Surface investigations on annealed and boron implanted Fe80Mo7B12Cu1 amorphous ribbons

Abstract

The effect of boron ion implantation (160 keV, (2–10)×1016 B+\\cm2) and thermal annealing (410–580°C, 2 h) on metallic glass Fe80Mo7B12Cu1 was investigated by means of STM (Scanning Tunneling Microscopy), CEMS (Conversion Electron Mössbauer Spectroscopy), TEM (Transmission Electron Microscopy) and X-ray diffraction. The chosen material is known to become nanocrystalline after a suitable heat treatment. N+ ion implantation can also promote partial crystallization (restricted to α-Fe phase formation) of metallic glasses, especially in the case of small boron contents, as it was shown in a previous work. The as-quenched Fe80Mo7B12Cu1 has only paramagnetic moment at room temperature which makes it very easy to detect even small amounts of ferrogmagnetic α-Fe. According to our X-ray and CEMS investigations, even the high dosage boron metalloid implantation did not lead to partial crystallization of the 150 nm thick implanted layer. This can be the consequence of the implanted boron which is the glass forming metalloid component in our alloy. In other words, we have only found the disordering effect of the boron implantation which is in accordance with expectations. However, STM images reveal clear changes in the surface roughness of the samples. The number of features in the 50–150 nm size range are reduced, larger objects remain persistent, while smallers seem to change their shape due to boron ion implantation.