A Three-dimensional Approach Using DLC Rods to Improve the Friction and Wear Behaviour of Hard Nanocomposite Coatings
DescriptionIn modern industry, hard nanocomposite coatings have been found to be an excellent candidate used in machining applications with the aim to reduce friction and wear and hence increase component life. In doing so, the real-life implications are not only preserving our limited energy resources, but also saving our planet from hazardous emission for generations to come. However, increasing demands such as low friction and high cutting temperature, the high-performance thin tribological coatings have quickly reached the limits of single-phase monolayers. Conventionally, introducing multiple layers and/or phases to the hard coatings can improve the wear properties of the coatings. Recently, the successful utilization of laser patterning method to improve friction and wear on engineering surfaces has aroused great interest in other areas. Laser processing by excimer laser can be applied with high precision to the surface of hard nanocomposite coatings to provide a reduction of friction and processing temperature with a minimum impact on the original coating quality.In this project, it is proposed to use a three-dimensional (3D) approach to improve the wear property of the hard nanocomposite coatings. Firstly, micro-dimples or required dimensions are introduced perpendicular to the coating surface by high precision excimer laser. Then solid lubricating diamond-like-carbon (DLC) is deposited to fill the dimples through a magnetron sputtering technique. In this manner, the continuous hard nanocomposite coating would be surrounded by rods of lubricating DLC. Eventually, these dimples can act as lubricating reservoirs and trap wear debris to reduce wear due to third bodies trapped at the sliding interface. This integrated approach exhibits advantages in simplicity and effectiveness, while keeping the original properties of surface largely unchanged. In this investigation, the effect of the parameters of laser ablation and DLC deposition on the wear performance of the modified hard coating surface is revealed. The parameters will be optimized to prepare nanocomposite coatings with the largest improvement in friction and wear performance, so as to be used in the conditions of high contact pressure, high running speed and high contact temperature. In addition, we seek to understand the origin of the improvement and to exploit its use as a reliable and efficient method for applications in engineering components and manufacturing processes.
|Effective start/end date||1/01/11 → 3/06/15|