Kinik Company pioneered diamond pad conditioners protected by DLC barrier (DiaShield® Coating) back in 1999 (Sung & Lin, US Patent 6,368,198) and there has been no follower since then. Kinik's offered two varieties of DiaShield® Coatings: ultrahard tetrahedral amorphous carbon and superhard hydrogenated DLC. Kink also evaluated Cermet Composite Coating (CCC or C3, patent pending). C3 is unique that the coating composition grades from a metallic (e.g. stainless steel) under layer to a ceramic (e.g. Al2O3 or SiC) exterior. The metallic under layer can form metallurgical bond with metallic matrix on the diamond pad conditioner. The ceramic exterior is both wear and corrosion resistant. The gradational design of C3 coating will assure its strong adherence to the substrate because there is no weak boundary between coating and substrate. By dipping diamond pad conditioners of various designs in acidic solution (e.g. copper cleaning solution) for extended periods of time (e.g. 50 hours) the chemical inertness of various matrix materials are determined with the decreasing ranking as: hydrogenated DLC > C3 coating > tetrahedral amorphous carbon > sintered nichrome > brazed alloy > electroplated nickel.