Measuring Method of Non-Crystallinity for Amorphous Alloy by Ion Beam Bombardment †

Amorphous alloy is one of the newest materials, recently used in many industrial fields and it has many useful properties such as magnetic or mechanical. The properties will deteriorate when amorphous alloys are crystallized by unexpected heating or low temperature annealing for a long time. In order to evaluate the amorphous grade, we propose a new method based on investigating topographical changes of the amorphous surface by ion bombardment. When an amorphous alloy contains crystal grains, characteristic microfeatures such as cones and pyramids are produced and developed in proportion to the number of the grains on the surface by irradiation with ions. In the present work, the topographical changes of thin amorphous alloy wires (Fe_<77.5>B_<7.5>Si_<15>, 125µm in diameter) annealed at several temperatures up to 650℃ about 10 hours for crystallization and then irradiated by 20 keV argon ions of 2x10＾23 ions/m＾2 were studied using a scanning electron microscope. The relation between the topographical changes and the annealing conditions: the non-crystallinity of amorphous alloys is reported.