Evaluation of DLC, WC/C, and TiN Coatings on Martensitic Stainless Steel and Yttria-Stabilized Tetragonal Zirconia Polycrystal Substrates for Reusable Surgical Scalpels

DLC, WC/C, and TiN coated SF 100 martensitic stainless steel and Yttria-Stabilized Tetragonal Zirconia Polycrystal (Y-TZP) surgical scalpels were tested, characterized, and comparatively evaluated with regard to chemical leach, micromorphology, and mechanical properties in order to evaluate their suitability as reusable surgical scalpels. Vickers microhardness (HV), Scratch Hardness Number ( ), and sharpening by grinding and cutting capabilities of all the coated scalpels were deemed appropriate for reusable surgical scalpels. However, coated Y-TZP scalpels demonstrated higher Vickers microhardness than martensitic stainless steel scalpels coated with the same coatings, except DLC coating on Y-TZP substrate that presented less adhesion than the other coatings. Uncoated and coated martensitic stainless steel scalpels presented corrosion and chemical leach when soaked for a defined period of time in a simulant physiological saline solution, while uncoated and coated Y-TZP scalpels did not present these drawbacks. Therefore, DLC, WC/C, and TiN coated SF 100 martensitic stainless steel surgical scalpels are unsuitable as reusable surgical scalpels, limiting their application to disposable scalpels only, as the uncoated ones, despite their higher microhardness and expected longer cutting capability duration. Based on these experimental results, WC/C and TiN coated Y-TZP scalpels can be proposed as candidates for reusable surgical scalpel applications. 1. Introduction The disposable surgical scalpel made of martensitic stainless steel is currently the standard tool for soft tissue surgery. A disposable scalpel is convenient as it is supplied individually, sharpened after hardening and tempering, and wrapped in sterile package, with no need for further sharpening and sterilization before use. The main reason behind the introduction of disposable, presharpened scalpels was the elimination of the sharpening operations, which are particularly uneconomical for hospitals, because they need dedicated skilled people and/or expensive precision sharpening equipment. This, in turn, imposes the use of large quantities of disposable knives, forcing hospital to manage the disposal of a large amount of waste scalpels, which fall into the category of special waste and therefore require special disposal procedures and additional cost. On the contrary, the sterilization operation does not represent a problem to the user, since it needs to be implemented anyway in surgery departments for all surgical tools and equipment that are used more than once (pliers, scissors,