Impedance Study of Adsorption of Chloride Ions in Ethanol on Bi(001) Single Crystal Plane

2003 ◽  
Vol 68 (9) ◽  
pp. 1555-1571 ◽  
Author(s):  
Mart Väärtnõu ◽  
Enn Lust
Keyword(s):  
Experimental Data ◽  
Single Crystal ◽  
Electrode Potential ◽  
Chloride Ions ◽  
Crystal Plane ◽  
Potential Range ◽  
Diffusion Resistance ◽  
Ionic Charge ◽  
Electrode Potentials ◽  
Adsorption Capacitance

The impedance spectra for Bi(001) single crystal plane in 0.1, 0.02 and 0.003 M LiCl solutions in ethanol have been measured. It was found that reproducible experimental data for Bi electrode in ethanol solutions could be obtained at ac frequencies between 0.1 and 10 000 Hz and electrode potentials from -1.6 to -0.2 V (vs saturated calomel electrode). Outside this potential region, faradaic processes were detected. By fitting the experimental data to various equivalent circuits it was found that the Frumkin-Melik-Gaikazyan model yields good fit in almost the whole potential range studied. Using this model the dependences of "true" and adsorption capacitance as well as diffusion resistance on electrode potential have been obtained. The ionic charge due to the specific adsorption has been obtained using the mixed-electrolyte method for both electrode charge and electrode potential as the independent electric variables. The Gibbs energy of adsorption of Cl- ions has been calculated using a simple virial adsorption isotherm. It was found that the adsorption of Cl- anion increases in the order methanol < ethanol < propan-2-ol. It was found that on the Bi(001) plane the electrosorption valency has a constant value in the potential range studied. It was concluded that the formed effective surface dipole is significantly screened by the solvent molecules and the metal electron gas.

Effects of Stress and Plastic Deformation on the Corrosion of Steel

CORROSION ◽  
1970 ◽  
Vol 26 (5) ◽  
pp. 189-199 ◽  
Author(s):  
W. D. FRANCE
Keyword(s):  
Plastic Deformation ◽  
Electrochemical Techniques ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
Dissolution Behavior ◽  
Potential Range ◽  
Chemical Corrosion ◽  
Effects Of Ph ◽  
Current Densities ◽  
The Stability

Abstract The rate and type of corrosion exhibited by mild steel in the annealed, stressed, and plastically deformed state have been investigated. Precise electrochemical techniques provided potential and polarization data to supplement the results of chemical corrosion tests. Experiments were conducted in 0.6M NH4NO3 solutions in which steel exhibits active-passive dissolution behavior as well as localized corrosion. At active potentials, the anodic polarization curves for annealed and deformed specimens were nearly identical, with only slight increases in current densities for the deformed steel. Results at passive potentials demonstrated that increased plastic deformation can markedly decrease the passive potential range, the stability of passivity, and the ability to passivate. At certain passive potentials, the deformed steel exhibited current densities that were 400 times greater than those for annealed steel. The effects of pH, chloride ions, and crevices on the corrosion of deformed steel were examined in detail. The differences between the dissolution behavior of annealed and deformed steel were most distinctive in the approximate pH range of 3 to 6. This work is relevant to the understanding of the initiation of localized corrosion and to anodic protection.

Structural Systematics of Rare Earth Complexes. VII. Crystal Structure of Bis(2,2'/6',2␛-Terpyridinium) Octaaquaterbium(III) Heptachloride Hydrate

1994 ◽  
Vol 47 (2) ◽  
pp. 391 ◽  
Author(s):  
CJ Kepert ◽  
BW Skeleton ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rare Earth ◽  
Single Crystal ◽  
Structural Characterization ◽  
Title Compound ◽  
Room Temperature ◽  
Chloride Ions ◽  
Full Matrix ◽  
X Ray

The room-temperature single-crystal X-ray structural characterization of the title compound (tpyH2)2[Tb(OH2)8]Cl7.~2⅓H2O is recorded. Crystals are triclinic, Pī , a 17.063(5), b 16.243(3), c 7.878(3) Ǻ, α 84.78(2), β 84.39(3), γ 87.81(2)°, Z = 2 formula units; 3167 'observed' diffractometer reflections were refined by full-matrix least-squares procedures to a residual of 0.057. Notable features of interest of the compound are the 'chelation' of chloride ions by the terpyridinium cations , and the existence of a free [Tb(OH2)8]2+ cation in the presence of an abundance of chloride ions.

X-Ray Fractography of Stress Corrosion Cracking in Aisi 4340 Steel Under Controlled Electrode potential

1987 ◽  
Vol 31 ◽  
pp. 269-276 ◽  
Author(s):  
Masaaki Tsuda ◽  
Yukio Hirose ◽  
Zenjiro Yajima ◽  
Keisuke Tanaka
Keyword(s):  
Residual Stress ◽  
Fracture Surface ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Electrode Potential ◽  
Diffraction Method ◽  
Corrosion Cracking ◽  
Fracture Mechanisms ◽  
X Ray ◽  
Electrode Potentials

The residual stress left on the fracture surface is one of the important parameters in X-ray fractography and has been used to analyze fracture mechanisms in fracture toughness and fatigue tests especially of high strength steels.In the present paper, the distribution of residual stress beneath the fracture surface made by stress corrosion cracking was measured by the X-ray diffraction method. Stress corrosion cracking tests were conducted by using compact tension specimens of 200°C tempered AISI steel in 3.5% NaCl solution environment under various electrode potentials. The effect of electrode potential on the growth kinetics of stress corrosion cracking is discussed on the basis of residual stress distribution.

Thermal Conductivity of Ultra Thin Single Crystal Silicon Layers: Part II — Experimental Data and Modeling at High Temperatures

2004 ◽  
Author(s):  
Wenjun Liu ◽  
Mehdi Asheghi ◽  
K. E. Goodson
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Single Crystal ◽  
High Temperatures ◽  
Single Crystal Silicon ◽  
Silicon Layer ◽  
Silicon On Insulator ◽  
Boltzmann Transport ◽  
Crystal Silicon ◽  
Strained Si

Simulations of the temperature field in Silicon-on-Insulator (SOI) and strained-Si transistors can benefit from experimental data and modeling of the thin silicon layer thermal conductivity at high temperatures. This work presents the first experimental data for 20 and 100 nm thick single crystal silicon layers at high temperatures and develops algebraic expressions to account for the reduction in thermal conductivity due to the phonon-boundary scattering for pure and doped silicon layers. The model applies to temperatures range 300–1000 K for silicon layer thicknesses from 10 nm to 1 μm (and even bulk) and agrees well with the experimental data. In addition, the model has an excellent agreement with the predictions of thin film thermal conductivity based on thermal conductivity integral and Boltzmann transport equation, although it is significantly more robust and convenient for integration into device simulators. The experimental data and predictions are required for accurate thermal simulation of the semiconductor devices, nanostructures and in particular the SOI and strained-Si transistors.

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