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:
Aug. 23, 1988
Filed:
Jul. 11, 1986
Kenneth J Saunders, Waltham, MA (US);
Richard L Gentilman, Acton, MA (US);
Raytheon Company, Lexington, MA (US);
Abstract
An optically transmittant body comprising a solid solution of a ternary sulfide and a selected binary sulfide such as a solid solution of calcium lanthanum sulfide and phase lanthanum sulfide is provided by precipitating out of a nitrate solution of calcium and lanthanum, a starting powder of calcium carbonate and lanthanum carbonate. The molar ratio of lanthanum to calcium is greater than 2.0 moles lanthanum to 1.0 moles of calcium nitrate. The starting powder is reacted with a sulfurizing agent such as hydrogen sulfide to convert such starting powder into a powder of the solid solution of calcium lanthanum sulfide and phase lanthanum sulfide. The precipitate ion reaction forms a homogenous fine particle size starting powder of calcium carbonate and lanthanum carbonate which is substantially and uniformly converted into the solid solution powder. The phase lanthanum sulfide has a similar crystallographic structure as the calcium lanthanum sulfide. The solid solution of calcium lanthanum sulifide and the phase lanthanum sulfide powder is then compacted into the desired form of the optically transmittant body, and is then sintered at an elevated temperature in an atmosphere of excess sulfur to increase the density of the compacted body. An atmosphere including sulfur is provided to prevent decomposition of the material and to aid in the conversion of any residual, unsulfurized calcium carbonate, lanthanum carbonate materials present in the solid solution. The sintered material is then compressed at an elevated pressure and temperature providing the material of the optically transmittant body.