Study on Electrochemical Corrosion Behavior Comparison between DLC and TiN Coatings under Different Corrosive Environment

Abstract

Diamond-like carbon (DLC) and TiN coatings were deposited on the 304 austenitic stainless steel(SUS304) substrates by using unbalanced magnetron sputtering and arc ion plating techniques, respectively. The phase structure and surface morphology of coatings were characterized by SEM and XRD.The electrochemical corrosion of two coatings in different electrochemical solutions (including3.5%NaCl,10%HCl,20%NaOH) were investigated by electrochemical workstation.The result showed that DLC coating was amorphous structure and TiN coating was nano-crystalline structure.The surface of DLC coating was smooth and dense,while TiN coating existed pits.In 10%HCl and 3.5%NaCl solutions,the corrosion resistance of DLC coating increased by 4.16 and 10.9 times compared with SUS304 and increased by 5.16 and 1.11 times compared with TiN coating,respectively.But in 20%NaOH solution, the corrosion resistance of DLC was not superior to SUS304 and TiN coating.In 10%HCl solution,the corrosion resistance of TiN coating increased by 9.81 times compared with 304 SUS304.But in 3.5%NaCl and 20%NaOH solutions,the corrosion resistance of TiN coating was worse than SUS304.