Micro-abrasion-corrosion maps of 316L stainless steel in artificial saliva

The role of salivary media is essential during mastication and ingestion processes; yet it can hinder the performance of foreign materials in the oral cavity. The aim of this study was to examine the effects of applied load and applied electrical potential on the tribo-corrosion mechanisms of 316L stainless steel in an environment similar to oral cavity conditions. 316L stainless steel is a material commonly used in dentistry for orthodontic braces, wires and in some cases as dental crowns. This is due to its favourable corrosion resistance. Relatively few studies have examined the materials performance in an oral environment. The results of this work were used to generate polarisation curves and wastage and mechanism maps to describe the material's tribo-corrosion behaviour. A significant difference in corrosion current densities was observed in the presence of abrasive particles suggesting the removal of the protective chromium oxide passive film. It was found that the corrosion resistant nature of 316L stainless steel made its wear mechanism micro-abrasion dominated for all test conditions. Nomenclature A a b b0 D E F H H’ Icorr Icorr 0 k Ka Kao Surface area of wear scar (m) Radius of wear scar (m) Scar diameter (m) Pure abrasion scar diameter (m) Abrasive particle diameter (m) Applied electrical potential (mV) Faraday’s constant, 96500 (C mol) Hardness (Pa) Combined hardness (of surface 1 & 2) (Pa) Corrosion current density (mA cm) Pure corrosion current density (mA/cm) Wear coefficient Abrasion weight loss (g) Pure abrasion weight loss (g) Kac Kc Kco L M R Ra ρ S t V v W Z Total weight loss (g) Corrosion weight loss (g) Pure corrosion weight loss (g) Total sliding distance (m) Atomic mass Cratering ball radius (m) Surface roughness (arithmetic average) (μm) Sample density (kgm) Coefficient of Severity Experiment duration (sec) Volume loss (m) Volume fraction Applied load (N) Number of valence electrons in corrosion P ag e2