Small-Angle Neutron Scattering Study of the Role of Feedstock Particle Size on the Microstructural Behavior of Plasma-Sprayed Yttria-Stabilized Zirconia Deposits

Published

March 1, 2003

Author(s)

H Boukari, Andrew J. Allen, Gabrielle G. Long, J Ilavsky, Jay S. Wallace, C C. Berndt, H Herman

Abstract

The microstructures of thick plasma-sprayed yttria-stabilized (8% mass) zirconia deposits have been studied in a series of Porod small-angle neutron scattering (SANS) and multiple small-angle neutron scattering (MSANS) experiments. Three main void components can be identified in the deposits: intrasplat cracks, interlamellar planar pores, and globular pores. The SANS and MSANS measurements have been analyzed using the traditional theory for Porod scattering and a recently-developed three-component model for MSANS evaluation. The average size, the volume fraction, the internal surface area, and the orientation distribution for each void component within the deposits have been determined. The present study has focused on gaining a better understanding of the effects of initial feedback particle size and of annealing temperatures on the microstructure of deposits sprayed under equivalent particle impact conditions. Quantitative results are presented for each of four deposit samples: one prepared using the as-received feedstock particle wide size distribution, and three prepared from feedstock powder of different and relatively narrow particle size ranges with average sized of 32 micron, 47 micron, and 88 micron. Except for the coarse (88 -micron) feedstock powder, only mild monotonic variations are found in the microstructural anisotropies, the porosities (13 +/- 1%), or the internal surface areas in the as-sprayed deposits. The internal surface area is independent of the feedstock particle size even with the coarse feedstock. When the deposits are annealed at high temperatures (1100 degrees celsius and 1400 degrees celsius) the microstructures are altered with a reduction of the total internal surface area and a mild coarsening of the voids. These changes in the microstructural evolution are well-captured and described by the three-component model. The results are compared and related with those obtained from SEM images and elastic moduli measurements.

Citation

Journal of Materials Research

Volume

18

Issue

No. 3

Pub Type

Journals

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Keywords

feedstock morphology, microstructure characterization, plasma spray, small-angle neutron scattering, thermal barrier-coatings, yltria-stabilized zirconia

Citation

Boukari, H. , Allen, A. , Long, G. , Ilavsky, J. , Wallace, J. , Berndt, C. and Herman, H. (2003), Small-Angle Neutron Scattering Study of the Role of Feedstock Particle Size on the Microstructural Behavior of Plasma-Sprayed Yttria-Stabilized Zirconia Deposits, Journal of Materials Research, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=850656 (Accessed October 7, 2024)