Amorphous alloys of (Fe_Co_x)_P_C_7 and (Fe_Co_x)_Si_B_ Were prepared by quenching from the melt by using the centrifugal type and roller type solidification techniques. Specimens were all ribbons in form. Measurements were made of B-H hysteresis loops, effective permeabilities at high frequencies, longitudinal magnetostrictions, electrical resistances, specific gravities and Vickers hardnesses. These alloys are magnetically very soft. The magnetostriction is zero at a composition near x=0.94, being positive in the range of 0≤x0.94. The coercive force and the permeability depends on the absolute value of magnetostriction. The alloy (x=0.94) having a vanishingly small magnetostriction exhibits the best soft magnetic properties : the coercive force is 0.006 Oe, the maximum permeability is 7.0×10^5 and the effective permeability is about 7×10^3 at higher frequencies up to about 100 KHz. In addition to these, this alloy has a high Vickers hardness of 910. Possible applications of this alloy are discussed
