Saturation magneto striction of (Fe100-xCox)(73.5)Cu1Nb3Si13.5B9 wires

A study on the effect of Co addition and annealing temperature performed be tween 400 degreesC and 600 degreesC for 1 hour on the saturation magnetostr iction, lambda (s), of (Fe100-xCox)(73.5)Cu1Nb3Si13.5B9 (x = 0-25 at.%) wir es 130 micrometers in diameter is presented. In the as-cast state the repla cement of Fe with Co leads to a progressive decrease of the saturation magn etostriction (20 x 10(-6) for x = 0 to 8 x 10(-6) for x = 25). After anneal ing at temperatures up to about 450 degreesC a small increase of the lambda (s) value is obtained corresponding to the internal stresses relaxation. I n the case of the samples annealed at temperatures above 500 degreesC, a si gnificant decrease of lambda (s) was observed. The samples annealed at 550 degreesC present nanocrystalline character and a minimum value of the lambd a (s) while the samples annealed at 600 degreesC are completely crystallize d.