Local, element-specific and time-resolved dissolution processes on a Mg–Y–RE alloy – Influence of inorganic species and buffering systems

Highlights: •Flow microcapillary based monitoring of soluble corrosion product formation. •Influence of the buffering system on Mg–Y–RE alloy corrosion mechanisms. •Presence of Ca/P slows Y/Nd intermetallic dissolution and related cathodic reaction. •Presence of carbonates partially counteracts detrimental Tris complexing effect. -- Abstract: The effect of body fluids inorganic species on element-specific dissolution of a Mg–Y–Rare earth elements (RE) alloy was investigated by flow microcapillary plasma mass spectrometry. A new important aspect of this method is the online monitoring of precipitation dynamic in solution. Adding calcium and phosphate to unbuffered NaCl solutions beneficially stabilises the corrosion products formed. But the choice of the buffer is critical for the Mg–Y–RE alloy degradation mechanisms. Tris(hydroxymethyl)aminomethane leads to strong active dissolution because it complexes the ionic species necessary for corrosion product stabilisation whereas a thin partially protective layer can form in borate and carbonate buffered solutions