TY  - BOOK
AU  - Roth,R.S.
AU  - Waring,J.L.
TI  - Phase Equilibrium Relations in the Binary System Bismuth Sesquioxide-Niobium Pentoxide
PY  - 1962///
PB  - [Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology, 
KW  - Text
KW  - local
N1  - /pmc/articles/PMC5324962
N2  - The phase equilibrium diagram for the binary system bismuth sesquioxide-niobium pentoxide has been constructed from observations of fusion characteristics and X-ray diffraction data. In the system five binary compounds were observed with Bi(2)O(3):Nb(2)O(5) ratios of 5:3, 1:1, 4:9, 1:5, and 1:6. The 1:1 compound was found to transform irreversibly (in laboratory time) from the orthorhombic bismutotantalite type structure to a triclinic form at about 1,020 °C and melt congruently at 1,245 °C. The 5:3 compound melts incongruently at 1,193 °C the 4:9 at 1,183 °C and the 1:6 at 1,242 °C. The 1:5 compound has a maximum temperature of stability at 1,095 °C and the 4:9 and 1:6 compounds have minimum temperatures of stability at 1,070 °C and 1,002 °C respectively. Nb(2)O(5) was found to enter into solid solution in Bi(2)O(3), up to about 23.5 mole percent Nb(2)O(5). The melting point is increased and the monoclinic-cubic phase transformation temperature is decreased. A morphotropic phase change occurrs at about 19.5 mole percent Nb(2)O(5) from the cubic to a pseudocubic structure
UR  - http://dx.doi.org/10.6028/jres.066A.046
ER  -