Crystal ultrafine particle (CUFP) films of the Fe-B alloys were prepared by the quick-cooling vapour-deposition method
and then studied by the positron annihilation technique. Results from the positron annihilation lifetime spectra agree with the three-state annihilation mode of positrons
The two-phase core-shell structure of CUFP of Fe-B alloy are determined
and it is inferred that the CUFP film possesses three-phase microstructure.