scholarly journals The properties of chromium electrodeposited with programmed currents. Part I. Direct current

2000 ◽  
Vol 65 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Bisenija Petrovic ◽  
Tanja Kostic
Keyword(s):  
Direct Current ◽  
High Pressures ◽  
High Current Density ◽  
Sulphuric Acid Solution ◽  
Average Thickness ◽  
High Current ◽  
Surface Distribution ◽  
Basic Properties ◽  
Coating Morphology ◽  
Non Destructive

The electrodeposition of chromium in programmed direct current (DC) was investigated in the regime of high current density (77Adm -2 ). Chromium was deposited in a system of plane-parallel electrodes in chromic-sulphuric acid solution, on specimens of steell, during one hour. The basic properties of deposits, the appearance, thickness, morphology, microhardness and brightness were investigated. Thicknesses of the coatings (between 28 and 82 mm) were measured at 36 points on the surface of the specimens by the non-destructive ferromagnetic method. Based on these results, graphic models of the surface distribution of the deposits were made. Three ranges of thickness could be seen on the model (range 1 - average thickness 29.87 mm, range 2 - average thickness 42.0 mm and range 3 - thickness 67.87 mm). For the whole speciments, the average thickness was 50.8 mm with a coefficient of variation of 0.3281. The basic properties of the coating, morphology and brightness changed depending on the deposit thickness being very different at different points of one and the same specimen. For this reason these chromium deposits should not be considered reliable protection against aggressive gases at high pressures and temperature of systems from corrosion, wear and erosion.

scholarly journals The properties of chromium electrodeposited with programmed currents. Part II. Reversing current

2000 ◽  
Vol 65 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Bisenija Petrovic ◽  
Tanja Kostic
Keyword(s):  
Current Density ◽  
Steel Substrate ◽  
Sulphuric Acid Solution ◽  
Cathodic Current Density ◽  
Anodic Current Density ◽  
Average Thickness ◽  
Parallel Plates ◽  
Cathodic Current ◽  
Surface Distribution ◽  
Basic Properties

The electrodeposition of chromium in programmed reversing current (RC), was investigated in the regime of high cathodic current density (77 A dm -2) and anodic current density (55 Adm -2). The ratio of the cathodic and anodic time (60 : 1) was used. Chromium was deposed on a steel substrate from a chromic-sulphuric acid solution, during one hour. Anode and cathode were suited in a system of parallel plates. Basic properties of deposits, like thickness, morphology, microhardness, brightness were examined. Surface distribution of the deposits was obtained from the measurements of the thicknesses of the deposits (between 32 and 67 mm).A ferromagnetic non-destructive method was used in the measurements. Based on the results, graphic models of deposit surface distribution were made. Two ranges of the thickness could be seen on the model (range 1 - average thickness 35.1 mm and range 2 - average thickness 57.81 mm). These results were statisticaly analysed by colums, rows and by the whole surface. For the whole specimens, the average thickness was 45.39 mm with a coefficient of variation of 0.2582. The basic properties of the deposits did not change with a variation of the thickness. Because of this, the coatings deposited with the reversing current could be much more considered reliable in wear and corrosion protection systems than ones deposited by direct current.

scholarly journals Interfacial friction-induced electronic excitation mechanism for tribo-tunneling current generation

2019 ◽  
Vol 6 (5) ◽  
pp. 1020-1026 ◽  
Author(s):  
Jun Liu ◽  
Keren Jiang ◽  
Lan Nguyen ◽  
Zhi Li ◽  
Thomas Thundat
Keyword(s):  
Direct Current ◽  
Current Density ◽  
Electronic Excitation ◽  
High Current Density ◽  
Tunneling Current ◽  
Sliding Contact ◽  
Interfacial Friction ◽  
High Current ◽  
Excitation Mechanism ◽  
Current Generation

Strong interfacial electronic excitation may be induced by Schottky sliding contact, giving rise to direct-current generation with high current density (J, on the order of 100 A m−2).

scholarly journals A High Current Density Direct‐Current Generator Based on a Moving van der Waals Schottky Diode

2018 ◽  
pp. 1804398 ◽  
Author(s):  
Shisheng Lin ◽  
Yanghua Lu ◽  
Sirui Feng ◽  
Zhenzhen Hao ◽  
Yanfei Yan
Keyword(s):  
Schottky Diode ◽  
Direct Current ◽  
Current Density ◽  
High Current Density ◽  
Van Der Waals ◽  
High Current ◽  
Current Generator

Galvanostatic dissolution of mercury from the surface of glassy carbon into thiocyanate solution

1980 ◽  
Vol 45 (1) ◽  
pp. 169-178 ◽  
Author(s):  
František Opekar ◽  
Karel Holub
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
High Current Density ◽  
High Current ◽  
Nernst Equation ◽  
Potential Oscillations ◽  
Thiocyanate Solution ◽  
Theoretical Assumptions ◽  
Solution Proceeds ◽  
Dissolution Current

The galvanostatic dissolution of mercury from the surface of glassy carbon into a thiocyanate solution proceeds in accord with theoretical assumptions, as manifested by the constant product of the dissolution current and transition time. Under certain relations between the amount of oxidised mercury and concentration of thiocyanate at the electrode surface, however, a small part of the mercury dissolves at more positive potentials than correspond to the Nernst equation. This dissolution can be accompanied by potential oscillations. The anomalous behaviour is elucidated by the concept about coverage of a certain part of mercury with a film of sparingly soluble compounds of SCN- ions with mercury. This film is formed at the end of the galvanostatic dissolution on certain places of the electrode surface covered with mercury droplets, where SCN- ions are much exhausted as a result of a high current density.

Self-Adjusting Characterization for Steady-State, Direct Current Cathode-Dominated Glow Discharge Plasmas at High Pressures

2013 ◽  
Vol 30 (8) ◽  
pp. 085201 ◽  
Author(s):  
Fang Ding ◽  
Shi-Jian Zheng ◽  
Bo Ke ◽  
Zhong-Liang Tang ◽  
Yi-Chuan Zhang ◽  
...  
Keyword(s):  
Steady State ◽  
Glow Discharge ◽  
Direct Current ◽  
High Pressures ◽  
Discharge Plasmas
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