scholarly journals Synthesis and characterization of nanocrystalline PZT powders: From sol to dense ceramics

2016 ◽  
Vol 10 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Ali Mirzaei ◽  
Maryam Bonyani ◽  
Shahab Torkian

In this study ferroelectric lead zirconate titanate PZT (0.523/0.477) nanocrystalline powders have been successfully synthesized by an alkoxide based sol-gel process. Crystallinity of the prepared ceramic powders was studied using X-ray diffractometer. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies were performed to study morphology of the calcined powders. EDX analysis was employed to demonstrate purity of the synthesized powders. Surface nature of the powders was studied by using FTIR technique. TGA/DTA analysis was employed to study thermal behaviour of powders. Spectroscopic techniques (FTIR and XRD) results indicated that the as-dried amorphous powders can be completely crystallized at 600?C. In order to investigate the densification behaviour of the calcined powders, the crystalline PZT powders were pelletized into discs and sintered at various temperatures from 900?C to 1150?C, with a heating rate of 10?C/min and holding time of 2 h to find the optimum combination of temperature and time to produce high density ceramics. Microstructural characterization was conducted on the fractured surface of the samples using SEM. It was found that the PZT ceramics calcined at 600?C for 4 h then sintered at 1050?C for 2 h had maximal density (98% of the theoretically density).

2012 ◽  
Vol 1427 ◽  
Author(s):  
Kanu priya Sharma ◽  
Thomas Oseroff ◽  
Leda Lunardi

ABSTRACTCrack free lead zirconate titanate (PZT) films for piezoelectric based MEMS devices have been prepared by a multiple coating sol gel process on platinized silicon (100) substrates. Rapid thermal annealing and Conventional furnace annealing were used for densification and crystallization of the amorphous PZT films. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Atomic force microscopy (AFM) were used to observe surface film morphology and grain growth. The phase content of the films was analyzed using X-ray diffraction. The role of intermetallics formed during the heat treatment in the growth of different orientations has also been observed. Film aging critical for device performance has been observed and methods to revert aging effects have been examined and discussed.


1994 ◽  
Vol 361 ◽  
Author(s):  
E.M. Griswold ◽  
L. Weaver ◽  
I.D. Calder ◽  
M. Sayer

ABSTRACTRapid thermal processing (RTP) has been used to examine the crystallization kinetics of lead zirconate titanate (PZT) fabricated using a sol gel process. Depth profiling of PZT films was performed with glancing angle x-ray diffraction and transmission electron microscopy. The films were annealed using RTP ramp rates from 10°C/s to 200°C/s and hold temperatures from 525°C to 650°C. The effect of ramp rate on the phase transformation is presented, and the growth of oriented columnar structures is demonstrated. Films subjected to RTP at 650°C for 1s using a ramp of 10°C/s began to transform to perovskite and were ferroelectric while a ramp of 100°C/s (same hold) produced a linear material which was pyrochlore. Longer hold conditions such as 650°C for 30s produced ferroelectric films with Pr in excess of 20μC/cm2 and relative permittivities ε > 600.


2001 ◽  
Vol 666 ◽  
Author(s):  
B.W. Olson ◽  
L.M. Randall ◽  
C.D. Richards ◽  
R.F. Richards ◽  
D.F. Bahr

ABSTRACTPiezoelectric oxide films, such as lead zirconate titanate (PZT), are now being integrated into MEMS applications. Many PZT derived systems are deposited using a sol-gel process, which can be used in a microelectronics processing route using spin coating as the deposition method. An application of interest for PZT films is in power generation, where a flexing membrane is used to transform mechanical to electrical energy. The current study was undertaken to identify the relationships between the processing, microstructure, and mechanical reliability of these films. Films were deposited onto both monolithic and bulk micromachined platinized silicon wafers using standard sol-gel chemistries, with roughness and grain size tracked using electron and scanning probe microscopy. Mechanical properties were evaluated in a dynamic bulge testing apparatus. Grain size variations in the Pt film between 35 and 125 nm are shown to have little effect on grain size of the subsequent PZT film and the adhesion of the PZT to the Pt film. Only the Pt film with 125 nm grains was shown to undergo any significant interfacial fracture. Fatigue tests suggest film lifetime is primarily limited by the number of pre- existing flaws in the film from processing. Reducing the microcrack density has been shown to produce films and devices that fail at strains of 1.4% and have mechanical fatigue lifetimes in excess of 100 million cycles at strains simulating the operating conditions.


1994 ◽  
Vol 360 ◽  
Author(s):  
D.A. Barrow ◽  
T.E. Petroff ◽  
M. Sayer

AbstractLead zirconate titanate (PZT) films of up to 60 μm in thickness have been fabricated on a wide variety of substrates using a new sol gel process. The dielectric properties (∈ = 900), ferroelectric (Ec = 16 kV/cm and Pr = 35 μC/cm 2) and piezoelectric properties are comparable to bulk values. The characteristic Curie point of these films is at 420 °C. Piezoelectric actuators have been developed by depositing thick PZT films on both planar and coaxial substrates. Stainless steel cantilevers and optical fibres coated with a PZT film exhibit flexure mode resonant vibrations observable with the naked eye. A low frequency in-line fibre optic modulator has been developed using a PZT coated optical fibre. The high frequency resonance of a 60 μm film on a aluminum substrate has been observed.


2019 ◽  
Vol 113 (1) ◽  
pp. 511-517
Author(s):  
Masumeh Ziaee ◽  
Asgar Babamir-Satehi

Abstract Nanostructured silica can be used as a carrier of pesticides to enhance stability and controlled release of agrochemicals with an effective concentration on target pests. Silica nanoparticles (SNPs) were synthesized by sol–gel process and employed as a carrier of three different insecticides including deltamethrin, pyriproxyfen, and chlorpyrifos. The SNPs were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis and the insecticides-loaded in SNPs were characterized by transmission electron microscopy (TEM). The toxicity of insecticides alone and loaded in SNPs was evaluated against small and large larvae of Trogoderma granarium Everts on concrete surfaces. The immediate mortality was counted after 1, 3, and 7 d of exposure, and then surviving individuals were transferred to untreated surfaces for seven more days, with delayed mortality was recorded. Small larvae were more susceptible than large ones on all insecticide treatments. In addition, insecticides loaded in silica nanoparticles were more effective when compared with application of the insecticides alone. For immediate mortality, deltamethrin loaded in SNPs was the most efficient treatment causing 70.5% mortality on small and 55.5% mortality on large larvae after 7 d of exposure to the highest concentration. Pyriproxyfen loaded in SNPs caused low immediate mortality, but the mortality increased in delayed count indicated that the insecticide could control the larvae even after they have been removed from treated surfaces. It can be concluded that loading insecticides in SNPs could significantly increase their insecticidal efficiency, but this increase was compound-dependent.


2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
C. Massard ◽  
S. Pairis ◽  
V. Raspal ◽  
Y. Sibaud ◽  
K. O. Awitor

The feasibility of surface nanopatterning with TiO2nanotanks embedded in a nanoporous alumina template was investigated. Self-assembled anodized aluminium oxide (AAO) template, in conjunction with sol gel process, was used to fabricate this nanocomposite object. Through hydrolysis and condensation of the titanium alkoxide, an inorganic TiO2gel was moulded within the nanopore cavities of the alumina template. The nanocomposite object underwent two thermal treatments to stabilize and crystallize the TiO2. The morphology of the nanocomposite object was characterized by Field Emission Scanning Electron Microscopy (FESEM). The TiO2nanotanks obtained have cylindrical shapes and are approximately 69 nm in diameter with a tank-to-tank distance of 26 nm. X-ray diffraction analyses performed by Transmission Electron Microscopy (TEM) with selected area electron diffraction (SAED) were used to investigate the TiO2structure. The optical properties were studied using UV-Vis spectroscopy.


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