%, and then the mechanical properties decreased in the bronze content range from 50 wt.% to 60 wt.%. Moreover, the composite coatings were tested for the corrosion behavior with potentiodynamic polarization. Corrosion test results showed that the low emissivity EPU/bronze composite coatings exhibited favorable corrosion resistance. By comparing EPU/bronze, PU/Cu, (ball-milled Ag–Cu)/PU and PU/Al coatings, the EPU/bronze coatings with 40 wt.% bronze have the best adherence, low infrared emissivity and good corrosion resistance.