Formation of macroscopic phase-separated dual-layer melt-spun ribbon from Co-Si-B-Cu alloy

A macroscopically phase-separated dual-layer ribbon can be obtained from (Co75Si10B15)70Cu30 alloy by using a conventional single-roller melt-spinning method, whereas such a structure cannot be obtained from (Fe75Si10B15)70Cu30 alloy. Liquid phase separation and amorphous phase formation take place simultaneously in Co-Si-B-Cu alloy, which leads to the formation of a unique structure during rapid solidification.