Tomographic atom probe investigation of MgO precipitates in silver

MgO-precipitates in a silver matrix formed after internal oxidation of a Ag–1 at.% Mg alloy kept at 600–850 °C for 3–7 days in normal atmosphere were investigated by means of conventional transmission electron microscopy, field ion microscopy (FIM), and the tomographic atom probe. The difference in the field evaporation rates between the Ag matrix and the MgO remains pronounced even at FIM imaging temperatures as low as 20 K. The influence of this difference on the reconstruction of three-dimensional images and on the quantitative analysis of the metal/ceramic interface is discussed. Results obtained by a systematic variation of the acquisition temperature and evaporation parameters are presented.