On the Effect of the Melt Cooling Rate upon Spinning on the Structure of the Surface Layers of Fe77Ni1Si9B13 Alloy Ribbons

Fast-quenched ribbons with thicknesses of 200, 50, 30, and 20 mu m have been obtained by melt spinning at hardening disk rotation speeds of 500, 1500, 2500, and 3500 rpm, respectively. The chemical composition of the ribbons has been determined by atomic emission spectroscopy on a Spectroflame Modula S spectrometer. X-ray diffraction patterns of the ribbons have obtained on a DRON-6 diffractometer (CuK alpha radiation) with a graphite monochromator. The effect of the melt cooling rate on the structural state of the contact and free sides of the Fe77Ni1Si9B13 alloy ribbons has been examined. It has been established that, by increasing the melt cooling rate, one can obtain fast-quenched Fe77Ni1Si9B13 alloy ribbons with different structures: X-ray amorphous at 3500, 2500, and 1500 rpm and crystalline at 500 rpm. Cooling of the melt at a quenching disk rotation speed of 500 rpm makes it possible to obtain Fe77Ni1Si9B13 alloy ribbons with crystallographic structures of three types: A2, C16, and D0(3) (A2 corresponds to the alpha-Fe(Si) phase; C16, to the Fe2B phase; and D0(3), to the Fe3Si phase). In the surface layers on the ribbon free side, texturing of the Fe3Si phase has been detected. It is noted that the crystal structure of the ribbons obtained by melt cooling on a quenching disk at a rotation speed of 500 rpm differs from the structure of the ribbons of this alloy crystallized from the amorphous state by annealing.