Constitution Of Boundaries Research Articles

Effect of texture, grain boundary constitution, and molybdenum partitioning on corrosion and hydrogen permeation behavior of pulse electrodeposited Ni-Mo coatings

Microstructural evolution, electrochemical corrosion and hydrogen permeation in pulse electrodeposited Ni-Mo coatings (2, 4, 8, and 11wt% Mo) were investigated. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements revealed improved corrosion resistance at an optimum Mo content. The corrosion current density icorr and polarization resistance Rp values obtained were 13.8 μA/cm2 and 1745 Ωcm2 respectively for pure Ni coating while the icorr and Rp values obtained were 1.7 μA/cm2 and 5406 Ωcm2 respectively for Ni-4wt% Mo coating. Further, increase in the Mo content beyond 4 wt% increased the corrosion rate. Nevertheless, corrosion resistance of Ni-Mo coatings was found to be higher than the pure Ni coating. Ni-Mo coatings contained relatively Mo-enriched clusters in a solid solution matrix. The highest corrosion resistance of Ni-4wt% Mo coating was due to lower energy (001) and (111) textures, lower energy grain boundary constitution, and low coating strain. In Ni-4wt% Mo coating, Mo-enriched Ni-Mo nanoclusters inhibited hydrogen passage by providing a torturous path. In contrast, a high fraction of high-angle grain boundaries (compared to pure Ni coating) facilitated hydrogen permeation leading to a similar extent of hydrogen permeation through pure Ni and Ni-4wt% Mo coatings.

Engineering Grain Boundary Constitution in Pulse Electrodeposited Nickel Coatings for Enhanced Resistance to Electrochemical Degradation

Engineering Grain Boundary Constitution in Pulse Electrodeposited Nickel Coatings for Enhanced Resistance to Electrochemical Degradation

Chromium partitioning induced evolution of texture, grain boundary constitution, and corrosion behavior of Cu[sbnd]Cr coatings electrodeposited at different temperatures

The corrosion behavior of CuCr coating electrodeposited at three different temperatures (15 °C, 30 °C, 45 °C) was examined. Cr is partitioned in the grain boundaries and as a solute in the Cu matrix. The formation of Cr-oxide at the grain boundaries enhanced the corrosion resistance of the coatings, whereas the presence of Cr as solute significantly altered the matrix micro-texture. The 15 °C deposited coating exhibited the lowest corrosion rate due to higher Cr solute, smaller grain size, (111) surface texture, and a higher fraction of coincidence site lattices. The 45 °C deposited coating exhibited the highest corrosion rate due to lower Cr solute, higher energy (110) surface texture, and higher fraction of high energy grain boundaries.

The Organization of Market Boundaries

Abstract In contrast to the main focus on market boundaries as spontaneous orders, this article investigates how and why market boundaries are ordered through organization. It proposes three elemental ordering processes – mutual adaptation, institutions, and organization – to conceptualise individual market boundary formation. Based on a longitudinal study of a financial market, the organization of both market demarcations and boundary constitution is analysed. It is illustrated how boundaries were subject to much organization and reorganization, to protect the market’s legitimacy and function. Explanations for the use of market boundary organization suggestively stem from both boundary competition and complementarity – to replace or reinforce boundaries formed by other ordering processes, in order to direct market content.

Telling People Apart: Outline of a Theory of Human Differentiation

Alongside subsystems, classes, and types of socials relations, societies differentiate between categories of their personnel, referring to their age, sex, “race,” (dis)ability, performance, geographic and social origin, sexual preference, religious conviction, profession, and so on. This article outlines a theory of human differentiation with the aim of viewing processes leading to reified memberships of human categories in an encompassing comparative approach. Differentiating humans distinguishes them perceptively, categorizes them lingually, shapes them physically, segregates them spatially, and subjects them to othering and unequal evaluative treatment. The analytic vocabulary developed in this article puts forward five elementary processes—prelingual distinction, lingual categorization, official classification, material marking/dissimilation, and segregation—and three advanced processes of asymmetrical differentiation: the alterization of humans, their differential evaluation, and the escalation into boundary constitution and polarization. Processes of human differentiation are stabilized via coupling with social and societal differentiation, but they can also be practically minimalized, normatively contained, and institutionally diluted.

Deposition current density-induced grain boundary engineering of electrodeposited cobalt coatings for enhanced electrochemical stability

ABSTRACT Cobalt coatings were electrodeposited at different deposition current densities (10 mA·cm−2, 20 mA·cm−2, 30 mA·cm−2, 40 mA·cm−2, 60 mA·cm−2) over mild steel substrate. The coating deposited at 30 mA·cm−2 showed the highest corrosion resistance (Rp = 7515Ω·cm2) due to a higher fraction of Low energy grain boundary constitution (i.e. coincidence site lattices (CSLs) and low angle grain boundaries (LAGB)) and exhibited higher fraction of stabler Co3O4 passive oxide layer. The coatings electrodeposited at 60 mAcm−2 exhibited lower corrosion resistance (Rp = 1304 Ω·cm2) due to a higher fraction of high-angle grain boundaries and a higher fraction of relatively lesser stable Co(OH)2.

Effect of selective atomic clustering, surface texture and grain boundary constitution on the corrosion behaviour of electrodeposited Sn-xBi coatings

Sn-xBi (x = 4, 7, 10, 14, and 17 wt%) coatings were electrodeposited onto mild steel to elucidate their corrosion behaviour. The B14 (Sn-14 wt% Bi) and B7 (Sn-7 wt% Bi) coating exhibited the highest (Polarization resistance (Rp) = 12,810.2 Ω·cm2) and least corrosion resistance (Rp = 2843.2 Ω·cm2), respectively. B14 coating exhibited the lower energy near (301) plane orientation against B7 coating which showed higher energy (321) and (111) plane orientation along the exposed surface. The galvanic coupling effect alleviated in B14 coating due to Sn nanoclusters into Bi grains as revealed by the atom probe tomography analysis.

Effect of molybdenum partitioning on the evolution of microstructure, grain boundary constitution and corrosion behaviour of electrodeposited zinc-molybdenum coatings

Effect of compositional partitioning on microstructural evolution and corrosion behaviour of Zn-Mo coatings (Mo: 2.8 – 6.5 wt%) electrodeposited on mild steel substrate has been explored. Corrosion resistance of Zn coating increased with Mo addition until an optimum addition (Zn-4.2 wt% Mo) beyond which it decreased for higher Mo content (Zn-6.5 wt% Mo). The corrosion current density (icorr) values for pure Zn, Zn-2.8 wt% Mo, Zn-4.2 wt% Mo, Zn-6.5 wt% Mo coating was 17 μA/cm2, 12.25 μA/cm2, 7.5 μA/cm2, 14.2 μA/cm2 respectively. Incorporation of Mo resulted in the formation of Zn-Mo solid solution and Zn3Mo2 compound phases along with segregation of Mo at Zn grain boundaries. High corrosion resistance of Zn-4.2 wt% Mo coating was due segregation of Mo at Zn grain boundaries, higher fraction of low angle grain boundaries and coincidence site lattices when compared to the pristine Zn coating. Lower corrosion resistance of Zn-6.5 wt% Mo coating was primarily due to higher coating strain because of the solid solution of Mo in Zn and formation of Zn3Mo2 particles in the coating matrix.

Correlation Between Texture, Grain Boundary Constitution and Corrosion Behaviour of Copper–Chromium Coatings Containing Graphene Oxide

Correlation Between Texture, Grain Boundary Constitution and Corrosion Behaviour of Copper–Chromium Coatings Containing Graphene Oxide

The Constitution of Boundaries: How the Embeddedness of Organizational Users Structures the Transfer of their Knowledge

Private and organizational users are widely treated as equal in the literature on the integration of users in innovation projects. Based on a practice-theoretical perspective, we argue in this paper that this equation is inconsistent and inadequate. While users are conceptualized as competent and embedded when it comes to the genesis of their user knowledge, both factors are ignored when their involvement in the innovation process is considered. Drawing on empirical findings on interorganizational knowledge transfer, we show that the social, formal, and material embeddedness of organizational users crucially structures their integration. By elaborating the role of different structural dimensions in detail, we highlight the distinctive features of organizational users. In doing so, we further develop a heuristic that enables a detailed and adequate analysis of their integration.

Effect of Deposition Temperature on the Evolution of Texture, Grain Boundary Constitution and Corrosion Behaviour of Sn–Cr Coatings

Effect of Deposition Temperature on the Evolution of Texture, Grain Boundary Constitution and Corrosion Behaviour of Sn–Cr Coatings

Effect of grain boundary constitution on corrosion behaviour in cobalt-carbon nanotube composite coatings

Corrosion behavior and micro-texture of electrodeposited cobalt coatings containing different volume fractions of carbon nanotubes (CNTs) were investigated and correlated. For lower CNT volume fractions, a compact and smoother coating morphology were observed. The morphology however, became coarser for higher CNT volume fractions. Corrosion properties of the coatings were determined using the electrochemical impedance spectroscopy and Tafel polarization techniques. Pristine cobalt coating showed corrosion potential (Ecorr), corrosion current density (icorr), and polarization resistance (Rp) values of -0.574 V, 21.48µA/cm2 and 2071 ohms.cm2 respectively. With the incorporation of CNTs, the coating corrosion resistance increased up to Co-CNT3 coating (produced by 20mg/L of CNT dispersion). Co-CNT3 coating showed Ecorr, icorr and Rp values of -0.521V, 5.33µA/cm2 and 3525 ohms.cm2 respectively. However, for higher volume fractions of CNTs, the coating corrosion resistance dropped to values lower than pristine cobalt coating. For Co-CNT6 coating (produced from 80 mg/L of CNT dispersion) the Ecorr, icorr and Rp values were -0.581V, 23.45µA/cm2 and 1409 ohms.cm2 respectively. Micro-texture analysis was conducted for pristine Co and Co-CNT3 coatings to investigate the correlation between the observed corrosion behavior and coating micro-texture. Both the coatings showed strong {211¯0} texture along the coating growth direction. When compared to printine Co coating, the Co-CNT3 coating showed lesser fraction of high angle grain boundaries as well as higher fraction of low energy special boundaries like STGBs (32°/ [211¯0], 62°/ [211¯0] angle axis pair) leading to better corrosion resistance performance for Co-CNT3 coatings.

Effect of Zn Incorporation on the Evolution of Texture, Strain, Grain Boundary Constitution, and Corrosion Behavior of Electrodeposited SnZn Coatings

Effect of Zn Incorporation on the Evolution of Texture, Strain, Grain Boundary Constitution, and Corrosion Behavior of Electrodeposited SnZn Coatings

Effect of electrodeposition temperature on texture, strain, grain boundary constitution and corrosion behavior of Ni-P coatings with low phosphorous content

Nickel-phosphorus (Ni-P) alloy coatings were electrodeposited over mild steel substrate from a constant current DC power source. Effect of deposition bath temperature (15 ˚C, 20 ˚C, 25 ˚C, 35 ˚C) on the coating corrosion behavior in 3.5 wt.% NaCl solution was investigated. Corrosion analysis was conducted using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The 15 ˚C coating showed lowest polarization resistance (Rp = 2818.52 Ω.cm2) value indicating degraded corrosion resistance, whereas the 25 ˚C coating showed highest polarization resistance (Rp = 6992.285 Ω.cm2) value implying highest corrosion resistance performance amongst all coatings. This was also confirmed by the potentiodynamic polarization measurement where the 15 °C coatings and 25 °C coating showed respectively the highest and lowest corrosion current density (Icorr) values. Icorr values of 15 °C and 25 °C coating was 7.79 μA.cm−2 and 1.534 μA.cm−2, respectively. Analysis of the coating texture, strain and grain boundary constitution by the electron back scatter diffraction (EBSD) technique showed that the predominance of (101) high energy texture, lower fraction of low angle grain boundaries (LAGBs), and higher coating strain yielded high vulnerability to the corrosive attack for 15 ˚C coating, while (001) low energy growth texture with a relatively higher fraction of LAGBs and lower coating strain led to improved corrosion resistance in 25 °C coating.

Evolution of Texture, Grain Boundary Constitution, Strain, and Corrosion Behavior of Electrodeposited Ni–P Coatings as a Function of Deposition Current Density

Evolution of Texture, Grain Boundary Constitution, Strain, and Corrosion Behavior of Electrodeposited Ni–P Coatings as a Function of Deposition Current Density

Correlation Between Texture, Grain Boundary Constitution, and Corrosion Behavior of Ni-Cu Coatings

Correlation Between Texture, Grain Boundary Constitution, and Corrosion Behavior of Ni-Cu Coatings

Evolution of Texture, Strain, and Grain Boundary Constitution in Copper–Chromium Coatings and its Effect on Coating Corrosion Behavior

Evolution of Texture, Strain, and Grain Boundary Constitution in Copper–Chromium Coatings and its Effect on Coating Corrosion Behavior

Low-temperature Sn electrodeposition: Texture evolution, grain boundary constitution and corrosion behavior

Electrodeposition of Sn was conducted at three different electrolyte bath temperatures: 25 °C, 20 °C, and 15 °C in galvanostatic conditions. Corrosion analysis using the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization revealed that decreasing the electrodeposition bath temperature reduced the corrosion resistance of Sn coatings. The 25 °C coating exhibited the highest polarization resistance (Rp) value of 71,460 Ω.cm2 and lowest corrosion current density (icorr) value of 0.251 μA.cm−2, whereas the 15 °C coating exhibited Rp value of 16,120 Ω.cm2 and icorr value of 0.891 μA.cm−2. The electrochemical response was correlated with the texture and grain boundary constitution using the electron backscatter diffraction (EBSD) technique. It was observed that decreasing the electrodeposition temperature decreased the predominance of the (100) texture, increased the strain, and reduced the average grain size of Sn grains. The Sn coating with the lowest corrosion resistance displayed a predominant (501) texture, lowest grain size, and highest strain within the Sn grains.

Influence of surfactant polarity on the evolution of micro-texture, grain boundary constitution and corrosion behavior of electrodeposited Zn coatings

Corrosion behavior, morphology and micro-texture of Zn coatings, electrodeposited from electrolyte bath without and with surfactants of different polarity, were investigated and correlated. Polarization resistance (Rp) value which is directly proportional to the corrosion resistance behavior, was determined from the electrochemical impedance spectroscopy technique. Rp value was highest for the coating with Cetyltrimethylammonium bromide [CTAB (cationic surfactant)], followed by coatings with Sodium lauryl sulphate [SLS (anionic surfactant)], and Triton X-100 (non-ionic surfactant) surfactant. Surfactant-free coating showed the lowest Rp value, indicating lowest corrosion resistance. Surfactant-free coating and coating with SLS showed large-sized columnar grains, whereas coatings with CTAB and Triton X-100 contained smaller-sized grains throughout the coating thickness. XRD and EBSD suggested low energy near basal micro-texture on the coating surface with SLS as surfactant. Whereas other coatings with CTAB and Triton X-100 showed higher energy micro-texture. SLS containing coatings and surfactant-free coatings exhibited higher percentage (greater than 60%) of high angle grain boundaries (HAGBs). Zn coatings with CTAB showed lower fraction of HAGBs followed by coatings with Triton X-100. With similar micro-texture and grain boundary constitutions, in coatings electrodeposited using CTAB and Triton X-100, higher corrosion resistance in the case of CTAB was due to more compact and relatively less defective surface morphology. Between the coatings, produced without surfactant and using SLS surfactant, both of which exhibited similar columnar grains and percentage of high angle grain boundaries, the higher corrosion resistance in the case of SLS surfactant coating was due to near basal micro-texture along coating growth direction and high fraction of low energy special boundaries (90°/211¯0 angle/axis pair).

Solving the corrosion behaviour and cobalt content correlation anomaly in electrodeposited Ni–Co coatings by analysis of coating micro-texture, strain and grain boundary constitution

ABSTRACT Ni–Co alloy coatings exhibit excellent tribological properties. However, these coatings are vulnerable to corrosion due to the lower corrosion potential of Co when compared to Ni. The decrease in the corrosion resistance of Ni–Co alloy with increasing Co content is not monotonous. At an optimum Co content, very high corrosion resistance behaviour is observed. This anomaly is investigated here. Ni–Co coatings (Ni, Ni–9 wt% Co and Ni–20 wt% Co) were electrodeposited over mild steel. Potentiodynamic polarisation illustrated Ni coatings highest corrosion resistance, whereas, between the Ni–Co coatings, Ni–20 wt% Co coating exhibited higher corrosion resistance in 3.5 wt% NaCl medium. Higher corrosion resistance in Ni–20 wt% Co coating was primarily due to uniform distribution of low energy grain boundaries like Σ3 coincidence site lattices (CSLs) in the coating. Higher corrosion rate for Ni–9 wt% Co coatings was due to strained grains and non-uniform distribution of low energy grain boundaries.