High Temperature FeB-type Phases in the Systems Ta-{Ti,Zr,Hf}-B

• Published in: Journal of phase equilibria and diffusion Vol. 36; no. 6; pp. 620 - 631
• Main Authors: Failamani, F., Göschl, K., Reisinger, G., Nunes, C. A., Coelho, G. C., Machado, A. J. S., Correa, L. E., dos Santos, J. C. P., Giester, G., Rogl, P.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2015; Springer Nature B.V
• Subjects: Ceramics; Composites; Crystallography and Scattering Methods; Engineering Thermodynamics; Glass; Heat and Mass Transfer; Metallic Materials; Natural Materials; Physics; Physics and Astronomy; Thermodynamics; crystal structure; x-ray analysis; microstructure; refractory materials
• ISSN: 1547-7037; 1863-7345; 1934-7243
• DOI: 10.1007/s11669-015-0418-y

Novel FeB-type phases have been evaluated in the systems Ta-{Ti,Zr,Hf}-B either from as cast or arc treated samples by x-ray powder and single crystal diffraction as well as electron probe microanalysis. In each of the three systems the formation of the FeB-type phase suggests a high temperature stabilization of a binary group IV metal monoboride with FeB-type. This holds true for Ti and Hf, while for Zr the single crystal study of (Ta,Zr)B proves that it is a true ternary phase, as no stable monoboride exists in the binary Zr-B system. EPMA analyses reveal that the FeB-type phases Ta{Ti,Zr,Hf}B are formed by substitution of Ta in TaB by rather small amounts of group IV elements (~3 at.% of Zr, ~7 at.% Hf, and ~10 at.% Ti).