Viscosities of the Nd and Fe-30% Nd-1% B-1% Co-1% Dy Melts

Neodymium is one the most widely used rare-earth metals, the main quantity of which is used in manufacturing permanent magnets. Experimental data on the physicochemical properties of neodymium and the Fe-30% Nd-1% B-1% Co-1% Dy alloy in the liquid state are reported. Initially, in manufacturing NdFeB magnets, an Fe-30% Nd-1% B-1% Co-1% Dy ingot is prepared. The kinematic viscosity and electrical resistivity of liquid Nd (99.85% purity) and the kinematic viscosity of the Fe-30% Nd-1% B-1% Co-1% Dy alloy are measured. The temperature dependence of the kinematic viscosity of the neodymium melt is described by the Arrhenius-Frenkel-Eyring equation and agrees with the results of theoretical calculation. The temperature of the kinematic viscosity of the Fe-30% Nd-1% B-1% Co-1% Dy melt exhibits anomalous behavior in a temperature range of 1320-1550 degrees C: the viscosity increases with the temperature. The increase in the viscosity with the temperature, i.e., so-called quasi-gas behavior of the melt is described in terms of physical chemistry concepts using the molar viscosity concept. The temperature dependence of the electrical resistivity of liquid neodymium is described by a linear function. The measured values of the electrical resistivity of the neodymium melt are 30% higher than the experimental values obtained by other investigators. The measured results are recommended to optimize the metallurgical production conditions of the sintered permanent NdFeB magnets in Ural Strip Casting.

Automated summary

Neodymium is a widely used rare-earth metal in the manufacturing of permanent magnets, with experimental data reported on its physicochemical properties in liquid state. The study also investigates the behavior of Fe-30% Nd-1% B-1% Co-1% Dy alloy. Results show the temperature dependence of kinematic viscosity and electrical resistivity, as well as anomalous behavior in the viscosity of the alloy at certain temperatures. The findings provide insights for optimizing production conditions of NdFeB magnets.