Self-Cleaning Properties of TiN/CrN Nanoscale Multi-layer Deposited on Surgical 420C Stainless Steel

The present paper focuses on the investigation of self-cleaning properties based on studding of water repellency and blood repellency for TiN- and CrN single-layer and TiN/CrN nanoscale multi-layer coatings deposited via Cathodic Arc Evaporation (CAE) method on medical grade 420C stainless steel substrate. X-ray diffraction (XRD) method and Field Emission Scanning Electron Microscope (FESEM) was used to characterize microstructure. Surface roughness parameters were measured by using Taylor-Habsson method. Blood contact angle and water contact angle measurements test were applied to characterize the self-cleaning properties of the specimens. The analysis of sample data shows that coated specimens have more water contact angle values in comparison to bare steel. Among the coated samples, CrN single-layer has the highest water contact angle (80°) due to its lower surface roughness (Ra=0.189µm) among the other samples. Moreover, the findings of the paper prove that samples had inverse behavior against blood and water in the contact angle measurement test. Bare steel has higher blood contact angle (76.1°) and more blood repellency than the coated specimens. It seems that the different behavior of samples against water and blood in contact angle tests is due to the nature of two fluids. TiN/CrN multi-layer coating results had minor differences in water and blood contact angle tests (67.3° and 62.2° respectively).