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:
Mar. 01, 1983
Filed:
Nov. 10, 1977
Irwin Schneider, Alexandria, VA (US);
William C Collins, Alexandria, VA (US);
Oscar Imber, Wheaton, MD (US);
Philipp H Klein, Silver Spring, MD (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
The improvement of the electrolytic and additive methods of coloring alkali fluoride crystals comprising the step of selecting an alkali fluoride crystal having the impurities of between 0 and 5 ppmA of OH; between 0 and 50 ppmA of one or more alkaline earth cations, of which between 0 and 10 ppmA Mg.sup.++ and between 0 and 10 ppmA Ca.sup.++ ; between 0 and 50 ppmA of non-fluorine halide anions; between 0 and 10 ppmA of SiF.sub.6.sup.= ; between 0 and 30 ppmA of other ions; and the method of preparing these crystals which comprises converting the alkali fluoride to alkali hydrofluoride, crystallizing and vacuum drying the alkali hydrofluoride crystals, regenerating the alkali fluoride by expelling hydrogen fluoride, and crystallizing the alkali fluoride.