THE FORMATION OF AMORPHOUS STRUCTURE DURING IRRADIATION OF FE-30-PERCENT NI-ALLOY BY PHOSPHORUS IONS

The relation between structure changes and element composition of Fe-30% Ni alloy during irradiation by P+ ions with an energy of 80 keV was investigated by transmission electron miroscopy and Rutherford backscattering spectrometry. Irradiation doses were from 10(16) to 4 x 10(17) ions/cm2. Within the dose range of 4 x 10(16)-8 x 10(16) ions/cm2, phosphides of (Fe, Ni)3P type, having a tetragonal structure, were formed. At a dose of 1.7 x 10(17) ions/cm2 the amorphization of iron-nickel film was observed. At higher implantation doses crystal material was obtained, containing phosphide phases with high phosphorus content. The composition of the amorphized films corresponds to a deep eutectic in the system metal-phosphorus. As it is known the alloys of Fe, Ni with boron or phosphorus of composition near to eutectic may be easily obtained in the amorphous state by a rapid quenching from fusion or by other methods. In our case the layer of Me-P eutectic is formed during phosphorus implantation and then the radiation amorphization of the implanted layer takes place.