Mössbauer spectroscopy of activated FeTi: I. Products of high temperature activation

Conversion electron Mössbauer spectroscopy has been performed on samples of FeTi powder for which the 57Fe isotope abundance had been raised to ∼10%. After activation for hydrogen absorption (at temperatures up to 500°C) followed by a heating to 800°C before being returned to room temperature, these samples gave additional Mössbauer spectra which came from the antiferromagnet Fe 2Ti produced in the surface region of the FeTi grains. The Mössbauer spectra could be very closely fitted by summing the FeTi and Fe 2Ti contributions only, with no requirement to include an Fe contribution in any other form. The activation and temperature treatment used was chosen to conform to the activation response of FeTi as measured earlier in our laboratory, using bulk magnetization measurements; FeTi alloys subjected to such treatment absorb hydrogen readily.