Effect of sintering parameters on the microstructure and properties of strontium modified PZT ceramics prepared using spray-dried powders

Lal, Ramji; Gokhale, N.M.; Krishnan, R.; Ramakrishnan, P.

doi:10.1007/bf02385646

Cited by 27 publications

(11 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5 show that on average the grain grew from 0.5 µm (sintered at 1000 ο C) to 2.5 µm (sintered at 1250 ο C). This result is close to that obtained from Lal et al who prepared ceramics from spray-dried granules using high purity chemicals [11].…”

Section: Resultssupporting

confidence: 91%

“…The tanδ, d 33 , and K p values of our results are in the ranges of 0.004 to 0.02, 130 to 168 pC/N, and 0.52 to 0.60 respectively. These are comparable to those obtained by Lal et al, Tunkasiri and Zhilun et al although the first two used high purity chemicals for their preparations and the last employed a mixed oxide route plus a low melting frit [7,11,17].…”

Section: Resultssupporting

confidence: 89%

“…This is probably due to the lead loss that normally occurs at the high sintering temperature thus resulting in shrinkage and subsequent porosities in the ceramics. The values of the dielectric constant, with the maximum of 780 obtained from the ceramics sintered at 1100 °C, are pretty well between those of the previous work [7,11,17]. The tanδ, d 33 , and K p values of our results are in the ranges of 0.004 to 0.02, 130 to 168 pC/N, and 0.52 to 0.60 respectively.…”

Section: Resultssupporting

confidence: 80%

“…In Table 1, the dielectric, piezoelectric, and physical properties of the prepared ceramics are compared with those of Tunkasiri, Lal et al and Zhilun et al [7,11,17]. It can be seen that the ceramic sintered at 1000 °C has the highest density (about 7.82 g/cm 3 or 97 % of theoretical density) which is close to that of Tunkasiri's, who used, however, the high-quality and high-cost chemicals [7].…”

Section: Resultssupporting

confidence: 62%

“…The spray-drying technique is of particular interest because quality powders may be produced in large quantity. Lal et al and Uematsu et al revealed that fine and very homogeneous particles of strontium-doped PZT and silicon nitride (Si 2 N 4 ), respectively, could be produced via this technique [11,12]. Both of them used the reagent grade of high cost chemicals as starting materials.…”

mentioning

confidence: 97%

See 4 more Smart Citations

Preparation And Characterization Of High-Purity PZT Powders And Ceramics Made By Modified Spray-Drying Techniques

Thamjaree¹,

Liu

Pengpat³

et al. 2006

Materials Research Innovations

View full text Add to dashboard Cite

IntroductionLead zirconate titanate (PZT) ceramics have been widely studied due to their very high electromechanical coupling coefficient. As a result, they have been employed in many applications such as hydrophones, ignitors, fine movement controllers, etc. [1,2]. Earlier studies revealed that the PZT properties are affected by their microstructures which partly depend on size and homogeneity of the starting powders [3,4,5]. Generally, conventional methods using ball milling of the constituent oxides have had difficulty in controlling the powder size, particle size distribution, and homogeneity of the PZT powders [6]. However, fine homogeneous PZT particles can be obtained via chemical processes [7,8,9,10]. Ceramics produced from these powders often yield encouraging piezoelectric and dielectric properties. The PZT ceramics produced via chemical processes usually require a very high purity (> 99.9 %) and high cost chemicals, which are not appropriate for large scale production. The spray-drying technique is of particular interest because quality powders may be produced in large quantity. Lal et al. and Uematsu et al. revealed that fine and very homogeneous particles of strontium-doped PZT and silicon nitride (Si 2 N 4 ), respectively, could be produced via this technique [11,12]. Both of them used the reagent grade of high cost chemicals as starting materials. However, the problem arises that the powders produced via the spray-drying technique in which the starting chemical was of reasonably lower purity (<99.9 wt%) often yielded unexpected secondary phase particles. In this work, attempts have been made to develop a modified chemical method via the spray-drying technique followed by a calcining process using low purity grade (< 99 wt %) and comparatively low priced chemicals to produce PZT powders, which have comparable properties with those produced via the previously described processes. The pH of the mixed nitrate solution of the constituents was carefully controlled and the spray drying process was carried out. The characteristics of the spray-dried PZT powders were investigated. The piezoelectricity, dielectricity, and densities of the corresponding ceramics were also studied. ExperimentalThe low-priced chemicals used in this work are solutions of lead nitrate (Pb(NO 3 ) 2 , 99 % by weight), zirconyl nitrate hydrate (ZrO(NO 3 ) 2 .6H 2 O, ~27 % of Zr by weight), and tetraisopropyl orthotitanate (C 12 H 28 O 4 Ti, ~99 % by weight). The molar ratio of these solutions were kept at 1:0.52:0.48 which corresponds to the crystal phase of Pb(Zr 0.52 Ti 0.48 )O 3 . By following the work done by Tunkasiri, the aqueous solutions of Pb(NO 3 ) 2 and (ZrO(NO 3 ) 2 .6H 2 O were mixed first [7]. Then a mixture of C 12 H 28 O 4 Ti solution and a strong nitric acid (HNO 3 , pH ~ 1) was gradually added to the solution. In order to stabilize the metals in the solution, hydrogen peroxide (H 2 O 2 ) was added. An aqueous ammonium solution was then slowly added to control the pH of the mixture solution. In order to obtain manga...

show abstract

Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 89%