Improved lubrication through texturing : effect of surface dimples

• Main Author: Yu, Shanshan
• Other Authors: Sam Zhang Shanyong
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Materials::Nanostructured materials
• Online Access: http://hdl.handle.net/10356/62123
• Institution: Nanyang Technological University

Friction wear of industrial components significantly affect the performance and efficiency of the entire system; therefore, there is a strong need to control the friction thereby prolong mechanical system’s lifetime as well as improve efficiency and reliability. Carbon composite thin film exhibited excellent lubricating performance; therefore, it had been developed as wear protection layer for nitride base coating and lead to significantly prolonged wear life time. However, its lubricating effect only presents on Carbon composite coating layer, once this layer is worn out, the coating will experience severe abrasive wear. Surface dimple texturing has potential to improve the surface tribological performance. It expects that dimples can entrap wear debris as well as store lubricant as secondary source. This project aims to develop surface textured carbon composite coating plus CrAlSiN nanocomposite coating and study how the surface textures’ depth, size, shape and distribution affect coating’s wear resistance performance. In this study, a carbon composite coating plus CrAlSiN nanocomposite coating was developed using sputtering-based plasma enhanced physical vapor deposition (PVD) system. The silicon wafer and stainless steel substrates were pre-textured by photolithography and wet chemical etching processes, and then coating’s textures realized accordingly. Textured coating’s wear performance was characterized by linear reciprocating wear test against alumina ball under dry sliding condition in atmosphere. It was found that the 10µm~20µm size, 5% area coverage density, 1:4 space ratio dimples textured carbon composite coating plus CrAlSiN nanocomposite coating demonstrated substantially reduced wear volume lost rate up to 28%. The textured lubricating functional nanocomposite coating demonstrates its potential as a high performance surface wear protective coating for industrial application.