Imperial College London

DrRichardChater

Faculty of EngineeringDepartment of Materials

Instrumentation Research Fellow, Surface Analysis
 
 
 
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Contact

 

+44 (0)20 7594 6740r.chater

 
 
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Location

 

LG62ARoyal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

167 results found

Brugge RH, Chater RJ, Kilner JA, Aguadero Aet al., 2021, Experimental determination of Li diffusivity in LLZO using isotopic exchange and FIB-SIMS, JOURNAL OF PHYSICS-ENERGY, Vol: 3, ISSN: 2515-7655

Journal article

Llewelyn SCH, Chater RJ, Jones NG, Hardy MC, Stone HJet al., 2021, The effect of systematic variation of Ni:Co ratio on the oxidation behaviour of gamma-gamma ' Ni-Co-Al-Ti-Cr alloys, CORROSION SCIENCE, Vol: 178, ISSN: 0010-938X

Journal article

Weiser M, Galetz MC, Chater RJ, Virtanen Set al., 2020, Growth Mechanisms of Oxide Scales on Two-phase Co/Ni-base Model Alloys between 800 degrees C and 900 degrees C, JOURNAL OF THE ELECTROCHEMICAL SOCIETY, Vol: 167, ISSN: 0013-4651

Journal article

Weiser M, Chater RJ, Shollock BA, Virtanen Set al., 2019, Transport mechanisms during the high-temperature oxidation of ternary gamma/gamma ' Co-base model alloys, NPJ MATERIALS DEGRADATION, Vol: 3

Journal article

Manalastas W, Rikarte J, Chater RJ, Brugge R, Aguadero A, Buannic L, Llordés A, Aguesse F, Kilner Jet al., 2019, Mechanical failure of garnet electrolytes during Li electrodeposition observed by in-operando microscopy, Journal of Power Sources, Vol: 412, Pages: 287-293, ISSN: 0378-7753

Metallic Li anodes are key to reaching high energy densities in next-generation solid-state batteries, however, major problems are the non-uniform deposition of Li at the interface and the penetrative power of Li metal during operation, which cause failure of the ceramic electrolyte, internal short-circuits and a premature end of battery life. In this work, we explore the anode-electrolyte interface instability of a Li metal-garnet electrolyte system during Li electrodeposition, and its implications for mechanical fracture, Li metal propagation, and electrolyte failure. The degradation mechanism was followed step-by-step during in-operando electrochemical cycling using optical and scanning electron microscopy. High amounts of Li electrodeposition in a localized zone of the interface lead to ceramic fracture followed by an electrode-to-electrode electrical connection via a conductor Li metal filament. This work enables deeper understanding of battery failure modes in all-solid-state batteries containing a ceramic electrolyte membrane.

Journal article

Pesci FM, Brugge RH, Hekselman AKO, Cavallaro A, Chater RJ, Aguadero Aet al., 2018, Elucidating the role of dopants in the critical current density for dendrite formation in garnet electrolytes, Journal of Materials Chemistry A, Vol: 6, Pages: 19817-19827, ISSN: 2050-7488

Garnet-type solid electrolytes have attracted great interest in solid state battery research thanks to their high ionic conductivity at room temperature (10−3 S cm−1) and their electrochemical stability against lithium metal anodes. However, the formation of lithium dendrites following charge/discharge limits their applicability and commercialisation. Although widely investigated, no clear explanation of dendrite formation has been previously reported. In this work, we employ cubic Al- and Ga-doped Li7La3Zr2O12, which represent two of the solid electrolytes with higher technological importance, to investigate the formation and chemical composition of dendrites. For the first time, this study elucidates the role that the dopants play in determining the critical current density for dendrite formation and highlights the importance of controlling the dopant distribution in the garnet structure. We use a combination of techniques including Secondary Electron Microscopy and Secondary Ion Mass Spectrometry in order to analyse the microstructure and chemical composition of dendrites in Li7La3Zr2O12. We show that, following electrochemical cycling, Li6.55Ga0.15La3Zr2O12 systematically displays a critical current density 60% higher than Li6.55Al0.15La3Zr2O12. Chemical analysis revealed that in Li6.55Al0.15La3Zr2O12 the dendritic features are composed of a mixture of Al and Li species, whereas in Li6.55Ga0.15La3Zr2O12 they are uniquely composed of Li. We also show that only in pristine Li6.55Al0.15La3Zr2O12, the dopant segregates at the grain boundaries suggesting that local chemical inhomogeneity can have a fundamental role in the nucleation and propagation of dendrites.

Journal article

Vardar G, Bowman WJ, Lu Q, Wang J, Chater RJ, Aguadero A, Seibert R, Terry J, Hunt A, Waluyo I, Fong DD, Jarry A, Crumlin EJ, Hellstrom SL, Chiang YM, Yildiz Bet al., 2018, Structure, chemistry, and charge transfer resistance of the interface between Li7La3Zr2O12 electrolyte and LiCoO2 cathode, Chemistry of Materials, Vol: 30, Pages: 6259-6276, ISSN: 0897-4756

All-solid-state batteries promise significant safety and energy density advantages over liquid-electrolyte batteries. The interface between the cathode and the solid electrolyte is an important contributor to charge transfer resistance. Strong bonding of solid oxide electrolytes and cathodes requires sintering at elevated temperatures. Knowledge of the temperature dependence of the composition and charge transfer properties of this interface is important for determining the ideal sintering conditions. To understand the interfacial decomposition processes and their onset temperatures, model systems of LiCoO2 (LCO) thin films deposited on cubic Al-doped Li7La3Zr2O12 (LLZO) pellets were studied as a function of temperature using interface-sensitive techniques. X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), and energy-dispersive X-ray spectroscopy (EDS) data indicated significant cation interdiffusion and structural changes starting at temperatures as low as 300°C. La2Zr2O7 and Li2CO3 were identified as decomposition products after annealing at 500°C by synchrotron X-ray diffraction (XRD). X-ray absorption spectroscopy (XAS) results indicate the presence of also LaCoO3, in addition to La2Zr2O7 and Li2CO3. Based on electrochemical impedance spectroscopy, and depth profiling of the Li distribution upon potentiostatic hold experiments on symmetric LCO|LLZO|LCO cells, the interfaces exhibited significantly increased impedance, up to 8 times that of the as-deposited samples after annealing at 500°C. Our results indicate that lower-temperature processing conditions, shorter annealing time scales, and CO2-free environments are desirable for obtaining ceramic cathode-electrolyte interfaces that enable fast Li transfer and high capacity.

Journal article

Brugge R, Hekselman A, Cavallaro A, Pesci F, Chater R, Kilner J, Aguadero Aet al., 2018, Garnet electrolytes for solid state batteries: visualization of moisture-induced chemical degradation and revealing its impact on the Li-ion dynamics, Chemistry of Materials, Vol: 30, Pages: 3704-3713, ISSN: 0897-4756

In this work, we reveal the impact of moisture-induced chemical degradation and proton–lithium exchange on the Li-ion dynamics in the bulk and the grain boundaries and at the interface with lithium metal in highly Li-conducting garnet electrolytes. A direct correlation between chemical changes as measured by depth-resolved secondary ion mass spectrometry and the change in transport properties of the electrolyte is provided. In order to probe the intrinsic effect of the exchange on the lithium kinetics within the garnet structure, isolated from secondary corrosion product contributions, controlled-atmosphere processing was first used to produce proton-free Li6.55Ga0.15La3Zr2O12 (Ga0.15-LLZO), followed by degradation steps in a H2O bath at 100 °C, leading to the removal of LiOH secondary phases at the surface. The proton-exchanged region was analyzed by focused ion beam secondary ion mass spectrometry (FIB-SIMS) and found to extend as far as 1.35 μm into the Ga0.15-LLZO garnet pellet after 30 min in H2O. Impedance analysis in symmetrical cells with Li metal electrodes indicated a greater reactivity in grain boundaries than in grains and a significantly detrimental effect on the Li transfer kinetics in the Li metal/garnet interface correlated to a 3-fold decrease in the Li mobility in the protonated garnet. This result indicates that the deterioration of Li charge transfer and diffusion kinetics in proton-containing garnet electrolytes have fundamental implications for the optimization and integration of these systems in commercial battery devices.

Journal article

Gasparrini C, Chater RJ, Horlait D, Vandeperre L, Lee WEet al., 2018, Zirconium carbide oxidation: kinetics and oxygen diffusion through the intermediate layer, Journal of the American Ceramic Society, Vol: 101, Pages: 2638-2652, ISSN: 0002-7820

Oxidation of hot‐pressed ZrC was investigated in air in the 1073‐1373 K range. The kinetics were linear at 1073 K, whereas at higher temperature samples initially followed linear kinetics before undergoing rapid oxidation leading to a Maltese cross shape of the oxide. The linear kinetics at 1073 K was governed by inward oxygen diffusion through an intermediate layer of constant thickness between ZrC and ZrO2 which was comprised of amorphous carbon and ZrO2 nanocrystals. Diffusion of oxygen through the intermediate layer was measured to be 9 × 10−10 cm2 s−1 using 18O as a tracer in a double oxidation experiment in 16O/18O. Oxidation at 1073 and 1173 K produced samples made of m‐ZrO2 and either t‐ or c‐ZrO2 with an adherent intermediate layer made of amorphous carbon and ZrO2, whereas oxidation at 1273 and 1373 K produced samples with a voluminous oxide made of m‐ZrO2 showing a gap between ZrC and the oxide. A substoichiometric zirconia layer was found at the gap at 1273 K and no carbon uptake was detected in this layer when compared with the top oxide layer. The loss of the intermediate layer and the slowdown of the linear rate constant (g m−2 s−1) at 1273 K compared to 1173 K was correlated with the preferential oxidation of carbon at the intermediate layer which would leave as CO and/or CO2 leaving a gap between ZrC and substoichiometric zirconia.

Journal article

Chater RJ, Weiser M, Virtanen S, 2018, Visualizing ion transport mechanisms through oxide scales grown on mixed nickel- and cobalt-base model alloys at 900 degrees C using FIB-SIMS techniques, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B, Vol: 36, ISSN: 2166-2746

Journal article

Hay RS, Chater RJ, 2017, Oxidation kinetics and strength of Hi-Nicalon<sup>TM</sup>-S SiC Fiber after oxidation in dry and wet air, Journal of the American Ceramic Society, Vol: 100, Pages: 4110-4130, ISSN: 1551-2916

Hi-NicalonTM-S SiC fiberstrengths and Weibull moduli were measured after oxidation for up to 100 hours between 700° and 1400°Cin wet and dry air. SiO2scale thickness and crystallization extent weremeasured by TEM.The effect of furnace environmentand bake-out on trace element levels in SiO2scales was characterized by secondary ion mass spectroscopy (SIMS).Crystallization kineticsand Deal-Grove oxidation kinetics for glass and crystalline scale, and the transition between them,were determinedand modeled. Crystallization retards oxidation kinetics, and scale that forms in the crystalline state is heavily deformedby the growth stress accompanying SiC oxidation volume expansion. Glass scales formed in dry air slightly increasefiber strength. Glass scales formed in wet air donot increase strength,and in some cases significantly decrease strength. Scales more than 200 nm thick were usually partially or completely crystallized,andthese fibers hadlowstrengths.Contamination of scales by trace impurities such as Al and Ca during heat-treatment significantly inhibited crystallization.The oxidationkineticsand the strengths of oxidized Hi-NicalonTM-S fibers are compared with results from previous studies. Empirical relationships between oxidation temperature, time, scale thickness, and strength are determined and discussed.

Journal article

Gasparrini C, Podor R, Horlait D, Chater R, Lee Wet al., 2016, Zirconium carbide oxidation: Maltese Cross formation and interface characterization, Oxidation of Metals, Vol: 88, Pages: 509-519, ISSN: 1573-4889

Oxidation of dense hot pressed ZrC specimens from 1073 –1473 K was investigated using an in-situtechnique:HT-ESEM. Cuboid specimens were monitored on the surface and on edges and corners during oxidation in order to understand the influence of crack formation and propagation on the Maltese cross shapedevelopmentof the oxide. The oxidation mechanism comprisedthree steps: (1) delamination of sample edges,(2) crack formation at corners and (3) crackpropagation towards the inner core and formation of microcracks parallel to the interfacethat increase the accessible surface areafollowed by a drastic volume expansion.The microcrackpattern is found to berepetitive as if a cyclicdebonding of the interfaceoccurred. Characterization of the interface by TEM and HRTEMrevealed the interface between ZrC and ZrO2 tocomprise a 2μm thick amorphouscarbonmatrix with ZrO2nanocrystals embedded in it.

Journal article

Mehonic A, Buckwell M, Montesi L, Munde MS, Gao D, Hudziak S, Chater RJ, Fearn S, McPhail D, Bosman M, Shluger AL, Kenyon AJet al., 2016, Silica: Nanoscale Transformations in Metastable, Amorphous, Silicon-Rich Silica (Adv. Mater. 34/2016), Advanced Materials, Vol: 28, Pages: 7549-7549, ISSN: 0935-9648

Electrically biasing thin films of amorphous, substoichiometric silicon oxide drives surprisingly large structural changes, apparent as density variations, oxygen movement, and ultimately, emission of superoxide ions. Results from this fundamental study are directly relevant to materials that are increasingly used in a range of technologies, and demonstrate a surprising level of field-driven local reordering of a random oxide network.

Journal article

Burriel M, Tellez H, Chater RJ, Castaing R, Veber P, Zaghrioui M, Ishihara T, Kilner JA, Bassat J-Met al., 2016, Influence of Crystal Orientation and Annealing on the Oxygen Diffusion and Surface Exchange of La2NiO4+delta, Journal of Physical Chemistry C, Vol: 120, Pages: 17927-17938, ISSN: 1932-7455

La2NiO4+δ is a mixed ionic–electronic conducting material with the 2D K2NiF4-type structure garnering much interest as a potential intermediate-temperature solid-oxide fuel cell (IT-SOFC) cathode. The oxygen diffusion along the ab-plane exhibiting the highest oxygen ionic conductivity governs the behavior of the bulk materials in this family of oxides. The oxygen surface exchange processes, however, are not well-understood and large differences in the surface exchange coefficient (k*) values can be found in the literature for this and other cathode materials. The isotopic exchange depth profiling (IEDP) technique was used in combination with low energy ion scattering (LEIS) measurements on two sets of La2NiO4+δ single crystals with precisely cut crystal faces but different thermal histories. For each set of single crystals, the oxygen diffusion and surface exchange coefficient were evaluated for two different orientations in the temperature range of 450–600 °C. The differences in k* have been correlated with differences in surface chemistry: surface termination, near-surface rearrangement, and the presence of extrinsic impurities. Finally, the predominant La termination at the immediate outer surface is evidenced, confirming recent results for other Ruddlesden–Popper phases with mixed ionic–electronic conducting properties.

Journal article

Chater RJ, Cavallaro A, Bayliss RD, Cook SN, Esser BD, McComb DW, Kilner JAet al., 2016, Fast grain boundary oxygen ion diffusion in the α-phase of Bi2O3, Solid State Ionics, Vol: 299, Pages: 89-92, ISSN: 0167-2738

The low temperature stable α-phase of pure Bi2O3 is known to have an oxygen ion diffusivity that is over 7 orders of magnitude lower than the high temperature fluorite-structured δ-phase. Tracer oxygen-18 diffusion studies of polycrystalline α-Bi2O3 at 600 °C using an ion microscope with lateral resolutions of ~ 50 nm for the surface distributions of the oxygen isotopes have resolved the secondary fast migration pathways as well as the normal bulk diffusion profile in the grains. A grain boundary pathway for the oxygen migration is distinguished from other extended defects, some of which are also active in the overall oxygen diffusivity. This experimental study highlights the potential manipulation of the micro-structure of this material for enhanced oxygen ion conduction in intermediate temperature solid oxide fuel cells as has been shown for perovskite MIEC electrode materials.

Journal article

Ollivier M, Harker RM, Chater RJ, Gourlay Cet al., 2016, Thermal etching of silver: Influence of rolling defects, Materials Characterization, Vol: 118, Pages: 112-121, ISSN: 1044-5803

Silver is well known to be thermally etched in an oxygen-rich atmosphere and has been extensively studied in the laboratory tounderstand thermal etching and to limit its effect when this material is used as a catalyst. Yet, in many industrial applicationsthe surface of rolled silver sheets is used without particular surface preparation. Here, it is shown by combining FIB-tomography,FIB-SIMS and analytical SEM that the kinetics of thermal etch pitting are significantly faster on rolled Ag surfaces than on polishedsurfaces. This occurs due to range of interacting phenomena including (i) the reaction of subsurface carbon-contamination withdissolved oxygen to form pores that grow to intersect the surface, (ii) surface reconstruction around corrosion pits and surfacescratches, and (iii) sublimation at low pressure and high temperature. A method to identify subsurface pores is developed to showthat the pores have {111} and {100} internal facets and may be filled with a gas coming from the chemical reaction of oxygen andcarbon contamination.

Journal article

Chater RJ, Smith AJ, Cooke G, 2016, Simultaneous detection of positive and negative secondary ions, Journal of Vacuum Science & Technology B, Vol: 34, ISSN: 1071-1023

A secondary ion mass spectrometer (SIMS) instrument is described that is configured with two SIMSdetectors that are both low-field extraction, quadrupole-based filters. Secondary ions are generated by sputtering with a liquid-metal ion gallium source and column of the type that is common on two-beam electron microscopes. The gallium ion beam, or focused ion beam achieves sub-100 nm focus with a continuous current of up to 300 pA. Positive secondary ions are detected by one SIMSdetector, and simultaneously, negative secondary ions are detected by the second SIMSdetector. The SIMSdetectors are independently controlled for recording mass spectra, concentration depth profiles, and secondary ion images. Examples of simultaneous positive and negative SIMS are included that demonstrate the advantage of this facility for surface analysis and depth profiling. The SIMS secondary ion collection has been modeled using the ray tracing program simion (“simion”, Scientific Instrument Services, Inc., Ringoes, NJ, 08551-1054, see http://www.simion.com) in order to understand the interaction of the secondary ions of opposite polarities in the extraction volume for the purpose of optimizing secondary ion collection.

Journal article

Buckwell M, Montesi L, Mehonic A, Kenyon AJ, Fearn S, Chater RJ, McPhail Det al., 2016, Structural investigation of resistance switching in silicon-rich silica films, IEEE-NANO 2015 - 15th International Conference on Nanotechnology, Publisher: IEEE, Pages: 489-492

Redox-based resistive RAM presents a development in non-volatile data storage, despite an incomplete understanding of switching mechanisms. However, in order to optimize and standardize device behavior it is necessary to have a better understanding of physical processes governing switching. Many oxide dielectrics have been studied in relation to switching, but silicon-based devices in particular offer a high capacity for integration into existing CMOS technologies at low cost. We present analyses of silicon-rich silica films to establish the chemical and structural processes underpinning electronic resistance switching behavior. Atomic force microscopy, x-ray photoelectron spectroscopy and secondary ion mass spectroscopy are used to characterize observed resistance changes. Reduction and structural reconfiguration of the oxide is seen to be concomitant with structural distortions and the appearance of conductive regions in otherwise-insulating material. Crucially, we demonstrate for the first time the correlation between resistance switching and the emission of oxygen from an electrically stressed dielectric film. These results confirm the current model of an oxygen-based mechanism and highlight the inherent limitations imposed by gradual oxygen depletion on device lifetime.

Conference paper

Bayliss RD, Cook SN, Kotsantonis S, Chater RJ, Kilner JAet al., 2015, Oxygen Ion Diffusion and Surface Exchange Properties of the alpha- and delta-phases of Bi2O3 (vol 4, 1301575, 2014), Advanced Energy Materials, Vol: 5, ISSN: 1614-6832

Journal article

Jayaseelan DD, Zapata-Solvas E, Chater RJ, Lee WEet al., 2015, Structural and compositional analyses of oxidised layers of ZrB2-based UHTCs, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, Vol: 35, Pages: 4059-4071, ISSN: 0955-2219

Journal article

Chapman TP, Chater RJ, Saunders EA, Walker AM, Lindley TC, Dye Det al., 2015, Environmentally assisted fatigue crack nucleation in Ti-6Al-2Sn-4Zr-6Mo, Corrosion Science, Vol: 96, Pages: 87-101, ISSN: 0010-938X

An unexplained feature was observed at the fatigue crack origin of a number of alpha/beta titanium specimens tested at 450 °C in the low cycle fatigue regime. The origin was discoloured blue but this was not a result of temper colouration; this feature sometimes resulted in large reductions in fatigue lives. A number of specimens were examined to determine the cause and formation mechanism of these “blue spots.” This feature was associated with elevated oxygen and chloride levels and the presence of sodium. A mechanism based on hot-salt stress-corrosion cracking is proposed and the implications for service components are discussed.

Journal article

Saunders EA, Chapman TP, Walker ARM, Lindley TC, Chater RJ, Vorontsov VA, Rugg D, Dye Det al., 2015, Understanding the “blue spot” sodium chloride hot salt stress-corrosion cracking in titanium-6246 during fatigue testing at low pressure, Engineering Failure Analysis, Vol: 61, Pages: 2-20, ISSN: 1873-1961

During hot component fatigue tests there have been two cases of low life crack initiation of gas turbine rotating parts manufactured from the Titanium alloy Ti-6246. Both exhibited a small (~ 0.1 mm) elliptical ‘blue spot’ at the origin. Through validated striation count work and fracture mechanics it was established that fatigue had propagated with a near-nil initiation life. Early investigation suggested that the ‘blue spot’ was possibly a region of stage 1 fatigue growth, and was therefore a material behaviour concern with potential implications for service. During an investigation of a later cracking incident in this alloy, subsequently shown to have resulted from stress-corrosion cracking (SCC), near-identical fractographic characteristics to that seen in the “blue spot” were found that subtly differentiated it from stage 1 fatigue. Also, similar ‘blue spots’ have since been identified on Ti6246 Laboratory hot LCF test specimens and found to have been due to contamination by NaCl, through the application of focussed long-term EDX examination and other novel chemical analyses techniques. By the application of those techniques, fractography, and comparison against these specimens, Rolls-Royce and Imperial College London have collaborated to show that the original two component ‘blue spots’ were subtle examples of NaCl-related Hot Salt Stress-Corrosion Cracking (HSSCC). Such cracking has not been found to occur in service components, due to air pressure within the engine, and the effect is therefore confined to Laboratory and component tests at near-atmospheric pressure or below.

Journal article

Mehonic A, Buckwell M, Montesi L, Garnett L, Hudziak S, Fearn S, Chater R, McPhail D, Kenyon AJet al., 2015, Structural changes and conductance thresholds in metal-free intrinsic SiOx resistive random access memory, Journal of Applied Physics, Vol: 117, ISSN: 1089-7550

We present an investigation of structural changes in silicon-rich silicon oxide metal-insulator-metal resistive RAM devices. The observed unipolar switching, which is intrinsic to the bulk oxide material and does not involve movement of metal ions, correlates with changes in the structure of the oxide. We use atomic force microscopy, conductive atomic force microscopy, x-ray photoelectron spectroscopy, and secondary ion mass spectroscopy to examine the structural changes occurring as a result of switching. We confirm that protrusions formed at the surface of samples during switching are bubbles, which are likely to be related to the outdiffusion of oxygen. This supports existing models for valence-change based resistive switching in oxides. In addition, we describe parallel linear and nonlinear conduction pathways and suggest that the conductance quantum, G0, is a natural boundary between the high and low resistance states of our devices.

Journal article

Lopez-Quintas I, Oujja M, Sanz M, Benitez-Canete A, Chater RJ, Vega Canamares M, Marco JF, Castillejo Met al., 2015, Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide, APPLIED SURFACE SCIENCE, Vol: 328, Pages: 170-176, ISSN: 0169-4332

Journal article

Chater RJ, 2015, Confidence limits in the oxygen transport parameters of the (La<inf>0.8</inf>Sr<inf>0.2</inf>)(Cr<inf>0.2</inf>Fe<inf>0.8</inf>)O<inf>3-δ</inf> determined by the isotopic exchange, depth profiling method, Pages: 631-649, ISSN: 1938-6737

The polycrystalline oxide (La0.8Sr0.2)(Cr0.2Fe0.8)O3-δ is a mixed ionic and electronic conductor of a type called "acceptor-doped transition metal oxide" that has been explored for application as an electrode material in SOFC and other electrochemical devices working at intermediate to high temperatures (500°C to 900°C). The isotopic exchange, depth profiling method allows both bulk oxygen transport parameters, the diffusion coefficient, D(T) and surface reaction coefficient, k(T), to be determined simultaneously once an appropriate solution of the diffusion equation has been identified. Error assessment of (D,k) through the numerical fit process is quantified for the variances that are used as weights in extracting the transport activation energies from the corresponding Arrhenius plots. As the dataset is generally small for a single anneal ambient composition, standard statistical F and t-tests are used and the 95% confidence limits reported that are essential for comparison between datasets.

Conference paper

Bayliss RD, Cook SN, Kotsantonis S, Chater RJ, Kilner JAet al., 2014, Oxygen Ion Diffusion and Surface Exchange Properties of the alpha- and delta-phases of Bi2O3 (vol 4, 1301575, 2014), ADVANCED ENERGY MATERIALS, Vol: 4, ISSN: 1614-6832

Journal article

Chater RJ, Shollock BA, McPhail DS, Smith AJ, Cooke Get al., 2014, Differentially pumped quadrupole SIMS probe on FIB-based and two-beam microscopes, 19th International Conference on Secondary Ion Mass Spectrometry (SIMS), Publisher: WILEY-BLACKWELL, Pages: 372-374, ISSN: 0142-2421

Conference paper

Bayliss RD, Cook SN, Kotsantonis S, Chater RJ, Kilner JAet al., 2014, Oxygen Ion Diffusion and Surface Exchange Properties of the alpha- and delta-phases of Bi2O3, ADVANCED ENERGY MATERIALS, Vol: 4, ISSN: 1614-6832

Journal article

Ruiz-Trejo E, Boldrin P, Lubin A, Tariq F, Fearn S, Chater R, Cook SN, Gruar RI, Tighe CJ, Brandon NP, Darr J, Atkinson Aet al., 2014, Novel Composite Cermet for Low-Metal-Content Oxygen Separation Membranes, Chemistry of Materials

Journal article

Cruchley S, Sun JF, Taylor MP, Evans HE, Bowen P, Sumner J, Nicholls JR, Simms NJ, Shollock BA, Chater RJ, Foss BJ, Hardy MC, Stekovic Set al., 2014, Cautionary note on use of focused ion beam sectioning as technique for characterising oxidation damage in Ni based superalloys, MATERIALS AT HIGH TEMPERATURES, Vol: 31, Pages: 27-33, ISSN: 0960-3409

Journal article

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