George Burton Brian C. Davis

John Mangum Elizabeth Palmiotti Yewon Shin

Welcome to the meeting!We are very pleased to welcome all of you to the 10th Annual CCAC Student Conference.We hope you will enjoy our variety of scientific research and speakers.

We would like to begin by thanking our industry sponsors: Thermo Fisher Scientific, Corning,and Deltech Furnaces; as well as the organizations affiliated with Colorado School of Mineswhich have sponsored this conference: the Colorado Fuel Cell Center (CFCC), the office ofthe Vice President for Research and Technology Transfer (VPRTT), and the Colorado Centerfor Advanced Ceramics (CCAC).

We would like to thank our keynote speakers: Dr. David Marshall from CU Boulder and Dr.Erica L. Corral from University of Arizona. We would also like to thank our CCAC Facultypresenters: Dr. Gregory Jackson, Mr. Michael Walker, and Dr. Steven DeCaluwe. We aregrateful to all of them for making room in their busy schedule to accept our invitation.

Last but not least, we would like to thank all of you for your hard work and active contributionto the conference.

Best Regards,

2018 CCAC Student Conference Committee*Cover Image Courtesy of George Burton

2018 CCAC Student ConferenceColorado Center for Advanced Ceramics

Program & Proceedings

August 6th, 2018

American Mountaineering CenterGolden, CO

Organized By

George Burton, Brian C. DavisJohn Mangum, Elizabeth Palmiotti, Yewon Shin

Thank you to our generous sponsors!

Gold Sponsors:

Silver Sponsors:

Deltech Furnaces

CFCC(Colorado Fuel Cell Center)

VPRTT(CSM Office of the Vice President for Research and

Technology Transfer)

CCAC(Colorado Center for Advanced Ceramics)

Conference Schedule

Monday, Aug 6th

Start EndCheck-in 8:00am –BreakfastOffered by conference, catered by Santiago’s 8:00am 9:00amIntroduction 9:00am 9:20amKeynote Speaker IDr. David Marshall - University of Colorado, Boulder 9:20am 10:20amCoffee Break 10:20am 10:40amStudent Presentation Session I (4 x 20min) 10:40am 12:15pmLunchOffered by conference, catered by Anthony’s 12:15pm 1:15pmCCAC Faculty Talk IDr. Gregory Jackson 1:15pm 2:15pmStudent Presentation Session II (3 x 20min) 2:15am 3:25pmCoffee Break 3:25pm 3:45pmCCAC Faculty Talk IITOF-SIMS - Mr. Michael WalkerXPS - Dr. Steven DeCaluwe 3:45pm 4:30pmKeynote Speaker IIDr. Erica L. Corral - University of Arizona 4:30pm 5:30pmDinnerOffered by conference, catered by Garbonzo’s 5:30pm 7:00pmStudent Poster Session and Social Hour 7:00pm 8:30pmExtended Social Hour at Mountain Toad 8:30pm Close

The American Mountaineering Museum (upstairs) is open to all guests ofthe conference until 6pm. We encourage you to visit the museum during

the scheduled meals and/or breaks.

Abstracts

Oxidation Behavior of High Temperature Aerospace Materials Using High En-thalpy FlowsE Corral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Fracture of Polycrystalline Boron Nitride Materials for Friction-Stir WeldingD Marshall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

In Operando Electron and X-ray Microscopies of Lithium Metal Evolution inCeramic All-Solid-State BatteriesN Seitzman, H Guthrey, H A S Platt, M Al-Jassim, S Pylypenko . . . . . . . . 3

Sharp Indentation of Silicate Glasses: Stress-Strain Field DependenciesB C Davis, I Reimanis, G S Glaesemann . . . . . . . . . . . . . . . . . . 4

Zinc-stabilized Manganese Telluride with Wurtzite Crystal StructureY Han, A M Holder, S Sol, S Lany, Q Zhang, A Zakutayev . . . . . . . . . . 5

Protonic-Ceramic Electrochemical Hydrogen CompressionB Kee, D Curran, J Porter, S Ricote, R Kee . . . . . . . . . . . . . . . . . 6

Computational Chemo-Thermal Stress Predictions from Sintering to Operatingof Protonic Ceramic Fuel CellsA Dubois, K Taghikhani, S Ricote, J R Berger, R J Kee, R J Braun . . . . . . 7

Wave Front Analysis Applications to Atom Probe TomographyS Jones, B Gorman . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Magnetic Characterization of Nickel Oxide Additions in Yttria-doped BariumZirconateM Knight, I Reimanis . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Identifying experimental conditions to avoid cracking in porous Ge filmsN Alkurd, D Young, A Ptak, C E Packard . . . . . . . . . . . . . . . . . . 10

Examining Evolution of Structure and Chemistry of Nickel/Yttrium doped Bar-ium ZirconateD Jennings, I Reimanis, M Knight . . . . . . . . . . . . . . . . . . . . . 11

Wafer-Scale Controlled Spalling and Reuse of (100)-Oriented GermaniumB Ley, C E Packard, A Cavalli, A Ptak, D Young . . . . . . . . . . . . . . . 12

Electron Microscopy of Roll-to-Roll Coated PEM Fuel Cell Electrode MaterialsS Medina, A Neyerlin, C Ngo, S Mauger, K C Neyerlin, M Ulsh, S Pylypenko . . 13

Post-Deposition Recrystallization of Chloride Treated Cu(InxGa(1-x))Se2 Thin-Film Solar CellsE Palmiotti, S Soltanmohammad, A Rockett, G Rajan, S Karki, B Belfore, S Mar-sillac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Introduction of Materials Characterization researches of Protonic Ceramic FuelCell (PCFC)Y Shin, M Sanders, S Harvey, R O’Hayre . . . . . . . . . . . . . . . . . . 15

Stereolithographic 3D Printing of Silicon Nitride CeramicsS Sortedahl, C Packard . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Depth Profiling on Two-Dimensional Layered Materials via Scanning Probe Mi-croscopyC Stetson, T Yoon, J Coyle, W Nemeth, M Young, A Norman, C Ban, C Jiang, MAl-Jassim, S DeCaluwe . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Computational Analysis of Chemical and Thermal Stress in PCFCK Taghikhani, A Dubois, J R Berger, S Ricote, R J Kee . . . . . . . . . . . . 18

Thermal stability and hardness of 37.5 nm nanocrystalline spinelS K Ullrich, B N Feigelson, J A Wollmershauser, C E Packard . . . . . . . . . 19

Inert and Reactive Oxides for High-Temperature Energy StorageG S Jackson, L Imponenti, K J Albrecht, D C Miller, and R J Braun . . . . . . . 20

TOF-SIMS and XPSM Walker, S DeCaluwe . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Oxidation Behavior of High Temperature Aerospace Materials UsingHigh Enthalpy Flows

E Corral1

1Materials Science and Engineering Department, The University of Arizona, Tucson, Arizona, USA

An approach towards understanding the oxidation behavior of carbon-carbon composites, ultra-high temperature ceramics, and coatings is pre-sented. The oxyacetylene torch facility is used to measure the ablationrates of graphite and the surface temperatures of different aerospace ma-terials. The free stream flame environment is characterized as a functionof flame chemistry for heat flux, pO2, and flow velocity. Measured ablationrates for graphite increase as a function of increasing heat flux and pO2which are validated by applying an oxygen diffusion based model. Themodel uses experimentally measured values for temperature, pO2, andgas velocity in order to confirm torch testing results are reliable and re-producible. Surface temperatures of ultra-high temperature ceramic com-posites are measured as a function of increasing heat flux and show anenthalpic cooling effect on the flame during oxidation testing. An diffusionlimited model for oxidation of high temperature ceramics is also presentedin order to discuss the effect of flow velocity and high enthalpy testing onobserved oxidation behavior for different aerospace materials.

1

Fracture of Polycrystalline Boron Nitride Materials for Friction-StirWelding

D Marshall1

1Mechanical and Aerospace Engineering Departments, University of Colorado Boulder, CO

Polycrystalline boron nitride (PCBN) materials offer unmatched perfor-mance as tools for friction-stir welding of high-temperature, high-hardnessmetals. However, their lifetimes are severely limited by fracture. In thispresentation, the following topics will be examined with the aim of provid-ing guidance for potential modifications of materials and/or tool design toimprove lifetime: (i) microstructural characteristics that influence fracture,strength and lifetime of these materials; (ii) the use of indentation meth-ods to measure fracture response at relevant scales; and (iii) studies offracture mechanisms and driving forces in PCBN tools during friction-stirwelding.

2

In Operando Electron and X-ray Microscopies of Lithium MetalEvolution in Ceramic All-Solid-State Batteries

N Seitzman1, H Guthrey2, H A S Platt3, M Al-Jassim2, S Pylypenko1

1 Colorado School of Mines, Golden, CO2 National Renewable Energy Laboratory, Golden, CO

3 Solid Power, Inc.

Ceramic materials capable of con-ducting lithium ions are good elec-trolyte candidates for all-solid batter-ies. Many ceramic electrolytes arestable over a wider voltage windowthan liquid counterparts and replacingthose flammable liquid electrolytes witha solid material provides a significantsafety improvement, making all-solidsystems particularly attractive for elec-tric vehicle applications. A key featureof solid electrolytes is their compatibil-ity with lithium metal anodes, which of-fer increased theoretical capacity overtraditional lithium-ion systems. Lithiumdendrite propagation from the anodethrough the electrolyte can be severely detrimental to battery lifetime anda greater understanding of the fundamental processes that drive this phe-nomenon in solid electrolytes is therefore critical for the success of solid-state lithium battery technologies. With microscopy techniques, lithiumhas been observed to plate along grain boundaries[1] or through intercon-nected pores[2] however, dendrite propagation occurs at hidden interfacesand within the internal microstructure of a battery. Therefore, this exper-iment utilizes X-ray microtomography to elucidate these effects via non-destructive observation of the internal microstructure of β-Li3PS4 sym-metric cells in operando.

In operando X-ray tomography allows the investigation of lithium be-havior throughout the whole system with high spatial and temporal reso-lution. The ceramic microstructure was observed for several electrochem-ical cycles, revealing expansion of pre-existing cracks caused by lithiummigration into void spaces. These data will clarify the relationship betweenlithium microstructure growth, current density, and internal microstructurein a ceramic material, enabling the engineering of longer-lasting high ca-pacity batteries for vital energy storage applications.

References (1) Porz, L.; Swamy, T.; Sheldon, B. W.; Rettenwander, D.; Fromling, T.; Thaman, H. L.; Berendts, S.; Uecker, R.; Carter, W. C.; Chiang,Y.-M. Adv. Energy Mater. 2017, 7 (20), 1701003. (2) Nagao, M.; Hayashi, A.; Tatsumisago, M.; Kanetsuku, T.; Tsuda, T.; Kuwabata, S. Phys. Chem.Chem. Phys. Phys. Chem. Chem. Phys 2013, 15, 18600.

3

Sharp Indentation of Silicate Glasses:Stress-Strain Field Dependencies

B C Davis1,2, I Reimanis1,2, G S Glaesemann3

1Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO2 Colorado Center for Advanced Ceramics (CCAC), Golden, CO

3 Corning Inc., Corning, NY

The mechanics associated with sharp indentation of silicate glassescontinues to garner considerable attention; however, there is still a sig-nificant need for understanding fundamental mechanical responses overseveral length scales. Most studies employ Vicker’s indenters to supplythe damage and supplement this experimental work with 3D FEA mod-els with 45◦ or 90◦ symmetry. The solve times of these models precludeextensive sensitivity studies involving indenter shape, force and materialproperties. In this research, a conical indenter and 2D axisymmetric FEAmodel are used to perform a sensitivity study with 102–103 unique modelsolutions. The FEA model is validated by experimental data generatedwith the conical indenter in select cases. The intention of this study is toindicate variable sensitivities and guide a more intelligent forward path forinvestigating and defining the mechanical response of glass to mechanicalcontact.

4

Zinc-stabilized Manganese Telluride with Wurtzite Crystal StructureY Han1,3, A M Holder2 , S Sol2 , S Lany2 , Q Zhang3 , A Zakutayev 2

1 Colorado School of Mines, Golden, CO2 National Renewable Energy Laboratory, Golden, Colorado, USA

3 Fudan University

Alloying of semiconductors with similar crystal structures often showssimilar properties as a function of composition. However, alloys betweencompounds with two different crystal structures, where properties can changedramatically when crystal structure changes, are much rarer. Even moreunusual are such heterostructural alloys where the structure and prop-erties can be changed with only a small amount of substitution (<10%).Here, experimental observation of such unusual behavior in zinc-stabilizedmanganese telluride (ZSMT) is reported. We also made theoretical expla-nation of its compositional stabilization in the wurtzite crystal structure. At400°C, thin films of Mn1-xZnxTe alloys change from the nickeline (NC) tothe wurtzite (WZ) crystal structure at x as low as 0.08. According to thetheoretical calculations, this structural transition origins from small MnTepolymorph energy differences, and strong preference of Zn atoms to adopttetrahedral vs. octahedral coordination environment. Band gap of WZ al-loys shows a much wider band gap (>2 eV) than NC MnTe ( 1 eV). 4-pointprobe measurements also indicate that WZ phases show 1,000-10,000times lower conductivity than the NC MnTe, due to low hole concentra-tions. Overall, the wide band gap and low hole density make ZSMT apromising candidate for p-type transparent transistors and other optoelec-tronic applications.

5

Protonic-Ceramic Electrochemical Hydrogen CompressionB Kee1, D Curran1, J Porter1, S Ricote1, R Kee1

1 Department of Mechanical Engineering, Colorado School of Mines, Golden, CO, USA

Electrochemical hydrogen compression (EHC) presents advantagesover mechanical compression. EHC with protonic-conducting ceramicsoffers significant opportunities for process intensification by combining cat-alytic hydrocarbon reforming chemistry with hydrogen separation and com-pression. Protonic-conducting ceramics (e.g., yttrium doped barium cer-ate/zirconate) offer attractive opportunities over polymer electrolyte mem-branes. Protonic-ceramic membranes prevent hydrogen gas back flow andare stable in reformate product gas streams. Reasonable ionic conductiv-ity requires the membranes to operate near 600°C, which introduce ther-mal management and packaging design constraints.

The presentation first considers computation modeling, including a Nernst-Planck-Poisson model that predicts charged-defect profiles within the MEA.The model also investigates thermal strategies to keep the membrane athigh temperature, while the reactor walls and cold zone seals remain cool.The design uses high-performance insulation to support the large tem-perature difference. The figure shows a cartoon of the lab-scale reactor.Reformate reactants enter the inside of the membrane. High-pressure hy-drogen is collected on the outside of the membrane.

6

Computational Chemo-Thermal Stress Predictions from Sintering toOperating of Protonic Ceramic Fuel Cells

A Dubois1, K Taghikhani1, S Ricote1, J R Berger1, R J Kee1, R J Braun1

1Department of Mechanical Engineering, Colorado School of Mines, Golden, CO, USA

Proton-conducting ceramic materi-als, such as yttrium-doped barium cer-ates and zirconates, are being devel-oped as membranes for a range ofpotential applications that include fuelcells and membrane reactors. PCFCsoperating at 500-600°C have shown po-tential high efficiencies at a competitivecost with existing fuel cell technology[1]. Although these materials have beendemonstrated at the laboratory scaleand have the potential to deliver effec-tive performance, the practical development is still in early stages. In ad-dition to electrochemical performance, understanding and controlling me-chanical robustness and reliability will be important in scaling to commer-cially viable technologies. The primary objective of the present study isto predict quantitatively the contribution of thermal stress during the high-temperature manufacturing process and the additional effect of chemicalexpansion due to hydration of the protonic ceramics present in the mem-brane accounting for the complex relationships between charged-defecttransport, lattice-scale strain, and macroscopic stress.

The present computational study is based on a 2D Comsol modelthat includes a reformulation of the Nernst-Planck-Poisson (NPP) includ-ing chemo-thermo-mechanical expansion effects. formulation that rep-resents charge-defect transport within dense mixed ionic-electronic con-ducting (MIEC) materials [2]. The particular focus is on yttrium-dopedbarium–cerium–zirconium oxide materials (BCZY). Although the theoret-ical foundations and modelling approaches are reasonably well developed[3], establishing the physical and chemical parameters needed to predictchemo-thermal-mechanical coupling remains challenging. The presentstudy uses X-ray-diffraction measurements [4] to determine the neededthermal and chemical expansion coefficients.

[1] Dubois A., Ricote S., Braun R.J., Benchmarking the expected stack manufacturing cost of next generation, intermediate-temperature protonicceramic fuel cells with solid oxide fuel cell technology. J. Power Sources 369 (2017) 65-77.[2] H. Zhu, S. Ricote, W.G. Coors, R.J. Kee, Interpreting equilibrium-conductivity and conductivity-relaxation measurements to establish thermody-namic and transport properties for multiple charged defect conducting ceramics, Farad. Discuss., 182, 49-74 (2015).[3] B.Euser, J.R. Berger, H. Zhu, and R.J. Kee, Defect-transport-induced stress in mixed ionic-electronic conducting (MIEC) ceramic membranes, J.Electrochem. Soc., 163, F264-F271 (2016).[4] G. Hudish, S. Ricote, A. Manerbino, W.G. Coors, Chemical expansion in BaZr0.9Y0.1O3-d and BaZr0.7Ce0.2Y0.1O3-δ upon hydration deter-mined by high temperature X-ray diffraction, submitted, 2017.

7

Wave Front Analysis Applications to Atom Probe TomographyS Jones1, B Gorman1

1 Colorado School of Mines, Golden, CO

Atom Probe Tomography (APT) is an ambitious tool that aims to com-bine the mass sensitivity of SIMs with 3D spatial resolution. It does so byevaporating the surface of a conic sample in the presence of a high voltageand detecting the atoms as they come off. While this technique works wellfor homogeneous samples, hetero-interfaces cause non-physical densitymeasurements in the reconstruction. Interpreting information in these re-gions is difficult due to a superposition of two signal types: angstrom scalecrystallographic biases and nano scale tip shape biases. Wave front anal-ysis has been used in adaptive optics for years to isolate these sorts ofbiases in other rapidly changing systems. Applying those techniques to anatom probe set allows for the isolation of both signals which paves the wayfor better reconstruction techniques.

8

Magnetic Characterization of Nickel Oxide Additions in Yttria-dopedBarium Zirconate

M Knight 1, I Reimanis 1

1 Colorado School of Mines, Golden, CO

Transition metal dopants in perovskite oxides for ionic conduction havebeen shown to influence microstructure development during processingand operating conditions. In this work, 0.5-3.0mol% NiO additions aremade in the perovskite oxide yttria-doped barium zirconate (BZY). Thesolid solubility and internal reduction of the dopant are characterized usingmagnetometry. Magnetometry provides a unique approach to characteriz-ing the behavior of the NiO dopant because different magnetic responsesare observed for Nickel(II) in solid solution (paramagnetic), as a secondaryphase as NiO (antiferromagnetic), and as metallic nickel (ferromagnetic orsuperparamagnetic). This research aims to advance fundamental under-standing of internal redox behavior of NiO dopant in the technologicallyrelevant perovskite oxide BZY.

9

Identifying experimental conditions to avoid cracking in porous Gefilms

N Alkurd1, D Young2, A Ptak2, C E Packard1

1Department of Metallurgical and Materials Engineering, Colorado School of Mines, Golden, CO2National Renewable Energy Laboratory, Golden, Colorado, USA

Porous Ge is a material of interest due to its potential to accommodat-ing large strains in applications such as lithium ion batteries and epitaxialgrowth substrates. In any application, the ability to produce a stable porousGe sample without large defects or pore collapse is imperative to enablingfurther study of this material. Porous Ge samples were produced by elec-trochemically etching a single-crystal, (100)-oriented, p-type Ge substrateusing an AC duty cycle. The stability of the porous Ge microstructure wascharacterized with Field-Emission Electron Microscopy. In our study, weobserved collapse and delamination of porous Ge films relative to the post-etching processing conditions. It was observed that the porous Ge sam-ples delaminate from the Ge bulk or collapse when processing the filmswith water or ethanol. The porous Ge microstructure was stable when pro-cessing the samples with a solvent exchange wash step where the poresare infiltrated with water, ethanol and hexanes, respectively. The porousGe instability was also found to be a function of the etching conditions.It was observed that samples etched at a 0.78 mA/cm2 were only unsta-ble when processed with water and samples etched at 4.68 mA/cm2 werefound to be unstable regardless of processing conditions. These resultsare comparable to porous Si which was found to also experience porouslayer delamination and collapse depending on the surface tension of thesolvent used during post-etch processing. Instability in Porous Si has alsobeen shown to be a function of porosity and porous layer thickness. Thiswork aims to identify instability in porous Ge films and propose practicesto produce stable porous Ge microstructure to enable future research intoporous Ge for any application.

10

Examining Evolution of Structure and Chemistry of Nickel/Yttriumdoped Barium Zirconate

D Jennings1 , I Reimanis1 , M Knight1

1 Colorado Center for Advanced Ceramics, Colorado School of Mines

Yttrium doped barium zirconate (BZY) has been shown to be an in-teresting candidate material for applications in catalysis, especially whennickel is added. To optimize performance it is critical to understand thestructure of Ni/BZY in its operating environments, and how that structureevolves over time. Transmission electron microscopy (TEM) was usedalong with other techniques to examine how Ni/BZY evolves in reducingand oxidizing environments. Focus was given on the analysis of structureand composition of interfaces and surfaces with the goal to understand theinteresting catalytic behavior of the material.

11

Wafer-Scale Controlled Spalling and Reuse of (100)-OrientedGermanium

B Ley1, C E Packard1, A Cavalli2, A Ptak2, D Young2

1Colorado School of Mines, Golden, CO, USA2National Renewable Energy Laboratory, Golden, Colorado, USA

Controlled spalling is a methodof exfoliating single-crystal sheetsby propagating a sub-surface crack,parallel to the surface, by applyingan external force to a sub-criticallystressed overlayer. It has been ex-perimentally observed that discon-tinuous application of the externalforce causes the fracture to formmorphological defects in the sur-face of the spalled film and waferconsisting of macroscopic fracturearrest lines, river patterns, andWallner lines. Removing or re-ducing arrest lines during spallingis desirable because spalled ger-manium is being examined as apotential substrate reuse path forgrowing high efficiency III-V solarcells. In this work, an apparatuswas designed that integrates a roller and linear actuator motor to facilitatecontrolled spalling of 2” (100)-oriented germanium wafers using a tensile-stressed layer of electrodeposited nickel-phosphorus. A vacuum chuckwas also incorporated into the apparatus to safely spall and handle waferswithout breakage. The motor-controlled spalling apparatus provides a sub-stantial improvement in control of the applied force and velocity comparedto manual spalling by peeling or a gravity-driven inclined ramp. Spacingbetween arrest lines on spalled surfaces was characterized by laser pro-filometry following spalling at several velocities. Additionally, river patternswere examined by TEM for the presence of dislocations. Proof of conceptexperiments have shown that full 2” germanium wafers can be spalled bythe jig without wafer breakage and dislocations were not observable in theTEM. Additionally, we present data from single junction GaAs solar cellsgrown on spalled Ge wafers, showing that high quality solar cells can begrown on previously spalled surfaces.

12

Electron Microscopy of Roll-to-Roll Coated PEM Fuel Cell ElectrodeMaterials

S Medina1, A Neyerlin2, C Ngo1, S Mauger2, K C Neyerlin2, M Ulsh2, SPylypenko1

1 Colorado School of Mines, Golden, CO2 National Renewable Energy Laboratory, Golden, CO

The main barrier to the widespread implantation of polymer electrolytefuel cells for automotive applications is the cost of the fuel cell stack. Largescale industrial manufacturing is limited by the lack of high-volume mem-brane electrode assembly (MEA) processing and low levels of quality con-trol. Improving large-scale MEA fabrication will reduce the overall fuel cellstack cost making this technology more affordable. The two main typesof MEAs consist of a polymer electrolyte membrane (PEM) between theanode and cathode electrodes, each adjacent to a microporous and thengas diffusion layers. Catalyst-coated membranes (CCM) are commonlyused for research purposes and extensive knowledge is available in theliterature, however, CCMs are difficult for manufacturing due to membraneswelling. Catalyst-coated diffusion media (CCDM), sometimes referredto as gas diffusion electrodes (GDEs), on the other hand are easier tomanufacture and preferred by industry, but an enhanced understandingof materials-process-performance relationships are necessary to improvethe scalability of electrode materials and MEA/cell design.

13

Post-Deposition Recrystallization of Chloride TreatedCu(InxGa(1-x))Se2 Thin-Film Solar Cells

E Palmiotti1, S Soltanmohammad1, A Rockett1, G Rajan2, S Karki2, BBelfore2, S Marsillac2

1 Colorado School of Mines, Golden, CO2 Old Dominion University, Norfolk, VA

Conditions promoting the recrystallization of CuInxGa(1-x)Se2 (CIGS)deposited by co-evaporation at a substrate temperature of 350°C werestudied. Cu-rich and Cu-poor CIGS samples were then annealed at 400,450, 500 and 550°C for 1 hour in the presence of alkali halide, In3Cl,Cu2Cl, SeCl4, and Se vapors. SEM images indicated that samples treatedwith In3Cl+Se, Cu2Cl+Se, Cu2Cl, and SeCl4 vapors at 550°C yielded sig-nificant grain growth. Smaller magnitude grain size increases resulted at400, 450, and 500°C. XRD analysis showed that the In3Cl+Se treatmentbest preserved the CIGS structure, however, results to date show addi-tional phases due to surface contamination. Further experiments will beconducted in quartz ampoules sealed under vacuum to reduce this. Weachieved similar, but non-uniform, results at 400, 450, and 500°C. Fur-ther experiments will optimize the annealing conditions for uniform graingrowth. The surface composition changed based on the treatment wherethe elemental composition of the added vapors increased on the annealedsample surface. This will also be addressed in experiments now in progressand the results will be reported at the conference.

14

Introduction of Materials Characterization researches of ProtonicCeramic Fuel Cell (PCFC)

Y Shin1, M Sanders1, S Harvey2, R O’Hayre1

1 Colorado School of Mines, Golden, CO2 National Renewable Energy Laboratory, Golden, CO 80401, USA

In this study, the triple conductivity of mixed protons, oxygen ions andelectron holes was studied by fundamental researches of PCFC materialscharacterization. Thermodynamics of the most two popular electrolyte ma-terials, BaZr0.8Y0.2O3-δ (BZY20) and BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb),was determined by mass change depending on different temperature(500-1200°C), atmosphere(1%O2, 1%H2 and air) and flow rate(16, 2, and 0.3sccm). In addition, defect kinetics in BaCo0.4Fe0.4Zr0.1Y0.1O3−δ (BCFZY0.1),the brand new PCFC cathode materials, was measured by using isotopeexchange depending on different temperature (700-900°C). The resultshelps understanding the behaviors of triple conductivity factors(protons,oxygen ions and electron holes) at different conditions of each three mate-rials and further indicates the optimized conditions for getting high perfor-mance of PCFC.

15

Stereolithographic 3D Printing of Silicon Nitride CeramicsS Sortedahl1, C Packard1

1 Colorado School of Mines, Golden, CO

Silicon nitride is a desirable material due to its high strength, low lin-ear thermal expansion coefficient, thermal shock resistance, and oxidationresistance. These properties allow it to be used in applications such asengine components, cutting tools, and bearings. Unfortunately, currentfabrication techniques of silicon nitride cannot produce complex part ge-ometries necessary for certain applications. The goal of this work is toproduce high quality silicon nitride parts using a low-cost desktop stere-olithography printer. In this study, the Form 2 stereolithography 3D printeris used and modified to print silicon nitride parts. The first challenge is todevelop a slurry that has minimal optical scattering and high solids loadingwhile minimizing viscosity. This slurry must also evenly disperse Si3N4particles and additives. Developing a slurry with optimum optical proper-ties is particularly challenging for silicon nitride due to its high refractiveindex. Once parts are created, their quality will be assessed through me-chanical testing and microstructural analysis. This work will help developa fast, low-cost, easily accessible method to produce 3D printed ceramics.

16

Depth Profiling on Two-Dimensional Layered Materials via ScanningProbe Microscopy

C Stetson1,2, T Yoon2, J Coyle2,3, W Nemeth2, M Young2, A Norman2, CBan2, C Jiang2, M Al-Jassim2, S DeCaluwe1

1Colorado School of Mines, Golden, CO2National Renewable Energy Laboratory, Golden, CO

3University of Colorado Boulder, Boulder, CO

Scanning spreading resistance microscopy (SSRM) is a two-probe tech-nique originally developed for carrier concentration mapping on semicon-ductor materials. In this work, SSRM is employed in a novel experimentalapproach to map electronic resistivity of materials in three dimensions bymechanically depth profiling away material using a diamond-coated, wearresistant probe. Correlation of resistance maps with depth of measure-ment permits for the generation of resistivity vs. depth profiles for layeredmaterials. Based on contrast in electronic properties (and/or mechanicalproperties), depth profiles can be utilized to determine thickness and ho-mogeneity of constituent layers and to locate buried interfaces with verticalresolution of 1-2 nm. The described technique is presented through anal-ysis of model reference samples with comparison to results obtained frommicroscopic and spectroscopic techniques including scanning transmis-sion electron microscopy (STEM), scanning electron microscopy (SEM),and dynamic secondary ion mass spectrometry (SIMS). An applicationof this technique is demonstrated through analysis of battery materialsand particular study of the solid electrolyte interphase (SEI), a thin filmformed on battery anodes originating from electrolyte decomposition prod-ucts. SSRM results on SEI formed on model Si anode systems show atrend of a resistive superficial layer of SEI, followed by a less resistivelayer, with clear contrast visible upon locating the SEI/Si interface. Resis-tivity vs. depth profiles and total SEI thickness are highly variable basedon electrochemical cycling conditions and electrolyte mixture. STEM crosssection analysis of the same SEI samples characterized with SSRM con-firm the total SEI thickness measurements as well as stratification in SEIchemical composition.

17

Computational Analysis of Chemical and Thermal Stress in PCFCK Taghikhani, A Dubois, J R Berger, S Ricote, R J Kee

1 Department of Mechanical Engineering, Colorado School of Mines, Golden, CO, USA

Doped-perovskite proton-conductingoxides such as yttrium doped bariumzirconate BZY and yttrium doped bar-ium zirconate-cerate BCZY have showngood proton conductivity at interme-diate temperatures (400-700°C). Thischaracteristic makes these proveskitessuitable to be used as membrane in pro-tonic ceramic fuel cells (PCFCs) andelectrolyzers (PCECs). The intermedi-ate operating temperature gives PCFCsadvantage over traditional solid oxidefuel cells (SOFCs) as it allows use ofinexpensive ferrite steel for intercon-nects, lower thermal stresses causedby thermal-expansion mismatch of dis-similar materials, more reliable seal-ing, and insignificant electrode sinter-ing.

BZY hydrogen separation membranes are supported by porous Ni-BZYsupports, which provide more mechanical stability and allow increase influx. However, the mismatch between mechanical properties of supportand membrane leads to increase in mechanical stress. An extended 2-Dmodel of Nernst–Planck–Poisson (NPP) model is developed and appliedto capture the stress due to chemical and thermal expansion and the ef-fect of mechanical properties mismatch between membrane and poroussupport. Mechanical properties of membrane and support are determinedexperimentally.

[1] Bryan Euser, J. R. Berger, Huayang Zhu, and Robert J. Kee, Chemically Induced Stress in Tubular Mixed Ionic-Electronic Conducting (MIEC)Ceramic Membranes, Journal of The Electrochemical Society, 163 (10) F1294-F1301 (2016).[2] H. Zhu and R. J. Kee, Membrane polarization in mixed-conducting ceramic fuel cells and electrolyzers., Intl. J. Hydrogen Energy, 41, 2931 (2016).[3] Robert J. Kee, Huayang Zhu, Brett W. Hildenbrand, Einar Vøllestad, Michael D. Sanders, and Ryan P. O’Hayre, Modeling the Steady-State andTransient Response of Polarized and Non-Polarized Proton-Conducting Doped-Perovskite Membranes.

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Thermal stability and hardness of 37.5 nm nanocrystalline spinelS K Ullrich1, B N Feigelson2, J A Wollmershauser2, C E Packard1

1 Department of Metallurgical and Materials Engineering, Colorado School of Mines,Golden, Colorado2 Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375, USA

Magnesium aluminate spinel has been developed for transparent ce-ramic windows and armor applications and is known to exhibit the Hall-Petch relationship, whereby reducing the grain size increases hardness.Recently, investigations of grain size effects in spinel to extremely smallgrain sizes ranging from 3.6 nm to 37.5 nm find that spinel maintains aHall-Petch hardness relationship down to 18.4 nm grain size. Fully densenanocrystalline spinel samples are produced using an environmentallycontrolled pressure-assisted sintering technique and pressless multianvilsplit sphere apparatus to suppress grain growth and promote sintering.In this work, the thermal stability of these samples with respect to graingrowth is evaluated at moderate temperatures up to 500 °C using x-raydiffraction. Hardness is characterized using high-temperature nanoinden-tation over the same range in the spinel sample with 37.5 nm grain size.This work is part of a larger study to determine the thermal stability ofnanostructured spinel and its properties.

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Inert and Reactive Oxides for High-Temperature Energy StorageG S Jackson1, L Imponenti1, K J Albrecht1, D C Miller1, and R J Braun1

1 Colorado School of Mines, Golden, CO

Oxide particles have potential as robust thermal energy storage (TES)media for concentrating solar power and other high-temperature thermalapplications. Reactive oxides, like CaMnO3−δ perovskites, can reduce attemperatures up to 1200 deg. C with the potential for almost twice thespecific energy storage (in kJ kg−1) as inert oxide materials like alumi-nosilicate. However, such high reduction for high specific storage, requiresa sweep gas flow to provide oxygen partial pressures PO2 down to 0.0001bar. This presentation compares the advantages and disadvantages of us-ing reactive oxides, notable Sr-doped CaMnO3−δ relative to low-cost alu-minosilicate for thermal energy storage with a particular emphasis towardCSP applications. Modeling of a simple indirect-particle-receiver configu-ration with angled surfaces for concentrated solar flux spreading exploreshow the sweep gas for O2 release and the particle morphology of the re-ducing perovskite can impact its viability for improved energy storage rel-ative to the inert oxide. These results are then placed within the context ofan entire TES system for a next-generation CSP plant with a supercritical-CO2 power block. Results indicate pathways to get to 90% solar receiverefficiencies and the importance of utilizing particle flows that sustain highparticle-to-wall heat transfer coefficients to drive cost-effective solar energycapture and subsequent particle energy release.

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TOF-SIMSMichael Walker

This talk will provide an overview of our brand new TOF-SIMS (Time-of-flight secondary ion mass spectrometry) system, which is located in theCenter for Multiscale Characterization in the CoorsTek building. Our TOF-SIMS is a unique capability in the U.S. for multidisciplinary research in con-ventional and environmentally sensitive samples and for emerging TOF-SIMS applications. TOF-SIMS enables exceptionally high spatial (<60nm) and depth (<1 nm) resolution, high sensitivity (<107 cm2 for somespecies), and specific chemical detection even in the presence of inter-ferences. It provides compositional depth profiling and lateral mapping invirtually all materials. It maps larger areas with greater mass range andresolution than atom probe tomography and higher sensitivity than elec-tron microscope-based methods, both with much simpler sample prepara-tion. The rudimentary basics of TOF-SIMS operation and analysis will bepresented and unique features of our instrument (in situ FIB, gas clustersource, and inert atmosphere transfer vessel) will be highlighted. Someapplications of TOF-SIMS to ceramics will be discussed. The instrumentis now available for testing, with the help of TOF-SIMS specialist, MichaelWalker, who will aide users in determining run conditions, instrument op-eration, and data analysis.

XPSDr. Steven DeCaluwe

The new Rocky Mountain Environmental XPS (E-XPS) user facility onMines’s campus has the potential to advance the state-of-the-art in sur-face characterization at CSM. Whereas conventional XPS gives quantita-tive surface state information under UHV and at room temperature, E-XPScan take measurements in a range of different thermal and chemical en-vironments (Temperatures up to 700 C and pressures up to 50 mbar),and with possible electrical biasing for measurement of non-equilibriumsurface states. Because surface states can vary significantly from bulkmaterial states and are extremely sensitive to local thermo-chemical con-ditions, measurements on this new system will represent a critical tool inunlocking new material insights for a range of engineered and natural sys-tems central to Mines’s research mission. Here, we will give an overviewof the instrument’s operating principles, measurement capabilities, and anexample study to demonstrate its potential.

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CCAC News: 2017-2018

The Keramos Student Club is now selling its Glass Shop piecesin the Hill Hall main lobby.

Faculty Awards, Honors & Achievements

Dr. Brian Gorman and Dr. David Diercks were awarded a patent entitledHybrid extreme ultraviolet imaging spectrometer (US Patent 9, 899, 197)in February 2018.

Dr. Geoff Brennecka received the Dean’s Excellence Award for significantand meritorious achievement in teaching and scholarship. He serves as aJournal of the American Ceramic Society editor.

Dr. Ryan O’Hayre and Dr. Chuancheng Duan published in the journalNature.

Dr. Ivar Reimanis has been invited to join the World Academy ofCeramics as an academician. He is also serving on the World Academyof Ceramics Forum Committee and the International Editorial Board ofCeramics International.

Dr. Corinne Packard will be on Sabbatical Fall 2018 working withCoorsTek R&D.

Dr. Angus Rockett will be the Incoming Chair of the American VacuumSociety Awards Committee.

Dr. Angus Rockett will be the Outgoing Chair of the IEEE PhotovoltaicSpecialists Conference Steering Committee.

Student Awards, Honors & Achievements

Rachel Sherbondy and Michael Knight received prestigious 2018 NSFGraduate Research Fellowship Awards providing three years of support.

George Burton and John Mangum received travel awards from theMicroscopy Society of America to attend the International MicroscopyCongress (IMC) in Sydney, Australia.

George Burton received the Joseph Goldstein Scholar Award to performresearch at Forschungszentrum Julich.

Dr. Chuancheng Duan won the CSM PhD Thesis Rath Award for thethesis that demonstrates the greatest potential for societal impact.

New Researchers

Michael Walker began as a TOF-SIMS Specialist.

Dr. Ryan O’Hayre group has added the following new members: YewonShin (PhD Student), Jake Huang (PhD Student), Liangzhu Zhu (ResearchProfessor), Liuzhen Bian (visiting PhD student).

Dr. Geoff Brennecka’s group has added the following new members:Megan Leppert (PhD), Alison Mis (PhD), Rachel Sherbondy (PhD)

Recent Graduates

The following students graduated in Spring of 2018:

Dr. Chuancheng Duan (PhD Materials Science) is now working as apostdoctoral fellow in the department.

Dr. Chuanziao Xiao (PhD Materials Science) is now working at NREL.

Brandon Cox (MS Materials Science) is now working at Honeywell.

Chloe Eileen Cook (BS) is now pursuing an MSc Materials Science.

Debora Barcellos Romero recently passed her Ph.D. defense and will beworking at AGP Glass in Peru.

New Equipment

The new TOF-SIMS, awarded to Dr. Corrine Packard through theNational Science Foundation’s Major Research Instrumentation Program,has been installed July 2018.

The Confocal/Raman instrument now has an in-situ high temperature cell.

Notes