Kinetics of High-Temperature Oxidation of Molybdenum by Dissociated Oxygen

Rosner, Daniel E.; Allendorf, H. D.

doi:10.1063/1.1725022

Cited by 28 publications

(16 citation statements)

References 8 publications

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“…The techniques and equipment used here are similar to those developed in connection with our previous 1 The present work considerably extends (from 1500 ~ to 2600~ the preliminary results for molybdenum reported by the authors in (6) and presents for the first time the corresponding oxidation behavior for tungsten and some observations on one industrially important alloy of molybdenum (TZM). Extensive results for the reaction order in 02 are also presented here, Most of the experiments were carried out with the pressure level at the specimen location maintained at 1 Torr (1.316 x 10 -3 atm) and the flow rate maintained at 21.7 cc (STP)/sec.…”

Section: Methodssupporting

confidence: 73%

“…For example, if (as is often done) an author has assumed that molybdenum trioxide is the major reaction product, then e (as defined here) would be larger than the reported fraction os O. the Hertz-Knudsen equation evaluated at the filament surface temperature i0 T Pi. (6), summarizes our data on the temperature dependence of for high-temperature molybdenum subjected to O or O2 attack at comparable partial pressures. It should be noted that if Z"(Mo) is experimentally found to be proportional to the n TM power of the oxygen partial pressure, where n is the reaction order, the probability e reported herein will be proportional to the n --1 power of oxygen partial pressure (and, hence, independent of the latter when the reaction is truly first order, i.e., n ~ 1).…”

Section: Results--molybdenum/oxygen Systemmentioning

confidence: 94%

“…In our previous work (6)(7)(8)(9) and in the present case, this may be done without any assumptions as to the product gas species distribution 9 by introducing the oxidation probability ~, defined here as the ratio of the flux of molybdenum atoms (regardless of their chemical state of aggregation) away from the surface to the collision flux of O(g) or O2(g) with the surface. In our previous work (6)(7)(8)(9) and in the present case, this may be done without any assumptions as to the product gas species distribution 9 by introducing the oxidation probability ~, defined here as the ratio of the flux of molybdenum atoms (regardless of their chemical state of aggregation) away from the surface to the collision flux of O(g) or O2(g) with the surface.…”

Section: Results--molybdenum/oxygen Systemmentioning

confidence: 99%

“…3), thereby providing a check on a portion of the present methods and, incidentally, demonstrating that the results of ref. 6 Atom detection.--Basic to the inference of reaction probabilities is the determination of absolute atom concentrations in the gas mixture emerging from the microwave discharge cavity. 6 Atom detection.--Basic to the inference of reaction probabilities is the determination of absolute atom concentrations in the gas mixture emerging from the microwave discharge cavity.…”

Section: Methodsmentioning

confidence: 99%

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Kinetics of the Attack of High-Temperature Molybdenum and Tungsten by Atomic Oxygen

Rosner¹,

Aliendorf²

1967

J. Electrochem. Soc.

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Using microwave discharge, fast-flow system techniques coupled with resistance heating and monitoring of the reacting specimens, the true kinetics of metal atom removal for polycrystalline molybdenum and tungsten filaments attacked by atomic oxygen have been obtained in the nominal temperature range 1000~176 at oxygen atom pressures in the range 10 -3 to 5 x 10 -2 Torr. Under these conditions the oxides of molybdenum and tungsten essentially volatilize as rapidly as they are formed, leaving the metal surface vulnerable to direct oxygen atom attack at constant (time independent) rates. Reaction probabilities are found to be up to 140 times those for O.~ attacking the same surface, are independent of O-atom partial pressure, and exhibit a much weaker temperature dependence than those for 02. These observations are in accord with a Rideal-type mechanism in which O atoms from the gas phase strike chemisorbed oxygen, leading either to product formation and desorption, or surface-catalyzed oxygen atom recombination. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.81.226.78 Downloaded on 2014-10-07 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.81.226.78 Downloaded on 2014-10-07 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 129.81.226.78ABSTRACT Part of the phase diagram of the system Mn-O was determined in the temperature range 1100~176 and the range of oxygen partial pressure

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Section: Methodssupporting

confidence: 73%

Section: Results--molybdenum/oxygen Systemmentioning

confidence: 94%

Section: Results--molybdenum/oxygen Systemmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Kinetics of the Attack of High-Temperature Molybdenum and Tungsten by Atomic Oxygen

Rosner¹,

Aliendorf²

1967

J. Electrochem. Soc.

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“…Indeed, these observations are consistent with the report of two orders of magnitude increase of oxidation rate in atomic oxygen relative to the rate in molecular oxygen during molybdenum oxidation. 18 Clearly under the conditions in our study, the supply of oxygen atoms to the oxide surface is not the ratelimiting step.…”

Section: Effect Of Substrate Bias In Marker Studiesmentioning

confidence: 98%

Transport Considerations in the Plasma-Assisted Oxidation of Copper Films

Hess

2004

J. Electrochem. Soc.

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The oxidation of copper films in a helical resonator oxygen discharge was performed over the temperature range of 150 to 300°C. Significant increases in the oxidation rate relative to thermal oxidation are observed. Oxidation rates followed a parabolic rate expression, with a rate constant of 6.74 ϫ 10 3 nm 2 /min at 250°C, and an effective activation energy over the temperature range studied of 0.58 eV. Marker experiments using either gold or molybdenum as the marker layer indicated that both oxygen and copper species transported during oxidation. The location of the copper/copper-oxide interface relative to the marker position demonstrated that copper is the primary transporting species responsible for oxidation, analogous to results reported for the thermal oxidation of copper at higher temperatures.

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Refractory metals and nickel in high temperature chlorine‐containing environments ‐ thermodynamic prediction of volatile corrosion products and surface reaction mechanisms: a review

Galetz

Rammer

Schütze

2015

Materials & Corrosion

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Thermodynamic calculations are an important tool for prediction of chemical reactions. In many cases the results help to understand and describe the experimental observations. In others, especially if reaction kinetics play a major role, their predictive value can be rather limited and the projected results have to be treated with care. One such case are high temperature chlorine corrosion conditions. For example, thermodynamically a similar corrosion behavior of nickel and molybdenum is predicted in chlorine‐containing atmospheres at low oxygen partial pressures. In contrast to their calculated similarity, experimental results showed much higher resistance of molybdenum against the chlorinating attack. Above 800 °C nickel is rapidly consumed, whereas molybdenum remains almost inert. This paper reviews the literature on the corrosion mechanisms and kinetics of nickel and molybdenum in chlorine‐containing environments as well as in mixed oxygen‐chlorine‐containing atmospheres. Based on the literature review, differences in their reaction kinetics are discussed, taking into account the deviation from an ideal thermodynamic correlation between the partial pressure and the reaction kinetics via the often used Hertz‐Langmuir equation. Finally it is shown that the findings concerning the special characteristics of molybdenum and nickel and the conclusions drawn from experimental observations on high temperature chlorine corrosion can also be transferred to other metals.

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Kinetics of High-Temperature Oxidation of Molybdenum by Dissociated Oxygen

Cited by 28 publications

References 8 publications

Kinetics of the Attack of High-Temperature Molybdenum and Tungsten by Atomic Oxygen

Kinetics of the Attack of High-Temperature Molybdenum and Tungsten by Atomic Oxygen

Transport Considerations in the Plasma-Assisted Oxidation of Copper Films

Refractory metals and nickel in high temperature chlorine‐containing environments ‐ thermodynamic prediction of volatile corrosion products and surface reaction mechanisms: a review

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