Experimental Investigation of the Epsilon Phase in Pb-Bi System

Autor(es)

Martins, V. B. ; Nagasima, T. P. ; Eleno, L. T. F. ; Schon, C. G.

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION; v. 38, n. 3, p. 195-200, JUN 2017.
• Citações Web of Science: 1

Resumo

The Pb-Bi (Lead-Bismuth) binary system has gained some prominence in recent years due to the possible use of eutectic alloys as primary-circuit coolant in generation IV nuclear reactors. Apart from the terminal solid solutions A1-Pb and A7-Bi, the system presents also one intermetallic phase with the hexagonal close-packed structure (A3), usually denoted epsilon phase. Due to the low temperatures involved in this system, attainment of equilibrium is difficult, and in addition, the proximity of x-ray scattering factors for both elements raises questions about a possible polymorphic transition. In the present work, three samples with compositions Pb-29 wt.%Bi, Pb-31 wt.%Bi and Pb-33 wt.%Bi were prepared and characterized by x-ray diffraction. The lattice parameters of epsilon are consistent with those reported in the literature, and their dependence on Bi content was determined as well. Only the hexagonal phase was identified in the 29 wt.%Bi sample, although the currently assessed Pb-Bi phase diagram predicts the presence of the Pb-rich A1 terminal solid solution in this composition. A 2-year annealing at room temperature was performed and the XRD characterization results for these samples are compared with the original data. (AU)

• Processo FAPESP: 12/04023-2 - Diagrama de fases do sistema ternário Pb-Bi-Po (chumbo-bismuto-polônio) através de cálculos ab-initio
• Beneficiário: Luiz Tadeu Fernandes Eleno
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado