Joule-heating Effects In the Amorphous Fe40ni40b20 Alloy

The effects of Joule heating on the amorphous Fe40Ni40B20 alloy are investigated by measuring the time behavior of the electrical resistance of ribbon strips during such a treatment. The structural transformations occurring in subsequent stages of the process are studied by means of x-ray-diffraction, differential-scanning-calorimetry, and magnetic-permeability measurements. A continuous evolution from a fully amorphous to a fully crystalline structure may be followed. The crystallization mechanisms observed in Joule-heated samples differ from the ones occurring under conventional heating conditions. The electrical resistance displays a bump in the course of Joule heating. A quantitative model relating such a bump to the extra heat released to the sample by fast crystallization is proposed and discussed

Saturation Magnetostriction and Volume Magnetostriction of Fe-Ni-Co Amorphous Ribbons(Metallurgy)

The saturation magnetostriction and the volume magnetostriction in amorphous ribbons of Fe-Ni-Co system were measured from 77K to room temperature, by a three terminal capacitance method. The ternary diagram were given of the saturation magnetostriction and volume magnetostriction in (Fe_xCo_yNi_) _Si_8B_ system. It was found that the largest saturation magnetostriction constant is 36×10^ for the composition Fe_Co_Si_8B_ at room temperature. The temperature dependence of the saturation magnetostriction and the volume magnetostriction in Fe-Ni-Co system were not a simple function of the temperature. The maximum value of volume magnetostriction δω/δH was observed for Fe_Si_8B_ to be 24×10^ Oe^ at room temperature