Feasibility Study of Using DLC Hard Coating in Conjunction with Laser Ablation to Improve the Tribological Performance of an Engineering Surface

Description

In recent years, solid lubricant diamond-like-carbon (DLC) coatings have attracted much attention in industry since they can achieve low friction and high wear resistance under dry or lubrication conditions. However, increasing demands such as low friction, low wear rate, long life-time and high-performance thin tribological coatings have reached their performance limits. In order to meet the requirements, we propose to use an integrated approach to improve the tribological property of an engineering surface. Firstly, micro-dimples are introduced perpendicular to an engineering surface by high precision excimer laser. Subsequently, solid lubricant DLC is prepared on the patterned surface by magnetron sputtering technique. Under such architecture, the hard DLC coatings protect the dimples, thereby ensuring micro-reservoirs to enhance lubricant retention or micro-traps to capture wear debris during lubricating sliding, and can improve load-bearing capacity. The use of powerful lasers with short-wavelengths and pulse durations allows a micrometer-level precision in reservoir size and location with a minimum collateral damage to surrounding areas. In particular, laser patterning offers the most promising concept for industry because it is fast and flexible for a wide range of materials. Overall, laser patterning followed with DLC deposition is simple, without complicated deposition system design and resources, while the unique properties of a surface coating can be maintained. With the integration of advanced coating technologies with laser texturing, further improvements in tribological performance become feasible. Such integrated surface engineering approaches aim to achieve a surface with superlubricity feature, which can in turn overcome the increasingly stringent tribological conditions potentially resulting from the use of lower viscosity oils with reduced sulphur and phosphorus content due to environmental concern. Engineered tribological interfaces that can be prepared by these methods can effectively fulfil the properties and performance demands of most tribological applications.