Control of the Surface Roughness and Magnetic Properties of Rapidly Quenched High Silicon Iron Alloy Ribbons

Abstract

This paper describes some surface features of rapidly solidified crystal ribbons and its relation to the pupdle flow behavior with particular attention to the Nozzle-Roll gap. Magnetic properties of the rapidly quenched High Silicon Iron Alloy ribbons are strongly affected by the ribbon surface topography. Therefore, ribbon surface roughness is examined in connection with pit formation as well as fluid-flow behavior. It is shown that pit size strongly depends on the Reynolds number (Re) and that there is a Critical Reynolds number (Re_crit). Below Re≤Re_crit, the puddle flow becomes a laminar flow. The increasing rate of pit size is so small that a smooth ribbon can be obtained. The apparent iron loss (W_0.5/50) halved and the apparent flux density (B₁₀) is doubled resulting in an improvement of the magnetic properties of the ribbon.