Corrosion of Copper in 1 M NaCl under Strictly Anoxic Conditions

2003 ◽  
Vol 807 ◽  
Author(s):  
Martin Bojinov ◽  
Timo Laitinen ◽  
Kari Mäkelä ◽  
Margit Snellman ◽  
Lars Werme
Keyword(s):  
Weight Loss ◽  
Closed System ◽  
Room Temperature ◽  
Corrosion Potential ◽  
Native Oxide ◽  
Anoxic Conditions ◽  
Homogeneous Oxidation ◽  
On Line ◽  
Chemical Conditions ◽  
Line Resistance

ABSTRACTThe corrosion of copper in 1 M NaCl has been investigated at room temperature and at 80°C by an on-line resistance probe, solution analysis of dissolved copper and weight loss measurements. At room temperature, corrosion of the copper as indicated by an increase of the probe resistance has been detected during the first 60–80 h of exposure. After the corrosion potential has reached the immunity region of Cu, a decrease in the resistance of the sensor is observed, probably due to redeposition of Cu from the solution. It can be concluded that the corrosion of copper at room temperature virtually stops after 60–80 h due to the anoxic conditions established in the experiments. The similarity in the trends of the corrosion and redox potential during exposure seems to indicate that Cu(II) contained in the native oxide on Cu and/or formed by homogeneous oxidation of Cu(I) during the initial oxic period of exposure acts as a redox-agent determining the chemical conditions in the closed system.

Molybdates as Corrosion Inhibitors in the Presence of Chlorides

CORROSION ◽  
1976 ◽  
Vol 32 (7) ◽  
pp. 263-266 ◽  
Author(s):  
E. A. LIZLOVS
Keyword(s):  
Weight Loss ◽  
Corrosion Rate ◽  
Potentiodynamic Polarization ◽  
Room Temperature ◽  
Corrosion Inhibitors ◽  
Corrosion Potential ◽  
Chloride Content ◽  
Passive State ◽  
Chloride Sulfate ◽  
Polarization Studies

Abstract The effect of the molybdate ion (MoO4=) concentration on the corrosion inhibition of 1010 steel was investigated in aerated chloride/sulfate-containing solutions. The chloride content was 304 ppm Cl−, and the sulfate was 352 ppm SO4=. Weight loss measurements and electrochemical methods were employed for the investigation. The pH was controlled at 8.7. Weight loss measurements indicated that about 165 ppm of molybdate reduced the corrosion rate below 10 mg·dm−2/day at room temperature. At 160 F (71 C), about 50 ppm of molybdate reduced the corrosion rate to 4 to 5 mg·dm−2/day. The potentiodynamic polarization studies and the examination of corrosion potential and immersion time relationship disclosed that the molybdate ion acts as a passivating agent in the presence of oxygen. Passivity was also obtained under potentiodynamic polarization conditions in a nitrogenated solution. No passivation was obtained in the absence of the molybdate ion. For spontaneous passivation, both molybdate and oxygen (oxidizing agent) were needed. Corrosion rates in a passive state according to the polarization curve should be nil.

On the use of Ozawa/Flynn/Wall method to determine aging activation energy for elastomers

2021 ◽  
pp. 009524432110203
Author(s):  
Sudhir Bafna
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Weight Loss ◽  
Oxygen Consumption ◽  
Dwell Time ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Degradation Mechanism ◽  
Kinetics Of ◽  
Wall Method

It is often necessary to assess the effect of aging at room temperature over years/decades for hardware containing elastomeric components such as oring seals or shock isolators. In order to determine this effect, accelerated oven aging at elevated temperatures is pursued. When doing so, it is vital that the degradation mechanism still be representative of that prevalent at room temperature. This places an upper limit on the elevated oven temperature, which in turn, increases the dwell time in the oven. As a result, the oven dwell time can run into months, if not years, something that is not realistically feasible due to resource/schedule constraints in industry. Measuring activation energy (Ea) of elastomer aging by test methods such as tensile strength or elongation, compression set, modulus, oxygen consumption, etc. is expensive and time consuming. Use of kinetics of weight loss by ThermoGravimetric Analysis (TGA) using the Ozawa/Flynn/Wall method per ASTM E1641 is an attractive option (especially due to the availability of commercial instrumentation with software to make the required measurements and calculations) and is widely used. There is no fundamental scientific reason why the kinetics of weight loss at elevated temperatures should correlate to the kinetics of loss of mechanical properties over years/decades at room temperature. Ea obtained by high temperature weight loss is almost always significantly higher than that obtained by measurements of mechanical properties or oxygen consumption over extended periods at much lower temperatures. In this paper, data on five different elastomer types (butyl, nitrile, EPDM, polychloroprene and fluorocarbon) are presented to prove that point. Thus, use of Ea determined by weight loss by TGA tends to give unrealistically high values, which in turn, will lead to incorrectly high predictions of storage life at room temperature.

Off-Line Direct Deposition Gas Chromatography/Surface-Enhanced Raman Scattering and the Ramifications for On-Line Measurements

2005 ◽  
Vol 59 (11) ◽  
pp. 1305-1309 ◽  
Author(s):  
David A. Heaps ◽  
Peter R. Griffiths
Keyword(s):  
Gas Chromatography ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Room Temperature ◽  
Warm Up ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
On Line ◽  
Enhanced Raman Scattering ◽  
Moving Liquid

Surface-enhanced Raman spectra (SERS) of molecules separated by gas chromatography (GC) were measured off-line by condensing the analyte on a moving, liquid-nitrogen-cooled ZnSe window on which a 5 nm layer of silver had been formed by physical vapor deposition. After the components that eluted from the chromatograph had been deposited, the substrate was allowed to warm up to room temperature and transferred to the focus of a Raman microspectrometer where the spectrum of each component was measured. Band intensities in the spectrum of 3 ng of caffeine prepared in this way were approximately the same as in the spectrum of bulk caffeine. By making some logical assumptions, it was shown that identifiable GC/SERS spectra of 30 pg of many molecules could be measured over a 300 cm−1 region in real-time and that if an optimized substrate were used the minimum identifiable quantity could be reduced to 1 pg or less.

Synthesis, Characterization and Thermooxidative Properties of Hybrid Block Poly(silane-b-arylacetylene)

2014 ◽  
Vol 1004-1005 ◽  
pp. 527-532
Author(s):  
Ying Jie Xu ◽  
Hui Min Qi ◽  
Ya Ping Zhu ◽  
Fan Wang
Keyword(s):  
Weight Loss ◽  
Oxidative Stability ◽  
Lewis Acid ◽  
Grignard Reagent ◽  
Room Temperature ◽  
Condensation Polymerization ◽  
Thermooxidative Stability ◽  
Thermal Cure ◽  
Inorganic Hybrid ◽  
Thermal And Oxidative Stability

Organic-inorganic hybrid block Poly (silane-b-arylacetylene) (PSbA) have been synthesized through condensation polymerization between chloro-terminated polysilane and diethynylbenzene Grignard reagent, and chloro-terminated polysilane was synthesized through condensation polymerization of dichloromethylvinylsilane in the presence of Mg metal and Lewis acid (ZnCl2, LiCl). The structures of PSbAs were characterized by FTIR, 1H, 13C, 29Si NMR, and GPC. The PSbAs are orange viscous liquid and can be soluble in common organic solvents at room temperature. The thermal cure behavior of PSbAs was determined by DSC, and the thermal and oxidative stability of the cured PSbAs were investigated using TGA. The results showed that the cured PSbAs exhibit high thermal and thermooxidative stability. The degradation temperatures at 5% weight loss for the cured PSbAs are 470-533°C under N2 and 378-456°C under air, and the residue yields at 1000°C are 77.9-82.8% under N2 and 40.4-50.5% under air.

scholarly journals Dissolution of chromium in sulfuric acid

2002 ◽  
Vol 67 (11) ◽  
pp. 777-782 ◽  
Author(s):  
Dragutin Drazic ◽  
Jovan Popic
Keyword(s):  
Corrosion Rate ◽  
Room Temperature ◽  
Corrosion Potential ◽  
Analytical Data ◽  
Electrochemical Corrosion ◽  
Spectrophotometric Analysis ◽  
Weight Loss Method ◽  
Loss Method ◽  
Anomalous Dissolution

By combining electrochemical corrosion rate measurements and spectrophotometric analysis of the electrolyte it was shown that at room temperature chromium dissolves in deaerated 0.1M Na2SO4 + H2SO4 (pH1) solution as Cr(II) and Cr(III) ions in he ratio Cr(II):Cr(III)?7:1. This process was stable over 4h without any detectable change. The total corrosion rate of chromium calculated from the analytical data is about 12 times higher, than that determined electrochemically by cathodic Tafel line extrapolation to the corrosion potential. This finding was confirmed by applying the weight-loss method for the determination of the corrosion rate. This enormous difference between these experimentally determined corrosion rates can be explained by the rather fast, "anomalous" dissolution process proposed by Kolotyrkin and coworkers (chemical reaction of Cr with H2O molecules) occurring simultaneously with the electrochemical corrosion process.

scholarly journals Effective ?-radiation Dose on Chitosan for Preservation of Mangoes (Mangifera indica)

2013 ◽  
Vol 2 ◽  
pp. 35-40 ◽  
Author(s):  
Ashna Islam ◽  
Mahfuza Sharifa Sultana ◽  
Fahmida Parvin ◽  
Mubarak A Khan
Keyword(s):  
Weight Loss ◽  
Radiation Dose ◽  
Shelf Life ◽  
Effective Dose ◽  
Room Temperature ◽  
Color Change ◽  
Mangifera Indica ◽  
Chitosan Solution ◽  
Effective Radiation Dose ◽  
Effective Radiation

The effective dose of ? radiation on chitosan for mango preservation was studies in this work. The 2% chitosan solution was irradiated with at various total doses (50-200 kGy). The mature green mangoes were soaked in un-irradiated and irradiated chitosan solutions and then they were stored at normal room temperature. The percentage of weight loss, color change and percentage of spoilage were observed for 15 days in control, un-irradiated and irradiated chitosan coated mangoes. The overall results showed the superiority of 50 kGy and 100 kGy irradiated chitosan in extending shelf life of mango as comared to control, un-irradiated and 120 kGy to 200 kGy irradiated chitosan. Jahangirnagar University Environmental Bulletin, Vol.2, 35-40, 2013 DOI: http://dx.doi.org/10.3329/jueb.v2i0.16328

scholarly journals Biocontrol of Pear Postharvest Decay by Kombucha

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Junping TAN ◽  
Xian ZHOU ◽  
Shuiyuan CHENG ◽  
Zexiong CHEN ◽  
Yuanyuan GOU ◽  
...  
Keyword(s):  
Weight Loss ◽  
Electric Conductivity ◽  
Room Temperature ◽  
Loss Rate ◽  
Economic Benefits ◽  
Control Group ◽  
Pear Fruit ◽  
Weight Loss Rate ◽  
Post Harvest ◽  
Mda Content

Kombucha is sweetened, slightly alcoholic, and lightly effervescent tea drink. Its acidity inhibits the growth of harmful bacteria. Here, we studied effect of kombucha on post-harvest preservation of pear. The Hosui pears were soaked with the kombucha for 15 minutes, and in distilled water as the control, respectively. Superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), hydrogen peroxide (H2O2), proline content, electric conductivity, weight loss rate and good fruit rate in pear were measured during storage at room temperature. The results showed that the kombucha could effectively prolong the storage time of pear fruit. The fruit quality of the treated group was 1.5 times higher than that of the control pear fruit when stored at room temperature for 18 days. The weight loss rate, MDA content and electric conductivity of the treatment group were lower than those of the control group during the whole storage period, indicating that kombucha can inhibit the transformation of polysaccharides such as starch and pectin, and delay the degradation of nutrients in the fruit, resulting in a decrease in weight loss rate, inhibition of membrane lipid peroxidation, reducing MDA content, electric conductivity, maintaining cell membrane stability, delaying pear fruit senescence. Kombucha can inhibit the content of H2O2 and proline, increase the activity of POD and SOD increase the storage stability of fruits. The purpose of this study was to elucidate the physiological mechanism of post-harvest preservation of pear by kombucha. The use of kombucha can prolong the supply period of pear, increase economic benefits and expand the market of pear.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Zn-TiO2 and ZnNi-TiO2 Nanocomposite Coatings: Corrosion Behaviour

2010 ◽  
Vol 636-637 ◽  
pp. 1079-1083 ◽  
Author(s):  
Augusto Gomes ◽  
I. Almeida ◽  
Tania Frade ◽  
Ana C. Tavares
Keyword(s):  
Room Temperature ◽  
Corrosion Potential ◽  
Corrosion Behaviour ◽  
Pulse Method ◽  
Nanocomposite Coating ◽  
Nanocomposite Coatings ◽  
Tio2 Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Steel Electrodes

This work presents the corrosion behaviour of the as-prepared of Zn-TiO2 and ZnNi-TiO2 films in neutral Na2SO4 solution and a first attempt to correlate with their composition, morphology and structure. The films were prepared by galvanostatic pulse method onto steel electrodes, at room temperature. The X-ray diffraction study revealed that the ZnNi alloy consists of a homogenous Ni5Zn21 phase and that the preferred crystallographic orientation of Zn deposits changes in the presence of TiO2. The SEM results show that the morphology of the metallic coating is function of the metal phase composition and become more porous in the presence of 1.5 wt% TiO2.The corrosion parameters for the nanocomposite coatings were compared with those of pure Zn and ZnNi electrodeposits, and the ZnNi-TiO2 nanocomposite coating shows the less cathodic corrosion potential.

scholarly journals UAE Neem Extract as a Corrosion Inhibitor for Carbon Steel in HCl Solution

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Ayssar Nahlé ◽  
Ideisan Abu-Abdoun ◽  
Ibrahim Abdel-Rahman ◽  
Maysoon Al-Khayat
Keyword(s):  
Weight Loss ◽  
Carbon Steel ◽  
Adsorption Isotherm ◽  
Corrosion Inhibitor ◽  
Room Temperature ◽  
Tannin Content ◽  
Neem Extract ◽  
Neem Leaves ◽  
Temkin Adsorption Isotherm ◽  
Hcl Solution

The effect of aqueous extract of UAE Neem (Azadirachta Indica) on the corrosion inhibition of carbon steel in 1.0 M HCl solution was investigated electrochemically, and by weight-loss experiments at temperatures ranging from 303 to 343 K. The percentage inhibition increased with the increase of the concentration of the inhibitor. At a concentration of 2.0 g/L, the percentage inhibition reached about 87% at room temperature and 80% at 303 K. The percentage inhibition decreased with the increase of temperature. The thermodynamic parameters for the adsorption of this inhibitor on the metal surface were calculated using the Temkin adsorption isotherm. The aqueous Neem leaves extract was found to be an excellent potential corrosion inhibitor because of the high content of tannin content as well as the presence of a series of complex triterpene glycosides.

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