ON THE POSSIBILITIES OF MAKING MULTIPLE LAYER RIBBONS BY SINGLE ROLLER MELT SPINNING

Abstract

This chapter provides an overview of the possibilities of making multiple-layer ribbons by single-roller melt spinning. An easy way of obtaining thin ribbons of different alloys is by single-roller melt spinning. It is also possible to cast rather brittle alloys in this form, but they usually fall to pieces when handled. One way of solving this problem is to cast two layers directly, one ductile layer supporting the second brittle layer. In a study described in the chapter, the method used to make multiple-layer ribbons was single-roller melt spinning. The method used for making multiple layer ribbons was single-roller melt spinning using two crucibles instead of one. The crucibles were made of quartz. At the base, there was either a circular opening with diameter variations of 0.6 or 0.8 mm or a slit with width variations of 0.3 or 0.6 mm. The most important parameters to control for obtaining a good quality two-layer ribbon are the speed of the roller, ejection pressure, the size of the nozzle, and the distance between the crucibles. All of these parameters can be varied, but it is important that they are synchronized. The distance between the crucibles is crucial to good quality. If they are too close, the first layer would not have been solidified when the second jet hits the ribbon and the alloys will be mixed. If the crucible distance is too far, the ribbon may leave the roller before the second layer has solidified.