This study investigates the effects of nanodiamonds (ND) on the wear behavior of WC-Co coatings during dry sliding under ambient and elevated temperature environments. The nanometric dimensions and exceptional hardness of ND are envisioned to enhance hardness while maintaining toughness, thereby enhancing wear resistance. ND reinforced WC-Co coatings were successfully fabricated by high velocity oxygen fuel spray (HVOF) and air plasma spraying (APS). The tribological behavior of WC-Co-ND composite coatings was evaluated at room temperature and at 300 °C using reciprocating dry sliding wear tests. At room temperature, the addition of ND led to an enhancement in wear resistance of 8.5% and 13% in HVOF and APS coatings, respectively. The composite coatings exhibited increased formation of a protective silica tribolayer, which was attributed to enhanced heat transfer induced by the excellent thermal conductivity of diamond. At 300 °C, however, the composite coatings exhibited poorer wear resistance than the counterpart WC-Co coatings as a result of the degradation of the ND phase. The loss of the diamond phase was believed to decrease hardness and weaken splat interfaces, which led to more facile delamination in HVOF coatings, as well as severe brittle wear and fracture in APS coatings.
Bibliographical noteFunding Information:
AN acknowledges support from the National Science Foundation (NSF) (1513669) East Asia and Pacific Summer Institutes (EAPSI) program, Award # 1513669; and from UC Davis through the Eugene Cota-Robles Fellowship. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIP) (No. 2010?0018289). Authors acknowledge Mahdi Khadem and Anle Yu at the Center for Nano-Wear at Yonsei University for assistance with wear testing and XPS characterization.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry