Crystallization of Eutectic Structures in the LaB₆–W₂B₅–NbB₂ System

Abstract—Crystallized alloys in the LaB₆–W₂B₅–NbB₂ system are obtained by melting in an electric arc discharge and rapid cooling in an inert gas (Ar) flow. The characteristic eutectic structures of the lamellar and rod types are investigated using scanning electron microscopy. Using X-ray phase and X-ray structural analysis, it is found that the phase composition of crystallized objects is represented by lanthanum hexaboride, an α-solid solution (W_xNb_{1 – x})₂B₅ and β-solid solution (Nb_xW_{1 – x})B₂. An assumption is made about the existence of a ternary phase in the Nb–W–B system, which is close to the composition of Nb_0.5W_0.5B₄. The concentrations of the components in the eutectic regions are determined by the methods of X-ray spectral microanalysis and statistical analysis of the area of the phase components.