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Investigating Volumetric Inclusions of Semiconductor Materials to Improve Flashover Resistance in Dielectrics

Steiner, Adam M.; Siefert, Christopher S.; Shipley, Gabriel A.; Redline, Erica M.; Dickens, Sara D.; Jaramillo, Rex J.; Chavez, Tom C.; Hutsel, Brian T.; Frye-Mason, Gregory C.; Peterson, Kyle J.; Bell, Kate S.; Balogun, Shuaib A.; Losego, Mark D.; Sammeth, Torin M.; Kern, Ian J.; Harjes, Cameron D.; Gilmore, Mark A.; Lehr, Jane M.

Abstract not provided.

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TYPE Conference Poster YEAR 2021
OSTIDOI

Phonon scattering mechanisms dictating the thermal conductivity of lead zirconate titanate (PbZr1-xTixO3) thin films across the compositional phase diagram

Journal of Applied Physics

Foley, Brian M.; Paisley, Elizabeth A.; DiAntonio, Christopher D.; Chavez, Tom C.; Blea-Kirby, Mia A.; Brennecka, Geoffrey L.; Gaskins, John T.; Ihlefeld, Jon I.; Hopkins, Patrick E.

This work represents a thorough investigation of the thermal conductivity (κ) in both thin film and bulk PbZr1-xTixO3 (PZT) across the compositional phase diagram. Given the technological importance of PZT as a superb piezoelectric and ferroelectric material in devices and systems impacting a wide array of industries, this research serves to fill the gap in knowledge regarding the thermal properties. The thermal conductivities of both thin film and bulk PZT are found to vary by a considerable margin as a function of composition x. Additionally, we observe a discontinuity in κ in the vicinity of the morphotropic phase boundary (MPB, x = 0.48) where there is a 20%-25% decrease in κ in our thin film data, similar to that found in literature data for bulk PZT. The comparison between bulk and thin film materials highlights the sensitivity of κ to size effects such as film thickness and grain size even in disordered alloy/solid-solution materials. A model for the thermal conductivity of PZT as a function of composition (κ (x)) is presented, which enables the application of the virtual crystal approximation for alloy-type material systems with very different crystals structures, resulting in differing temperature trends for κ. We show that in the case of crystalline solid-solutions where the thermal conductivity of one of the parent materials exhibits glass-like temperature trends the compositional dependence of thermal conductivity is relatively constant for most values of x. This is in stark contrast with the typical trends of thermal conductivity with x in alloys, where the thermal conductivity increases dramatically as the composition of the alloy or solid-solution approaches that of a pure parent materials (i.e., as x = 0 or 1).

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TYPE Journal Article YEAR 2017
ScopusOSTIDOI

Thermal characterization and properties of a copper-diamond composite

DiAntonio, Christopher D.; Chavez, Tom C.; Coker, Eric N.

The thermal properties of a commercial copper-diamond composite were measured from below -50°C to above 200°C. The results of thermal expansion, heat capacity, and thermal diffusivity were reported. These data were used to calculate the thermal conductivity of the composite as a function of temperature in the thickness direction. These results are compared with estimated values based on a simple mixing rule and the temperature dependence of these physical properties is represented by curve fitting equations. These fitting equations can be used for thermal modeling of practical devices/systems at their operation temperatures. The results of the mixing rule showed a consistent correlation between the amount of copper and diamond in the composite, based on density, thermal expansion, and heat capacity measurements. However, there was a disparity between measured and estimated thermal diffusivity and thermal conductivity. These discrepancies can be caused by many intrinsic material issues such as lattice defects and impurities, but the dominant factor is attributed to the large uncertainty of the interfacial thermal conductance between diamond and copper.

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TYPE SAND Report YEAR 2014
OSTIDOI

New composite separator pellet to increase power density and reduce size of thermal batteries

Mondy, L.A.; Evans, Lindsey E.; Roberts, Christine C.; Grillet, Anne M.; Soehnel, Melissa M.; Barringer, David A.; DiAntonio, Christopher D.; Chavez, Tom C.; Ingersoll, David I.; Hughes, Lindsey G.

We show that it is possible to manufacture strong macroporous ceramic films that can be backfilled with electrolyte to form rigid separator pellets suitable for use in thermal batteries. Several new ceramic manufacturing processes are developed to produce sintered magnesium oxide foams with connected porosities of over 80% by volume and with sufficient strength to withstand the battery manufacturing steps. The effects of processing parameters are quantified, and methods to imbibe electrolyte into the ceramic scaffold demonstrated. Preliminary single cell battery testing show that some of our first generation pellets exhibit longer voltage life with comparable resistance at the critical early times to that exhibited by a traditional pressed pellets. Although more development work is needed to optimize the processes to create these rigid separator pellets, the results indicate the potential of such ceramic separator pellets to be equal, if not superior to, current pressed pellets. Furthermore, they could be a replacement for critical material that is no longer available, as well as improving battery separator strength, decreasing production costs, and leading to shorter battery stacks for long-life batteries.

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TYPE SAND Report YEAR 2013
OSTIDOI

Creation and characterization of magnesium oxide macroporous ceramics

Materials Engineering and Sciences Division - Core Programming Topic at the 2011 AIChE Annual Meeting

Mondy, L.A.; DiAntonio, Christopher D.; Chavez, Tom C.; Hughes, Lindsey G.; Grillet, Anne M.; Roberts, Christine C.; Ingersoll, David I.

We examine several methods to create a sheet of magnesium oxide (MgO) macroporous ceramic material via tape casting. These methods include the approach pioneered by Akartuna et al.1 in which an oil/water emulsion is stabilized by surface-modified metal oxide particles at the droplet interfaces. Upon drying, a scaffold of the self-assembled particles is strong enough to be removed from the substrate material and sintered. We find that this method can be used with MgO particles surface modified by short amphiphilic molecules. This approach is compared with two more traditional methods to induce structure into a green ceramic: 1) creation of an MgO ceramic slip with added pore formers, and 2) sponge impregnation of a reticulated foam with the MgO slip. Green and sintered samples made using each method are hardness tested and results compared for several densities of the final ceramics. Optical and SEM images of the materials are shown.

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TYPE Conference YEAR 2011
ScopusOSTI

Synthesis and electrical analysis of nano-crystalline barium titanate nanocomposites for use in high-energy density applications

DiAntonio, Christopher D.; Monson, Todd M.; Winter, Michael R.; Roesler, Alexander R.; Chavez, Tom C.; Yang, Pin Y.

Ceramic based nanocomposites have recently demonstrated the ability to provide enhanced permittivity, increased dielectric breakdown strength, and reduced electromechanical strain making them potential materials systems for high energy density applications. A systematic characterization and optimization of barium titanate and PLZT based nanoparticle composites employing a glass or polymer matrix to yield a high energy density component will be presented. This work will present the systematic characterization and optimization of barium titanate and lead lanthanum zirconate titanate nanoparticle based ceramics. The nanoparticles have been synthesized using solution and pH-based synthesis processing routes and employed to fabricate polycrystalline ceramic and nanocomposite based components. The dielectric/ferroelectric properties of these various components have been gauged by impedance analysis and electromechanical response and will be discussed.

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TYPE Conference YEAR 2010
OSTI

Aqueous synthesis and electrical properties of nano-crystalline PLZT capacitors

DiAntonio, Christopher D.; Monson, Todd M.; Chavez, Tom C.; Stevens, Tyler E.; Roesler, Alexander R.; Huber, Dale L.

Devices with nano-crystalline microstructures have been shown to possess improved electrical properties. Further advantages include lower processing temperatures; however, device fabrication from nano-particles poses several challenges. This presentation describes a novel aqueous synthesis technique to produce large batch sizes with minimal waste. The precipitate is readily converted at less than 550 C to a phase pure, nano-crystalline Pb{sub 0.88} La{sub 0.12}(Zr{sub 0.70} Ti{sub 0.30}){sub 0.97} O{sub 3} powder. Complications and solutions to sample fabrication from nano-powders are discussed, including the use of glass sintering aids to improve density and further lower sintering temperatures. Finally, electrical properties are presented to demonstrate the potential benefits of nano-crystalline capacitors.

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TYPE Conference YEAR 2010
OSTI

Dielectric and ferroelectric analysis of nanoparticle/nanocrystalline barium titanate and PLZT

DiAntonio, Christopher D.; Monson, Todd M.; Yang, Pin Y.; Winter, Michael R.; Roesler, Alexander R.; Chavez, Tom C.

Attractive for numerous technological applications, ferroelectronic oxides constitute an important class of multifunctional compounds. Intense experimental efforts have been made recently in synthesizing, processing and understanding ferroelectric nanostructures. This work will present the systematic characterization and optimization of barium titanate and lead lanthanum zirconate titanate nanoparticle based ceramics. The nanoparticles have been synthesized using several solution and pH-based synthesis processing routes and employed to fabricate polycrystalline ceramic and nanocomposite based components. The dielectric and ferroelectric properties of these various components have been gauged by impedance analysis and electromechanical response and will be discussed.

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TYPE Conference YEAR 2010
OSTI

Nano-crystalline PLZT for dielectric applications

DiAntonio, Christopher D.; Monson, Todd M.; Roesler, Alexander R.; Huber, Dale L.; Chavez, Tom C.; Stevens, Tyler E.

Nano-materials have shown unique crystallite-dependent properties that present distinct advantages for dielectric applications. PLZT is an excellent dielectric material used in several applications and may benefit crystallite engineering; however complex systems such as PLZT require well-controlled synthesis techniques. An aqueous based synthesis route has been developed, using standard precursor chemicals and scalable techniques to produce large batch sizes. The synthesis will be briefly covered, followed by a more in-depth discussion of incorporating nanocrystalline PLZT into a working device. Initial electrical properties will be presented illustrating the potential benefits and associated difficulties of working with PLZT nano-materials.

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TYPE Conference YEAR 2010
OSTI

Development of low-cost, compact, reliable, high energy density ceramic nanocomposite capacitors

Monson, Todd M.; DiAntonio, Christopher D.; Winter, Michael R.; Huber, Dale L.; Roesler, Alexander R.; Chavez, Tom C.; Stevens, Tyler E.; Vreeland, Erika C.

The ceramic nanocomposite capacitor goals are: (1) more than double energy density of ceramic capacitors (cutting size and weight by more than half); (2) potential cost reductino (factor of >4) due to decreased sintering temperature (allowing the use of lower cost electrode materials such as 70/30 Ag/Pd); and (3) lower sintering temperature will allow co-firing with other electrical components.

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TYPE Conference YEAR 2010
OSTI

Barium titanate nanocomposite capacitor FY09 year end report

Stevens, Tyler E.; DiAntonio, Christopher D.; Winter, Michael R.; Chavez, Tom C.; Yang, Pin Y.; Roesler, Alexander R.

This late start RTBF project started the development of barium titanate (BTO)/glass nanocomposite capacitors for future and emerging energy storage applications. The long term goal of this work is to decrease the size, weight, and cost of ceramic capacitors while increasing their reliability. Ceramic-based nanocomposites have the potential to yield materials with enhanced permittivity, breakdown strength (BDS), and reduced strain, which can increase the energy density of capacitors and increase their shot life. Composites of BTO in glass will limit grain growth during device fabrication (preserving nanoparticle grain size and enhanced properties), resulting in devices with improved density, permittivity, BDS, and shot life. BTO will eliminate the issues associated with Pb toxicity and volatility as well as the variation in energy storage vs. temperature of PZT based devices. During the last six months of FY09 this work focused on developing syntheses for BTO nanoparticles and firing profiles for sintering BTO/glass composite capacitors.

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TYPE SAND Report YEAR 2009
OSTIDOI
81 Results
81 Results