The Oxidation of a Monophase Co-8.03 Wt% Cu Alloy at 700 to 1000 C

CORROSION ◽  
1981 ◽  
Vol 37 (11) ◽  
pp. 638-644 ◽  
Author(s):  
F. Viani ◽  
F. Gesmundo
Keyword(s):  
Rate Constant ◽  
Defect Structure ◽  
Copper Alloy ◽  
Copper Ions ◽  
Suitable Model ◽  
Detailed Calculation ◽  
Pure Cobalt ◽  
Copper Addition ◽  
Experimental Profile ◽  
Cu Alloy

Abstract The oxidation of a monophase cobalt-copper alloy at high temperature has been Studied to examine the effect of the copper addition to cobalt on the oxidation kinetics as well as on the scale morphology and composition. The rate law remains parabolic as for pure cobalt but the rate constant is higher at all temperatures. This result is interpreted as being due mainly to the doping of CoO by monovalent copper ions by means of a detailed calculation of the rate constant for the alloy making use of the experimental profile of the copper concentration in the scale and of a suitable model for the defect structure of cobalt oxide.

scholarly journals Antiparasitic Effect of Copper Alloy Surface on Cryptocaryon irritans in Aquaculture of Larimichthys crocea

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Fei Yin ◽  
Peibo Bao ◽  
Xiao Liu ◽  
Youbin Yu ◽  
Lei Wang ◽  
...  
Keyword(s):  
Copper Alloy ◽  
Copper Ions ◽  
Copper Alloys ◽  
Antimicrobial Properties ◽  
Alloy Surface ◽  
Larimichthys Crocea ◽  
Content Type ◽  
Cryptocaryon Irritans ◽  
Metal Levels

ABSTRACT Copper and alloys containing >60% copper by weight are antimicrobial. In aquaculture, copper alloys are used as part of corrosion-resistant cages or as part of copper coating. To test whether a copper alloy surface prevents the outbreak of parasitosis in the aquaculture of Larimichthys crocea, we covered the bottom of the aquaculture tank with sheets of copper alloy containing 74% to 78% copper, and we cultured L. crocea juveniles that had been artificially infected with the protozoan parasite Cryptocaryon irritans. Our results showed that these copper alloy sheets effectively blocked the infectious cycle of C. irritans within a 1-week period and significantly reduced the number of C. irritans trophonts and tomonts, thereby decreasing the mortality rate of L. crocea. In in vitro assays, the cytoplasmic membranes of protomonts disintegrated and the cytoplasm overflowed after just 5 minutes of contact with copper alloy surfaces. Although the same cytoplasmic membrane disintegration was not observed in tomonts, the tomonts completely lost their capacity for proliferation and eventually died following direct contact with copper alloy sheets for 1 h; this is likely because C. irritans tomonts took in >100 times more copper ions following contact with the copper alloy sheets than within the control aquaculture environment. Exposure to copper alloy sheets did not lead to excessive heavy metal levels in the aquacultured fish or in the culture seawater. IMPORTANCE Cryptocaryon irritans, a parasitic ciliate that penetrates the epithelium of the gills, skin, and fins of marine fish, causes acute suffocation and death in cultured fish within days of infection. Much of the existing research centers around the prevention of C. irritans infection, but no cure has been found. Studies demonstrate that copper has strong antimicrobial properties, and fish grown in copper-containing cages have lower rates of C. irritans infection, compared to those grown in other currently used aquaculture cages. In this study, we found that an alloy containing 74% to 78% copper by weight effectively killed C. irritans cells and prevented cryptocaryoniasis outbreaks within a 1-week period. These findings offer a new perspective on the prevention and control of cryptocaryoniasis.

Kinetics of reconstitution of apotyrosinase by copper

1990 ◽  
Vol 68 (2) ◽  
pp. 476-479
Author(s):  
Donald C. Wigfield ◽  
Douglas M. Goltz
Keyword(s):  
Rate Constant ◽  
Copper Concentration ◽  
Copper Ions ◽  
Copper Ion ◽  
Order Rate Constant ◽  
First Order ◽  
Order Rate ◽  
Pseudo First Order ◽  
Rate Limiting ◽  
Kinetics Of

The kinetics of the reconstitution reaction of apotyrosinase with copper (II) ions are reported. The reaction is pseudo first order with respect to apoenzyme and the values of these pseudo first order rate constants are reported as a function of copper (II) concentration. Two copper ions bind to apoenzyme, and if the second one is rate limiting, the kinetically relevant copper concentration is the copper originally added minus the amount used in binding the first copper ion to enzyme. This modified copper concentration is linearly related to the magnitude of the pseudo first order rate constant, up to a copper concentration of 1.25 × 10−4 M (10-fold excess), giving a second order rate constant of 7.67 × 102 ± 0.93 × 102 M−1∙s−1.Key words: apotyrosinase, copper, tyrosinase.

The Annealing Effect on Optical Properties of Silver Copper Alloy Films

2013 ◽  
Vol 320 ◽  
pp. 329-335
Author(s):  
Guang Yang ◽  
Ji Zhou
Keyword(s):  
Magnetron Sputtering ◽  
Copper Alloy ◽  
Annealing Temperature ◽  
Effective Medium Theory ◽  
Annealing Effect ◽  
Medium Theory ◽  
Alloy Films ◽  
Silver Copper ◽  
Cu Alloy ◽  
P Type

In this paper, the dielectric functions of Ag-30.3at.%Cu alloy films upon the annealing effect were investigated by variable angle spectroscopy ellipsometry (VASE). The silver copper alloy films were deposited onto p-type silicon (100) substrate by direct current (DC) magnetron sputtering. With the increase of annealing temperature from 100 °C to 300 °C, the image part of the permittivity for Ag-30.3at.%Cu is significantly decreased in the wavelength below ~500 nm. The structure and surface topography of the alloy films were characterized using high resolution scanning electron microscopy (HR-SEM) and X-ray diffraction (XRD). The effective medium theory (EMA) has been utilized for the treating of surface roughness. The dielectric functions can be manipulated by changing the annealing temperature. Key words: Dielectric functions; silver copper alloy films; magnetron sputtering

Equilibrium and Kinetic Studies on Removal of Binary Metal Ions Using Immobilized Saccharomyces cerevisiae

2014 ◽  
Vol 661 ◽  
pp. 39-44
Author(s):  
Nur Khalida Adibah Md Rodzi ◽  
Senusi Faraziehan ◽  
Alrozi Rasyidah
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metal Ions ◽  
Copper Ions ◽  
Binding Capacity ◽  
Kinetic Studies ◽  
Suitable Model ◽  
Zinc Ions ◽  
Copper And Zinc ◽  
Maximum Sorption ◽  
Pseudo Second Order

In this study, biosorption of copper and zinc ions on Baker’s yeast, Saccharomyces Cerevisiae was investigated. The data of batch experiments was used to perform equilibrium and kinetic studies. The experimental results were fitted well to the Langmuir and Freundlich model isotherms. According to the parameters of Langmuir isotherm, the maximum biosorption capacities of copper and zinc ions onto immobilized yeast were 5.408mg/g and 1.479mg/g at 293 Kfor the treated beads. Competitive biosorption of two metal ions was investigated in terms of maximum sorption quantity. The binding capacity for copper ions is more than the zinc ions for both untreated and treated immobilized yeast.While, for the kinetic studies, the pseudo second order model was found the most suitable model for the present systems.

Highly efficient catalytic oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid with bimetallic Pt-Cu alloy nanoparticles catalyst

2022 ◽  
Author(s):  
Xiaomeng Cheng ◽  
Shaopeng Li ◽  
Shulin Liu ◽  
Xin Yu ◽  
Junjuan Yang ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Copper Alloy ◽  
Active Catalyst ◽  
Alloy Nanoparticles ◽  
Turnover Frequency ◽  
High Turnover ◽  
Highly Efficient ◽  
Highly Active ◽  
Cu Alloy ◽  
Furandicarboxylic Acid

Bimetallic platinum-copper alloy nanoparticles is a highly active catalyst for the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) under base-free conditions, with a high turnover frequency up to 135...

INFLUENCE OF DEFECT STRUCTURE ON CATALYTIC ACTIVITY OF NANOMETRIC MATERIALS BASED ON CERIA-DOPED COPPER

2011 ◽  
Vol 04 (02) ◽  
pp. 165-169 ◽  
Author(s):  
MAŁGORZATA M. ZAITZ ◽  
MARCIN MOLENDA ◽  
LUCJAN CHMIELARZ ◽  
ZOFIA PIWOWARSKA ◽  
BARBARA DUDEK ◽  
...  
Keyword(s):  
Defect Structure ◽  
Copper Content ◽  
Copper Ions ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
Conductivity Measurements ◽  
Icp Oes ◽  
Evolved Gas ◽  
Bet Analysis ◽  
Morphology And Structure

A series of nanometric materials based on copper-doped cerium (IV) oxide was synthesized using a reverse (w/o) microemulsion method. The obtained powder precursors were tested by the thermal analysis methods coupled with evolved gas analysis (EGA-TGA/DTG/SDTA). Morphology and structure of the samples were characterized by XRD and BET analysis. The content of copper ions was determined using a ICP-OES spectrometer. The electronic structure of the catalysts was characterized by high-temperature electrical conductivity measurements at different pO 2. The obtained materials were tested in catalytic incineration of the selected VOCs (methanol and ethylene). The correlation between the activity of the catalysts and copper content as well as electrical properties has been confirmed.

scholarly journals Kinetic Modeling of Flocculation and Coalescence in the System Emulsion of Water-Xylene-Terbutyl Oleyl Glycosides

2019 ◽  
Vol 14 (1) ◽  
pp. 60 ◽  
Author(s):  
Harsa Pawignya ◽  
Tutuk Djoko Kusworo ◽  
Bambang Pramudono
Keyword(s):  
Rate Constant ◽  
Kinetic Modeling ◽  
Suitable Model ◽  
Emulsion System ◽  
Flocculation Mechanism ◽  
Emulsion Droplets ◽  
Coalescence Rate ◽  
Emulsion Systems ◽  
The Stability ◽  
Kinetics Of

The development of a mathematical model for explaining the kinetics of flocculation and coalescence of emulsion droplets is essential to study the stability of an emulsion system of the kinetics of emulsion stability. Mathematic models was developed from the equation Van Den Tempel by modifying emulsion systems. The emulsion was made by mixing water-xylene and surfactant tert-butyl oleyl glycosides. This research studied the effect of stirrer speed on the value of flocculation rate constant (a) and coalescence rate constant (K). The model identified the emulsion development condition whether controlled by coalescence or flocculation. It was observed that under lower agitation speed (1000 rpm) the emulsion development was controlled by flocculation mechanism, while a faster agitation (2000 rpm or higher) exhibited coalescence controlled mechanism. The results confirmed that the 1st model was the most appropriate for water-xylene-TBOG emulsion system. From four models after fitting with experimental data, the most suitable model is 4th model, because it has the smallest error of 2.22 %. Copyright © 2019 BCREC Group. All rights reservedReceived: 2nd May 2018 ; Revised: 17th September 2018 ; Accepted: 18th September 2018; Available online: 25th January 2019; Published regularly: April 2019How to Cite: Pawignya, H., Kusworo, T.D., Pramudono, P. (2019). Kinetic Modeling of Flocculation and Coalescence in the System Emulsion of Water-Xylene-Terbutyl Oleyl Glycosides. Bulletin of Chemical Reaction Engineering & Catalysis, 14 (1): 60-68 (doi:10.9767/bcrec.14.1.2594.60-68)Permalink/DOI: https://doi.org/10.9767/bcrec.14.1.2594.60-68 

On the Defect Structure and Transport Properties of Co3O4 Spinel Oxide

2012 ◽  
Vol 31 (4-5) ◽  
pp. 371-379 ◽  
Author(s):  
A. Kaczmarska ◽  
Z. Grzesik ◽  
S. Mrowec
Keyword(s):  
Transport Properties ◽  
Rate Constant ◽  
Oxygen Pressure ◽  
Defect Structure ◽  
Pressure Range ◽  
High Pressures ◽  
Parabolic Rate Constant ◽  
Cation Sublattice ◽  
Low Oxygen ◽  
Parabolic Rate

AbstractDefect structure and transport properties of Co3O4 cobalt oxide have been studied as a function of temperature and oxygen pressure, using marker and thermogravimetric techniques. It has been found that the oxidation of CoO to form Co3O4 follows parabolic kinetic, being thus diffusion controlled. Marker experiments have demonstrated that cation sublattice of Co3O4 oxide is predominantly disordered, but the defect structure is rather complex. At very low oxygen pressures, close to the dissociation pressure of the oxide, interstitial cations are the predominant point defects, while at high pressures cation vacancies predominate. This behavior is reflected in complex dependence of the parabolic rate constant of CoO oxidation on oxygen pressure. At low pressures, namely, parabolic rate constant of the reaction increases with oxygen pressure, reaching then virtually constant value in intermediate pressure range and increases again in highest pressure range. Theoretical analysis of kinetic results in terms of point defect thermodynamics confirmed the above conclusion, concerning complex defect structure of Co3±yO4 oxide. Finally, self-diffusion coefficient of cations in the discussed oxide has been calculated as a function of temperature and oxygen pressure from kinetic rate measurements, using Wagner's theory of metals oxidation.

Microdiffraction, EDS, and HREM Investigation for Phase Identification With the Electron Microscope

1999 ◽  
Vol 589 ◽  
Author(s):  
P. Ruterana ◽  
A. Redjaïmia
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Copper Alloy ◽  
Phase Identification ◽  
Cu Alloy ◽  
Heat Treated ◽  
Duplex Steel ◽  
Aluminium Copper ◽  
Ideal Method ◽  
The Ideal

AbstractAbstract: For micro or nanophase identification, the ideal method is electron microscopy which combines experimental technique and theoretical analysis in order to solve the problem which is typical in non homogeneous materials. In this work, two heterogeneous materials have been investigated: a Fe- 22Cr - 5Ni -0.3Mo - 0.03C (wt%) duplex stainless steel and a 6H-SiC reinforced Al-Cu alloy fabricated by the Ospray technique followed by extrusion and aging. This aging often gives rise to the precipitation of intermetallic compounds some of which can be new phases. Using microdiffraction, EDS and HREM, it was possible to identify two new phases: the orhorhombic τ phase in the heat treated duplex steel and the tetragonal Al7Cu3Zr2 in the reinforced aluminium copper alloy

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