Properties of Nitride-Coated Surgical Scalpel Blades

Surgical tools are used in many medical treatments and procedures that expose them to a wide range of biological conditions that induce corrosion, abrasion, and wear. A protective layer is often needed to prolong its useful life. Thus, it is essential to use appropriate coating techniques to improve the mechanical properties and chemical stability of the substrate. This work used a custom-built radio frequency-powered magnetron sputtering system for the deposition of titanium-(Ti-) based coatings, which were selected because of their reported biocompatibility and superior mechanical qualities. Titanium nitride (TiN) and titanium aluminum nitride (TiAlN) thin films were deposited on AISI 304 stainless steel substrates and on Indoplas^TM sterile scalpel blades. TiN was grown using a Ti target while TiAlN used a Ti-Al combinatorial target. Both films were deposited using a 90:10 admixture of argon (Ar) and nitrogen (N₂) gases. The substrate bias was varied into three different potentials: 0, -100, and -200 V Substrate heating of 200°C was applied, and the deposition time was set at 120 min. The optimal parameters and material for surgical tools are found to be TiN deposited at -100 V and TiAlN deposited at -200 V substrate bias as they show the highest resistance to abrasion and corrosion, respectively, and without reducing the sharpness of the blades. This work aims to offer the medical community a practical and inexpensive method of protecting surgical instruments while extending service life.