Though magnesium (Mg) alloys are highly attractive for their use as biodegradable/temporary implants, they can be critically compromised in such applications due to their susceptibility to corrosion and stress corrosion cracking (SCC) in human body fluid (such as Hanks’ solution). This study investigated the role of additions of bovine serum albumin (BSA) and glucose to Hanks’ solution in SCC of a Mg alloy, ZK60. The study reproducibly demonstrated the novel and unique characteristic of the acutely elliptical shape of the overall fracture surface of alloy subjected to SCC tests, exclusively when BSA was added to the Hanks’ solution, whereas tests in the Hanks’ solution without BSA produced the fracture surface of usual circular shape. Also, the BSA addition to the Hanks’ solution produced contrasting influences on SCC and electrochemical corrosion. The study provides a comprehensive mechanistic explanation for the two phenomena.

Biodegradable implants are critical for regenerative orthopaedic procedures, but they may suffer from too fast corrosion in human-body environment. This necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical integrity. In this study, an AZ91 magnesium alloy, as a representative for a biodegradable Mg implant material, was modified with a thin reduced graphene oxide (RGO)-calcium carbonate (CaCO₃) composite coating. Detailed analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity, and thus has the potential to greatly extend the related application field.