Mg–Ca Surgical Wires Degradation in Animal Serum

The degradation of Mg–Ca alloys designed for veterinary applications (hard tissue bonding) obtained by the hot and cold plastic deformation process was investigated. Weight loss and electrochemical tests were carried out on wires with various contents of Ca (0.7, 0.9, and 1.2 pct) in an animal serum, an environment that most closely resembles the conditions of a living organism. The results showed that corrosion resistance increases slightly with an increase in the Ca content. This fact is probably related to the lower solubility of calcium compounds which, deposited on the wire surface, block the corrosion processes. The surface coverage with corrosion products was confirmed by SEM analysis. XPS and FTIR measurements showed that the surface layer consists mainly of sparingly soluble Ca and Mg compounds. SEM micrographs of the cross-section of the wires indicated a slightly higher layer thickness for alloys with a higher Ca content, which is consistent with the results of electrochemical tests.