Smooth, bright films containing 12-48wt% iron, 32-70wt% nickel and 5-40wt% tungsten were obtained from 1-hydroxyethane-1, 1-diphosphonic baths. The tungsten content of the alloys increased with increases in the concentrations of potassium tangstate and ferrous chloride in the baths, but was unrelated to current density. Vickers hardness rose from 400 to 800 when tungsten content increased from 5wt% to 40wt%. The results of X-ray diffraction (Cu-Kα) showed that the alloy is amorphous when the tungsten content exceeds a critical value, which is lowered from 30wt% to 20wt% when the iron content of the alloy is increased from 12 to 48wt%.