EFFECTS OF CU ADDITION ON BETA-PHASE FORM ATION RATE IN FE2SI5-B ALLOYS AND THEIR THERMOELECTRIC-POWER

The formation behavior of a beta-phase in the newly proposed Fe2Si5-B alloy with a small amount of Cu and their thermo-electric power were e xamined. The results are summarized as follows: The as-solidified stru cture of the Fe2Si5 based alloys with B and Cu was found to be mostly the a single phase by conventional X-ray diffractometry while a few B- rich and epsilon phase were observed by SEM. The beta-phase formation rate in a conventional (FeSi2)(99)B-1 alloy was increased by the addit ion of Cu, but still quite a long annealing period was necessary to at tain the complete formation of beta-phase. In the case of the Cu-added (Fe2Si5)(99)B-1 alloy, the B formation was completed by annealing at 1073 K for 1.8 x 10(2) s. It is 100 times shorter than that in the bin ary Fe2Si5. The thermoelectric power of the newly proposed (Fe2Si5)(99 )B-1 alloy elucidated to be comparable with the conventional (Fe2Si5)( 99)B-1 alloy. The Si phase retained in the final state also found to c ause no deterioration on the thermoelectric power.