Characterization of durability of coatings for cell phone cover by wear, erosion, and pull-off tests

The durability of coatings for cell phone covers was investigated by conducting wear, erosion, and pull-off tests. The highly functionalized coatings of a cell phone cover serve the purpose of maintaining visual appeal as well as protecting the inner components. The motivation of this work was to gain a better understanding regarding the surface damage characteristics of a cell phone cover by conducting a comprehensive evaluation. Wear tests conducted using soft and hard counter surfaces resulted in completely different wear patterns on the cell phone cover. In the case of the soft counter surface, burnishing wear was observed whereas distinct abrasive wear occurred when hard counter surfaces were used. The erosion tests conducted using a sand blasting method showed that a certain surface damage pattern found on used cell phone covers could be reproduced by this testing method. Finally, the pull-off testing method was developed to quantify the adhesion and shear strengths of the coatings. Using this method, the weakest interface within the multilayer coatings could be identified. The shear strength of the coatings was found to be significantly higher than the tensile strength. The results of this work are expected to aid in development of superior protective coatings for various devices.