Development of Granular Structure in [Cu.sub.90] [Co.sub.10] Ribbons Through Furnace and Current Annealing

On-line measurements of resistance and temperature in melt-spun [Cu.sub.90] [Co.sub.10] ribbons are made using two different annealing techniques: conventional furnace annealing, and linearly varying current Joule heating. The aim of this paper is to consider the current, flowing through the sample during the annealing, as a possible parameter to control thermal treatment parameters and thus the microstructure of these systems. Although an exact way to obtain the temperature from the annealing current remains a difficult task, the on-line changes in resistance with current allows one to identify structural changes in the sample during annealing. Also, because the temperature is found to increase continuously with electrical current, it is possible to calibrate the Joule heating system to precisely determine the annealing temperature. Index Terms--Joule heating, binary alloys, nanocrystalline materials.