Tribological and corrosive behavior of PTFE composites filled with PTW in sulfuric acid solution

The tribological behavior and corrosion resistance of poly tetrafluoroethene (PTFE) composites filled with various amount of potassium titanate whiskers (PTW) and carbon fibers (CF) in sulfuric acid solution and under dry conditions were investigated respectively. The related mechanisms were discussed based on the SEM examinations of worn surfaces and optical micrographs of transfer behavior. The results indicated that the wear resistance of pure PTFE in acid increased by two orders of magnitude than that sliding in dry condition, and the friction coefficient was only 15.3% of that in dry condition. Compared with CF/PTFE composites, PTW/PTFE composites showed higher wear and corrosion resistance in acid. The wear rate and friction coefficient of PTFE in acid can be further decreased by PTW. At 15% (mass) PTW filler content, the wear rate of PTW/PTFE composites reached the lowest value, which increased the wear resistance of PTFE in acid by 13.8 times, and also 3.2 times higher than that of CF/PTFE composites. Owing to the cooling and lubricating effects of acid solution, the friction coefficient of PTFE composites decreased obviously than that in dry condition. However, the transfers onto the counterpart rings were significantly hindered when they were sliding in acid. When filler content was above 15% (mass), furrow and abrasive wear were the main mechanisms for PTFE composites whether sliding in dry condition or in acid.