In Situ Observations of Templated Grain Growth in (Na_0.5K_0.5)_0.98Li_0.02NbO₃ Piezoceramics: Texture Development and Template-Matrix Interactions

Journal Article · Mon Aug 13 00:00:00 EDT 2012 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1551-2916.2012.05268.x· OSTI ID:1048559

Tutuncu, Goknur; Chang, Yunfei; Poterala, Stephen; Messing, Gary L; Jones, Jacob L ^[1]

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1. Florida

Nucleation, texture development, and phase equilibria were observed during templated grain growth (TGG) of (Na_0.5K_0.5)_0.98Li_0.02NbO₃ (NKLN) via in situ X-ray diffraction (XRD). Initially, NaNbO₃ templates and NKLN matrix powder exist as distinct phases with unique lattice parameters. Above 850 °C, the templates and matrix begin to react via interdiffusion as characterized by an increase in diffuse scattering between the NaNbO₃ and NKLN peaks. This process intensifies immediately prior to template growth, leading to merging of diffraction peaks for these two phases. TGG in this system is thus homoepitaxial in nature as it occurs after the NKLN matrix and NaNbO₃ templates form a solid solution. The degree of alignment in the matrix phase is quantified in situ using the March-Dollase parameters r and f. The degree of orientation of the textured NKLN mirrors the initial alignment of the template particles (r ~ 0.3), while the texture fraction f increases from 0.04 to ~0.67 after 3 h at 1138 °C. This increase in texture fraction follows n = 1/3 power law kinetics consistent with liquid-phase-assisted normal grain growth on plate-like templates. As the observed template-matrix interdiffusion and the onset of texture development proceed extremely rapidly, this work demonstrates the utility of in situ XRD for observing details of TGG that cannot easily be seen via ex situ methods.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: NSFDOD
• OSTI ID: 1048559
• Journal Information: Journal of the American Ceramic Society, Vol. 95, Issue 8; ISSN 0002-7820
• Publisher: American Ceramic Society
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
ALIGNMENT
DIFFRACTION
DIFFUSE SCATTERING
GRAIN GROWTH
KINETICS
LATTICE PARAMETERS
MIRRORS
NUCLEATION
ORIENTATION
SOLID SOLUTIONS
TEXTURE
X-RAY DIFFRACTION