Effect of Sintering Conditions on Wear Mechanisms of Metal-Polymer Composites Based PTFE and Nanosized Zirconium Dioxide

The aim of the work is to increase the wear resistance and improve the tribotechnical characteristics of PTFE–based metal polymer composites filled with nanoscale ZrO₂ by optimizing sintering conditions and identifying the mechanisms of transfer film formation.

PTFE composites with a content of 8 wt. % ZrO₂ was obtained with cold pressing (80 MPa) followed by sintering at 360 °C and holding for 20 min and 9 min per 1 mm section. Tribological tests were carried out according to the “finger–disk” scheme under friction conditions without lubricant, at a sliding speed of

0.75 m/s and a load of 2 MPa. The microstructure and elemental composition of the transfer films were studied using scanning electron microscopy and energy-dispersive spectroscopy.

It was established the reducing the exposure time to 9 min/mm reduces the wear rate to 0.4 mg/h (500 times lower than that of unfilled PTFE) and decreases the friction coefficient from 0.35 to 0.11. Prolonged exposure (20 min/mm) causes residual thermal stresses and leads to abrasive wear with the formation of grooves up to 159 μm wide. EDS analysis of the steel counterbody showed that at a rate of 9 min/mm, a denser and more stable transfer film is formed, with an increased oxygen content (6.43 % versus 2.54 % at 20 min/mm) and zirconium content (3.78 % versus 0.03 %). ZrO₂ nanoparticles provide directed heat dissipation from the contact zone, preventing thermal softening and plastic deformation of the polymer matrix. Optimal sintering conditions (9 min/mm) ensures the formation of a durable oxide-metallic transfer film that protects the counterbody from catastrophic wear. The recommended running-in period is about 6,000 s.

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