Corrosion Behaviors of Mg-7Gd-5Y-1Nd-0.5Zr Alloys in CO2 Atmosphere under Different Relative Humidity

2014 ◽  
Vol 900 ◽  
pp. 39-42
Author(s):  
Quan Tong Jiang ◽  
Xing Gang Li ◽  
Yong Jun Li ◽  
Ming Long Ma ◽  
Guo Liang Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Relative Humidity ◽  
Influence Factors ◽  
Corrosion Morphology ◽  
Corrosion Rates ◽  
Corrosion Behaviors ◽  
Peak Aged ◽  
Residual Mechanical Properties ◽  
Loss Rates

The corrosion behaviors of peak-aged Mg-7Gd-5Y-1Nd-0.5Zr alloys in CO2atmosphere under different relative humidity were investigated by OM, SEM. The weight loss rates, corrosion morphology and residual mechanical properties were also analyzed. The corrosion rates of specimens in CO2atmosphere at 70% relative humidity were highest than others. Relevancy of the influence factors included relative humidity and concentration of CO2were researched. The results show that relative humidity and concentration of CO2in the environment both played an important role in corrosion behaviors.

Corrosion behaviors of X70 steel under direct current interference

2019 ◽  
Vol 66 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Jun Wang ◽  
Zili Li ◽  
Gan Cui ◽  
JianGuo Liu ◽  
Chuanping Kong ◽  
...  
Keyword(s):  
Weight Loss ◽  
Corrosion Rate ◽  
Soil Solution ◽  
Direct Current ◽  
Polarization Curves ◽  
Solution Ph ◽  
Corrosion Morphology ◽  
Content Type ◽  
Tafel Polarization ◽  
Corrosion Behaviors

Purpose The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution. Design/methodology/approach The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy. Findings The results showed that E-I polarization curves under 200-1,200 A/m2 interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution. Originality/value All tests were conducted at a relative higher DC density (200-1,200 A/m2). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.

Effect of CO2 Partial Pressure on CO2/H2S Corrosion of Oil Tube Steels

2014 ◽  
Vol 962-965 ◽  
pp. 407-410
Author(s):  
Ying Wang
Keyword(s):  
Corrosion Rate ◽  
Partial Pressure ◽  
Corrosion Morphology ◽  
Corrosion Tests ◽  
Corrosion Rates ◽  
Tube Steels ◽  
Corrosion Behaviors ◽  
Rate Calculation

The CO2/H2S corrosion behaviors of oil tube steels N80 and P110 at different CO2 partial pressure (45psi, 135psi, 225psi, 315psi) were investigated by corrosion tests, corrosion rate calculation and corrosion morphology observation. The results show that at different CO2 partial pressure, super-serious CO2/H2S corrosion occurs on steel N80 and steel P110. With the increase of CO2 partial pressure, the CO2/H2S corrosion rates of both steels increase gradually.

Effect of H2S Partial Pressure on CO2/H2S Corrosion of Oil Tube Steels

2011 ◽  
Vol 239-242 ◽  
pp. 3131-3134
Author(s):  
Ying Wang ◽  
Ping Li
Keyword(s):  
Corrosion Rate ◽  
Partial Pressure ◽  
Corrosion Morphology ◽  
Corrosion Tests ◽  
Corrosion Rates ◽  
Tube Steels ◽  
Corrosion Behaviors ◽  
Rate Calculation

The CO2/H2S corrosion behaviors of oil tube steels N80 and P110 at different H2S partial pressure (0.2psi, 3psi, 9psi, 18psi) were investigated by autoclave corrosion tests, corrosion rate calculation and corrosion morphology observation. The results show that with the increase of H2S partial pressure the CO2/H2S corrosion rates of both steels increase at first and then decrease after the peaks appear at 3psi H2S.

Effect of Temperature on CO2/H2S Corrosion of Oil Tube Steels

2014 ◽  
Vol 908 ◽  
pp. 111-114 ◽  
Author(s):  
Ying Wang
Keyword(s):  
Corrosion Rate ◽  
Effect Of Temperature ◽  
Corrosion Morphology ◽  
Corrosion Rates ◽  
Tube Steels ◽  
Corrosion Behaviors ◽  
Rate Calculation

The CO2/H2S corrosion behaviors of oil tube steels N80 and P110 at different temperature were investigated by corrosion rate calculation and corrosion morphology observation. The results show that with the increase of temperature, the CO2/H2S corrosion rates of both steels increase at first and then decrease, and reach the peak at 90°C. The corrosion rate of steel P110 is higher than that of steel N80.

Corrosion Behaviors of 25CrMnVA Steel in CO2 Flooding Enhanced Oil Recovery System

2013 ◽  
Vol 816-817 ◽  
pp. 1243-1249
Author(s):  
Chong Sun ◽  
Jian Bo Sun ◽  
Yong Wan ◽  
Xin Su ◽  
Yong Zhang
Keyword(s):  
Corrosion Rate ◽  
Partial Pressure ◽  
Oil Recovery ◽  
Oil Field ◽  
Uniform Corrosion ◽  
Corrosion Morphology ◽  
Corrosion Rates ◽  
Corrosion Scale ◽  
Corrosion Behaviors ◽  
Local Defects

Influences of temperature and CO2 partial pressure on CO2 corrosion behaviors of 25CrMnVA steel were investigated in the simulated oil field environments. The corrosion rates were measured under high temperature and high pressure condition. SEM, EDS and XRD were used to analyze the morphologies and characteristics of corrosion scales on the steels. The results shows that the corrosion rates of 25CrMnVA steel change little below 65°C, the corrosion feature is uniform corrosion. The corrosion rates increase rapidly after 65°C, mesa corrosion is found on the surface of steel. The corrosion rates decrease firstly and increase subsequently with the rising of CO2 partial pressure, and the minimal corrosion rate presents near CO2 critical pressure. The compactness of corrosion scale improves with the increase of CO2 partial pressure below 8MPa, which causes uniform corrosion rate reduced. Under supercritical CO2 condition, the local defects in the surface of corrosion scale increase, and the compactness of corrosion scale reduces,which cause the increase of corrosion rate sharply. The corrosion rate and corrosion morphology are closely related to the state of corrosion scale.

scholarly journals Evolution of the viscoelastic properties of painting stratigraphies: a moisture weathering and nanoindentation approach

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Mathilde Tiennot ◽  
Davide Iannuzzi ◽  
Erma Hermens
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Cultural Heritage ◽  
Mechanical Behaviour ◽  
Viscoelastic Properties ◽  
Viscoelastic Behaviour ◽  
Storage And Loss Moduli ◽  
Heritage Studies ◽  
Paint Films ◽  
The Impact

AbstractIn this investigation on the mechanical behaviour of paint films, we use a new ferrule-top nanoindentation protocol developed for cultural heritage studies to examine the impact of repeated relative humidity variations on the viscoelastic behaviour of paint films and their mechanical properties in different paint stratigraphies through the changes in their storage and loss moduli. We show that the moisture weathering impact on the micromechanics varies for each of these pigment-oil systems. Data from the nanoindentation protocol provide new insights into the evolution of the viscoelastic properties dsue to the impact of moisture weathering on paint films.

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.

scholarly journals Corrosion behaviors of 316 stainless steel and Inconel 625 alloy in chloride molten salts for solar energy storage

2020 ◽  
Vol 39 (1) ◽  
pp. 340-350
Author(s):  
Mingjing Wang ◽  
Song Zeng ◽  
Huihui Zhang ◽  
Ming Zhu ◽  
Chengxin Lei ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Molten Salt ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Inconel 625 ◽  
Transfer Resistance ◽  
316 Stainless Steel ◽  
Corrosion Rates ◽  
Inconel 625 Alloy ◽  
Corrosion Behaviors

AbstractCorrosion behaviors of 316 stainless steel (316 ss) and Inconel 625 alloy in molten NaCl–KCl–ZnCl2 at 700°C and 900°C were investigated by immersion tests and electrochemical methods, including potentiodynamic polarization and electrochemical impedance spectroscopy. X-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy were used to analyze the phases and microstructures of the corrosion products. Inconel 625 alloy and 316 ss exhibited high corrosion rates in molten chlorides, and the corrosion rates of these two alloys accelerated when the temperature increased from 700°C to 900°C. The results of the electrochemical tests showed that both alloys exhibited active corrosion in chloride molten salt, and the current density of 316 ss in chloride molten salt at 700°C was 2.756 mA/cm−2, which is about three times the value for Inconel 625 alloy; and the values of the charge transfer resistance (Rt) for Inconel 625 were larger than those for 316 ss. The corrosion of these two alloys is owing to the preferred oxidation of Cr in chloride molten salt, and the corrosion layer was mainly ZnCr2O4 which was loose and porous and showed poor adherence to metal.

scholarly journals Performance Evaluation of Cellulose Nanofiber with Residual Hemicellulose as a Nanofiller in Polypropylene-Based Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1064
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Hidayah Ariffin ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Mohd Ali Hassan ◽  
Nor Azowa Ibrahim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Weight Loss ◽  
Tensile Strength ◽  
Performance Evaluation ◽  
Flexural Strength ◽  
Decomposition Temperature ◽  
Cellulose Nanofiber ◽  
Hemicellulose Removal ◽  
Reinforcement Material

Residual hemicellulose could enhance cellulose nanofiber (CNF) processing as it impedes the agglomeration of the nanocellulose fibrils and contributes to complete nanofibrillation within a shorter period of time. Its effect on CNF performance as a reinforcement material is unclear, and hence this study seeks to evaluate the performance of CNF in the presence of amorphous hemicellulose as a reinforcement material in a polypropylene (PP) nanocomposite. Two types of CNF were prepared: SHS-CNF, which contained about 11% hemicellulose, and KOH-CNF, with complete hemicellulose removal. Mechanical properties of the PP/SHS-CNF and PP/KOH-CNF showed an almost similar increment in tensile strength (31% and 32%) and flexural strength (28% and 29%) when 3 wt.% of CNF was incorporated in PP, indicating that hemicellulose in SHS-CNF did not affect the mechanical properties of the PP nanocomposite. The crystallinity of both PP/SHS-CNF and PP/KOH-CNF nanocomposites showed an almost similar value at 55–56%. A slight decrement in thermal stability was seen, whereby the decomposition temperature at 10% weight loss (Td10%) of PP/SHS-CNF was 6 °C lower at 381 °C compared to 387 °C for PP/KOH-CNF, which can be explained by the degradation of thermally unstable hemicellulose. The results from this study showed that the presence of some portion of hemicellulose in CNF did not affect the CNF properties, suggesting that complete hemicellulose removal may not be necessary for the preparation of CNF to be used as a reinforcement material in nanocomposites. This will lead to less harsh pretreatment for CNF preparation and, hence, a more sustainable nanocomposite can be produced.

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