KINETICS OF THE OXIDATION OF TITANIUM

1950 ◽  
Vol 28b (2) ◽  
pp. 60-72 ◽  
Author(s):  
L. M. Pidgeon ◽  
W. A. Alexander
Keyword(s):  
Low Temperatures ◽  
Oxidation Process ◽  
Film Formation ◽  
Surface Film ◽  
Diffusion Constant ◽  
Initial Oxidation ◽  
Temperature Range ◽  
Logarithmic Equation ◽  
Kinetics Of ◽  
And Diffusion

The rates of oxidation of titanium powder and sintered bar have been investigated in the temperature range 25° to 550 °C. at pressures of 2 and 20 cm. oxygen maintained constant throughout each experiment. It has been shown that the oxidation process can be divided into two mechanisms, viz., the formation of a thin surface film and diffusion of oxide into the metal. The surface film formation at low temperatures follows the logarithmic equation:[Formula: see text]on vacuum annealed metal surface. The diffusion process at higher temperatures is described by the equation:[Formula: see text]after the initial oxidation. This equation leads to preliminary values of the diffusion constant of the order of 10 × 10−8 cm2. per min. in the temperature range 463° to 565 °C.

Fast kinetics of Mg2+/Li+ hybrid ions in a polyanion Li3V2(PO4)3 cathode in a wide temperature range

2019 ◽  
Vol 7 (16) ◽  
pp. 9968-9976 ◽  
Author(s):  
Muhammad Rashad ◽  
Hongzhang Zhang ◽  
Xianfeng Li ◽  
Huamin Zhang
Keyword(s):  
Wide Temperature Range ◽  
Low Temperatures ◽  
Room Temperature ◽  
Excellent Performance ◽  
Fast Kinetics ◽  
Temperature Range ◽  
Kinetics Of

A Li3V2(PO4)3 based Mg2+/Li+ hybrid battery with excellent performance both at room temperature and low temperatures (0, −10, −20, −30, and −40 °C) is presented.

Accumulation and diffusion of charges in kinetics of polymer electric breakdown

2021 ◽  
Author(s):  
I. K. Aliyeva ◽  
T. M. Veliyev
Keyword(s):  
Activation Energy ◽  
Low Temperatures ◽  
Opposite Sign ◽  
Constant Electric Field ◽  
Strength Properties ◽  
Mean Value ◽  
Time Interval ◽  
Kinetics Of ◽  
And Diffusion ◽  
Mean Value Formula

In this paper, the distribution in electric durability [Formula: see text] of polymers in constant electric field at low temperatures has been measured. The results of continuous experiments and experiments of field discontinuous effect on polymer samples being remained not disruptive after exposure for time equal to mean value [Formula: see text] have been compared. During the interval, we have varied the time interval, temperature [Formula: see text] and electric intensity of opposite sign [Formula: see text] according to which various degree of regeneration of polymer electric strength properties has been observed. By the degree of regeneration, relaxation time [Formula: see text] of the accumulated charges in polymers causing breakdown has been found. It is established that the process of charge diffusion, which accumulation leads to breakdown has a thermofluctuation behavior and the activation energy of given process depends on the counter field intensity magnitude.

The time dependence of scintillation intensity in aromatic materials

1966 ◽  
Vol 289 (1418) ◽  
pp. 424-439 ◽  
Keyword(s):  
Theoretical Model ◽  
Ionizing Radiation ◽  
Triplet State ◽  
Diffusion Length ◽  
Diffusion Constant ◽  
Delayed Luminescence ◽  
Singlet States ◽  
State Diffusion ◽  
Kinetics Of ◽  
And Diffusion

A description is given of the kinetics of the prompt and delayed luminescence components from aromatic materials excited by ionizing radiation. A theoretical model has been developed to describe the origin of the delayed scintillation component. From initial assumptions of molecular triplet state diffusion and triplet-triplet annihilation to form delayed singlet states, equations are obtained defining the intensity of the delayed component with time. These equations are shown to agree well with existing experimental results. From the comparison the following parameters for triplet excitations in anthracene and stilbene crystals have been calculated: diffusion constant, 6 x 10 -6 cm 2 s -1 (anthracene) and 3 x 10 -6 cm 2 s -1 (stilbene); triplet-triplet interaction rate constant, 1·3 x 10 -11 cm 3 s -1 (anthracene) and 7·5 x 10 -12 cm 3 s -1 (stilbene); and diffusion length, 3·5 x 10 -4 cm (anthracene).

In-Situ Chronoamperometry for CMP Slurry Investigations

2005 ◽  
Vol 867 ◽  
Author(s):  
Jian Zhang ◽  
Steven Grumbine ◽  
Phillip W. Carter ◽  
Thomas Werts
Keyword(s):  
Film Formation ◽  
Surface Film ◽  
Surface Reactivity ◽  
Current Response ◽  
Applied Potential ◽  
Exponential Equation ◽  
Kinetics Of ◽  
Fitting Parameters ◽  
Slurry Characterization

AbstractA new application of the electrochemical method, in situ chronoamperometry, has been developed and used as a tool for CMP slurry characterization. The measured current response, i, resulting from a small applied potential is fit to an exponential equation, i = io + A1exp(-t/tD). The fitting parameters serve as a measure of surface reactivity (io), surface film robustness (A1), and the kinetics of film formation (tD). A description of the method and correlations to polishing performance are discussed in this paper.

Diffusion of Non-Gaseous Fission Products in UO2 Single Crystals II

1965 ◽  
Vol 20 (5) ◽  
pp. 673-675 ◽  
Author(s):  
Noboru Oi ◽  
Jinzaburo Takagi
Keyword(s):  
Diffusion Process ◽  
Single Crystals ◽  
Process Analysis ◽  
Diffusion Constant ◽  
Fission Products ◽  
Post Irradiation ◽  
Temperature Range ◽  
Gaseous Fission ◽  
Kinetics Of

The release of short-lived non-gaseous fission products from UO2 single crystals was studied in the temperature range of 1400 —2500°C by means of post-irradiation annealing. The release of the fission products studied appears to follow the kinetics of a diffusion process. Analysis of the data obtained gives the following diffusion constant,DΜο = 3.9 × 10-4 exp(-54,000/RT), DI = 1.5 x 10-3 exp(-59,000/RT), DTe = 6.6 × 10-3 exp(— 70,000/RT), DLa (tentative) =2.2 x 10-6 exp (— 35,000/RT)where the dimensions of D and RT are cm2/sec and cal/mol, respectively.

Study on the oxidation process of cobalt hydroxide to cobalt oxides at low temperatures

RSC Advances ◽  
2016 ◽  
Vol 6 (83) ◽  
pp. 80059-80064 ◽  
Author(s):  
Zhifang Huang ◽  
Yan Zhao ◽  
Yuehong Song ◽  
Yawen Li ◽  
Gongjuan Wu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Low Temperatures ◽  
Oxidation Process ◽  
Transformation Process ◽  
Cobalt Hydroxide ◽  
Cobalt Oxides ◽  
Temperature Range

The transformation process of cobalt hydroxide (Co(OH)2) to cobalt oxides (Co3O4/CoOOH) in aqueous solution was studied in the temperature range of 50–90 °C.

Study on Initial Oxidation Film Formation Mechanism of T23 Steel at 600°C

2013 ◽  
Vol 690-693 ◽  
pp. 252-255
Author(s):  
Wei Wang ◽  
Zhi Wu Wang ◽  
Wan Li Zhong ◽  
Tao Song ◽  
Wei Wei
Keyword(s):  
Formation Mechanism ◽  
Oxidation Process ◽  
Film Formation ◽  
Film Structure ◽  
Initial Oxidation ◽  
Rich Phase ◽  
Initial Formation ◽  
Film Layer ◽  
Double Oxidation ◽  
Film Formation Mechanism

Using scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS), the morphology observations and composition analtyses of a T23 steel oxidized in water vapor for 10~150min at 600°C were investigated, to study the initial formation mechanism. The result showed that the initial oxidation film was changed from acicular to flake shape. The second oxidation film layer appeared after oxidation for 40 min, and obvious double oxidation film structure was formed after 150 min with inner Cr-rich protective isometric crystal and outer Fe primarily columnar crystal.The oxide was Fe-rich phase in the whole oxidation process.

scholarly journals The kinetics of the oxidation of copper. Part I. -The initial oxidation of copper at low pressures

1930 ◽  
Vol 128 (808) ◽  
pp. 394-406 ◽  
Keyword(s):  
Oxide Layer ◽  
Oxidation Process ◽  
Protective Action ◽  
Low Temperature Oxidation ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
First Case ◽  
The Subject ◽  
Low Pressures ◽  
Kinetics Of

The oxidation of copper has been the subject of several investigations. It was first treated quantitatively by Pilling and Bedworth in their study of the oxidation of metals. They showed that metals, in so far as the kinetics of their oxidation is concerned, may be divided into two classes, according as the oxide occupies a greater or less volume than that of the metal from which it is formed. In the first case it is clear that the oxide will protect the remaining unoxidised metal from attack, while in the second, owing to the necessarily porous nature of the oxide no such protective action can arise. Copper belongs to the first group. Pilling and Bedworth pointed out that when the oxide protects the metal, as soon as a complete oxide layer is formed, the factor controlling the rate of oxidation is the rate of diffusion of oxygen through the oxide. If now it is assumed that the rate of diffusion is inversely proportional to the thickness of the oxide layer, then we may write dx / dt = k / x , (1) where x is the weight of oxide formed at time t and k a constant. Integrating we obtain x 2 = kt . This equation was found to describe the rate of oxidation of metals belonging to the first group accurately. Copper, however, provided an exception; for, although the increase of volume accompanying oxidation is in the ratio of 1 to 1•67, it was only at high temperatures that the oxidation process followed equation (2). At lower temperatures the rate of oxidation varied in a capricious manner with time. This was attributed to the cracking of the oxide film. More recently, Dunn has reinvestigated the low temperature oxidation of copper. He finds that between 200° and 300°C. the oxidation of commercial copper follows (2) over short ranges of time. The behaviour of copper activated by oxidation and reduction was, however, anomalous. The results could not be expressed by (2) even over the shortest ranges of time.

Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

2020 ◽  
pp. 66-73
Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Molecular Mobility ◽  
Fe3o4 Nanoparticles ◽  
Low Temperatures ◽  
Frost Resistance ◽  
Relaxation Processes ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

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