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:
May. 12, 1992
Filed:
Dec. 09, 1988
William J Dawson, Columbus, OH (US);
Scott L Swartz, Dublin, OH (US);
Battelle Memorial Institute, Columbus, OH (US);
Abstract
A process for making a crystalline ceramic powder having a perovskite structure, ABO.sub.3, that includes the steps of preparing a first acidic solution containing one or more elements selected from the group consisting of hafnium, zirconium, titanium, niobium, tantalum, uranium, iron, antimony, lanthanum, bismuth, thorium, indium, nickel, manganese, neodymium, samarium, cobalt, tungsten, tin, vanadium, dysprosium, praseodymium, yttrium, promethium, europium, cerium, ytterbium, lutetium, scandium, gadolinium, terbium, holmium, erbium, thulium, chromium, potassium, and lithium; preparing a second basic solution containing a sufficient concentration of hydroxide to provide a predetermined pH when mixed with the first solution; adding the first acidic solution to the second basic solution to precipitate a substantially pure mixture of hydroxides; washing the precipitate to remove hydroxide and salt impurities that solubilize lead or other constituent elements of the powder; preparing an aqueous slurry of the washed precipitate and adding oxides or hydroxides of one or more of the elements selected from the group consisting of barium, strontium, calcium, magnesium, lead, zinc, yttrium, magnesium, manganese, cobalt, zinc and nickel; hydrothermally treating the slurry at an elevated temperature and pressure for a time sufficient to form the powder; and drying the powder; wherein when lead, zirconium and titanium are selected the perovskite has the general formula: Pb(Zr.sub.1-x Ti.sub.x)O.sub.3, wherein x has a value of: