Influence of bovine serum albumin in Hanks' solution on the corrosion and stress corrosion cracking of a magnesium alloy

It is essential for any temporary implant to possess adequate strength to maintain their mechanical integrity under the synergistic effects of mechanical loading characteristics of human body and the corrosive physiological environment. Such synergistic effects can cause stress corrosion cracking (SCC). The aim of the present study is to investigate the effect of the addition of bovine serum albumin (BSA) to Hanks' solution in corrosion and SCC susceptibility of AZ91D magnesium alloy. The electrochemical impedance spectroscopy (EIS) results indicated that the addition of BSA increased corrosion resistance of the alloy during the first 48 h of immersion and then decreased it rapidly. The energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses indicated adsorption of BSA on the alloy surface during initial hours of immersion. However, with the increasing immersion time, BSA chelated with the corrosion products causing disruption of the protective film; thus, it accelerated the corrosion of the alloy. Both the mechanical data and fractographic evidence have confirmed susceptibility of the alloy to SCC. However, in the presence of BSA, the alloy suffered greater SCC which was attributed to its increased susceptibility towards localized corrosion. (C) 2017 Published by Elsevier B.V.