Investigation of surface properties and mechanical and tribological behaviors of polyimide based composite coatings

This article focuses on the development and characterization of thermoset polyimide (PI) based composite coatings on aluminum substrates. In order to improve the tribological behavior, PTFE and SiC fillers were added into pure PI to develop composite coatings. A thermal study to validate the condition of the pure PI coating after the elaboration process was performed using DSC analyses and the Tg evolution with the temperature of a pure polyimide sample was investigated. Then, the influence of the fillers (PTFE and SiC) on surface properties, and mechanical and tribological behaviors of the PI composite coatings is considered. Results showed that, by adding PTFE particles into the pure PI, lower surface energies and lower and stable friction coefficients can be obtained. Besides, the addition of SiC particles improved the mechanical behavior such as hardness and wear resistance of the composite PI-FTFE-SiC coatings. Following the obtained results, correlations between wear rate depending on total surface energy and microhardness were established. Thermogravimetric analysis (TGA) of the PI and PI composite coatings was carried out. The results revealed that the addition of fillers into PI pure matrix improved the thermal stability of the composite coatings. (C) 2013 Elsevier B.V. All rights reserved.