Optimization of Process Parameters for a Chemi-Absorbed Graphene Coating and Its Nano Tribological Investigation

Abstract

A reduced graphene oxide coating was deposited on a titanium substrate for potential anti-friction applications in nano- or micro-mechanical systems. A γ-aminopropyltriethoxysilane coating was self-assembled on the substrate as an adhesive interlayer beforehand. The process parameters of self-assembly and hydrothermal reduction of graphene oxide coating were explored via water contact angle and tribological tests. Insufficient self-assembly duration of graphene oxide layer can be detected by water contact angle results, and the corresponding coating displayed a higher coefficient of friction and shorter anti-wear lifetime than the optimized one. Proper hydrothermal temperature and duration were also confirmed by its water contact angle, coefficient of friction and anti-wear lifetime. Noticeably, excessive hydrothermal temperature or duration would reduce the coefficient of friction, but diminish the anti-wear resistance. The optimized process parameters were confirmed as assembly duration of graphene oxide coating for 12 h, hydrothermal reduction duration of 6–8 h at 135 °C. Nano tribological behaviors of the obtained hydrothermal reduced graphene oxide coating by AFM tester were then investigated under various testing circumstances. The results showed that the coating performed reliable and low adhesion and friction forces under all circumstances. The nanowear resistance of the titanium substrate was significantly strengthened by the prepared coating.

A review of bipolar plates materials and graphene coating degradation mechanism in proton exchange membrane fuel cell

“…It was proposed that temperatures between 120 C and 180 C can be an effective reaction temperature for the fabrication of graphene coating. 79 External factors can also influence the corrosion behavior of coating as coating deposited on the metal surface can contain some inhomogeneity that can appear on the coating in form of cracks, microvoids, contaminants, etc. It was demonstrated that each of the factors can affect the integrity of the coating and influence the transport of aggressive species through the coating and the coating-substrate interface, thereby affecting the degradation process of the coating.…”

“…It was demonstrated that each of the factors can affect the integrity of the coating and influence the transport of aggressive species through the coating and the coating-substrate interface, thereby affecting the degradation process of the coating. 79 Controlling the parameter can enhance the quality and efficiency of the produced graphene coating as well as improve its corrosion resistance. Optimizing the CVD process parameter is another attempt explored to improve the performance of the graphene coating since variation in the process parameters can influence defect density of the graphene and affect the coating corrosion resistance.…”

Chemical- and Mechanical-Induced Lubrication Mechanisms during Hot Rolling of Titanium Alloys Using a Mixed Graphene-Incorporating Lubricant

“…The Raman results are obtained by detecting both inside and outside of the wear marks, as shown in Figure 14. It is generally believed that the characteristic peak of graphene exists the D peak at 1350 cm -1 and the G peak at 1580 cm -1 [46][47][48]. The diffraction peaks have been detected at 1350 cm -1 and 1580 cm -1 in both curves with a similar tendency.…”

Advanced Surface Modification for 3D-Printed Titanium Alloy Implant Interface Functionalization

“…PEALD can operate at lower temperatures than traditional thermal ALD, which is conducive to depositing unstable polymers at a high temperature. However, PEALD needs to provide the energy required for the reaction through plasma dissociation, which leads to damage of the substrate surface exposed to the environment of plasma discharge and high-energy electron bombardment ( Li P et al, 2019 ). REALD is similar to PEALD in that, it exposes the cultured substrate and film to free radicals and eliminates substrate exposure to high-energy ions and electron bombardment.…”

“…Therefore, the design of the micro morphology of the implant surface may be able to promote the osteogenesis of the implant surface, inhibit the growth of bacteria and improve the wear resistance of the implant. In addition, LSE is well suitable for high temperature-resistant inorganic coating of materials (e.g., CaP, Si 3 N 4 , TiN-TiB, SiC) ( Das et al, 2014 ; Sahasrabudhe and Bandyopadhyay 2018 ; Li P et al, 2019 ; Zanocco et al, 2020 ). Niobium (Nb) is a costly refractory material with greater wear resistance and biocompatibility ( Zhang Y et al, 2015 ).…”