Friction and wear durability study of epoxy-based polymer (SU-8) composite coatings with talc and graphite as fillers

SU-8, an epoxy-based polymer, is industrially very useful material for fabricating microsystems such as micro-electro-mechanical systems. However, for optimal performance, it is necessary to further improve the mechanical and tribological properties of SU-8. Different weight percentages (wt%) of graphite and talc particles are added to SU-8 for the enhancement of mechanical as well as tribological properties. The composite with the optimized composition of SU-8+15 wt% graphite+15 wt% talc has shown superior properties compared with pure SU-8 and other composites tested. This composite shows similar to 4 times lesser steady-state coefficient of friction (similar to 0.2), similar to 3 times higher elastic modulus (similar to 7.97 GPa) and similar to 2 times greater hardness (similar to 0.52 GPa) over those of pure SU-8. Also, there is a decrease in the wear rate by similar to 10(3) times. This optimized composite, which showed nano to micron scale texturing on the surface, has performed better in comparison with single or mixed fillers with different wt% ratios. The wear mechanism for filler content up to 10 wt% was found to be fatigue and delamination, whereas for higher filler content the abrasive wear mechanism was dominant. (C) 2016 Elsevier B.V. All rights reserved.