S. Zhong, M.D. O'Neil
ABB US Research Center,
Keywords: surface coating, ceramic coating, in-mold decoration, IMD, coating performance
Summary:While most ABB products are inherently robust and resistant to environmental wear, additional coatings can provide supplemental protection as well as aesthetic enhancements. Wear, flammability, and thermal resistance are some of the attributes further enhanced by the application of these protective coatings. Herein four coating technologies: traditional powder coating, Cerakote© ceramic coating, in-mold decoration (IMD), and water transfer graphics (also referred to as Hydrographics) were tested for the purpose of providing beneficial aesthetic qualities and enhanced abrasion resistance. Powder coating is widely employed in industries and has been included in evaluation for purposes of providing a performance baseline. IMD, WTG and Cerakote© are available in a wide variety of popular colors and patterns, as well as varying levels of additional protection. While Hydrographics require an abrasion resistant clear topcoat, powder coat, Cerakote© and IMD do not. During the testing process, the coatings were evaluated for wear resistance via Taber abrasion testing per ASTM D4060. Among these four coatings, the IMD coating and Cerakote© demonstrated the best wear resistance, while the WTG coating failed prematurely with tripled wear rate compared to the latter. The analysis of the IMD coating failure indicates that multilayered IMD coating contributes to wear resistance, especially its metallic inner layer. Flammability as well as thermal resistance of the coating were also evaluated. Furthermore, the IMD coating contributed to an overall improvement in thermal resistance even though its thickness is less than 0.5 mm. High voltage breakdown strengths of the coatings, as well as IMD thin film, were measured. Although IMD film has lower breakdown strength compared to its bulk sample, limited damage to the overall breakdown strength of the coated sample. Considering its compatibility in automated manufacturing process, IMD coating technology has great potential in industry. Cerakote© ceramic coatings also exhibited exceptional performance. When compared to traditional powder coating, Cerakote© proved to be robust, exhibiting 2x-6x the abrasion resistance of powder coating depending on the type of Cerakote© employed. Cerakote© ceramic coating is applied in the same manner as powder coating and costs roughly the same, while having the additional benefits of improved aesthetics and abrasion resistance.