Contamination in vacuum‐evaporated iron films by conversion electron Mössbauer spectroscopy

Iron films, about 800 A thick, were prepared by evaporation under low pressure conditions [2×10−7 Torr (2.7×10−5 Pa)] and were examined by conversion electron Mossbauer spectroscopy to determine the amount and nature of contaminants. After deposition the films exhibited a spectrum suprisingly similar to that of Fe–C martensite. The quantity of carbon present in the film could be estimated from the spectrum of the film after precipitation of Fe3C at 500°C and was found to be on the order of 8 at.%. Besides carbon, no other contaminant was detected. The implications of these findings on the interpretation of studies of surface and subsurface reactions on vacuum‐evaporated Fe films are discussed.