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 | Effect of Heating Rate on Electromechanical Properties of PNN–PZT Solid Solution
Author : Singh, Virendra;Kumar, H. H.;Kharat, D. K.;Kulkarni, M. P.
Source : Defence Science Journal ; Vol:57(1) ; 2007 ; pp 51-54
Subject : 66 Chemical Technology
Keywords : PNN-PZT;Piezoelectric properties;Piezoelectric ceramic materials;Ceramic actuator material;Electronic materials;Perovskite
Abstract : Lead nickel niobate–lead zirconate titanate (Pb(Ni1/3Nb2/3)0.5 –Pb(Zr0.15Ti0.35O3), (PNN-PZT)) solid solution was synthesised by columbite process. Samples sintered at various heating rates for 4 h holding and their effect on electromechanical properties have been studied. When heating rate was 8 °C/min from room temperature to 900 °C and holding for 4 h at 1280 °C, highest relative permittivity and piezoelectric charge constant were observed, whereas heating rate of 3.5° C/min and holding for 4 h at 1280 °C have shown inferior electromechanical properties and grain coarsening. The piezoelectric charge constant (d33) ~612 pC/N and dielectric constant (e)~ 5950 observed in fast heating rate specimen as against to d33~ 137 pC/N and e~4294. XRD result shows the formation of pyrochlore-free perovskite phase. Fine grains were observed for fast heating rate specimens. |
| | Processing of Lead Zirconate Titanate-graphite 3-3 Piezocomposites
Author : Praveenkumar, B. ;Kumar, H. H. ;Kharat, D. K.
Source : Defence Science Journal ; Vol:57(1) ; 2007 ; pp 47-50
Subject : 66 Chemical Technology
Keywords : PZT;BURPS process;Corona poling technique;Piezoelectric;Lead zirconate titanate;PZT Graphite composites;Piezocomposites;Pervoskite structure
Abstract : The lead zirconate titanate (PZT)-graphite piezocomposites have potential for higher piezoelectric sensitivity, lower acoustic impedance, higher piezoelectric voltage constants, higher electromechanical coupling coefficient, and higher hydrostatic coefficients as compared to dense PZT materials. In addition, the properties of piezocomposites can be tailored for various weight percentage of graphite powder. To study the phenomena, PZT-graphite 3-3 composites were prepared by mixing calcined PZT and commercially available graphite powder. The mixed powder was compacted, sintered, and poled by corona poling technique. Scanning electron microstructures were recorded to study the effect of graphite on processing of 3-3 piezocomposites. The polarising behaviour, piezoelectric and dielectric properties of PZT-graphite composites were studied. |
| | Computer-controlled Sophisticated Ultrasonic Cleaner
Author : Muthurajan, H.;Kumar, H. H.;Kharat, D. K.
Source : Defence Science Journal ; Vol:57(1) ; 2007 ; pp 105-108
Subject : 66 Chemical Technology
Keywords : Ultrasonic cleaning technique;Ultrasonic vibrator;Piezoceramic-based transducer;PC-based ultrasonic cleaner
Abstract : The significant advantage of ultrasonic cleaning technique is the abilities to clean the delicate and complex shape materials without damaging their surfaces quickly. Ultrasonic cleaners have found increasing applications in a variety of industries because these offer an environmentally good alternative to ozone-depleting compounds and hazardous solvents. Also, ultrasonic vibration is one of the methods for chemical synthesis (chemical reaction) and of yield enhancement of chemical engineering process. Consequently, there is a need to develop multipurpose ultrasonic cleaner/vibrator using computer control, which can be used to set the various performance parameter of ultrasonic vibrator such as frequency, duty cycle, continuous/pulsed mode, duration of operation, and thermal profile of tank during the process. An ultrasonic cleaner was developed using an oscillator circuit and the duration of oscillator circuit functioning can be set through the computer. Computerised ultrasonic cleaner using indigenously made piezoceramic transducers and their advantages over the conventional ultrasonic cleaners are discussed. |
| | Manufacturing technology of Lead Zirconate Titanate cylindrical elements for passive transducer arrays
Author : Gaware, P. S.;Yadav, O. P.;Kumar, H. H.
Source : Defence Science Journal ; Vol:53(3) ; 2003 ; pp 275-279
Subject : 629.5 Marine Sciences;623.8 Naval Science
Keywords : PZT;Lead zirconate titanate ;Piezoceramics;Passive transducer arrays
Abstract : State-of-the-art technology has been developed for the fabrication of 33 mm hollow cylindrical elements from Lanthanum-doped lead zirconate titanate based material suitable for passive surveillance arrays of SONAR systems. It covers properties of the material composition, isostatic pressing technique, precision machining, sintering to produce dielectrically sound distortion-free cylindrical elements, ceramic grinding, electroding, poling to achieve electromechanical properties, and evaluation of dielectric, piezoelectric, and elastic properties of the cylinders. |
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