Effects of metalloid content on viscosity of Fe-Si-B-P-C alloy melt

Viscosity of Fe85−x(C1B11Si2P3)(15+x)/17 (x = 0, 2, 4, 6 and 8) alloy melts has been investigated in the temperature range of 1200-1500 °C by the oscillating cup method. An anomalous viscosity decrease for Fe85−x(C1B11Si2P3)(15+x)/17 alloy melts near 1350-1400 °C has been demonstrated in the heating process, and viscosity hysteresis in subsequent cooling process has been observed. The above phenomena are explained by the evolution of cluster in melts. The relationship between viscosity and temperature during cooling processes is well described by the Arrhenius equation. The viscosity almost increases with the increasing total metalloid content at different temperatures. The activation energy calculated by the Arrhenius equation has shown an evident minimum at x = 4, which is supposed to be close to the eutectic composition. The thermal results further confirm the eutectic composition.