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The Penn State Research Foundation

Umesh Kumar

Clive A Randall

Joseph P Dougherty

Wayne Huebner

Ulagaraj Selvaraj

Sea-Fue Wang

John P Witham

Sea Fue Wang

Hydrothermal BaTiO,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,ceramics with either 3.0 wt % equivalent Bismuth oxide or 5.0 wt % equivalent Bismuth oxide were made by sintering the compacts between 700&deg; C. and 1000&deg; C. BaTiO,ceramics that were coated by Bi-neodecanoate densified >90% theoretical as low as 800&deg; C. for 3.0 wt % equivalent Bi,O,. Average grain sizes of 0.2-0.4 &mgr;m were observed for Bi-coated BaTiO,ceramics, for sintering temperatures below 950&deg; C. Dielectric K versus temperature measurements of Bismuth-coated BaTiO,ceramics, sintered in the lower temperature ranges, showed consistently superior dielectric characteristics.

Solution coated hydrothermal BaTiO3 for low-temperature firing

A relaxor ferroelectric composition that has the components lead magnesium niobate, lead titanate, and lead magnesium tungstate. The components are preferably present in relative molar amounts of (1-x-y) lead magnesium niobate, (x) lead titanate, and (y) lead magnesium tungstate, where 0.11.ltoreq.x.ltoreq.0.13 and 0.01.ltoreq.y.ltoreq.0.03. Also disclosed is a tunable ultrasonic transducer made of a relaxor ferroelectric composition that has the components lead magnesium niobate, lead titanate, and lead magnesium tunstate. A method of making a relaxor ferroelectric material comprising the step of adding an effective amount of lead magnesium tungstate to a lead magnesium niobate-lead titanate composition is also disclosed.

Relaxor ferroelectric compositions for field induced ultrasonic

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Surfside Beach, SC, United States of America

Umesh Kumar