Electrochemical Tests in Stainless Steel Surgical Implants

Publication date: 2015 Source:Procedia Materials Science, Volume 9 Author(s): Alex Kociubczyk , Claudia Mendez , Ricardo Gregorutti , Alicia Ares In the present work the corrosion resistance of stainless steels was evaluated following the specifications of ASTM F-745 standards. The specimens were obtained by two methods, the conventional process of investment casting and countergravity low pressure casting. Cyclic polarization tests were performed according to ASTM F 2129, using a conventional three-electrode cell, with Pt as a counter electrode and saturated calomel as a reference electrode. The experiments were performed at (37 ± 1) °C and, before starting the test, the electrolyte was purged with N2 gas for 15minutes. As electrolyte, a solution of 0.9% NaCl was used (pH≈7), the open circuit potential (OCP) was monitored for 1 hour and then the potentiodynamic scanning started in the anodic direction, at a speed of 0.167mV/s, from a potential of 100mV below the OCP. The sweep was reversed after passing the threshold of current density at a value hundred times greater than the current density of pitting. Measurements of electrochemical impedance spectroscopy were performed after one hour of exposure of the specimens to OCPs performed in a frequency range from 100kHz to 1 mHz and potential amplitude of ± 10mV. The microstructure of the samples was analyzed before and after testing using optical microscopy. The results indicated that the samples in general exhibit...
Source: Procedia Materials Science - Category: Materials Science Source Type: research