THE BEHAVIOR OF LEAD ELECTRODES IN SULPHURIC ACID SOLUTIONS

1964 ◽  
Vol 42 (6) ◽  
pp. 1355-1364 ◽  
Author(s):  
K. Ekler
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Current Density ◽  
The Self ◽  
Acid Solutions ◽  
Time Data ◽  
Passivation Time ◽  
Lead Electrodes ◽  
Passivation Potential

Lead electrodes were anodically etched in NH2SO3H. Immersion potentials, self-passivation potentials, passivation times, PbO2/O2 potential, and the potential of the first discharge plateau were determined in H2SO4 solutions ranging from 0.5 to 20.0 N and were found to be concentration-dependent. Interruption of the anodizing current had no detectable influence on passivation time. Data obtained with the anodizing current turned on fall into three categories; those obtained with (1) short-immersion anodes, (2) anodes which had reached a hydrogen-like potential, and (3) anodes which were self-passivated before the current was switched on. An inflection in the relation between potential and time during charging was investigated. Its length was dependent upon acid concentration and current density, while its potential was +300 ± 30 mv, and seemed to correspond to the self-passivation potential. The lengths of the first and second discharge plateaus increased with the number of coulombs passed and were dependent upon acid concentration, but were identical for electrodes treated by four different methods. The hydrogen-like potential appeared to be due to the presence of PbO•PbSO4. The self-passivation potential seemed to be caused by formation of PbO.

Behavior of lead electrodes in sulfuric acid solutions. II

1969 ◽  
Vol 47 (12) ◽  
pp. 2191-2196 ◽  
Author(s):  
E. Tarter ◽  
K. Ekler
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Discharge Rate ◽  
Acid Solutions ◽  
Stabilizing Effect ◽  
Two Factors ◽  
Passivation Time ◽  
Lead Electrodes ◽  
Sulfuric Acid Solutions

An attempt was made to clarify the question whether the variation in the length of the "first discharge plateau" with change in H2SO4 concentration was caused by a change in the efficiency of PbO2 formation or by a variation in its discharge rate. The relationships between acid concentration, "passivation time", amount of PbSO4 formed during passivation, and the quantity of PbO2 derived therefrom during charging were investigated. The amount of PbSO4 on the anode increased with a decrease in passivating acid concentration. More PbO2 was formed at lower charging acid concentrations. The higher the discharge acid concentration, the greater was its stabilizing effect on PbO2 discharge. The combination of two factors, i.e. a decrease of the amount of PbO2 formed at higher acid concentrations together with an increase in the PbO2 stability, gave rise to the maximum 10.5 N H2SO4.

Effect of current density and perchloric acid concentration on the formation of lead anodes in sulphuric acid baths

1972 ◽  
Vol 23 (2) ◽  
pp. 105-109 ◽  
Author(s):  
A. Ragheb ◽  
W. Machu ◽  
W. H. Boctor
Keyword(s):  
Sulphuric Acid ◽  
Acid Concentration ◽  
Current Density ◽  
Perchloric Acid

Anodic Polarization Behavior Of Nickel-Chromium Alloys In Sulfuric Acid Solutions

CORROSION ◽  
1965 ◽  
Vol 21 (9) ◽  
pp. 277-287 ◽  
Author(s):  
J. R. MYERS ◽  
F. H. BECK ◽  
M.G. FONTANA
Keyword(s):  
Sulfuric Acid ◽  
Critical Current Density ◽  
Critical Current ◽  
Acid Concentration ◽  
Current Density ◽  
Anodic Polarization ◽  
Chromium Content ◽  
Acid Solutions ◽  
Polarization Behavior ◽  
Sulfuric Acid Solutions

Abstract Anodic polarization behavior of annealed high-purity Ni, Cr and selected Ni-Cr alloys in hydrogen-saturated, 1, 5, 10 and 20N sulfuric acid solutions was investigated at 25 ± 1 C (77 F) using a potentiostatic technique. All specimens except pure Ni in 20N acid had an active-to-passive transition. Decreasing acid concentration increased passive potential range of pure Ni while acid concentration did not appreciably affect the passive region of pure Cr or the Ni-Cr alloys. Increasing acid concentration and decreasing chromium content increased the secondary passivation tendency in the transpassive region. No oxygen evolved in the transpassive region except for pure Ni and the higher nickel alloys. Tafel slopes for anodic dissolution, early transpassive region and oxygen evolution were determined. Corrosion potentials for pure Ni and Ni-Cr alloys containing up to 90 w/o Cr behaved as a reversible hydrogen electrode over the pH range 1.63 to −0.44. This linear relationship did not exist for the higher acid concentrations. Slope dependence for pure Cr and the 99Cr-1Ni alloy was −0.110. A minimum in critical current density versus percent Cr curves was established at 90 to 95 w/o Cr. Passivation potentials were determined. Passive current density decreased with increasing chromium content over the composition range 0 to 33 w/o Cr. It was established that increased specimen purity decreases the magnitude of critical current density and shifts corrosion and passivation potentials in the noble potential direction.

The oxidation of porous lead electrodes in sulphuric acid solutions

1979 ◽  
Vol 4 (1) ◽  
pp. 21-32 ◽  
Author(s):  
N.A. Hampson ◽  
J.B. Lakeman
Keyword(s):  
Sulphuric Acid ◽  
Acid Solutions ◽  
Lead Electrodes

Surface preparation of planar lead electrodes for electrochemical studies in sulphuric acid solutions

1991 ◽  
Vol 34 (4) ◽  
pp. 289-301 ◽  
Author(s):  
K. Murugan ◽  
P.G. Balakrishnan ◽  
P.V. Vasudeva Rao
Keyword(s):  
Sulphuric Acid ◽  
Surface Preparation ◽  
Electrochemical Studies ◽  
Acid Solutions ◽  
Lead Electrodes

THE HYDROLYSIS OF PROPIONITRILE IN CONCENTRATED SOLUTIONS OF MINERAL ACIDS

1942 ◽  
Vol 20b (8) ◽  
pp. 168-173 ◽  
Author(s):  
J. D. McLean ◽  
B. S. Rabinovitch ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Sulphuric Acid ◽  
Acid Concentration ◽  
Rate Increase ◽  
Acid Solutions ◽  
Concentrated Solutions ◽  
Consecutive Reactions ◽  
Mineral Acids ◽  
Hydrolysis Of

The study of the hydrolysis of propionitrile in concentrated acid solutions has been extended to hydrobromic, nitric, and sulphuric acids for a range of acid concentrations. For the system of irreversible, unimolecular consecutive reactions, nitrile [Formula: see text] amide [Formula: see text] acid, [Formula: see text] for all acid concentrations below 4 N. At higher concentrations, k1 and k2 are of the same order, and, in the case of sulphuric acid, k1 becomes [Formula: see text]k2 at concentrations above 20 N. The observed activation energy decreases with increasing acid concentration for all acids. The specific differences in rate increase with acid concentration may be accounted for by the specific variations of A and E for each acid.

The role of surface crystalline heterogeneities in the electrooxidation of carbon monoxide adsorbed on Rh(111) electrodes in sulphuric acid solutions

1997 ◽  
Vol 432 (1-2) ◽  
pp. 1-5 ◽  
Author(s):  
Roberto Gómez ◽  
JoséM. Orts ◽  
Juan M. Feliu ◽  
Jean Clavilier ◽  
Lorena H. Klein
Keyword(s):  
Carbon Monoxide ◽  
Sulphuric Acid ◽  
Acid Solutions

Extraction of TcO-4 Ions by Use of Crown Ethers from Sulphuric Acid Solutions

1986 ◽  
Vol 39 (4) ◽  
Author(s):  
M. G. JALHOOM
Keyword(s):  
Sulphuric Acid ◽  
Crown Ethers ◽  
Acid Solutions

Study of the Effect of Hole Clearance and Thread Fit on the Self-Loosening of Threaded Fasteners

2006 ◽  
Vol 129 (6) ◽  
pp. 586-594 ◽  
Author(s):  
Sayed A. Nassar ◽  
Basil A. Housari
Keyword(s):  
Analytical Investigation ◽  
The Self ◽  
Time Data ◽  
Experimental Procedure ◽  
Test Setup ◽  
Threaded Fasteners ◽  
Service Load ◽  
Real Time Data ◽  
Theoretical Results ◽  
Simplified Mathematical Model

This study provides an experimental and theoretical investigation of the effect of hole clearance and thread fit on the self-loosening of tightened threaded fasteners that are subjected to a cyclic transverse service load. An experimental procedure and test setup are developed in order to collect real-time data on the rate of clamp load loss per cycle as well as the loosening rotation of the bolt head. Three levels of hole clearance are investigated; namely, 3%, 6%, and 10% of the bolt nominal diameter. For the commonly used 2A thread fit for a selected bolt size, three classes of the nut thread fit are considered; namely, 1B, 2B, and 3B. A simplified mathematical model is used for the analytical investigation of the effect of the hole clearance and thread fit on threaded fasteners self-loosening. The experimental and theoretical results are presented and discussed.

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