Showing papers on "Lead zirconate titanate published in 1970"

Space Charge Effect in Lead Zirconate Titanate Ceramics Caused by the Addition of Impurities

Abstract: Lead zirconate titanate ceramics containing metal oxides as impurities are subjected to poling, in order to give rise to piezoelectric activity, at various temperatures. Impurities contained in the ceramics are found to be divided into three groups according to their effects on poling temperatures. (1) When the amounts are small, piezo-electric activity is lowered by poling at low temperatures, but not so when the amounts increase. (2) Irrespective of the amounts the activity is lowered by poling at low temperatures. (3) Irrespective of the amounts the activity is independent of poling temperatures. Lowering of piezoelectric activity is accompanied by an increase of specific resistivity. The lowering is explained by the effect of space charge which is generated by the addition of impurities. An empirical formula on poling efficiency is derived in terms of space charge and specific resistivity of the ceramics.

Some optical and electrical switching characteristics of a lead zirconate titanate ferroelectric ceramic

Abstract: The optical and electrical switching characteristics of a lead zirconate titanate ferroelectric ceramic 'with Bi or La doping were studied for possible application in a high speed light valve array. Of particular interest were the requirements for coincident voltage selection and stable operation for at least 1010 switching cycles. Excitation aging was found to decrease the contrast achievable when the ceramic is used as an electrically controlled retarder. A more pronounced result of aging is a large increase in the degree of partial switching caused by half-select pulses. Such effects could be temporarily reversed by appropriate cycling to higher temperatures. Little variation in aging with different electrode materials was observed.

Acoustoelectric Amplification in a Many-Carrier System

Abstract: Acoustoelectric amplification, in the linear approximation, is considered for a system containing several types of carriers in the two limiting cases of fast and slow carrier equilibration. The pertinent expressions are first derived for a piezoelectric semiconductor and then expanded to the more practical case of a layered system containing one or more semiconducting layers coupled to a piezoelectric element. An experimental example is given in the form of a guided elastic plate wave in lead zirconate titanate coupled to a plate of near‐intrinsic Ge.

Electromechanical resonator employing piezoelectric ceramic consisting of lead zirconate-titanate containing manganese monoxide

Abstract: An electromechanical resonator having a ceramic piezoelectric member consisting of MnO-containing lead zirconate-titanate of the composition Pb(ZrxTi1 x)03 + y % by weight of MnO, where x 0.52 - 0.58 and y 0.22 - 0.40.

Aging of Barium Titanate and Lead Zirconate-Titanate Ferroelectric Ceramics

Abstract: : The report reviews the present knowledge of the aging process in barium titanate and lead zirconate-titanate ferroelectric ceramics. By 'aging' is meant the passive change in the mechanical and electrical properties of a ferroelectric with time. Experimental data show that these constants vary linearly with the logarithm of time. The Smith, Street and Woolley, and Plessner theories for this logarithmic dependence are revised to remove some of the obscurity in the usual derivation. The experimental evidence of Ikegami and Ueda and of Bradt and Ansell, which is described in some detail, supports the hypothesis that aging is associated with the relief of internal stress through the formation of 90 deg-domains.

Improvements in or relating to ceramic metal-oxide films

Abstract: 1,216,470. Films of metallic oxide material. PLESSEY CO. Ltd. 8 Jan., 1968 [11 Jan., 1967], No. 1643/67. Heading C1A. [Also in Division H1] A substrate having thereon a film of a metallic oxide material is prepared by dissolving an organic precursor of the oxide material in a solvent, applying the solution to a substrate, drying and firing the resultant film. The solvent may be an alcohol, a chlorinated hydrocarbon, an ether or a terpene, and additives such as a viscosifying agent may be used to facilitate application. The application may be by dipping, painting or spraying. The ot,bstrate may be an electrical conductor. The oxide material may be a piezoelectric material, a perovskite type ferroelectric such as lead zirconate titanate or a ferrite and may be used in an electrical device which itself may be used in a capacitor, gramophone pickup, microphone or strain gauge. The example given uses lead naphthenate, zirconium naphthenate and titanium resinate dissolved in white spirit, applied to a ceramic material dried and fired for a few minutes at 600-900‹ C.

Studies on the Sintering Between PbO and PZT

Abstract: Sintering and the electrical properties of lead zirconate titanate (PZT) containing excess amount of PbO over the Stoichiometric composition have been presented.(1) The formation and sintering of PZT were nearly complete at about 900°C, as examined by X-ray diffraction analysis, dilatometry and electron microscopy.(2) Abnormal expansion was observed between 400°C and 700°C. Well-defined ceramics have been obtained by heating slowly at this temperature range.(3) An electro-mechanical coupling coefficient comparable to that of BaTiO3 has been obtained by firing at temperatures as low as 900°C.