FE80B20-XSIX GLASSES - STUDY OF SOME PHYSICAL-PROPERTIES AS DEPENDING ON METALLOID CONTENT

It is found that the formation of Fe80B20-xSi x metallic glasses and their thermal stability improve considerably upon substituting silicon for boron in the range 0<x<5, but diminish again at higher concentration. This behavior is suggested to be of structural origin. The dependence of the magnetic moment and Curie temperature on x is relatively small. The variation of the magnetic properties, being different from those of corresponding cobalt glasses, is discussed in terms of change in the band shape through electron hybridization and of charge transfer which occurs when transition metals are alloyed with metalloid elements. The microhardness decreases continuously as boron is replaced by silicon. With a simple model, by treating atoms as macroscopic pieces of material, it is shown that this effect is due to variations of the molar volume and compressibility of the different metalloid elements.