Anti-corrosion and erosion properties of multilayers with diamond-like carbon and silicon films deposited on low-carbon steel

A multilayer of diamond-like carbon (DLC) and silicon (Si) films were deposited on low-carbon steel (CS) using a combination of bipolar-pulsed magnetron sputtering (MS) and the radio frequency plasma enhanced chemical deposition (RF-PECVD) methods. Spectroscopic techniques such as Raman spectroscopy, synchrotron-based X-ray photoemission spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy were used to investigate the chemical and structural properties of the film. The mechanical properties were measured using nanoindentation and nano-scratch testers. The films' electrochemical performance and corrosion behavior were evaluated in the 3.5 wt% NaCl solution at room temperature. The erosion resistance of the films was studied under the sand jet impingement apparatus. The results indicate that the 2 Si-layers in the DLC film and CS substrate increase the C‒sp3 content at the DLC film surface resulting in high mechanical hardness. The adhesion of the DLC film on the CS substrate was also improved by adding the Si layer between the CS substrate and DLC film. Consequently, multilayer Si/DLC film resists the elastic deformation of films caused by graphitization. [Display omitted] •The high sp3 content depends on the number of Si layers agreeing with hardness results.•Si layer showed promising results for interlayer applications.•Adding Si layer between the carbon steel substrate and diamond-like carbon coatings revealed excellent corrosion resistance.•The erosion performance of multilayer Si/DLC film coatings is more outstanding than low-carbon steel.