Anodic behavior of silver in alkaline solutions

1969 ◽  
Vol 47 (22) ◽  
pp. 4253-4266 ◽  
Author(s):  
M. J. Dignam ◽  
H. M. Barrett ◽  
G. D. Nagy
Keyword(s):  
Film Thickness ◽  
The Other ◽  
Alkaline Solutions ◽  
Precipitation Process ◽  
Anodic Behavior ◽  
Silver Electrodes ◽  
Galvanostatic Conditions ◽  
Highly Porous ◽  
Silver Metal ◽  
Period Of Oscillation

Data, covering a range of pH and temperature, were obtained for the anodic oxidation of electropolished silver and the results compared with electrodes which had undergone repeated oxidation and reduction cycles. The behavior of the electrode is, in the main, complex, showing, for example, autopotential cycling under certain galvanostatic conditions (∼3 μA/cm2, 25 °C, 0.7 N NaOH), the period of oscillation being about [Formula: see text]. Several other hitherto unreported phenomena were also observed. The main conclusions reached are (i) that 2 different mechanisms are involved in the anodic formation of Ag2O on silver electrodes in basic electrolytes resulting in 2 types of film, 1 mechanism involves a dissolution–precipitation process, the other possibly a direct interfacial reaction; (ii) that the reduction of anodically formed Ag2O films either electrochemically or in hydrogen at 800 °C leaves behind a highly porous layer of silver metal; and (iii) that the limiting Ag2O film thickness is probably determined by a diffusion process occurring within the film.

A dynamical method for the determination of Young's modulus by stretching

1928 ◽  
Vol 24 (2) ◽  
pp. 276-279
Author(s):  
C. F. Sharman
Keyword(s):  
Young’S Modulus ◽  
Elastic Constants ◽  
Young's Modulus ◽  
The Other ◽  
Static Deformation ◽  
Elastic Forces ◽  
Dynamical Method ◽  
Period Of Oscillation

There are two general methods of measuring the elastic constants of bodies; one involves a study of the static deformation produced by the appropriate kind of stress, and the other a measurement of the period of oscillation of a system of known inertia under the elastic forces.

Breakthrough of Sublimation Drying by Liquid Phase Deposition

2021 ◽  
Vol 314 ◽  
pp. 172-177
Author(s):  
Yuta Sasaki ◽  
Yousuke Hanawa ◽  
Masayuki Otsuji ◽  
Naozumi Fujiwara ◽  
Masahiko Kato ◽  
...  
Keyword(s):  
Free Energy ◽  
Liquid Phase ◽  
Film Thickness ◽  
Process Parameters ◽  
Interfacial Free Energy ◽  
The Other ◽  
Liquid Phase Deposition ◽  
Drying Method ◽  
Substrate Side ◽  
Drying Technology

Damage-free drying becomes increasingly difficult with the scaling of semiconductor devices. In this work, we studied a new sublimation drying technology for 3nm node and beyond. In order to investigate the collapse factor by conventional sublimation drying, we observed the pattern with cryo-SEM and revealed that the collapse occurred when the liquid film on the substrate solidified. Based on this result, we considered that it was important to deposit a solidified film uniformly from the substrate side to suppress collapse. Two key process parameters were evaluated to achieve the uniform formation of the solidified film. One is interfacial free energy and the other is film thickness of solution just before solidification. By optimizing two key parameters, it was successfully demonstrated to suppress pattern collapse of challenging devices. In this paper, we report on a new drying method: sublimation drying by LPD (Liquid-phase deposition).

Uranium(VI) Uptake by Synthetic Calcium Silicate Hydrates

2008 ◽  
Vol 1107 ◽  
Author(s):  
J. Tits ◽  
T. Fujita ◽  
M. Tsukamoto ◽  
E. Wieland
Keyword(s):  
Solid Phase ◽  
Near Field ◽  
Sorption Isotherms ◽  
Alkaline Solutions ◽  
Precipitation Process ◽  
Direct Reaction ◽  
Reaction Method ◽  
Calcium Silicate Hydrates ◽  
Chemical Conditions ◽  
Co Precipitation

AbstractThe immobilization of U(VI) by C-S-H phases under conditions relevant for the cementitious near field of a repository for radioactive waste has been investigated. C-S-H phases have been synthesized using two different procedures: the “direct reaction” method and the “solution reaction” method.The stabilities of alkaline solutions of U(VI) (presence of precipitates or colloidal material) were studied prior to sorption and co-precipitation tests in order to determine the experimental U(VI) solubility limits. These U(VI) solubility limits were compared with the U(VI) solubilities obtained from thermodynamic speciation calculations assuming the presence of combinations of different solid U(VI) phases. The solid phase controlling U(VI) solubility in the present experiments was found to be CaUO4(s).The U(VI) uptake kinetics and sorption isotherms on C-S-H phases with different C:S ratios were determined under various chemical conditions; e.g., sorption and co-precipitation experiments and different pH’s. U(VI) was found to sorb fast and very strongly on C-S-H phases with distribution ratios (Rd values) ranging in value between 103 L kg-1 and 106 L kg-1. Both sorption and co-precipitation experiments resulted in Rd values which were very similar, thus indicating that no additional sorption sites for U(VI) were generated in the co-precipitation process. Furthermore, C-S-H synthesis procedures did not have a significant influence on U(VI) uptake. The U(VI) sorption isotherms were found to be non-linear, and further, increasing Ca concentrations resulted in increasing U(VI) uptake. The latter observation suggests that U(VI) uptake is controlled by a solubility-limiting process, while the former observation further indicates that pure Ca-uranate is not the solubility-limiting phase. It is proposed that a solid solution containing Ca and could control U(VI) uptake by C-S-H phases.

scholarly journals On Measuring Section Thickness

2001 ◽  
Vol 9 (4) ◽  
pp. 17-17
Author(s):  
Ron Doole
Keyword(s):  
Film Thickness ◽  
Cross Section ◽  
Accurate Result ◽  
The Other ◽  
Section Thickness ◽  
Plan View ◽  
Tilt Axis ◽  
Measuring Section ◽  
Easy Case

Section thickness can be measured by placing beads of some kind on the top and bottom surfaces of the section. This is then a simple parallax problem.Imagine the specimen in cross section. If there are two particles, one vertically above the other they are separated by the film thickness T. Tilt the film through an angle A and in plan view the particles will separate by a distance D. This can also be extended to account for two particles not vertically above each other but I'll stick to the easy case for the explanation.Take two negatives one at zero tilt and one at tilt of A and measure the separation D. The thickness can be calculated by T=D/sinA.The direction of the tilt axis must be known for the measurements and it is easy to see that the larger the tiit angle and the more accurately the separation is measured, the more accurate the measurement will be. Tilt at both positive and negative angles to get a more accurate result.

Bubble Entrapment in Sprayed Films

2014 ◽  
Author(s):  
A. Dalili ◽  
S. Chandra ◽  
J. Mostaghimi ◽  
H. T. Charles Fan ◽  
J. C. Simmer
Keyword(s):  
Surface Tension ◽  
Film Thickness ◽  
The Other ◽  
Bubble Motion ◽  
Sauter Mean Diameter ◽  
Glass Substrates ◽  
Buoyancy Forces ◽  
Mean Diameter ◽  
Imagej Software ◽  
Bubble Movement

A compressed air sprayer was used to spray model paint onto two glass substrates at the same time. Afterwards, one glass substrate was placed on a LED light source and still photographs were taken from the top using a DSLR camera with a timer system. The other substrate was put on a balance to record weight. Pictures and weight measurements were taken at 5 second intervals for 15 minutes. The sprayed film thickness was varied. The pictures were analyzed using ImageJ software. Bubble Count vs. Time, Sauter Mean Diameter (SMD) of Bubbles vs. Time as well as Weight vs. Time was plotted. It was seen that the pace of weight loss was faster for thinner films. The rate of bubble escape also depended on film thickness. It took a longer time for thicker films to lose the bubbles entrapped in them. In the first 30 seconds, large bubbles escaped due to buoyancy forces and afterwards surface-tension driven flows became dominant. There was also a lot of bubble movement in thicker films. The effect of gravity was studied as well. Gravity did not affect the bubble escape rate since a downward facing film had the same bubble count as an upward facing film confirming that bubble motion was not due to buoyancy forces alone. However, the SMD of bubbles in a downward facing film was larger than an upward facing film. Buoyancy is not a factor in bubble escape from the downward facing film and only surface-tension driven flows play a role.

scholarly journals Surface Roughness and Porosity of Hydrated Cement Pastes

10.14311/1374 ◽  
2011 ◽  
Vol 51 (3) ◽  
Author(s):  
T. Ficker ◽  
D. Martišek ◽  
H. M. Jennings
Keyword(s):  
The Other ◽  
Porous Solids ◽  
Surface Irregularity ◽  
Hydrated Cement ◽  
Cement Pastes ◽  
Cement Ratio ◽  
Fracture Surfaces ◽  
Water To Cement Ratio ◽  
The One ◽  
Highly Porous

. Seventy-eight graphs were plotted to describe and analyze the dependences of the height and roughness irregularities on the water-to-cement ratio and on the porosity of the cement hydrates. The results showed unambiguously that the water-to-cement ratio or equivalently the porosity of the specimens has a decisive influence on the irregularities of the fracture surfaces of this material. The experimental results indicated the possibility that the porosity or the value of the water-to-cement ratio might be inferred from the height irregularities of the fracture surfaces. It was hypothesized that there may be a similarly strong correlation between porosity and surface irregularity, on the one hand, and some other highly porous solids, on the other, and thus the same possibility to infer porosity from the surfaces of their fracture remnants.

The Influence of Thin Film Thickness on the Characteristics of Bismuth Titanate Oxide

2007 ◽  
Vol 336-338 ◽  
pp. 129-132
Author(s):  
Cheng Fu Yang ◽  
Wei Kuo Chia ◽  
Ying Chung Chen ◽  
Chien Min Cheng
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Room Temperature ◽  
Bismuth Titanate ◽  
Electrical Breakdown ◽  
Rf Magnetron Sputtering ◽  
The Other ◽  
Thin Film Thickness ◽  
Sims Analysis ◽  
Xrd Patterns

Bi4Ti3O12 thin films were deposited on Pt/Ti/Si(p-100) substrate by RF magnetron sputtering at room temperature, and crystallized in a RTA furnace at temperature of 675°C for 10 minutes. SIMS analysis identifies that bismuth content in the Bi4Ti3O12 thin film reduced slightly from the surface into a depth of approximately 200 nm. XRD patterns revealed (117) phase was dominated regardless the film thickness, and the intensity of the other peaks increased with the increase of film thickness. (200) peak became dominant when the thickness of films were greater than 680 nm. SEM observation showed that the grains were stripe plate-like, and the grain size increased with the increase of film thickness. Dielectric constant increased with the increase of film thickness, and kept around a certain value with the thickness ranging from 300 to 640 nm, then it rose again as the film thickness above 680 nm. The leakage current and electrical breakdown also strongly depended on the film thickness.

Correlation between global thermodynamic functions and experimental data in multicomponent heterogeneous systems

2016 ◽  
Vol 94 (2) ◽  
pp. 113-119 ◽  
Author(s):  
Igor Povar ◽  
Oxana Spinu
Keyword(s):  
Experimental Data ◽  
Thermodynamic Functions ◽  
Solid Phase ◽  
Heterogeneous Systems ◽  
Thermodynamic Characteristics ◽  
Alkaline Solutions ◽  
Precipitation Process ◽  
Mutual Transformation ◽  
Homogeneous Solutions ◽  
Different Temperatures

The correlation between global thermodynamic functions and such experimental data, which quantitatively characterize the precipitation–dissolution processes of sparingly soluble compounds, as the degree of precipitation and residual concentrations of the solid-phase components in saturated solutions under real conditions, taking into account the complex formation reactions, has been deducted. The paper intends also to introduce widely formal thermodynamic methods for forecasting the conditions of mutual transformation of solid phases through chemical synthesis by precipitation methods, optimization of coprecipitation methods, fractional precipitation from homogeneous solutions, and separation and analysis of chemical compounds. Within the method of residual concentrations, the thermodynamic parameters of the process of precipitating cadmium ions with potassium decanoate from acid and alkaline solutions for different temperatures were investigated. On the basis of the experimentally determined degree of precipitation and its dependence on temperature, the temperature coefficients and overall thermodynamic characteristics of the precipitation process ([Formula: see text], [Formula: see text], and [Formula: see text]) were determined. The optimum conditions of the investigated process of precipitation have been established.

Reliability of Railroad Roller Bearings

1977 ◽  
Vol 99 (1) ◽  
pp. 30-36
Author(s):  
J. M. McGrew ◽  
A. I. Krauter ◽  
G. J. Moyar
Keyword(s):  
Fatigue Life ◽  
Film Thickness ◽  
The Other ◽  
Bearing Failure ◽  
Lubricant Film Thickness ◽  
Defect Modes ◽  
Roller Bearings ◽  
Defect Rate ◽  
Bearing Defect ◽  
The Relationship

Bearing defect data from 8,000 railroad roller bearings are analyzed to determine their defect modes and defect rate distributions. Cone bore growth, brinelling, and fatigue are identified as the predominant defect modes as bearings age at least through age 12 years. The results of the study show that, after only two years of service, ten percent of all railroad roller bearings exhibit a defect of one type or another for which at least one component would be condemned if it were in a rework shop. The present AFBMA method of calculating fatigue spalling, modified to account for lubricant film thickness effects, correlates reasonably well with the observed incidence of spalling (10 percent fatigue life of about 11 years). The problem lies in the fact that the AFBMA calculation procedure ignores the other competing defect modes which contribute far more to the overall defect rate than does spalling. The relationship between “defect rate” and “failure rate” is not direct, of course, and an examination of “condemning limit” definitions relative to the progression of bearing failure in service is needed.

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