Fundamental understanding of the corrosion and biomineralization of MgO surfaces – An in situ AFM study

Graphical abstract: - Highlights: • Stability and dissolution of MgO(1 0 0) surfaces in Simulated body fluids (SBF). • Delicate interplay between the dissolution and growth of surface layers. • The biomineralization process occurs via two-step process. • Development of square etch pits agrees with the most stable thermodynamic corrosion mechanism on MgO surfaces. - Abstract: In this study, the corrosion behavior of single crystalline MgO surfaces in simulated body fluid (SBF) is investigated. The corrosion mechanism and the nucleation and growth of surface layers relevant for biomineralization was studied by means of in situ atomic force microscopy (AFM) and complemented with X-ray photoelectron spectroscopy (XPS). At initial immersion stages, the dissolution of the surface dominates the overall corrosion behavior whereas biomineralization becomes relevant at later stages. Square etch pits are observed for the first time at the physiological pH-value. The results are discussed in terms of delicate interplay between the dissolution and growth of surface layers.