Under certain conditions the Cu‐Zn alloys are found to corrode by a process known as dezincification. As the term implies, zinc is removed from the alloy, leaving as a residue a…
Abstract
Under certain conditions the Cu‐Zn alloys are found to corrode by a process known as dezincification. As the term implies, zinc is removed from the alloy, leaving as a residue a porous mass of copper having little or no mechanical strength. Since corrosion is a surface phenomenon this process is initiated at the surface and, thereafter, gradually makes its way inwards until either leaks or cracks render the component useless for further service. Dezincification is a frequent type of corrosion failure encountered with brass handling waters contaminated with chloride ions.
As pitting corrosion is probably the most damaging type of wet corrosion, an understanding throughout industry of this phenomenon, which is the condition between complete immunity…
Abstract
As pitting corrosion is probably the most damaging type of wet corrosion, an understanding throughout industry of this phenomenon, which is the condition between complete immunity to attack and general corrosion, is essential. This article is concerned with pitting corrosion in general, but it also contains the results of some original research recently completed by the author on the corrosion pitting of stainless steels.
A. El Warraky, H.A. El Shayeb and E.M. Sherif
The pitting corrosion of copper in chloride solution has been studied using potentiostatic polarisation and surface analysis techniques. X‐ray photoelectron spectroscopy (XPS…
Abstract
The pitting corrosion of copper in chloride solution has been studied using potentiostatic polarisation and surface analysis techniques. X‐ray photoelectron spectroscopy (XPS) results enabled conclusions to be drawn about the nature of the film formed in different chloride concentrations. In dilute chloride solutions (C≤10−3 M), XPS proved the existence of Cu2O film on the copper surface. It was found that, depending on the chloride content, pitting of copper was evident only after the formation of a protective film of Cu2O. A current‐time trend plot showed the onset of fluctuations, which were dependent on the NaCl content. On the other hand, introduction of O2 into the solution during prepolarisation time period increased the current value of the fluctuations at the same concentration of NaCl in comparison with the freely aerated solution. These results, together with the surface analysis, confirm the role of chloride ion on the mechanism of pitting attack on copper metal.
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Hongda Deng, Yongliang Liu, Zhen He, Xiantao Gou, Yefan Sheng, Long Chen and Jianbing Ren
The purpose of this paper is to investigate and explain thermal oxide effect on electrochemical corrosion resistance anodized stainless steel (SS).
Abstract
Purpose
The purpose of this paper is to investigate and explain thermal oxide effect on electrochemical corrosion resistance anodized stainless steel (SS).
Design/methodology/approach
Electrochemical corrosion resistance of thermal oxides produced on anodized 304 SS in air at 350°C, 550°C, 750°C and 950°C in 3.5 wt.% NaCl solution have been investigated by dynamic potential polarization, EIS and double-loop dynamic polarization. Anodized 304 SS were obtained by anodization at the constant density of 1.4 mA.cm-2 in the solution containing 28.0 g.L-1H3PO4, 20.0 g.L-1C6H8O7, 200.0 g.L-1H2O2 at 70°C for 50 min. SEM and EDS had been also used to characterize the thermal oxides and passive oxide.
Findings
Interestingly, anodized 304SS with thermal oxide produced at 350°C displayed more electrochemical corrosion and pitting resistance than anodized 304 SS only with passive oxide, as related to the formation of oxide film with higher chromium to iron ratio. Whereas, anodized 304SS with thermal oxide formed at 950°C shows the worse electrochemical corrosion and pitting resistance among those formed at the high temperatures due to thermal oxide with least compact.
Originality/value
When thermally oxidized in the range of 350°C–950°C, electrochemical corrosion and pitting corrosion resistance of anodized 304 SS decrease with the increase of temperature due to less compactness, more defects of thermal oxide.
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V.K.V. Unni and T.L. Rama Char
Anode weight loss and polarization studies of brass in nitric, hydrochloric and sulphuric acids indicate that the copper dissolves in the cuprous state in hydrochloric acid…
Abstract
Anode weight loss and polarization studies of brass in nitric, hydrochloric and sulphuric acids indicate that the copper dissolves in the cuprous state in hydrochloric acid whereas it is in cupric form in the other two acids. In nitric acid the local cell corrosion is completely stopped, when made sufficiently anodic showing a positive difference effect.
Aleksandr Georgievich Tyurin, Dmitriy Andreevich Manannikov, Vladimir Pavlovich Parshukov, Anna Valeryevna Antonova and Pavel Anatolyevich Nikolaychuk
The purpose of this study is to develop a method of thermodynamic and kinetic evaluation of corrosion properties of alloys.
Abstract
Purpose
The purpose of this study is to develop a method of thermodynamic and kinetic evaluation of corrosion properties of alloys.
Design/methodology/approach
Method of estimation of corrosion-electrochemical behaviour of multicomponent alloys is proposed. The method takes into account both thermodynamic and kinetic data and is based on mutual construction of equilibrium and polarization potential – pH diagrams. The usage of the proposed method is illustrated in the example of the structural steel 20KT.
Findings
Passivation of steel 20KT is determined by formation of oxide film based on magnetite (Fe3O4); silicon, manganese and copper oxides as well as manganese sulphides can be locally included into the inner side of the passivation layer. An experimental potential – pH diagram of steel 20KT is constructed. Interpreting the results of polarization measurements revealed good agreement between equilibrium and polarization potential – pH diagrams.
Originality/value
It is shown in the example of structural steel 20KT that for interpretation of experimental potential – pH diagrams, one should compare them with corresponding equilibrium diagrams for multicomponent alloys rather than with Pourbaix diagrams for pure metals. The corrosion properties of steel 20KT are estimated using equilibrium and polarization potential – pH diagrams.
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Jing Jian Xiao and Chunsheng Tao
The purpose of this literature review paper is to define consumer finance, describe the scope of consumer finance and discuss its future research directions.
Abstract
Purpose
The purpose of this literature review paper is to define consumer finance, describe the scope of consumer finance and discuss its future research directions.
Design/methodology/approach
In this paper, consumer finance is used as a synonym of household finance. Consumers refer to individuals and families. After defining the term “consumer finance,” we conducted a critical review of consumer finance as an interdisciplinary research field in terms of money managing, insuring, borrowing and saving/investing. Future research directions are also discussed.
Findings
This paper discusses similarities and differences among several terms such as consumer finance, household finance, personal finance, family finance and behavioral finance. The paper also reviewed key studies on consumer financial behavior around four key financial functions, namely, money management, insurance, loan and saving/investment and several nontraditional topics such as fintech and financial capability/literacy. The paper also introduced several datasets of consumer finance commonly used in the United States and China.
Originality/value
This paper clarified several similar terms related to consumer finance and sorted out the diverse literature of consumer finance in multiple disciplines such as economics, finance and consumer science, which provide a foundation for generating more fruitful research in consumer finance in the future.
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The Howard Shuttering Contractors case throws considerable light on the importance which the tribunals attach to warnings before dismissing an employee. In this case the tribunal…
Abstract
The Howard Shuttering Contractors case throws considerable light on the importance which the tribunals attach to warnings before dismissing an employee. In this case the tribunal took great pains to interpret the intention of the parties to the different site agreements, and it came to the conclusion that the agreed procedure was not followed. One other matter, which must be particularly noted by employers, is that where a final warning is required, this final warning must be “a warning”, and not the actual dismissal. So that where, for example, three warnings are to be given, the third must be a “warning”. It is after the employee has misconducted himself thereafter that the employer may dismiss.
Boyung Suh, Andrew Sanghyun Lee, Sookyung Suh, Stacy Sattovia, Anna T. Cianciolo and Susan Thompson Hingle
This study aims to represent the initial impact analysis of a human resource development (HRD) intervention – the Center for Human and Organizational Potential (cHOP) – for…
Abstract
Purpose
This study aims to represent the initial impact analysis of a human resource development (HRD) intervention – the Center for Human and Organizational Potential (cHOP) – for faculty and staff at an academic medical center in the Midwestern US. cHOP seeks to unleash faculty and staff potential and advance organizational outcomes by fulfilling employees’ basic psychological needs, posited by self-determination theory (SDT, Ryan and Deci, 2000): competence, autonomy and relatedness.
Design/methodology/approach
Using Cianciolo and Regehr’s (2019) layered analysis framework as a guide, the authors conducted a program evaluation to analyze, in-depth, the nature and impact of two representative cHOP programs: Accelerate and BOOST. Specifically, the authors examined whether the implementation of these programs was consistent with SDT, as reflected in participants’ reported program experiences (i.e. “Did the intervention, in fact, occur as intended?”). The authors also examined program outcomes and opportunities for improvement based on program participants’ voices (i.e. did the intervention, implemented as intended, work?). Because SDT is a theory of individual motivation, the authors identified a need to evaluate outcomes at the individual level and beyond, broadly exploring what would happened if program participants’ basic psychological needs had been addressed. The aim was to determine the potential downstream consequences of intrinsically motivated faculty and staff, while promoting divergent thinking on program impact and sustainability.
Findings
Participants reported experiences suggest that Accelerate and BOOST addressed all three psychological needs and strengthened their intrinsic motivation to advance their leadership and career development and improve the performance of their teams and departments. These outcomes suggest the potential for impact at the individual level and beyond, such as the institution and external, professional societies.
Research limitations/implications
The study assessed two representative programs among cHOP’s many offerings. A comprehensive study of cHOP’s impact, directly linking psychological need fulfillment and organizational impact, is beyond the scope of a single study and requires further research.
Social implications
The authors suggest expanding scholarly discussions in the HRD and health professions education (HPE) literature to characterize the promise of HRD-HPE partnerships and to account for their impact more fully.
Originality/value
The study contributes to both HRD and HPE scholarship by providing a layered account of academic medical center (AMC) faculty and staff development using an HRD approach; and examining the impact of a theory- and evidence-based novel HRD intervention (i.e. cHOP) at the individual level and beyond in an AMC context.
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Kasturie Premlall, J. Herman Potgieter and S. Potgieter‐Vermaak
The effect of chlorides on corrosion of reinforcing steel is well documented in the literature. However, few studies have focused attention on the effect of sulphates on the…
Abstract
Purpose
The effect of chlorides on corrosion of reinforcing steel is well documented in the literature. However, few studies have focused attention on the effect of sulphates on the corrosion of low carbon steel in alkaline media. This paper aims to address this issue.
Design/methodology/approach
This paper describes the results of the investigation into the corrosion behaviour of low carbon steel (typically used as reinforcing steel), exposed to alkaline media at a pH of 9 and 12 with varying concentrations of sulphate and chloride ions, as well as, in sulphate only solutions. An attempt was made to inhibit corrosion of steel exposed to the corrosive media using laser surface treatment of the steel specimens. Mass loss tests and electrochemical tests were conducted to evaluate the effect of sulphate only and the combined effect of sulphate and chloride ions in an alkaline media on steel.
Findings
It was found that sulphate ions could cause corrosion of steel in alkaline media. The severity of the attack increased with increasing sulphate ion concentrations, as well as with combinations of sulphate and chloride ions. The pH 12 conditions seem to show much more critical attack with evidence of pitting corrosion as compared to uniform corrosion for test conditions at a pH of 9. The attempt to inhibit the observed corrosion of steel exposed to the corrosive high alkaline media containing sulphate ions on their own and in combination of chloride ions by laser surface treatment proved to be successful.
Originality/value
The research undertaken here adds to the body of knowledge relating to the effect of sulphate ions on reinforcing steel corrosion in highly alkaline media. Most literature points out that sulphate ions on their own do not have a corrosive effect, but rather, a passivating effect!