Lead zirconate

Simple ABO compounds in addition to BaTiO are cadmium titanate [12014-14-17, CdTiO lead titanate [12060-00-3] PbTiO potassium niobate [12030-85-2] KNbO sodium niobate [12034-09-2], NaNbO silver niobate [12309-96-5], AgNbO potassium iodate [7758-05-6], KIO bismuth ferrate [12010-42-3], BiFeO sodium tantalate, NaTaO and lead zirconate [12060-01 -4], PbZrO. The perovskite stmcture is also tolerant of a very wide range of multiple cation substitution on both A and B sites. Thus many more complex compounds have been found (16,17), eg, (K 2 i/2) 3 ... 

The development of active ceramic-polymer composites was undertaken for underwater hydrophones having hydrostatic piezoelectric coefficients larger than those of the commonly used lead zirconate titanate (PZT) ceramics (60—70). It has been demonstrated that certain composite hydrophone materials are two to three orders of magnitude more sensitive than PZT ceramics while satisfying such other requirements as pressure dependency of sensitivity. The idea of composite ferroelectrics has been extended to other appHcations such as ultrasonic transducers for acoustic imaging, thermistors having both negative and positive temperature coefficients of resistance, and active sound absorbers. 

Another important class of titanates that can be produced by hydrothermal synthesis processes are those in the lead zirconate—lead titanate (PZT) family. These piezoelectric materials are widely used in manufacture of ultrasonic transducers, sensors, and minia ture actuators. The electrical properties of these materials are derived from the formation of a homogeneous soHd solution of the oxide end members. The process consists of preparing a coprecipitated titanium—zirconium hydroxide gel. The gel reacts with lead oxide in water to form crystalline PZT particles having an average size of about 1 ]lni (Eig. 3b). A process has been developed at BatteUe (Columbus, Ohio) to the pilot-scale level (5-kg/h). 

Lead zirconate [12060-01 -4] PbZrO, mol wt 346.41, has two colorless crystal stmctures a cubic perovskite form above 230°C (Curie point) and a pseudotetragonal or orthorhombic form below 230°C. It is insoluble in water and aqueous alkaUes, but soluble in strong mineral acids. Lead zirconate is usually prepared by heating together the oxides of lead and zirconium in the proper proportion. It readily forms soHd solutions with other compounds with the ABO stmcture, such as barium zirconate or lead titanate. Mixed lead titanate-zirconates have particularly high piezoelectric properties. They are used in high power acoustic-radiating transducers, hydrophones, and specialty instmments (146). 

Nickel is being used ia magnetostrictive transducers ia some ultrasonic devices, eg, solderiag irons and ultrasonic cleaners, because of its moderate magnetostriction and availabiUty. This market, however, is dominated by piezoelectric transducers of lead zirconate—titanate (PZT) (see Ultrasonics). 

Zirconate compounds exhibit several interesting properties. Lead zirconate—titanate [12626-81 -2] compositions display piezoelectric properties which are utilized in the production of EM-coupled mode filters, resonators in microprocessor clocks, photoflash actuators, phonograph cartridges, gas... 

Usually, in AFM the position of the tip is fixed and the sample is raster-scanned. After manual course approach with fine-thread screws, motion of the sample is performed with a piezo translator made of piezo ceramics like e. g. lead zirconate tita-nate (PZT), which can be either a piezo tripod or a single tube scanner. Single tube scanners are more difficult to calibrate, but they can be built more rigid and are thus less sensitive towards vibrational perturbations. 

The measures of solid state reactivity to be described include experiments on solid-gas, solid-liquid, and solid-solid chemical reaction, solid-solid structural transitions, and hot pressing-sintering in the solid state. These conditions are achieved in catalytic activity measurements of rutile and zinc oxide, in studies of the dissolution of silicon nitride and rutile, the reaction of lead oxide and zirconia to form lead zirconate, the monoclinic to tetragonal transformation in zirconia, the theta-to-alpha transformation in alumina, and the hot pressing of aluminum nitride and aluminum oxide. 

PZT (lead zirconate titanate) and PLZT (lead lanthanum zirconate titanate) combine ferroelectic, optical, and electronic properties and are used in optoelectronic and piezoelectric devices. Powders for hot pressing produced by CVD are being investigated. 

Recent development of mbber nanocomposites by other nanofillers includes piezo-mbber application by incorporating lead-zirconate by Tandon et al. [69], Fe-containing silicone mbber by Yurkov et al. [70], and crab shell whisker-reinforced natural mbber nanocomposites by Nair and Durfreshe [71]. 

Material Quartz and ceramic materials (Barium titanate (BaTiOQ, Lead metaniobate (PbNb2Os) and the mixed crystal Lead-zirconate titanate) Nickel or an alloy of Nickel. Also, some other high-tech alloys with ferrite materials (MFe204, M = divalent metal like Ni, Zn and Pb)... 

Some perovskites are widely used as piezo-transducers, BaTi03 for example, and lead zirconate (PbZr03) which is a well-known ferroelectric material sensitive to stresses. Also, some perovskites are good pyro-transducers that is, heat causes electric polarization of them. 

These reactions have been studied in detail for materials such as silica, and understanding of reaction mechanisms, as well as of the role of the precursor and catalyst (acid or base), has been well documented.63,64 Similar studies have been carried out in other material systems, most notably, lead zirconate titanate [Pb(Zr,Ti)03 PZT].52,65-68 For multicomponent (mixed-metal) systems such as those noted, prehydrolysis of less reactive alkoxides is sometimes employed to improve solution compositional uniformity. Other synthetic strategies to achieve molecular level mixing of reagents have also been employed. Here, synthesis of mixed-metal alkoxides has been a focus of investigators.40-42 A key point is to restrict the amount of water and to control how it is added to form solubalizable precursor species, rather than to induce precipitation.1,52,69,70... 

The alcohol exchange reaction was shown above in equation (2). The reactive alkoxy group (OR) is replaced by an alkoxy group that has less hydrolysis sensitivity (OR ). A representative example here is the use of reagents such as zirconium n-propoxide and titanium /-propoxide, both of which possess polar bonds, for the production of lead zirconate titanate films. Commonly in these processes, R OH is 2-methoxyethanol (CH3OCH2CH2OH), which is generally present as a bidentate ligand.35... 

Barrow, D. A. Petroff, T. E. Tandon, R. P Sayer, M. 1997. Characterization of thick lead zirconate titanate films fabricated using a new sol gel based process. I. Appl. Phys. 81 876-881. 

Merklein, S. Sporn, D. Schonecker, A. 1992. Crystallization behavior and electrical properties of wet-chemically deposited lead zirconate titanate. In Ferroelectric Thin Films III, edited by Tuttle, B. A. Myers, E. R. Desu, S. B. Larsen, P. K. Mat. Res. Soc. Symp. Proc. 310 263-268. 

Losego, M. D. Trolier-McKinstry, S. 2004. Mist deposition of micron thick lead zirconate titanate thick films. In Ferroelectric Thin Films XII, edited by Hoffmann-Eifert, S. Funakubo, H. Kingon, A. I. Koutsaroff, I. Joshi, V. Mat. Res. Soc. Symp. Proc. 784(C11.28) l-6. 

Reaney, I. M. Brooks, K. Klissurka, R. Pawlaczyk, C. Setter, N. 1994. Use of transmission electron microscopy for the characterization of rapid thermally annealed solution-gel, lead zirconate titanate films. /. Am. Ceram. Soc. 77 1209-1216. 

A variety of piezoelectric transducers have been employed for PAC. Ceramic transducers, usually lead zirconate titanate, are most commonly employed because of their sensitivity, time resolution and commercial availability. However, their acoustic response is often dominated by their own resonance, and so polymeric film detectors, such as polyvinylidenedifluoride, are often used. These piezoelectric materials are non-resonant, but not as sensitive as the ceramic detectors. Again, each detector has its own advantages (and disadvantages).14,15... 

In lead zirconate, PbZr03, the larger lead ions are displaced alternately from the cube comer sites to produce an antiferroelectric. This can readily be converted to a ferroelectric by the substitution of Ti4+ ions for some of the Zr4+ ions, the maximum value of permittivity occurring at about the 50 50 mixture of PbZrC>3 and PbTiC>3. The resulting PZT ceramics are used in a number of capacitance and electro-optic applications. The major problem in the preparation of these solid solutions is the volatility of PbO. This is overcome by... 

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