Improvement of Thermal Stability and Tribological Performance of Diamond-Like Carbon Composite Thin Films

Abstract

Diamond-like carbon (DLC) is a metastable amorphous film that exhibits unique properties. However, many limitations exist regarding the use of DLC, for example, its tribological characteristics at high temperature, as well as its limited thermal stability. In this study, silicon/oxygen and silicon/nitrogen co-incorporated diamond-like carbon (Si-O-DLC and SiN -DLC) films are studied, taking into account the thermal stability and tribological performance of these films compared with pure DLC. All the films were prepared on Si wafers, WC-Co materials, and aluminum foils using a plasma-based ion implantation (PBII) technique using acetylene (C 2 H 2), tetramethylsilane (TMS, Si(CH 3) 4), oxygen (O 2) and nitrogen (N 2) as plasma sources. The structure of the films was characterized using Raman spectroscopy. The thermal stability of the films was measured using thermogravimetric and differential thermal analysis (TG-DTA). The friction coefficient of the films was assessed using ball-on-disk friction testing. The results indicate that SiN -DLC films present better thermal stability due to the presence of Si-O networks in the films. The SiN -DLC (23 at.%Si, 8 at.%N) film was affected using thermal annealing in an air atmosphere with increasing temperature until 500˚C. The film can also resist thermal shock by cycling 10 times between the various temperatures and air atmosphere until 500˚C. Further, Si-O-DLC and SiN -DLC films exhibit excellent tribological performance, especially the SiN -DLC (23 at.%Si, 8 at.%N) film, which exhibits excellent tribological performance at 500˚C in an air atmosphere. It is concluded that Si-O-DLC and SiN -DLC films improve upon the thermal stability and tribological performance of DLC.

Surface structural features and wear analysis of a multilayer Ti6Al4V-B4C thin film coated AISI 1040 steel

“…Chavin et al stated that pure DLC films were totally demolished over 500°C, signifying the evaporation of the pure DLC films. However, the Ti-6Al-4V-4B 4 C films were still stable until heating to 650°C; on the other hand, the diamond-like carbon coating disappeared during heating up to 600°C [24]. In the present study, all the thin films were heated to 1000°C.…”

“…The oxidation rate of Ti-6Al-4V-4B 4 C coating is depending on the percentage of B 4 C in the coating. It is assumed that the weight gain of the films with an increase in temperature may have arisen due to the adsorption of oxygen from the atmospheric air into the film surface during heating [24]. The ignition temperature of the Ti-6Al-4V-4B 4 C thin film increases with the addition of B 4 C in the coating.…”

Deposition and Thermal Stability of DLC/Si-N Composite Films Synthesized Using a Sputtering-PBII Hybrid System

“…The reduction in residual stress and the enhancement in thermal stability of nitrogen-incorporated DLC films were previously reported [20] [21] [22]. In our previous study [23], it was found that the silicon/nitrogen co-incorporated DLC films fabricated by PBII using acetylene (C 2 H 2 ), tetramethylsilane (TMS, Si(CH 3 ) 4 ) and nitrogen (N 2 ) as plasma sources showed the good thermal stability under a temperature environment of about 600˚C that has never been reported before. However, it is of interest to develop DLC films that can achieve thermal stability in the region exceeding this temperature.…”

Coating-substrate-simulations applied to HFQ®forming tools

“…The limited thermal stability of conventional DLC can be increased with special coating technologies like silicon/oxygen and silicon/nitrogen (Si-O-DLC and Si-N-DLC) films [11]. In addition, other metal-modified hydrogenated amorphous carbon coatings, particularly tungsten-modified variants (a-C:H:W), and secondarily pure hydrogenated amorphous carbon coatings can be used as functional coating layer.…”