Preparation And Study Of Self-Lubricating Ceramic Coating On Surface Of Titanium Alloy

Because of its superior properties of high specific strength, high thermal strength and good anti-corrosion performance, titanium alloy is considered one of the most promising structural materials in aeronautics, astronautics and chemical industries. TC4(Ti-6A1-4V) titanium alloy was most widely used which occupied more than half of all titanium alloys. However, the low hardness, poor wear resistance limit its application in the friction and wear and other related industries. In order to overcome the deficiencies in mechanical properties, using surface modification to improve the wear resistance of titanium has become a new research focus in area.In this paper, the antifriction and wearable self-lubricating ceramic coating was successfully prepared on the surface of TC4titanium alloy respectively by the technology of Ni-P-PTFE electroless composite plating and by micro-arc oxidation and PTFE coating. Microstructure of the coatings was characterized using XRD, SEM, EDS techniques. The tribological properties of the coatings were examined by friction and wear tester.The technology of Ni-P-PTFE electroless composite plating was investigated. The effects of surfactant, PTFE, pH and temperature on the deposition behavior of electroless composite films were focused. The results showed that the wear resistance of Ni-P alloy coating and Ni-P-PTFE composite coating is superior to that of TC4titanium alloy. Ni-P-PTFE composite coating obtained better wear resistance and had a low friction coefficient0.2when PTFE content reached20.39vol%, when the volume fraction of PTFE particle is about26.4%the friction coefficient was reduced to0.13, but the adhesion strength got poor.The technology of micro-arc oxidation and PTFE coating was investigated. Obtained the composite wear-resistant anti-friction coating formed on the TC4titanium alloy surface by TiO2porous film and PTFE membrane filling in the hole. The effects of technical parameters (such as the voltage, the time) on the morphology, the crystal structure of TiO2porous film were investigated. The results showed that after coated with PTFE, the holes on the surface of TiO2were covered by polymer PTFE, and the friction coefficient of composite film significantly reduced to about0.12with good wear resistance.