MICROSTRUCTURAL STUDY OF THE CRYSTALLIZATION PRODUCT OF THE CO100-XPX AMORPHOUS SYSTEM

The crystallization process of amorphous electrodeposited samples of composition Co100-xPx (10 < x < 25) has been monitored by differential scanning calorimetry (DSC) and the resulting microstructure has been studied by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Samples of composition given by x < 21 crystallize through two consecutive stages, while those with x > 21 crystallize through a single one. Depending on the composition and crystallization stage, activation energies varying from 1.76 to 2.02 eV and frequency factors of the order of 10(13)-10(14) s-1 have been evaluated. The DSC measurements are compatible with the coexistence of two amorphous phases with different compositions in the regions that are located near the edges of the samples. The analysis of the microstructure resulting from crystallization has shown the existence of two different types of texture for samples with values of x respectively above and below 21, as well as the presence of linear structures oriented perpendicular to the plane of the samples. The development of these features can be attributed to the fundamental role that the polarization, due to magnetization, plays in the crystallization process of this system. A gradual variation of the grain size has also been observed, indicating that crystallization takes place by an inhomogeneous nucleation and growth mechanism.