FORMATION OF AMORPHOUS FE1-XBX ALLOYS DURING SOLID-STATE ALLOYING WITH HEXANE

Fe1-x-B-x alloys were synthesized in an argon atmosphere using a high performed in argon with hexane as a process control. agent (PCA). With powders and crystalline FeB and Fe2B phases with nanometer size exist ed. The amorphous phase content increased with the increase of the bor on content. When hexane was used as a process control agent the carbon content of the ball-milled powder was found to increase as a function of the ball-milling time, A maximum carbon content of 37 at.% was mea sured after 500 h of milling, The increase in the carbon content being caused by the dissolution of the hexane. The dissolved carbon was fou nd to increase the formation of the amorphous phase in the structures. Within a composition range of 0.1 less than or equal to x less than o r equal to 0.2 a single phase amorphous structure exists, Within a com position range of 0.2 < x less than or equal to 0.5 the structure cons ists of a mixture of an amorphous phase and crystalline FeB and Fe2B p hases. The average Curie temperature of the alloys milled in argon was 780 degrees C, and that of alloys milled with hexane only a little le ss than 750 degrees C. The onset of the exothermic reaction temperatur es during annealing of the powders was about the same, 450 degrees C, for both alloy types. Mossbauer measurements revealed that the carbon does not form carbides but remains in a solid solution within the amor phous matrix. (C) 1998 Elsevier Science B.V.