The protective mechanism of the native rust layer on Cr-containing steels exposed to marine atmosphere

2002 ◽  
Vol 93 (6) ◽  
pp. 590-594
Author(s):  
Q. C. Zhang ◽  
J. S. Wu ◽  
W. L. Zheng ◽  
J. G. Chen ◽  
A. B. Li
Keyword(s):  
Protective Mechanism ◽  
Marine Atmosphere ◽  
Rust Layer

Effect of Sn on the corrosion behavior of weathering steel in a simulated tropical marine atmosphere

2020 ◽  
Vol 67 (2) ◽  
pp. 129-139
Author(s):  
Cheng Jiang ◽  
Ying Yang ◽  
Xuequn Cheng ◽  
Jinbin Zhao ◽  
Xiaogang Li
Keyword(s):  
Real Time ◽  
Corrosion Behavior ◽  
Weathering Steel ◽  
Marine Atmosphere ◽  
Rust Layer ◽  
Monitoring Technology ◽  
Content Type ◽  
X Ray ◽  
Tropical Marine Atmosphere ◽  
Current Monitoring

Purpose This study aims to study the effect of Sn on the corrosion behavior of weathering steel (WS) in a simulated tropical marine atmosphere. Design/methodology/approach Indoor alternate immersion tests, electrochemical measurements and real-time current-monitoring technology based on the galvanic corrosion principle were used and the scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and electron probe microanalyzer were used to analyze the morphology and component of the rust layer. Findings The results indicated that Sn has a positive influence on the corrosion process. Sn participated in the composition of the rust layer in the form of SnO2 and is enriched in the inner rust layer. SnO2 participated in the coprecipitation process with iron oxides and oxyhydroxides, which promoted further transformation of γ-FeOOH to α-FeOOH. As a result, the rust layer of Sn-containing steel was continuous, compact and effectively blocked the invasion of aggressive Cl−. Therefore, the additive of Sn enhanced the corrosion resistance of WS in a simulated tropical marine atmosphere. Originality/value The corrosion behaviors of WS were researched by the real-time current-monitoring technology which was rarely used.

scholarly journals Mechanical Properties of Native Rust Layer Formed on a Low Alloy Steel Exposed in Marine Atmosphere.

2002 ◽  
Vol 42 (5) ◽  
pp. 534-539 ◽  
Author(s):  
Q. C. Zhang ◽  
F. Ma ◽  
J. S. Wu ◽  
W. L. Zhazheng ◽  
J. G. Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Alloy Steel ◽  
Marine Atmosphere ◽  
Low Alloy Steel ◽  
Rust Layer

scholarly journals Corrosion Behavior and Mechanical Properties of 30CrMnSiA High-Strength Steel under an Indoor Accelerated Harsh Marine Atmospheric Environment

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 629
Author(s):  
Ning Li ◽  
Weifang Zhang ◽  
Hai Xu ◽  
Yikun Cai ◽  
Xiaojun Yan
Keyword(s):  
Mechanical Properties ◽  
Corrosion Behavior ◽  
High Strength Steel ◽  
High Strength ◽  
Atmospheric Environment ◽  
Composition Analysis ◽  
Marine Atmosphere ◽  
Rust Layer ◽  
The Matrix ◽  
Atmosphere Environment

In this work, the corrosion behavior and mechanical properties of 30CrMnSiA high-strength steel under a harsh marine atmosphere environment were systematically studied using accelerated test technology, along with corrosion kinetic analysis, microstructure and phase composition analysis, electrochemical measurements, and mechanical property tests. The influence of corrosion time on corrosion kinetics was characterized by the weight loss method. The corrosion layer and its product evolution were analyzed by SEM, EDS, XRD, and XPS. The corrosion behavior of steel was studied by a potentiodynamic polarization curve and EIS. Finally, the influence of corrosion on mechanical properties was studied by tensile and fatigue tests. The results show that 30CrMnSiA high strength steel has good corrosion resistance in a harsh marine atmosphere environment. Its corrosion behavior is cyclical: the outer rust layer exfoliated, the inner rust layer became the outer rust layer, and the matrix became inner rust due to the attack by the corrosive medium. The rust layer had a great protective effect on the matrix. The mechanical properties of 30CrMnSiA high-strength steel were reduced under the corrosive environment, and corrosion had a significant effect on its fatigue resistance.

ABOUT SOME PECULIARITIES OF THE PHYSIOLOGICAL HETEROGENEITY OF THE POPULATION OF SCENEDESMUS QUADRICAUDA (TURP.) BREB. IN THE PRESENCE OF LOW CONCENTRATIONS OF METALS

2018 ◽  
pp. 34-43
Author(s):  
V. I. Ipatova ◽  
A. G. Dmitrieva ◽  
О. F. Filenko ◽  
T. V. Drozdenko
Keyword(s):  
Cell Division ◽  
Toxic Effect ◽  
Copper Chloride ◽  
Single Cells ◽  
Physiological State ◽  
Scenedesmus Quadricauda ◽  
Physiological Status ◽  
Lag Phase ◽  
Protective Mechanism ◽  
Low Concentrations

The structure of the laboratory population of green microalgae Scenedesmus quadricauda (Turp.) Breb (=Desmodesmus communis E. Hegew.) was studied at different stages of its growth (lag-phase, log-phase and stationary phase) at low concentrations of copper chloride and silver nitrate by the method microculture, allowing to monitor the state and development of single cells having different physiological status. The response of the culture of S. quadricauda - the change in the number of cells and the fractional composition (the fraction of dividing, «dormant» and dying cells) depended not only on the concentration of the toxicant in the medium, but also on the physiological state of the culture: the level of synchronization and the growth phase. Silver ions at low concentrations had a more pronounced toxic effect on the culture than copper ions at different phases of its development, especially at a concentration of 0.001 mg/l (10-9 M). The main mechanism of the toxic effect of metals is to inhibit the process of cell division. At low concentrations of toxicants, especially at a concentration of 0.001 mg/l, a «paradoxical» effect expressed in the predominance of the fraction of «dormant» cells was revealed. The temporary inhibition of the process of cell division can be regarded as a protective mechanism that allows preserving the integrity of the population and its ability to survive in a changing environment. The obtained data explain the effect of action of low concentrations of substances due to their inclusion in the cell, the subsequent accumulation in the cell and their low excretion.

Inhibition of Autophagy Potentiated Hippocampal Cell Death Induced by Endoplasmic Reticulum Stress and its Activation by Trehalose Failed to be Neuroprotective

2019 ◽  
Vol 16 (1) ◽  
pp. 3-11
Author(s):  
Luisa Halbe ◽  
Abdelhaq Rami
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Er Stress ◽  
Cell Damage ◽  
Protective Mechanism ◽  
Unfolded Proteins ◽  
Neuronal Viability ◽  
Hippocampal Cell ◽  
Trigger Cell Death ◽  
Autophagy Inhibition

Introduction: Endoplasmic reticulum (ER) stress induced the mobilization of two protein breakdown routes, the proteasomal- and autophagy-associated degradation. During ERassociated degradation, unfolded ER proteins are translocated to the cytosol where they are cleaved by the proteasome. When the accumulation of misfolded or unfolded proteins excels the ER capacity, autophagy can be activated in order to undertake the degradative machinery and to attenuate the ER stress. Autophagy is a mechanism by which macromolecules and defective organelles are included in autophagosomes and delivered to lysosomes for degradation and recycling of bioenergetics substrate. Materials and Methods: Autophagy upon ER stress serves initially as a protective mechanism, however when the stress is more pronounced the autophagic response will trigger cell death. Because autophagy could function as a double edged sword in cell viability, we examined the effects autophagy modulation on ER stress-induced cell death in HT22 murine hippocampal neuronal cells. We investigated the effects of both autophagy-inhibition by 3-methyladenine (3-MA) and autophagy-activation by trehalose on ER-stress induced damage in hippocampal HT22 neurons. We evaluated the expression of ER stress- and autophagy-sensors as well as the neuronal viability. Results and Conclusion: Based on our findings, we conclude that under ER-stress conditions, inhibition of autophagy exacerbates cell damage and induction of autophagy by trehalose failed to be neuroprotective.

scholarly journals Daily Stimulation and Cognitive Functioning: The Importance of the Participation of Healthy Older People in Cognitively Demanding Everyday Activities

2014 ◽  
Vol 4 (3) ◽  
pp. 309-319
Author(s):  
José Antonio Labra Pérez ◽  
Julio Menor
Keyword(s):  
Cognitive Functioning ◽  
Urban Areas ◽  
Ad Hoc ◽  
The Elderly ◽  
Protective Mechanism ◽  
Everyday Activity ◽  
Neuropsychological Measures ◽  
Rural And Urban Areas ◽  
Everyday Activities ◽  
Rural And Urban

The participation of the elderly in cognitively demanding activities is considered an enhancing factor of cognitive function. However, the life cycle psychosocial variables such as education and type of profession also influence in cognitive functioning. The objective of this study is to analyze the relationship between daily stimulation and cognitive functioning in a sample of healthy older adults, controlling the effects of education and the type of profession. The study involved 164 adults over 60 years, from rural and urban areas, with different levels of education and professional level which were assessed with an extensive battery of neuropsychological measures, as well as in an inventory of everyday activities built ad hoc. The results show that different cognitively demanding everyday activities are related to with cognitive processes, both fluids and crystallized. Furthermore, it was found that daily stimulation plays an important role in cognitive functioning outside of education and the type of profession performed. Overall, the results of this study shows the importance of everyday activity as a protective mechanism against cognitive decline, as well as the need to adopt a model of active aging

scholarly journals Effect of Oxide Scale Microstructure on Atmospheric Corrosion Behavior of Hot Rolled Steel Strip

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 517
Author(s):  
Bin Sun ◽  
Lei Cheng ◽  
Chong-Yang Du ◽  
Jing-Ke Zhang ◽  
Yong-Quan He ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Scale ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Atmospheric Corrosion ◽  
Corrosion Mechanism ◽  
Type I ◽  
Rust Layer ◽  
Hot Rolled

The atmospheric corrosion behavior of a hot-rolled strip with four types (I–IV) of oxide scale was investigated using the accelerated wet–dry cycle corrosion test. Corrosion resistance and porosity of oxide scale were studied by potentiometric polarization measurements. Characterization of samples after 80 cycles of the wet–dry corrosion test showed that scale comprised wüstite and magnetite had strongest corrosion resistance. Oxide scale composed of inner magnetite/iron (>70%) and an outer magnetite layer had the weakest corrosion resistance. The corrosion kinetics (weight gain) of each type of oxide scale followed an initial linear and then parabolic (at middle to late corrosion) relationship. This could be predicted by a simple kinetic model which showed good agreement with the experimental results. Analysis of the potentiometric polarization curves, obtained from oxide coated steel electrodes, revealed that the type I oxide scale had the highest porosity, and the corrosion mechanism resulted from the joint effects of electrochemical behavior and the porosity of the oxide scale. In the initial stage of corrosion, the corrosion product nucleated and an outer rust layer formed. As the thickness of outer rust layer increased, the corrosion product developed on the scale defects. An inner rust layer then formed in the localized pits as crack growth of the scale. This attacked the scale and expanded into the substrate during the later stage of corrosion. At this stage, the protective effect of the oxide scale was lost.

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