Anti-bacterial Properties of Wear Resistant Thermal Diffusion Coatings

Abstract

Bacterial sensitivity of thermally diffused stainless steel grade 316L has been studied in this paper. Thermal diffusion heat treatment processes like salt bath nitriding and slurry paste boronizing have been explored for their anti-bacterial properties. SS316L has been chosen as the substrate material due to its acceptance as a general bio-material in the medical industry. The results from the surface hardness and cross section analysis of the treated specimens revealed their characteristic nitride and boride layers confirming the success of the nitriding and boronizing processes. Surface roughness, prior- and post-heat treatment were studied through tactile profilometer. Bacterial sensitivity tests were conducted on the treated and unprocessed specimens with Bacillus subtilis bacteria in nutrient agar. Upon incubating for 24 h, the tests displayed a distinct zone of inhibition adjacent to the treated specimens. Both the nitrided and borided SS316L specimens exhibited anti-bacterial behaviour in response to B. subtilis bacteria. These anti-bacterial surfaces can potentially prevent the formation of infectious biofilm on medical implants and devices.