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Section III: Supplemental Literature Review

B-Nb (Boron-Niobium) H. Okamoto

The B-Nb phase diagram was updated most recently by [2008Oka] based on the thermodynamic modeling reported by [2007Pec]. This system was studied further by [2008Tan] by using metallographic analysis, DTA, and x-ray diffraction and by

Table 1

[2008Wit] by means of thermodynamic modeling. Figure 1 shows the B-Nb phase diagram calculated by [2008Wit]. A new phase B3Nb2 was found in this system. B-Nb crystal structure data in [Massalski2] were modified in Table 1 based on [2008Wit].

B-Nb crystal structure data

Phase

Composition, at.% Nb

Pearson symbol

Space group

Strukturbericht designation

Prototype

(bB) B2Nb B3Nb2 B4Nb3 B6Nb5 BNb B2Nb3 (Nb)

0-0.5 29.7-39 40 42.9 45.5 50-51.2 60 98-100

hR108 hP3 oC20 oI14 oC* oC8 tP10 cI2

R3m P6/mmm Cmcm Immm Cmmm Cmcm P4/mbm Im3m

… C32 … D7b … Bf D5a A2

… AlB2 B3V2 Ta3B4 … CrB Si2U3 W

Fig. 1

B-Nb phase diagram

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Journal of Phase Equilibria and Diffusion Vol. 31 No. 2 2010

Supplemental Literature Review: Section III References 2007Pec: R.M. Pec¸anha, F. Ferreira, G.C. Coelho, C.A. Nunes, and B. Sundman, Thermodynamic Modeling of the Nb-B System, Intermetallics, 2007, 15, p 999-1005 2008Oka: H. Okamoto, B-Nb (Boron-Niobium), J. Phase Equilib. Diffus., 2008, 29(6), p 539

2008Tan: Z. Tang, M.J. Kramer, and M. Akinc, Evaluation of Phase Equilibria in the Nb-Rich Portion of Nb-B System, Intermetallics, 2008, 16, p 255-261 2008Wit: V.T. Witusiewicz, A.A. Bondar, U. Hecht, S. Rex, and T.Ya. Velikanova, The Al-V-Nb-Ti System, I. Re-assessment of the Constituent Binary Systems B-Nb and B-Ti on the Basis of New Experimental Data, J. Alloys Compd., 2008, 448, p 185-194

Journal of Phase Equilibria and Diffusion Vol. 31 No. 2 2010

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