Thermodynamic modeling of the Nb–B system

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• 作者：Rockfeller Maciel Peç ; anha ; Flá ; vio Ferreira ; Gilberto Carvalho Coelho ; Carlos Angelo Nunes ; Bo Sundman
• 刊名：Intermetallics
• 出版年：2007
• 出版时间：August 2007
• 年：2007
• 卷：15
• 期：8
• 页码：999-1005
• 全文大小：280 K

文摘

In the present work, the Nb–B binary system was thermodynamically optimized. The stable phases in this system are BCC (niobium), Nb₃B₂, NbB, Nb₃B₄, Nb₅B₆, NbB₂, B (boron) and liquid L. The borides Nb₃B₂, NbB, Nb₃B₄ and Nb₅B₆ and the B (boron) were modeled as stoichiometric phases and the liquid L, BCC (niobium) and NbB₂ as solutions, using the sublattices model, with their excess terms described by the Redlich–Kister polynomials. The Gibbs energy coefficients were optimized based on the experimental values of enthalpy of formation, low temperature specific heat, liquidus temperatures and temperatures of invariant transformations. The calculated Nb–B diagram reproduces well the experimental values from the literature.