Process for the chemical preparation of bismuth telluride
US5458867A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 9, 1994 |
| Grant date | Oct 17, 1995 |
| Priority date | — |
| Expiry date | Sep 9, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/82
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for producing bismuth telluride including dissolving tellurium to form a first solution; heating the first solution to approximately 70.degree. C.; stirring the first solution; slowly and quantatively adding an amount of bismuth trioxide (Bi.sub.2 O.sub.3) to produce a Bi/Te second solution wherein the ratio of Bi: Te=2:3; cooling the second solution to approximately 25.degree. C.; preparing a solution of concentrated aqueous ammonia and distilled water; adding the solution of aqueous ammonia and distilled water dropwise to the second solution at approximately 25.degree. C. to form a third solution; rapidly stirring the third solution to produce a precipitate therefrom; separating the precipitate from the third solution by centrifugation; washing the separated precipitate in distilled water; drying the washed precipitate in air to produce a Bi.sub.2 Te.sub.3 O.sub.9.xH.sub.2 O, where x=1, precursor powder; heating predetermined quantities of the dried precursor powder to 250.degree. C.-275.degree. C., and exposing the heated precursor powder to flowing hydrogen at 1 atmosphere pressure for a period in the range of 3 to 12 hours to produce a final black powder of bismuth t…
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