Mechanical and tribological properties of diamondlike carbon-coated polycarbonate

Abstract

To improve the mechanical and tribological properties of polycarbonate, diamondlike carbon (DLC) coating was deposited on its surface by pulsed vacuum arc deposition with different pulse repetition rates at low substrate temperature (not more than 80 °C). The surface hardness increased by 20–33 times, the plasticity index increased by 1.6–2.5 times, the resistance to plastic deformation increased by 50–200 times, and the wear rate decreased by 170–600 times compared to untreated polycarbonate depending on the pulse frequency in the process of coating deposition. It has been shown that decreasing the pulse frequency during DLC deposition from 3 to 1 Hz increases the content of sp3-hybridized carbon atoms and level of internal stresses in the coating and increases its hardness. However, this is accompanied by an increase in the number of microcracks in the coating. Deposition with an optimal pulse frequency formed a polycarbonate/DLC system with high hardness and wear resistance as well as a low number of microcracks.