No abstract

The rusts on the gauge face and non-gauge face of two rail steels (traditional C-Mn and novel CuMo rail steel) were characterised after two years of service to corelate with an apparent visual observation of a lower corrosion rate in the case of the Cu-Mo rails. Rust samples were characterised by X-ray diffraction, Fourier transform infrared spectroscopy and Mö ssbauer spectroscopy. X-ray diffraction patterns showed diffuse peaks indicating poorly crystallised rust phases, while the phases identified by the other techniques were c-FeOOH (lepidocrocite), a-FeOOH (goethite), Fe 32x O 4 (magnetite), d-FeOOH and a-Fe 2 O 3 (haematite). The enhanced corrosion of the gauge face compared to non-gauge face for both rails and that of C-Mn rails compared to Cu-Mo rails was related to the higher amount of c-FeOOH and lower amount of Fe 32x O 4 .

No abstract

The transition 7-Fe203 --*~t-Fe20 3 has been investigated in oxygen and argon using DSC measurements in the temperature range 298 to 820 K. The results have been interpreted by taking into account the method of preparation, the specific microstructure of the samples and the nature of the gas used. It has been shown that the transformation temperature, and in general the absolute value of the negative enthalpy of the transformation as well, rises with increase of the specific surface area of the y-Fe20 3. The observed fluctuations in this trend are attributed to differences in the microporosity, gas sensitivity and crystallinity of the samples.

No abstract