Preparation of carbon coated ceramic foams by pyrolysis of polyurethane

摘要

Electronically conducting carbon coatings over alumina foams were prepared by the foams’ impregnation in a polyurethane solution, followed by pyrolysis of the polymer layer. An optimal coating procedure was developed, using a commercial polyurethane lacquer. Pyrolysis was performed by heating the coated foams to 650–1,200 °C in Argon for 2–8 h. Coating characterization included surface area, phase composition, morphological and electrical conductivity measurements. Auger electron spectroscopy (AES) showed the composition was mostly carbon, with trace levels of oxygen impurities. Thickness, microstructure and interface between the alumina foam surface and the carbon film were analyzed using scanning electron microscopy (SEM and HR-SEM).