Bio-compatible low reflective coatings for surgical tools using reactive d.c.-magnetron sputtering and arc evaporation — a comparison regarding steam sterilization resistance and nickel diffusion

Abstract

Abstract The reflection and scattering of bright light from the surfaces of surgical tools disturb the visual operating field of the surgeon. To decrease this kind of disturbance, a hard black PVD thin film is used as a possible precaution. In the present paper, the two dark PVD finish layers TiAlN and TiCN on stainless-steel substrates were considered. For corrosion protection, a Nb intermediate layer as diffusion barrier was studied. One of the questions to be answered was the long-term steam oxidation resistance due to multiple sterilization cleansings of the surgical tools. The long-term oxidation stability of multilayer Nb/TiAlN and Nb/TiCN could be significantly affected by the PVD coating methods and their very different conditions in reactive modes. Here, the results of unbalanced d.c.-magnetron sputtering and arc-evaporation coatings are represented for an industrial PVD engine of the HTC 1000/4 ABS ™ type. To study the effect of the Nb diffusion barrier layer, GDO(E)S depth-profile analyses were carried out. Because of the so-called nickel allergy problem, which restricts surgical operations in some cases, a special emphasis was the study of nickel diffusion into the coating layers. Furthermore, the bio-compatibility of the multilayers has been estimated. Summarizing the obtained results, all of the investigated coatings have fulfilled the requirements for application to surgical instruments independent of the coating method used.