Low thermal conductivity vapor deposited zirconia microstructures

Hass, D. D.; Slifka, Andrew J.; Wadley, H.N.G.

doi:10.1016/s1359-6454(00)00403-1

Cited by 149 publications

(92 citation statements)

References 29 publications

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“…Many researches have been done to fabricate YSZ ceramics as thermal barrier coatings (TBCs). [3][4][5][6] Although TBCs show good thermal insulating impact, their applications are limited due to the bear-loading requirement. Appropriate thermal protection materials require not only low thermal conductivity but also high strength and toughness.…”

Section: Introductionmentioning

confidence: 99%

Effect of YSZ fiber addition on microstructure and properties of porous YSZ ceramics

Dong

Wang²,

Zhou³

2012

J Mater Sci

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Yttria-stabilized zirconia (YSZ) fiber was introduced as the reinforcement for porous YSZ ceramics fabricated by tert-butyl alcohol-based gel-casting process and pressureless sintering. Effect of YSZ fiber addition on the microstructure and properties of porous YSZ ceramics was studied systematically. Results showed that YSZ fiber obviously obstructed densification during the sintering process and therefore higher porosity could be achieved with the same solid loading of the initial slurry. Mean pore size regularly increased with increasing fiber addition. The reinforcing effect reached its optimum with 10 wt% YSZ fiber addition, yet decreased with increasing porosity. Fiber addition significantly changed the fracture mode of the porous ceramics from brittle to quasi-ductile with increasing fiber additions; fiber pull-out and crack deflection play major roles in the process. Compared with the porous ceramics without fibers, the thermal conductivity decreased a little. With improved mechanical and thermal properties, YSZ fiber-reinforced porous YSZ ceramics are more applicable in thermal insulation materials.

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Section: Introductionmentioning

confidence: 99%

Effect of YSZ fiber addition on microstructure and properties of porous YSZ ceramics

Dong

Wang²,

Zhou³

2012

J Mater Sci

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“…The rapid progress in the synthesis and processing of materials with the structure on nanometer scale has increased interest in the manufacture tetragonal zirconia thin films that operate as insulating thermal with phase stability at high temperatures. A variety of techniques have been used to deposit YSZ, including plasma spray [8], electron beam physical vapor deposition [9], and sol gel process [10]. Among these techniques, the magnetron sputtering methods are suitable technologies to deposit ceramic coatings whose crystal structure and microstructure are strongly dependent on processing parameters such as pressure sputtering, distance substrate-target and sputtering power [11,12].…”

Section: Introductionmentioning

confidence: 99%

Influence of bias voltage on the crystallographic orientation and morphology of sputter deposited yttria stabilized zirconia (YSZ) thin films

Amaya

Caicedo

Bejarano

et al. 2007

Phys. Status Solidi (c)

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ZrO 2 -8% mol. Y 2 O 3 (8YSZ) thin films were deposited onto silicon [100] and AISI 304 stainless steel substrates by r.f. (13.56 MHz) multi-target magnetron sputtering. To improve the adhesion of a YSZ monolayer to the stainless steel substrate, a buffer layer of Al 2 O 3 was incorporated too. Crystal structure and Infrared (IR) absorption bands of YSZ were investigated as functions of substrate bias by X-ray diffraction (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR), respectively. The influence of the bias voltage on the roughness, grain size, and microstructure of deposited thin films was determined by AFM and SEM. XRD results show the presence of a tetragonal phase with [111] and [200] orientations. On the other hand, FTIR spectra exhibit the 2E u and F 1u modes as two broad bands in the frequency range of 450 ~ 550 cm -1 and 550 ~ 650 cm -1 , corresponding to the tetragonal and cubic phases of ZrO 2 , respectively. In this work we present the systematic influence of the bias voltage on the crystalline structure, the presence of the tetragonal phase and morphology of the YSZ thin films. The XRD, FTIR, and AFM results indicate that when the bias voltage increases from -20 V to -60 V the preferential crystallographic orientation of YSZ tetragonal phase changes from [111] to [200], and the percentage of the tetragonal phase diminishes, as well as the grain size of deposited films from (560 ± 5) to (470 ± 5) nm.

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“…As a result, DVD will be able to deposit the vast majority of its vapor stream onto the coating surface for efficient material utilization. Third, through a complex set of carrier gas / vapor atom / coating surface interactions that are just now being understood [6,7], the presence Figure 2 a) The new DVD system uses an e-beam to evaporate material from source pools. The vapor is then transported to the coating surface in a flowing gas.…”

Section: The Technology Of Directed Vapor Depositionmentioning

confidence: 99%

“…As soon as the zirconium vapor left the evaporation crucible, it was captured in a mixed gas flow containing helium and oxygen. The total gas flow through the system was 4.15 standard liters per minute (4.00 slm of Figure 5 a) Thermal barrier coatings are multilayer coatings that protect superalloy components from the corrosive high temperature environment in turbine power systems [5,6]. b) DVD studies suggest that the method has an ability to create thermal conducting structures from polymer foam precursors.…”

Section: High Rate Depositionmentioning

confidence: 99%

Directed Vapor Deposition: Low Vacuum Materials Processing Technology

Groves¹,

Mattausch²,

Morgner³

et al. 2000

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Directed vapor deposition (DVD) is a recently developed electron beam-based evaporation technology designed to enhance the creation of high performance thick and thin film coatings on small area surfaces (generally 100 cm 2 or less). DVD technology development has been driven by a desire to combine four processing capabilities into one industrially appealing system. These capabilities are: 1) very high rate deposition (5 µm/min and higher over a 100 cm 2 area), 2) very high material utilization efficiencies (on 100 cm 2 areas, efficiencies should at least triple that of other coating technologies), 3) precise control of growing film atomic structure, and 4) highly flexible definition of growing film atomic composition. These criteria have led to the development of a unique plasmaenhanced electron beam evaporation tool which will be described here. Initial experimental and modeling results will also be presented to demonstrate how the selected technology solution is allowing the desired processing features to be achieved.Keywords: directed vapor deposition, DVD, high rate evaporation, low vacuum materials processing, electron beam evaporation IntroductionFor many years vapor deposited coatings have been recognized as valuable components of numerous engineered consumer products. Such coatings are regularly incorporated into products to provide functionality unachievable through other means. Sometimes the coatings act as a barrier, e.g. environmental protection or surface wear resistance. In other instances they play roles as active components in the engineering system, e.g. converting the sun's energy to electricity or storing bits of computer information in magnetic domains. In all cases, introduction of the vapor deposited coating is motivated by some product specification which cannot be met through other means. Engineers recognize that each coating makes it possible to deliver the specified product with the required performance characteristics. At the same time, they know that use of the coating adds to the cost of the product. The competition between performance need and product cost drives the search for new vapor deposition technology which can provide desired performance at a lower market cost. Report Documentation Page Form Approved OMB No. 0704-0188Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information ...

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Low thermal conductivity vapor deposited zirconia microstructures

Cited by 149 publications

References 29 publications

Effect of YSZ fiber addition on microstructure and properties of porous YSZ ceramics

Effect of YSZ fiber addition on microstructure and properties of porous YSZ ceramics

Influence of bias voltage on the crystallographic orientation and morphology of sputter deposited yttria stabilized zirconia (YSZ) thin films

Directed Vapor Deposition: Low Vacuum Materials Processing Technology

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