The Friction And Wear Properties Of PTFE-Based Metal Composites

PTFE-based metal composites have been prepared by two different methods. The tests were performed in the block-on-plate configuration at room temperature. Friction and wear properties were characterized by mass loss and friction coefficient. Morphologies of worn surfaces were observed by optical microscopy. The changes of material structure were investigated by XRD, which maybe explain the chemical reaction of PTFE-based composites coatings during the testing process.The friction and wear properties of PTFE composite-thermal spray metallic binary coatings have been investigated firstly. These PTFE-based binary coatings were composed of law carbon steel as substrate, a bottom layer of metal coatings deposited using atmospheric plasma spray process and a top layer of PTFE-based mixtures which were obtained by compression molding. Fourteen samples were made of PTFE and metal powders with various proportions. All the samples showed low friction coefficients similar to that of pure PTFE in the whole sliding distance. The composites-thermal spray metallic binary coatings presented the enhanced wear resistance than that of the pure PTFE-metal coatings. The optimum result was obtained in the sample PTFE+Mo-Cu composed of PTFE and Mo, where the coating metal was AI bronze. This result would be attributed to the cooperation of Mo particles in sintered layer and Al bronze in sprayed layer. The sintered layer composed of Mo could support the load more because of its outstanding hardness. On the other side, the sprayed layer coated using Al bronze was helpful to the reservoir of PTFE.Wear mechanism of PTFE composite-thermal spray metallic binary coatings was cooperation of adhesive and abrasive; however it was only adhesive for the pure...