Tribological Behaviors of Polymer Based Composites under Alkaline Conditions

Abstract

In this paper, polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE) based composites reinforced with various amounts of potassium titanate whiskers (PTWs) or short carbon fibers (CF) were designed and fabricated respectively. The friction and wear properties of PEEK and PTFE based composites sliding under rigorous alkaline were comparatively investigated. Also, the morphologies of the worn and counterpart surfaces were studied by scanning electron microscopy (SEM). Because of the stable tunnel crystal structure and frame structure micro-reinforcement capacity, PTWs show outstanding performances in increasing the wear resistance and reducing the friction coefficients of both PEEK and PTFE based composites under alkaline. However, CF leads to the degradation of wear resistance and the increase of friction coefficient of PEEK based composites under alkaline. Furrows and abrasive wear were the main mechanisms for CF/PTFE/PEEK and CF/PTFE composites sliding in alkali. The results show that PTW/PTFE composites exhibit higher wear resistance under lower load, while PTW/PTFE/PEEK composite is more suitable for higher load under alkaline condition. Owing to the primary cooling and boundary lubricating effects of alkali, the wear rates and friction coefficients of PTFE composites and PTW/PTFE/PEEK composites decreased obviously, though the transfer films onto the counterpart steel surface were hindered considerably.