“…5 , where oxide can be seen penetrating into the metal. Although the mass spectra of mixed oxides are challenging to work with in APT due to the many molecular ions and overlaps [32] , the oxide compositions were investigated. The average oxygen content of the analysed oxides was found to be 50.9 at.%, but it should be noted that it is common that the O content of oxides is somewhat underestimated in APT measurements [32][33][34] .…”