Corrosion resistance of resorbable Ca-Mg-Zn-Yb metallic glasses in Ringer's solution

The corrosion behavior of Ca65−xMg10+xZn25 (x = 0,10) and Ca32Mg12Zn38Yb18 alloys was studied by potendiodynamic tests and electrochemical impedance spectroscopy in Ringer's solution. The solution of NaCl, KCl and CaCl2 components reacted with outer layer of alloys and produced corrosion products. The influence of Ca content on the hydrogen volume as a function of time was discussed. The measurements exhibited significantly less hydrogen evolution volumes for Ca55Mg20Zn25 alloy (5.0 ml/cm2) than for Ca65Mg10Zn25 glass (11.3 ml/cm2) after 2 h. The lowest value of hydrogen evolution was observed for Ca32Mg12Zn38Yb18 glass (1.1 ml/cm2). The hydrogen volume for Ca32Zn38Mg12Yb18 sample fulfilled the non-toxic amount of H2, which must be low than ~1 ml/h. The XPS survey spectra for the glassy samples after corrosion test in Ringer's solution represent the surface components. The corrosion products were identified as to be CaCO3, Mg(OH)2, CaO, MgO and ZnO compounds. In addition, the EDS and X-ray analysis of a layer of corrosion products after immersion tests in Ringer's solution identified calcium and ytterbium hydroxide, calcium carbonate and also calcium zinc hydroxide hydrate.