JOM KITA KE POLITEKNIK
Image from Google Jackets

Phase Equilibrium Relations in the Binary System Bismuth Sesquioxide-Niobium Pentoxide

By: Contributor(s): Publication details: [Gaithersburg, MD] : U.S. Dept. of Commerce, National Institute of Standards and Technology, 1962.Subject(s): Genre/Form: Online resources: Summary: 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.
Item type:
Tags from this library: No tags from this library for this title. Log in to add tags.
Star ratings
    Average rating: 0.0 (0 votes)
No physical items for this record

/pmc/articles/PMC5324962/

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.

https://creativecommons.org/publicdomain/zero/1.0/

The Journal of Research of the National Bureau of Standards Section A is a publication of the U.S. Government. The papers are in the public domain and are not subject to copyright in the United States. Articles from J Res may contain photographs or illustrations copyrighted by other commercial organizations or individuals that may not be used without obtaining prior approval from the holder of the copyright.

en

There are no comments on this title.

to post a comment.