A novel functional multilayer coating with periodically stacked nanolayers of amorphous carbon (a:C)/tungsten carbide (WC) and an adhesion layer of chromium (Cr) was deposited on 304 stainless steel using a dual magnetron sputtering technique. Through process optimization, highly densified coatings with high elasticity and shear modulus, excellent wear resistance, and minimal susceptibility to corrosive and caustic media could be acquired. The structural and mechanical properties of the optimized coatings were studied in detail using a variety of analytical techniques. Furthermore, finite element method simulations indicated that the stress generated due to contact against a steel ball was distributed well within the coating, which allowed the stresses to be lower than the yield threshold of the coating. Thus, an ultralow wear rate of ∼10-12mm3/N mm could be achieved in dry sliding conditions under relatively high Hertzian contact pressures of ∼0.4-0.9 GPa. The amorphous and pinhole-free structure of the individual layers, sufficient number of pairs, and the relatively dense stacked layers resulted in significant polarization resistance (Z″ = 5.5 × 106 ω cm2) and increased the corrosion resistance of the coating by 10-fold compared to that of recently reported corrosion-resistant coatings.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2010-0018289) and Brain Korea 21 Plus Project in 2017.
© 2017 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)