Friction and Wear Characteristics of Cr-CNTs Composite Coating End Faces of High-Temperature Mechanical Seals

Abstract

To improve the reliability of the end faces of high-temperature mechanical seals, a high-performance composite material that introduces carbon nanotubes (CNTs) into the laser-melted Cr coating is proposed. In this study, for high-temperature and high-speed mechanical seals under actual working conditions, friction and wear tests were conducted under different working conditions and using different end face materials. The high-temperature tribological properties of the Cr-CNTs coatings were analyzed, and the strengthening mechanism of the Cr-CNTs coatings on end faces was investigated. The results indicate that the wear resistance of the Cr-CNTs coating at high temperatures is first enhanced and then weakened with the increase in the CNTs content. The composite coating end face performance is optimal when the CNTs content is 10 wt%. The presence of CNTs between the end faces when grinding against the graphite ring favors the generation of a graphite film. The coefficient of friction of the Cr-CNTs coating is reduced by at least 12.46% compared to the Cr coating at a temperature of 483 K. This study provides reference examples for the application of carbon nanotubes in high-performance mechanical seals and new research ideas for improving the performance of mechanical seal end faces.