Fabrication and tribological characterization of gradient carbon layer derived from SiC-TiC composites

Abstract

Carbide based ceramics are frequently used for the tribological applications, such as mechanical seals, owing to their good mechanical and chemical properties. Recently, studies of the tribological properties of these applications have become increasingly important due to the increasing need for severe operating conditions. In this study, the surface modification of carbide ceramics was attempted to improve the triblogical properties. Carbon layers were prepared on SiCTiC ceramics using a moderate and high temperature chlorination process. The microstructure and worn surfaces were analyzed by scanning electron microscopy and an ¡-step profilometer, respectively. Tribological tests were carried out on chlorinated SiCTiC surfaces using a ball on disc wear tester. Since carbon atoms in TiC were derived at lower temperatures than SiC, the distribution of carbon atoms within the modified layers were synthesized by the difference in reaction temperature and reaction time. The tribological properties were varied by the volume fraction of carbon and SiC in the modified layer. The friction coefficient and wear rate were decreased by controlling the structure and composition of the carbon based layer from 0.22 to 0.18 and 7.91 to 1.92 (©10 ¹6 mm 3 /N·m), respectively.

Carbide derived carbon: from growth to tribological application

“…In addition, the tribological properties of CDC films can be improved by modifying the film surface with a gradient carbon layer fabricated using SiC and TiC composites. 35) The Ti and Si components are etched at lower and higher temperatures, respectively, since TiC and SiC are chlorinated at 600 and 1000°C, respectively. Therefore, a carbon film consisting of a mixture of carbon and SiC grains is formed as a gradient layer, depending on the TiC and SiC compositions and the reaction time at each reaction temperature.…”

Improved frictional behavior of SiC derived carbon coating using MoS3 as a solid lubricant

“…Despite the characteristics of low friction and high wear resistance, the tribological properties of CDC coatings should be improved to use under extreme conditions [7][8][9][10][11][12]. Carroll et al demonstrated that CDC coatings with an onion-like structure exhibited low friction in dry nitrogen [10].…”

“…McNallan et al reported that the friction coefficient of CDC coatings was significantly reduced by hydrogen post-treatment [11]. Additionally, the tribological behavior of CDC coatings was modified by a gradient SiC/C structure and optimized by controlling the residual SiC grain content [12]. These methods mainly focused on the optimization of the processing parameters for CDC coatings.…”