Study of the Electrochemical Properties of 316LVM Steel with TiO₂ Layer Deposited by Means of the ALD Method

Abstract

ALD is a variation of CVD, which, for example, found application in depositing two-component compounds, such as SiO₂ or TiO₂. In the case of layers applied to the surfaces of products intended for contact with blood, important determinants include, aside from chemical composition, achieving an appropriate thickness and adequate sealing. A secure layer of the right thickness forms an effective barrier that protects the metal nanomaterial from the effects of corrosive environments (Shan et al. in Surf Coat Technol 202:2399–2402, 2008 [1]). Thin oxide layers based on such elements such as Ti or Si (up to 250 nm) are more hemocompatible, which significantly reduces the risk of complications related to the disseminated intravascular coagulation (DIC) process, for example. Aside from improved hemocompatibility, another important issue related to creating surface layers is the ability to achieve an appropriate set of electrochemical parameters. For this reason, tests were performed concerning the electrochemical properties of the TiO₂ layers deposited on the surfaces of AISI 316LVM steel samples using ALD under varied process parameters. First, potentiodynamic and potentiostatic measurements were taken, which enabled pitting and crevice corrosion resistance to be assessed. Secondly, impedance measurements were performed to enable interpretation of the processes and phenomena occurring at the TiO₂ layer—electrolyte (synthetic plasma) interface. Complementary examination of surface topography was performed using a scanning electron microscope (SEM).