The influence of pH on the corrosion rate of high-purity Mg, AZ91 and ZE41 in bicarbonate buffered Hanks' solution

Corrosion of high purity (HP) Mg, AZ91 and ZE41, was studied in CO2-bicarbonate buffered Hanks' solution, using mass loss and hydrogen evolution. Corrosion rates were in the following decreasing order: ZE41 > HP Mg > AZ91. Corrosion rates of ZE41 were much higher than those of the other Mg alloys. HP Mg and AZ91 had comparable corrosion rates, but HP Mg corroded more quickly. All corrosion rates decreased slightly with increasing pH, attributed to more stable protective films. A slow fluid flow caused a slightly higher corrosion rate and a more-uniform corrosion morphology for all Mg alloys. (C) 2015 Elsevier Ltd. All rights reserved.