The surfaces of D16 and V95 alloy samples bearing conventional microarc oxidation coatings and coatings modified with polytetrafluoroethylene were examined before and after tribological testing. Comparison of the chemical composition of the initial samples shows that polytetrafluoroethylene-modified coatings contain regions with a high fluorine content of about 50 wt %, indicating the formation of a polymer layer on the surface. Cross-sectional specimens of end faces were prepared to analyze the distribution of the modifier within the coating. Polytetrafluoroethylene particles accumulate at the surface of both samples rather than being distributed through the coating thickness. After tribological testing, the surfaces undergo substantial changes, becoming smoother, while the fluorine content decreases to about 3 wt %. These results indicate that friction leads to abrasion of the fluorine-containing ceramopolymer, which is not supplied in sufficient quantity to the contact zone during subsequent wear. At the same time, interaction with the polymer results in pronounced smoothing of the wear track, which is favorable for further frictional interaction.
Shcherbakova et al. (Mon,) studied this question.