Kinetics of the Fluorination of Iron

O'Donnell, Patricia M.

doi:10.1149/1.2426550

Cited by 9 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…June 15, 1970. This was Paper 408 presented at the Montreal Meeting of the Society, Oct. [6][7][8][9][10][11]1968. Any discussion of this paper will appear in a Discussion Section to be published in the June 1971 JOURNAL.…”

Section: Discussionmentioning

confidence: 99%

A Kinetic Study of the Fluorination of Silver

O'Donnell

1970

J. Electrochem. Soc.

View full text Add to dashboard Cite

IS. Supplementary Notes AbstractT h e kinetics of the reaction of fluorine with s i l v e r w e r e studied at t e m p e r a t u r e s f r o m 25' to 300' C (298 to 573 K ) and 50-t o 600-toor (6666-t o 79 993-N/m 2 ) fluorine p r e s s u r e . T h e reaction is p r e s s u r e dependent and can b e d e s c r i b e d by t h e equation yn = k r t + c. T h r e e products are identified: s i l v e r subfluoride, s i l v e r monofluoride, and s i l v e r difluoride. T h e calculated value of t h e diffusion constant is 0.10 c m 2 / s e c , and the activation energy f o r t h e diffusion p r o c e s s is 10 kcal/mole (41.8 kJ/mole).S i l v e r ion vacancy migration is proposed as t h e diffusion mechanism. Reaction-rate constants are l i s t e d . SUMMARYThe effect of the variables temperature and p r e s s u r e on the kinetics of the reaction of fluorine gas with silver w a s studied. The temperature range studied w a s 25' to 300' C (298 to 573 K ) at total fluorine p r e s s u r e s of 50 to 600 t o r r (6666 to 79 993 N/cm 2 ).The reaction was followed by the pressure-drop method and was found to b e p r e s s u r e de pendent. The applicable rate law was yn = krt + c , w h e r e y is the amount of fluorine consumed per unit area of silver surface, k r is the reaction-rate constant, t is the time in minutes, and c is a constant. The value of n w a s 1 during the initial course of the reaction, indicating a boundary controlled process. At a l a t e r time, the process be c a m e diffusion controlled, w h e r e the value of n w a s 2. The reaction is complex due to the formation of three products: s i l v e r subfluoride, s i l v e r monofluoride, and s i l v e r di fluoride. Rate constants are calculated, and activation energies are given. The reac tion appears to be cation diffusion controlled, and the diffusion through the barrier layer is by a vacancy mechanism. The calculated value of the diffusion constant is 0.10 centi m e t e r squared p e r second, and the activation energy for the diffusion is 10 kilocalories p e r mole (41.8 kJ/mole).

show abstract

Section: Discussionmentioning

confidence: 99%

A Kinetic Study of the Fluorination of Silver

O'Donnell

1970

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…30 Previously, surface fluorination of stainless steel leading to iron fluoride (FeF 3 ) formation by use of perfluoropolyether (PFPE)-based lubricants was reported by NASA in 1989 but the detailed reaction mechanism has not been investigated. 31,32 Similar to other perfluorinated compounds, PFPEs are low molecular weight, fluorinated oligomers that are chemically inert, thermally stable, and resistant to degradation under a wide range of conditions because of strong CF bonds, which arise from the small covalent radius size and the high electronegativity of the fluorine atom. Because they are nonvolatile and their viscosities are nearly temperature independent, PFPEs have been commonly used as surface lubricants in severe environments such as in magnetic recording material, automotive applications, aerospace engines, satellite instruments, and machining.…”

Section: ■ Introductionmentioning

confidence: 99%

Lithium Insertion Mechanism in Iron Fluoride Nanoparticles Prepared by Catalytic Decomposition of Fluoropolymer

Vijayakumar

Cho

Govind

et al. 2019

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

Metal fluorides with high redox potential and capacity from strong metal–fluoride bond and conversion reaction make them promising cathodic materials. However, detailed lithium insertion and extraction mechanisms have not yet been clearly understood and explained. Here we report low-temperature synthesis of electrochemically active FeF3/FeF2 nanoparticles by catalytic decomposition of a fluoropolymer [perfluoropolyether (PFPE)] using a hydrated iron oxalate precursor both in air and in inert atmosphere. Freshly synthesized FeF3 nanoparticle delivered specific capacity above 210 mAh/g with decent cycling performance as a Li-ion battery cathode. Both in situ and ex situ characterization techniques were used to investigate the detailed PFPE decomposition and fluorination mechanisms leading to FeF3/FeF2 formation as well as the lithium insertion mechanism in a FeF3 cathode. Specifically, a detailed understanding was investigated using thermogravimetry–mass spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, nuclear magnetic resonance, transmission electron microscopy, scanning electron microscopy/energy dispersive spectroscopy, and X-ray absorption near-edge structure. The novel synthesis route developed not only offers access to electrochemically active metal fluorides but also offers a catalytic approach for decomposing highly inert fluoropolymers for environmental protection.

show abstract

“…Beim AufreiRen der Deckschicht heilt diese sofort aus [14]. Kurzzeitversuche zur Beurteilung des Korrosionsverhaltens von Eisen in Fluor sind unbrauchbar [15]. [20].…”

unclassified

Gegen Fluor und Fluorwasserstoff korrosionsbeständige Werkstoffe

Hauffe¹

1984

Materialwissenschaft Werkst

View full text Add to dashboard Cite

Unter den Metallen sind Aluminium und Duralumin gegen Fluor und trockenen Fluorwasserstoff bis 600 bzw. 700 K beständig. Die Beständigkeit von Nickel und seiner Legierungen, insbesondere Monel, gegen Fluor und Fluorwasserstoff reicht sogar bis etwa 900 bzw. 800 K. Beim Angriff von Fluor auf Nickel‐Chromlegierungen zwischen 1000 und 1300 K tritt auch eine innere Fluorierung ähnlich der inneren Oxidschichtbildung auf. Die Beständigkeit von Titan in wasserfreiem flüssigem Fluor ist bei niedrigen Temperaturen mit < 0,3 mm · a−1 vergleichbar mit der von Nickel und Monel. In gasförmigem Fluor aber beträgt die Korrosion von Titan bei 377 K nur 0,0082 mm · a−1. Trotz ihrer bedingten Beständigkeit gegen Fluor und Fluorwasserstoff werden reinstes Molybdän und Wolfram wegen ihrer Festigkeit bei hohen Temperaturen in der Raketentechnik beim Antrieb mit Fluor‐Wasserstoff bzw. Fluor‐Hydrazin eingesetzt. Lanthan‐ und Calciumboride widerstehen Fluor‐Hydrazinflammen zwischen 1400 und 1800 K und sind allen Speziallegierungen weit überlegen. Dieses gilt auch im niedrigeren Temperaturbereich (290–400 K) für die Fluorcarbonharze. Organische Werkstoffe verdrängen immer mehr metallische und nichtmetallische anorganische Werkstoffe.

show abstract

Kinetics of the Fluorination of Iron

Cited by 9 publications

References 6 publications

A Kinetic Study of the Fluorination of Silver

A Kinetic Study of the Fluorination of Silver

Lithium Insertion Mechanism in Iron Fluoride Nanoparticles Prepared by Catalytic Decomposition of Fluoropolymer

Gegen Fluor und Fluorwasserstoff korrosionsbeständige Werkstoffe

Contact Info

Product

Resources

About