The effect of the melt-spinning processing parameters on the rate of cooling

The effect of the melt-spinning processing variables such as wheel speed, gas ejection pressure and melt temperature on cooling rates measured by a thermoelectric technique has been investigated. It is found that cooling rates during melt spinning of Fe40Ni40P14B6 ribbons increase in the range 4×104–6.9×106 K s−1 while ribbon thickness decreases from 92 to 18 μm with increasing wheel speed from 9 to 30.5 m s−1. The resultant strong dependence of the rate of cooling on ribbon thickness (in this case Ṫ∝d−3.1) is obtained. Cooling rates and ribbon thickness are found to increase with increasing ejection pressure and to decrease as melt superheat grows. As a result of improving thermal contact at the wheel–ribbon interface with increasing gas ejection pressure, the cooling rates of melt-spun ribbons tend to increase with their thickness.