Recombination of oxygen atoms on the surface of oxidized polycrystalline nickel—temperature and pressure dependences

Paul, Domen; Zaplotnik, Rok; Ekar, Jernej; Vesel, Alenka; Primc, Gregor; Đonlagić, Denis

doi:10.1088/1361-6595/ace129

Cited by 2 publications

(2 citation statements)

References 44 publications

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“…Still, some recent studies reported that the atom loss coefficient for some materials decreases with increasing pressure [49][50][51]. The pressure dependence of the atom loss coefficient for oxygen atoms on nickel and cobalt was studied systematically previously, and the results were published recently [52,53]. Still, any differences between the effects of the mean free path and the pressure dependence of the atom loss coefficient are impossible to distinguish from the results summarized in table 4.…”

Section: Resultsmentioning

confidence: 96%

The penetration depth of atomic radicals in tubes with catalytic surface properties

PAUL,

MOZETIČ,

ZAPLOTNIK

et al. 2024

Plasma Sci. Technol.

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Catalysis of molecular radicals is often performed in interesting experimental configurations. One possible configuration is tubular geometry. The radicals are introduced into the tubes on one side, and stable molecules are exhausted on the other side. The penetration depth of radicals depends on numerous parameters, so it is not always feasible to calculate it. This article presents systematic measurements of the penetration depth of oxygen atoms along tubes made from nickel, cobalt, and copper. The source of O atoms was a surfatron-type microwave plasma. The initial density of O atoms depended on the gas flow and was 0.7, 2.4, and 4.2 〖∙10〗^21 m^(-3) at the flow rates of 50, 300, and 600 sccm, and pressure of 10, 35, and 60 Pa, respectively. The gas temperature remained at room temperature throughout the experiments. The dissociation fraction decreased exponentially along the length of the tubes in all cases. The penetration depths for well-oxidized nickel were 1.2, 1.7, and 2.4 cm, respectively. For cobalt, they were slightly lower at 1.0, 1.3, and 1.6 cm, respectively, while for copper, they were 1.1, 1.3, and 1.7 cm, respectively. The results were explained by gas dynamics and heterogeneous surface association. These data are useful in any attempt to estimate the loss of molecular fragments along tubes, which serve as catalysts for the association of various radicals to stable molecules.

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Section: Resultsmentioning

confidence: 96%

The penetration depth of atomic radicals in tubes with catalytic surface properties

PAUL,

MOZETIČ,

ZAPLOTNIK

et al. 2024

Plasma Sci. Technol.

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“…The accuracy of the method is about 20%. Details regarding this method are disclosed in our recent paper [35].…”

Section: Methodsmentioning

confidence: 99%

Loss of Oxygen Atoms on Well-Oxidized Cobalt by Heterogeneous Surface Recombination

Paul,

Mozetič,

Zaplotnik

et al. 2023

Materials

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Calorimetry is a commonly used method in plasma characterization, but the accuracy of the method is tied to the accuracy of the recombination coefficient, which in turn depends on a number of surface effects. Surface effects also govern the kinetics in advanced methods such as atomic layer oxidation of inorganic materials and functionalization of organic materials. The flux of the reactive oxygen atoms for the controlled oxidation of such materials depends on the recombination coefficient of materials placed into the reaction chamber, which in turn depends on the surface morphology, temperature, and pressure in the processing chamber. The recombination coefficient of a well-oxidized cobalt surface was studied systematically in a range of temperatures from 300 to 800 K and pressures from 40 to 200 Pa. The coefficient increased monotonously with decreasing pressure and increasing temperature. The lowest value was about 0.05, and the highest was about 0.30. These values were measured for cobalt foils previously oxidized with oxygen plasma at the temperature of 1300 K. The oxidation caused a rich morphology with an average roughness as deduced from atomic force images of 0.9 µm. The results were compared with literature data, and the discrepancy between results reported by different authors was explained by taking into account the peculiarities of their experimental conditions.

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Recombination of oxygen atoms on the surface of oxidized polycrystalline nickel—temperature and pressure dependences

Cited by 2 publications

References 44 publications

The penetration depth of atomic radicals in tubes with catalytic surface properties

The penetration depth of atomic radicals in tubes with catalytic surface properties

Loss of Oxygen Atoms on Well-Oxidized Cobalt by Heterogeneous Surface Recombination

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