Development and Evaluation of Anti-Abrasion Polymer Coatings for Circulation Coins

The motivation behind this research is to provide anti-abrasion abilities in attempt to increase the life span of coins in circulation. Polyurethane, polytetrafluoroethylene, advanced liquid glass, standard liquid glass and silicon R-2180 are selected and applied onto brass plated blank coins (loonies) and their wear resistance is investigated. Following coating application using a spin coater, polyurethane, advanced liquid glass and silicon R-2180 show satisfactory visual appearance. Pin-on-disc wear test is conducted on coated brass blanks; both advanced liquid glass and polyurethane exhibit superior results when compared to silicon R-2180. An additional abrasion test was carried out using a tumbling machine. Periodic tumbling is carried out in increments of 5 hr for 25 hr to assess the wear resistance of the three candidate materials. Over all, advanced liquid glass maintains 40% of the coating after 25 hr of tumbling compared to only 20% and 5% for polyurethane and silicon R-2180, respectively.