Determination of hydrogen in materials

Khabibullaev, P. K.; Skorodumov, B.G.

doi:10.1007/bfb0044541

Cited by 6 publications

(6 citation statements)

References 87 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the determination of hydrogen there are also a variety of nuclear physics methods [43]. Typical precisions of about C 0.001%, H 0.01%, N 0.01%, S 0.02% and O 0.01% are achieved.…”

Section: Elemental Analysismentioning

confidence: 99%

Bulk Chemical Composition

Albers¹

2008

Handbook of Heterogeneous Catalysis

View full text Add to dashboard Cite

where P 1 is the initial weight of the fresh sample after sieving, P 2 the weight of the tested sample after sieving and P 3 the weight of fines.3.1.4.3.1 Grains or Powders Conventional catalyst attrition testing has been used for years to provide refiners with a relative measure of catalyst attrition resistance (commonly referred to as ''hardness''). Some tests use a high-velocity stream of gas to cause attrition of the catalyst. The major attrition test uses an air jet device. This apparatus measures the creation of 0-20-µm particles formed by particle-to-particle collisions in a high-velocity air jet. This measurement best represents the tendency of the catalyst to undergo attrition due to high jet velocities inside a fluid bed reactor.For quantification of the results of attrition tests, Grace Davison has specified the DI (Davison Index), which is measured using a jet-cup technique. In some tests, a small-scale plant which simulates the commercial plant is used. The amount of attrition measured in all these tests is very dependent on the exact procedure used. Reproducibility among laboratories is likely to be possible only if precise details of the method are given.In essence, the attrition test results are not scalable as a good indicator of unit retention performance. Attrition Resistance of Coated MonolithsWashcoated catalyst supports suffer from several disadvantages in use. In service, the supports are exposed to a flow of gases that often contain dusts or particulate matter, which can cause abrasion of the active layer. Adhesiveness of CoatingsApart from high dust exposure, a high surface area coating can flake off from the underlying ceramic or metallic support when the support is exposed to temperature cycles because the wash coat and the underlying ceramic material often have different thermal expansion coefficients.Several techniques have been developed by individual producers for testing the adhesiveness of a catalytic wash coat on a metallic or ceramic support. A simple example is to scratch with a specially designed tip of a needle at constant force on a plain part of a wash coat. The result should be a microscopically clear cut and no flake-off. A slightly more complicated test is the DIN EN ISO 2409 Cross Cutting, which also shows the adhesiveness of coatings on the carrier surface. The adhesiveness is determined by cutting in the varnish surface at a distance of 2 mm (1 mm in case of a layer less than 60 µm thick) in parallel lines down to the carrier surface and repeating this process after rotating the specimen by 90 • so that the cuts cross.The results are classified into different characteristic values (GT 0-5) by comparison with standard images of increasingly damaged coatings stating the adhesive loss on the test surface as a percentage. However, because the morphology of most of the monolith catalysts is characterized by a very fine fin structure, the cross cutting test needs to be performed on an equally treated separate plain model piece.Other methods such as those that are used in th...

show abstract

“…For the determination of hydrogen there are also a variety of nuclear physics methods [43]. Typical precisions of about C 0.001%, H 0.01%, N 0.01%, S 0.02% and O 0.01% are achieved.…”

Section: Elemental Analysismentioning

confidence: 99%

Bulk Chemical Composition

Albers¹

2008

Handbook of Heterogeneous Catalysis

View full text Add to dashboard Cite

show abstract

“…There are several different nuclear physics based techniques available to determine and profile hydrogen [4][5][6]. This range of techniques exist both because of the low Coloumb barrier generally favoring any light ion induced nuclear reaction with hydrogen, and because the control and determination of the hydrogen content of metals is one of the earliest and most pervasive problems in nuclear technology [7].…”

Section: Introductionmentioning

confidence: 99%

“…Among the various nuclear physical techniques available [4,5,8], NRRA by the 1 H( 15 N,αγ) 12 C resonance at 6.4 MeV is a preferred choice. This Email address: d.bemmerer@hzdr.de (Daniel Bemmerer) reaction combines high sensitivity (down to hydrogen concentrations of 10 18 cm −3 for bulk materials) with excellent depth resolution down to a few nm near surfaces [8].…”

Section: Introductionmentioning

confidence: 99%

Absolute hydrogen depth profiling using the resonant $^{1}$H($^{15}$N,$αγ$)$^{12}$C nuclear reaction

Reinhardt,

Akhmadaliev,

Bemmerer

et al. 2016

Preprint

View full text Add to dashboard Cite

Resonant nuclear reactions are a powerful tool for the determination of the amount and profile of hydrogen in thin layers of material. Usually, this tool requires the use of a standard of well-known composition. The present work, by contrast, deals with standard-less hydrogen depth profiling. This approach requires precise nuclear data, e.g. on the widely used 1 H( 15 N,αγ) 12 C reaction, resonant at 6.4 MeV 15 N beam energy.Here, the strongly anisotropic angular distribution of the emitted γ-rays from this resonance has been remeasured, resolving a previous discrepancy. Coefficients of (0.38±0.04) and (0.80±0.04) have been deduced for the second and fourth order Legendre polynomials, respectively. In addition, the resonance strength has been re-evaluated to (25.0±1.5) eV, 10% higher than previously reported. A simple working formula for the hydrogen concentration is given for cases with known γ-ray detection efficiency. Finally, the absolute approach is illustrated using two examples.

show abstract

“…Direct detection of the ubiquitous hydrogen by an electron beam has been an elusive goal. Indeed hydrogen concentrations are usually obtained using nuclear methods [3]. In this paper, we present a method that allows for the direct detection of hydrogen (and possibly other light elements) when present in large concentrations.…”

Section: Introductionmentioning

confidence: 99%

Detection of hydrogen by electron Rutherford backscattering

Vos

2002

Ultramicroscopy

View full text Add to dashboard Cite

A novel method for detection of hydrogen by an electron beam in extremely thin samples is described. Elastically scattered electrons impinging with 20-30 keV on a thin formvar film were detected at a scattering angle near 451: In these large momentum transfer elastic collisions a clear separation of the signal of hydrogen and heavier elements was found. By changing the momentum transfer we can verify that the hydrogen signal is not due to inelastic energy loss contributions. The width of the hydrogen elastic peak is much larger than the elastic peaks due to heavy elements (carbon and oxygen). The ratio of the hydrogen elastic peak and the main elastic peak is smaller than expected by 30-50% depending on the energy of the impinging electron. This could be due to electronic excitations directly coupled to the elastic collision. The stability of the formvar film under electron radiation was studied. A reduction in thickness of the film with increasing fluence, as well as the preferential depletion of hydrogen, was found. Possible improvements of the experimental configuration for this type of experiments are discussed. r

show abstract

Determination of hydrogen in materials

Cited by 6 publications

References 87 publications

Bulk Chemical Composition

Bulk Chemical Composition

Absolute hydrogen depth profiling using the resonant $^{1}$H($^{15}$N,$αγ$)$^{12}$C nuclear reaction

Detection of hydrogen by electron Rutherford backscattering

Contact Info

Product

Resources

About