For electron energy-loss spectroscopy (EELS) magnifications between ×25,000 and ×40,000 were chosen. The measurement area for EELS was defined by a 100 μm spectrometer entrance aperture and 5–7 integration cycles were taken per measurement. Cr and Fe were detected at the L-2,3 edge at an electron loss of 570 eV and 708 eV respectively. Illumination angles between 1 and 1.6 mrad, exposure times between 2 and 5 s and a spectrum magnification of 200× was used. For the detection of Pb via the M4,5 edge at a high energy loss of 2484 eV, a micrograph of the spectrum was captured as previously described by