The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 1995
Filed:
Sep. 09, 1994
Joseph J Ritter, Mt. Airy, MD (US);
The United States of America as represented by the Secretary of Commerce, Washington, DC (US);
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 telluride.