Imperial College London
Professor Alan Atkinson

ProfessorAlanAtkinson

Faculty of Engineering, Department of Materials

Emeritus Professor
 
 
 
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Contact

 

+44 (0)20 7594 6780alan.atkinson

 
 
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Location

 

214Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

280 results found

Atkinson A, Smart DW, Taylor RI, 1987, GRAIN BOUNDARY DIFFUSION IN Cr-DOPED NiO AND THE OXIDATION OF Ni-Cr ALLOY., Werkstoffe und Korrosion, Vol: 38, Pages: 704-709, ISSN: 0043-2822

We have measured the diffusion of **6**3Ni radiotracer into polycrystalline NiO, nominally doped with 0. 1% Cr (Cr/Ni ratio) in the temperature range 600 to 900 degree C. The experiments show that Cr doping increases diffusion of Ni in the oxide lattice, but decreases diffusion of Ni along grain boundaries provided that the grain boundary Cr/Ni ratio is sufficiently large (greater than about 1%). This is believed to be due to the formation of immobile Cr-vacancy pairs which block fast boundary diffusion. The oxidation rate of Ni 0. 1% Cr alloy is, however, slightly faster than that of pure Ni at 700 degree C, at which temperature grain boundary diffusion should be dominant. This apparent discrepancy between oxidation rates and diffusion studies, it is argued, is due to the complicating effects of low Cr mobility, a duplex film structure and inward oxygen transport during oxidation of the alloy.

Journal article

ATKINSON A, SMART DW, TAYLOR RI, 1987, GRAIN-BOUNDARY DIFFUSION IN CR-DOPED NIO AND THE OXIDATION OF NI-CR ALLOY, WERKSTOFFE UND KORROSION-MATERIALS AND CORROSION, Vol: 38, Pages: 704-709, ISSN: 0947-5117

Journal article

ATKINSON A, 1987, GROWTH OF NIO AND SIO2 THIN-FILMS, PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES, Vol: 55, Pages: 637-650, ISSN: 0141-8637

Journal article

HARRIS LB, TAYLOR RI, ATKINSON A, 1987, PREPARATION OF POLYCRYSTALLINE NICKEL-OXIDE FOR DIFFUSION STUDIES, JOURNAL OF MATERIALS SCIENCE, Vol: 22, Pages: 1993-1998, ISSN: 0022-2461

Journal article

Atkinson A, Goult DJ, Hearne JA, 1986, ASSESSMENT OF THE LONG-TERM DURABILITY OF CONCRETE IN RADIOACTIVE WASTE REPOSITORIES., Pages: 239-246, ISSN: 0272-9172

A preliminary assessment of the long-term durability of concrete in a repository sited in clay is presented. The assessment is based on recorded experience of concrete structures and both field and laboratory studies. It is also supported by results of the examination of a concrete sample which had been buried in clay for 43 years. The engineering lifetime of a 1m-thick reinforced concrete slab, with one face in contact with clay, and the way in which pH in the respository as a whole is likely to vary with time have both been estimated from available data. The estimates indicate that engineering lifetimes of about 10**3 years are expected (providing that sulfate-resisting cement is used) and that pH is likely to remain above 10. 5 for about 10**6 years.

Conference paper

ATKINSON A, MOON DP, SMART DW, TAYLOR RIet al., 1986, TRACER DIFFUSION STUDIES IN NIO BICRYSTALS AND POLYCRYSTALS, JOURNAL OF MATERIALS SCIENCE, Vol: 21, Pages: 1747-1757, ISSN: 0022-2461

Journal article

Atkinson A, Nelson K, Valentine TM, 1986, Leach test characterisation of cement-based nuclear waste forms, Nuclear and Chemical Waste Management, Vol: 6, Pages: 241-253, ISSN: 0191-815X

The release of radionuclides from two cement-based waste forms has been measured experimentally using five different leach testing procedures. One waste form was a simple OPC matrix whereas the other contained a contaminated zeolite ion exchange material. The tests were also simulated mathematically using only two parameters, Deff and α, to characterise each radionuclide/waste form combination. Deff is an effective diffusion coefficient that describes the kinetic behaviour and is most easily measured at high flowrates (e.g., in a Soxhlet test), whereas a describes the distribution of radionuclide between aqueous and solid phases at equilibrium and is best measured in a static test. It was established that these two parameters could describe the behaviour of each radionuclide/waste form combination in the different tests reasonably well and are therefore convenient parameters for characterising leaching performance. The product αDeff is approximately constant and equal to the intrinsic diffusion coefficient in the cement matrix. It is concluded that in these cement-based matrices the main reason for different radionuclides having different leaching characteristics is their different chemical interaction with the solid phases (and expressed by α). The apparent equilibria reached with monolithic specimens are significantly different from those reached using crushed material. © 1986.

Journal article

Atkinson A, 1986, Application of mass transport studies to industrial problems., Kinetics and Mass Transport in Silicate and Oxide Systems, Pages: 287-296

The current understanding of diffusion-controlled processes in oxides, which contribute to such phenomena as high-T corrosion, is briefly examined. The rate of growth of an oxide film in thermal oxidation is an example of a process controlled by the faster-diffusing oxide component. The oxidation of some transition metals is discussed in terms of the diffusion characteristics of the relevant oxides, and it is shown that diffusion of metal ions along oxide grain boundaries controls the oxidation rate. The discussion is extended to the use of amorphous SiO2 films as corrosion-resistant barrier layers. Creep is an example of a process controlled by the slower-diffusing component of the oxide. The creep of single-crystal and polycrystalline NiO is discussed in terms of the diffusion of oxygen. The observed creep rates indicate that, in single-crystals, creep is controlled by lattice diffusion of oxygen to allow dislocation climb, whereas in polycrystalline material it is controlled by grain boundary diffusion of oxygen to allow grain boundary sliding and changes in grain shape. -P.Br. Materials Development Div., Building 552, AERE Harwell, Didcot, OX11 ORA, UK.

Journal article

ATKINSON A, TAYLOR RI, 1986, IMPURITY DIFFUSION IN NIO GRAIN-BOUNDARIES, JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, Vol: 47, Pages: 315-323, ISSN: 0022-3697

Journal article

Atkinson A, Nelson K, Valentine TM, 1985, LEACH TEST CHARACTERIZATION OF CEMENT-BASED NUCLEAR WASTE FORMS., Pages: 319-320

The release of radionuclides from two cement-based waste forms has been measured experimentally using five different leach testing procedures. The release can be characterised by two parameters, D//e//f//f and alpha , for each radionuclide/waste form combination. D//e//f//f describes the kinetic behaviour and is best measured in a Soxhlet test whereas alpha describes an apparent equilibrium and is best measured in a static test. The apparent equilibria reached with monolithic specimens are significantly different from those reached using crushed material.

Conference paper

Atkinson A, 1985, The influence of wasteform permeability on the release of radionuclides from a repository, Nuclear and Chemical Waste Management, Vol: 5, Pages: 203-214, ISSN: 0191-815X

A rudimentary analysis has been performed of the release of radionuclides from a simple model of a repository to assess the influence of its permeability on release rate. A further simple model has been used to relate the effective permeability of the repository to the permeabilities of its constituent backfill and wasteforms. The analysis shows that in the case of a deep repository, the release rate is not a sensitive function of these permeabilities, relative to that of the surrounding geology. The release rate is much more sensitive in the case of a shallow repository. The analysis also indicates limits for the ranges of relative permeabilities which are sufficient to minimise the release rate. A survey of measured permeabilities of likely materials shows that these limiting conditions can be achieved using cement-based backfill and wasteforms. Finally, a brief survey is presented of available laboratory techniques for the measurement of permeability. © 1985.

Journal article

ATKINSON A, TAYLOR RI, 1985, DIFFUSION OF FE-55 IN FE2O3 SINGLE-CRYSTALS, JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, Vol: 46, Pages: 469-475, ISSN: 0022-3697

Journal article

ATKINSON A, 1985, TRANSPORT PROCESSES DURING THE GROWTH OF OXIDE-FILMS AT ELEVATED-TEMPERATURE, REVIEWS OF MODERN PHYSICS, Vol: 57, Pages: 437-470, ISSN: 0034-6861

Journal article

Atkinson A, Nelson K, Valentine TM, 1984, Matrix dissolution and leaching of radionuclides from Zr-O-F ceramic wasteforms, Radioactive Waste Management and the Nuclear Fuel Cycle, Vol: 5, Pages: 345-362

The aqueous dissolution and leaching characteristics of Zr-O-F ceramics for the immobilization of waste Zircaloy nuclear fuel cladding have been studied in both static and dynamic laboratory tests. The kinetics of matrix dissolution are consistent with a mechanism in which Zr and F (in the stoichiometric proportions ZrF//4) are preferentially dissolved from the oxyfluoride (Zr//1//0O//1//3F//1//4) phase in the ceramics to leave a surface layer of ZrO//2 corrosion product which eventually protects the ceramic from further dissolution. Further evidence for the formation of this protective layer is provided by transmission electron diffraction of thin corroded ceramic foils and surface analysis of corroded surfaces. The kinetics of leaching of the waste radionuclides **6**0Co, **8**5Sr and **1**3**7Cs are qualitatively similar to the kinetics of matrix dissolution indicating that the ZrO//2 protective layer also limits the release of radionuclides.

Journal article

Hughes AE, Atkinson A, Chadwick AT, 1984, SHORT-CIRCUIT DIFFUSION PROCESSES IN OXIDATION FILMS., Pages: 27-37, ISSN: 0272-9172

Basic experiments on the oxidation of nickel and direct tracer measurements of diffusion coefficients show that grain boundaries are the most important short-circuit paths under protective oxidation conditions. Similar conclusions can be drawn for other metals including chromium. The methods used in this work have been extended to study the way in which a surface treatment with CeO//2 reduces the oxidation rate of nickel, apparently by inhibiting the outward transport of metal ions along grain boundaries. Segregation of cerium ions to grain boundaries increases the diffusion coefficient of nickel; the inhibition is caused instead by particulates of CeO//2 in the middle region of the scale.

Conference paper

ATKINSON A, NICKERSON AK, 1984, THE DIFFUSION OF IONS THROUGH WATER-SATURATED CEMENT, JOURNAL OF MATERIALS SCIENCE, Vol: 19, Pages: 3068-3078, ISSN: 0022-2461

Journal article

ATKINSON A, NICKERSON AK, VALENTINE TM, 1984, THE MECHANISM OF LEACHING FROM SOME CEMENT-BASED NUCLEAR WASTEFORMS, RADIOACTIVE WASTE MANAGEMENT AND ENVIRONMENTAL RESTORATION, Vol: 4, Pages: 357-378

Journal article

ATKINSON A, 1984, DIFFUSION ALONG GRAIN-BOUNDARIES AND DISLOCATIONS IN OXIDES, ALKALI-HALIDES AND CARBIDES, SOLID STATE IONICS, Vol: 12, Pages: 309-320, ISSN: 0167-2738

Journal article

MYHRA S, SAVAGE D, ATKINSON A, RIVIERE JCet al., 1984, SURFACE MODIFICATION OF SOME TITANATE MINERALS SUBJECTED TO HYDROTHERMAL CHEMICAL ATTACK, AMERICAN MINERALOGIST, Vol: 69, Pages: 902-909, ISSN: 0003-004X

Journal article

MYHRA S, ATKINSON A, RIVIERE JC, SAVAGE Det al., 1984, SURFACE ANALYTICAL STUDY OF SYNROC SUBJECTED TO HYDROTHERMAL ATTACK, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Vol: 67, Pages: 223-227, ISSN: 0002-7820

Journal article

Atkinson A, Taylor RI, Hughes AE, 1983, OXIDATION BY GRAIN BOUNDARY DIFFUSION - A QUANTITATIVE DEMONSTRATION OF THE MECHANISM., Pages: 110-114, ISSN: 0361-4409

Conference paper

Atkinson A, Corish J, 1983, CORROSION., Pages: 477-504

The chapter discusses the principles which govern the formation and maintenance of corrosion product layers on metallic substrates exposed to gaseous environments at high temperatures, theories to describe the kinetics of layer growth on pure metal substrates, the sulphidation of silver, and the role of grain boundary diffusion in oxidation. The phenomenological theory for oxidation of binary alloys is applied to the Fe-Si system with particular reference to the formation of protective layers. The use of oxidation resistant coatings and carburization processes in high-temperature austenitic alloys are also covered.

Conference paper

Atkinson A, O'Dwyer ML, Taylor RI, 1983, <sup>55</sup>Fe DIFFUSION IN MAGNETITE CRYSTALS AT 500 degree C AND ITS RELEVANCE TO THE OXIDATION OF Fe., Pages: 169-172, ISSN: 0033-7579

A computer controlled sputter-sectioning apparatus has been developed which is particularly useful for self diffusion studies at low temperatures (D in the range 10** minus **1**2 to 10** minus **1**9 cm**2 s** minus **1). The technique has been applied to measure the diffusion coefficient of **5**5Fe in the magnetite lattice as a function of oxygen activity at 500 degree C. The results are in broad agreement with an extrapolation of pre-existing high temperature diffusion data. The low temperature data have been used to estimate the rate constant for magnetite formation on Fe in CO//2 plus 1% CO at 500 degree C and this is found to be 250 times smaller than the experimentally measured value. This disagreement is probably attributable to diffusion along oxide grain boundaries during oxidation.

Conference paper

ATKINSON A, ODWYER ML, TAYLOR RI, 1983, FE-55 DIFFUSION IN MAGNETITE CRYSTALS AT 500-DEGREES-C AND ITS RELEVANCE TO OXIDATION OF IRON, JOURNAL OF MATERIALS SCIENCE, Vol: 18, Pages: 2371-2379, ISSN: 0022-2461

Journal article

ATKINSON A, 1983, MATHEMATICAL-MODELING OF LEACHING FROM POROUS NUCLEAR WASTE-FORMS, RADIOACTIVE WASTE MANAGEMENT AND ENVIRONMENTAL RESTORATION, Vol: 3, Pages: 371-386

Journal article

Atkinson A, Taylor RI, 1982, <sup>55</sup>Fe and <sup>18</sup>O tracers in magnetite scales growing on iron and dilute iron-silicon alloys., High Temperatures - High Pressures, Vol: 14, Pages: 571-580, ISSN: 0018-1544

The dominant transport process controlling the magnetite growth rate is the outward diffusion of Fe along the magnetite grain boundaries.-C.M.B.H.

Journal article

ATKINSON A, 1982, CONDITIONS FOR THE FORMATION OF NEW OXIDE WITHIN OXIDE-FILMS GROWING ON METALS, CORROSION SCIENCE, Vol: 22, Pages: 347-357, ISSN: 0010-938X

Journal article

ATKINSON A, 1982, A THEORETICAL-ANALYSIS OF THE OXIDATION OF FE-SI ALLOYS, CORROSION SCIENCE, Vol: 22, Pages: 87-102, ISSN: 0010-938X

Journal article

ATKINSON A, NICKERSON AK, TAYLOR RI, 1982, THE FABRICATION AND PROPERTIES OF ZR-O-F CERAMICS FOR THE IMMOBILIZATION OF ZIRCALOY NUCLEAR WASTE, JOURNAL OF MATERIALS SCIENCE, Vol: 17, Pages: 2979-2989, ISSN: 0022-2461

Journal article

ATKINSON A, TAYLOR RI, HUGHES AE, 1982, A QUANTITATIVE DEMONSTRATION OF THE GRAIN-BOUNDARY DIFFUSION MECHANISM FOR THE OXIDATION OF METALS, PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES, Vol: 45, Pages: 823-833, ISSN: 0141-8610

Journal article

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