Title:
Nanoindentation of YSZ-alumina ceramic thin films grown by combustion chemical vapor deposition

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dc.contributor.advisor Carter, W. Brent
dc.contributor.advisor Hampikian, Janet M.
dc.contributor.author Stollberg, David Walter en_US
dc.contributor.committeeMember Cochran, Joe K., Jr.,
dc.contributor.committeeMember Saxena, A.
dc.contributor.committeeMember Breder, K.
dc.contributor.department Materials Science and Engineering en_US
dc.date.accessioned 2012-06-14T15:59:02Z
dc.date.available 2012-06-14T15:59:02Z
dc.date.issued 2000-05 en_US
dc.description.abstract Combustion chemical vapor deposition (combustion CVD) is a thin film deposition process that uses a flame created by the ignition of an aerosol containing precursors dissolved in a flammable solvent. Combustion CVD is a relatively new technique for creating thin film oxide coatings. Combustion CVD has been successfully used to deposit high quality thin oxide films for potential applications such as thermal barrier coatings, dielectric thin films, composite interlayer coatings, etc. The present work involved developing the optimum parameters for deposition of thin films of yttria-stabilized zirconia (YSZ), alumina (Al₂O₃), and YSZ-alumina composites followed by a determination of the mechanical properties of the films (measured using nanoindentation) as a function of composition. The optimized parameters for deposition of YSZ, alumina, and YSZ-alumina composites onto single crystal a-plane alumina involved using an organic liquid as the flammable solvent and Y 2-ethylhexanoate, Zr 2-ethylhexanoate and Al acetylacetonate as the metal precursors at a 0.002 M concentration delivered at 4 ml/min at flame temperatures of 155 ℃ and substrate temperatures of 105 ℃. The resulting films were grown with deposition rates of ~ 1.5 μm/hr. Measurement of the mechanical properties (hardness, elastic modulus and fracture toughness) of the films was performed using a mechanical properties microprobe called the Nanoindenter®. In order to obtain valid results from nanoindentation, the combustion CVD films were optimized for minimum surface roughness and grown to a thickness of approximately 0.8 μm. With the penetration depth of the indenter at approximately 150 nm, the 800 nm thickness of the film made influences of the substrate on the measurements negligible. The hardnesses and elastic moduli of the YSZ-alumina films did not vary with the composition of the film. The fracture toughness, however, did show a dependence on the composition. It was found that second phase particles of alumina grown into a YSZ matrix increased the fracture toughness of the films (on average, 1.76 MPa• m⁰.⁵ for 100% YSZ to 2.49 MPa• m⁰.⁵ for 70 mol% YSZ/30 mol% alumina). Similarly, second phase particles of YSZ grown into an alumina matrix also increased the fracture toughness (on average, 2.20 MPa• m⁰.⁵ for 100% alumina to 2.45 MPa• m⁰.⁵ for 37.2 mol% YSZ/62.8 mol% alumina). Modeling of the fracture toughness of the YSZ-alumina films was successfully achieved by using the following toughening mechanisms: crack deflection from the second phase particles, grain bridging around the particles, and residual stress from the CTE mismatch between the film and the substrate and between the second phase particles and the matrix of the film.
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/43977
dc.publisher Georgia Institute of Technology en_US
dc.subject.lcsh Nanoindentation en_US
dc.subject.lcsh Combustion chemical vapor deposition en_US
dc.subject.lcsh Thin film deposition en_US
dc.subject.lcsh Yttria-stabilized zirconia en_US
dc.subject.lcsh Nanotechnology
dc.subject.lcsh Surfaces (Technology)
dc.subject.lcsh Thin films
dc.subject.lcsh Ceramic coatings
dc.subject.lcsh Zirconium oxide
dc.subject.lcsh Aluminum oxide
dc.subject.lcsh Yttrium
dc.title Nanoindentation of YSZ-alumina ceramic thin films grown by combustion chemical vapor deposition en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Carter, W. Brent
local.contributor.corporatename School of Materials Science and Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 962d2ffa-8219-498e-949c-524333215dd6
relation.isOrgUnitOfPublication 21b5a45b-0b8a-4b69-a36b-6556f8426a35
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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