Characterization of surface oxides on water-atomized steel powder by XPS/AES depth profiling and nano-scale lateral surface analysis

Chasoglou, Dimitris; Hryha, Eduard; Norell, Mats; Nyborg, Lars

doi:10.1016/j.apsusc.2012.12.155

Cited by 57 publications

(57 citation statements)

References 18 publications

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“…Industrial water‐atomized steel powder particles are covered by heterogeneous surface oxide, formed by thin iron oxide layer with the thickness of about 6 to 8 nm, depending on the powder alloy composition, powder manufacturing, and handling . Spherical particulate oxides sizing up to 500 nm in diameter and composed of more thermodynamically stable oxide phases, as, for example, [Fe‐Cr–Mn–Si– X ] m O n , constitute second type of the surface oxides present.…”

Section: Introductionmentioning

confidence: 99%

“…Reduction by solid carbon (graphite)—direct carbothermal reduction described by Eq. —is possible only in the places of direct contacts between the surface oxide and carbon source powder and is dependent on the carbon source properties . This reaction is thermodynamically possible above Boudouard equilibrium (> ~720°C), however, experimentally is observed above ~900°C according to the results obtained applying a number of different gas analysis techniques …”

Section: Introductionmentioning

confidence: 99%

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Effect of Active Components of Sintering Atmosphere on Reduction/Oxidation Processes During Sintering of Cr‐Alloyed PM Steels

et al. 2015

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Water atomized steel powder particles are covered by heterogeneous surface oxide, formed by thin (~ 6 to 8 nm) iron oxide layer covering most of the powder surface, and particulate features formed by thermodynamically stable oxides containing, for example, Cr and Mn with surface coverage about 5%. Development of sufficiently strong interparticle necks requires as minimum full removal of the iron surface oxide layer that can be achieved by gaseous reducing agents as CO and H2 as well as by carbon typically admixed in the form of graphite. The study evaluates the effect of concentration of reactive components of the sintering atmosphere, with special focus on carbon monoxide, on the reduction/oxidation and carburization/decarburization processes taking place during the whole sintering process. Results of the thermal analysis, SEM analysis of oxide characteristics, metallographic, and chemical analysis of the sintered compacts were correlated with thermodynamic simulation of the oxide stability in applied sintering atmospheres. High oxidation potential of the CO‐containing atmospheres in case of Cr‐alloyed PM steels was detected during heating stage until ~1000°C. Oxidation potential is linearly increasing with the increasing content of the carbon monoxide in the processing atmospheres and rather severe oxidation is observed if CO content exceeds 1 vol%.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Active Components of Sintering Atmosphere on Reduction/Oxidation Processes During Sintering of Cr‐Alloyed PM Steels

et al. 2015

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“…In the case of the indicated method (the so called "peak shape analysis"), various methods for sig nal processing make it possible to determine the quan titative composition of the sample. To describe the X ray photoelectron spectra, the straight line approx imation is used [3,4]; it ignores the elastic scattering process.…”

Section: Introductionmentioning

confidence: 99%

“…The widespread popularity of the straight line approximation [1][2][3][4] is related to its simplicity and obviousness. Because the cross sections for inelastic scattering and elastic scattering are of the same order, this approach applied to an arbitrary case must be regarded as qualitative rather than quantitative.…”

Section: Introductionmentioning

confidence: 99%

Angle-resolved photoelectron spectra of layers of finite thickness

Afanas'ev

Kaplya

Gryazev

2015

J. Synch. Investig.

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The procedure for calculating X ray photoelectron spectra in wide ranges of energy losses and viewing angles is developed. The spectra of semi infinite samples and finite thickness layers are studied. The angular and energy spectra are analyzed via a solution to the problem for the function of photoelectron emis sion flux density by means of the invariant embedding method. The energy spectrum is represented in the form of a number of inelastic collisions. The results of exact numerical solution of the problem of multiple photoelectron scattering in solids using the straight line and small angle approximations, experimental data, and results of Monte Carlo simulation are compared. Errors in calculations using the straight line approxi mation and the advantages of models for describing the spectra in the framework of the small angle approx imation are revealed.

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“…These techniques enable evaluation of the distribution of the secondary phases on the nano-level (thickness of the surface oxide films, presence, size and distribution of the secondary phases, etc. ), as well as powder surface morphology [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Copper Bronze Powder Surface Studied by XPS and HR SEM

Shvab

Hryha

Tahir³

et al. 2016

Powder Metallurgy Progress

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The state of the powder surface represents one of the main interests in the whole cycle of components' production using powder metallurgy (PM) INTRODUCTIONComponents produced by casting, forming, shaping and even made by near-net or netshape methods, often require further operations before the product is ready for use. Machining, which involves secondary and finishing operations, is usually applied at the end of the manufacturing process to meet all the demands required for the component [1]. Grinding is one of the most important finishing operations because of its capability to impart high dimensional accuracy and surface finish. Grinding is a metal cutting process using tools with multiple cutting edges provided by randomly bonded abrasive grits of natural and/or synthetic origin which remove material at high speed. Metal-bonded grinding wheels use the metal bond to hold the abrasive grit (cubic boron nitride, diamond, etc.) for high performance applications. Using different powder metallurgy (PM) techniques, abrasive grits are mixed with metal bond powder and some additives and subsequent bonding is carried out under high pressure and temperature. The high thermal conductivity, strength and wear resistance of Cu bronze makes it an interesting candidate for the metal bond [1][2][3][4]. Taking into account a high specific surface area of the powder in comparison with the bulk material, surface chemical state is one of the most important aspects determining usability of powder for PM processing. Exposure of the powder to the oxygen

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Characterization of surface oxides on water-atomized steel powder by XPS/AES depth profiling and nano-scale lateral surface analysis

Cited by 57 publications

References 18 publications

Effect of Active Components of Sintering Atmosphere on Reduction/Oxidation Processes During Sintering of Cr‐Alloyed PM Steels

Effect of Active Components of Sintering Atmosphere on Reduction/Oxidation Processes During Sintering of Cr‐Alloyed PM Steels

Angle-resolved photoelectron spectra of layers of finite thickness

Copper Bronze Powder Surface Studied by XPS and HR SEM

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