Patent Number: 6,169,049

Title: Solution coated hydrothermal BaTiO3 for low-temperature firing

Abstract: Hydrothermal BaTiO.sub.3 crystallites were coated with Bismuth solutions prepared from Bismuth metal-organics and anhydrous solvents. The Bismuth metal-organics were Bi 2-ethylhexanoate and Bi-neodecanoate. Bismuth oxide was also used as a comparison to the Bismuth solutions. BaTiO.sub.3 ceramics with either 3.0 wt % equivalent Bismuth oxide or 5.0 wt % equivalent Bismuth oxide were made by sintering the compacts between 700.degree. C. and 1000.degree. C. BaTiO.sub.3 ceramics that were coated by Bi-neodecanoate densified >90% theoretical as low as 800.degree. C. for 3.0 wt % equivalent Bi.sub.2 O.sub.3. Average grain sizes of 0.2-0.4 .mu.m were observed for Bi-coated BaTiO.sub.3 ceramics, for sintering temperatures below 950.degree. C. Dielectric K versus temperature measurements of Bismuth-coated BaTiO.sub.3 ceramics, sintered in the lower temperature ranges, showed consistently superior dielectric characteristics.

Inventors: Witham; John P. (Fountain Valley, CA), Randall; Clive A. (State College, PA), Kumar; Umesh (Surfside Beach, SC), Selvaraj; Ulagaraj (Apex, NC), Wang; Sea-Fue (Brookfield, CT), Dougherty; Joseph P. (State College, PA)

Assignee:

International Classification: C04B 35/622 (20060101); C04B 35/462 (20060101); C04B 35/468 (20060101); C04B 035/468 ()

Expiration Date: 01/02/2018