We performed neutron, &ggr; and Mo¨ssbauer spectroscopic experiments in order to study the possibility of cold nuclear fusion in Fe90Zr10and Fe89Zr11amorphous ribbons having high hydrogen absorbing ability. No significant changes in the neutron and &ggr; spectra were found at deuterization performed at different cathodic potentials. The observed differences in the Mo¨ssbauer spectra of samples deuterized in air and in nitrogen atmosphere can be explained by decrease of deuterium uptake as well as by a small heat effect due to reaction of hydrogen with oxygen dissolved in water in the case of electrolysis carried out in air.