Antifriction and Wear Characteristics of Electrolessly-Deposited Ni-P with PTFE Composites

摘要

This aim of this study was to investigate the tribological properties of a self-lubricating Ni-P-polyflu-orotetraethylene (PTFE) composite coating prepared by the electroless plating method. The effects of PTFE contents in the coating, load and rotation speed on the tribological behaviors were evaluated using a ring-on-disk wear machine. The results show that there was a distinct decrease in the average value of the friction coefficient from 0.33 to 0.12 at 70 N with an increase in PTFE content from 4.2 to 15.2 wt%. The coating of Ni-P-4.2 wt% PTFE had good antifriction and wear properties at a load of 30-70 N, and that of Ni-P-10.6 wt% PTFE had passable wear resistance and better antifriction at <50 N. Antifriction and wear mechanisms of Ni-P-PTFE are discussed in detail based on the results from micrograph and element analyses of the worn surface, subsurface stratum and wear debris analysis by scanning electronic microscopy (SEM), and energy-dispersive X-ray analysis (EDAX), respectively. The lubricating film (LF) generated during wear played a key role in the antifriction effect, which in turn was dependent on the integrity and thickness of the film determined by the PTFE concentration and wear conditions. The formation, fracture, and delamination course of the LF during wear were also analyzed and characterized.