Alternating-Current Impedance Measurements Applied to Corrosion Studies and Corrosion-Rate Determination

2009 ◽  
pp. 150-150-17 ◽  
Author(s):  
I Epelboin ◽  
C Gabrielli ◽  
M Keddam ◽  
H Takenouti
Keyword(s):  
Corrosion Rate ◽  
Alternating Current ◽  
Impedance Measurements ◽  
Corrosion Studies

scholarly journals ELECTRIC IMPEDANCE OF SINGLE MARINE EGGS

1938 ◽  
Vol 21 (5) ◽  
pp. 591-599 ◽  
Author(s):  
Kenneth S. Cole ◽  
Howard J. Curtis
Keyword(s):  
Preliminary Data ◽  
Sea Water ◽  
Membrane Conductance ◽  
Glass Tube ◽  
Alternating Current ◽  
Electric Impedance ◽  
Frequency Range ◽  
Impedance Measurements ◽  
Membrane Capacity ◽  
Thin Walled

Alternating current impedance measurements have been made on several single marine eggs over the frequency range from 1 to 2500 kilocycles per second. The eggs were placed in the center of a short capillary made by heating the end of a 2 mm. thin walled glass tube until it nearly closed, and electrodes were placed in the sea water on each side of the egg. When it is assumed that the membrane conductance is negligible, the membrane capacity and internal resistances of unfertilized and fertilized Arbacia eggs agree with the values obtained from suspensions. Preliminary data on centrifugally separated half Arbacia eggs, and whole Cumingia and Chaetopterus eggs are given.

Laser Welding Influence on Corrosion Rate of Galvanized Sheets of DP600 Automobilistic Alloy

2020 ◽  
Vol 1012 ◽  
pp. 436-440
Author(s):  
Viviane Teleginski Mazur ◽  
Sílvia Rosa Nascimento ◽  
Marilei de Fátima Oliveira ◽  
Willer Cézar Braz ◽  
Correard Gilson Carlos de Castro ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Open Circuit Potential ◽  
Scanning Speed ◽  
Open Circuit ◽  
Galvanized Steel ◽  
Beam Power ◽  
Laser Weld ◽  
Corrosion Studies ◽  
Laser Beam Power ◽  
Rate Behavior

Corrosion rate behavior of laser welded dual-phase galvanized steel, DP 600, has been assessed in comparison with the material without the laser weld, in 3.5% NaCl solution. Three combinations of both scanning speed and laser power parameters were selected, maintaining the thermal input of 30 J mm-1, calculated as the ratio between the laser beam power [W] and the scanning speed [mm s-1]. The corrosion studies included measurements of open circuit potential, micro and macro polarization, showing higher corrosion rates as scanning speed decreased. Optical microscopy showed the formation of a grain size refined morphology in the heat affected zone and fusion zone. A mechanism has been proposed to explain the corrosion behavior as a function of the laser parameters, which dictated the galvanized coating vaporization.

Aluminium corrosion studies. II. Corrosion rates in water

1977 ◽  
Vol 30 (4) ◽  
pp. 721 ◽  
Author(s):  
A Berzins ◽  
JV Evans ◽  
RT Lowson
Keyword(s):  
Corrosion Rate ◽  
Dissolved Oxygen ◽  
Chloride Concentration ◽  
Chloride Ions ◽  
Oxide Surface ◽  
Corrosion Rates ◽  
Saturated Water ◽  
Corrosion Studies ◽  
Competitive Action ◽  
Ph Range

The corrosion rate of aluminium in flowing neutral waters at 50�C has been determined as a function of pH, oxygen concentration and chloride concentration. The corrosion rate, At, as total aluminium lost between the 4th and 80th day was observed to be logarithmic according to At = B log t+C with a minimum rate in the pH range 5-6, and with B c. 3 x 10-5g cm2, C c. 20 x 10-5 g cm-2 and t in days for oxygen-saturated water. Saturating the water with nitrogen or adding up to 15 mg Cl- l-1 increased the corrosion rate. It was concluded that this was due to competitive action on the oxide surface, between dissolved oxygen and chloride ions.

scholarly journals Corrosion of Biocompatible Mg66+xZn30-xCa4 (x=0.2) Bulk Metallic Glasses

2016 ◽  
Vol 61 (2) ◽  
pp. 807-810 ◽  
Author(s):  
R. Nowosielski ◽  
K. Cesarz-Andraczke ◽  
P. Sakiewicz ◽  
A. Maciej ◽  
A. Jakóbik-Kolon ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
X Ray Diffraction ◽  
Electrochemical Tests ◽  
Simulated Environment ◽  
Corrosion Studies ◽  
Physiological Fluid

Abstract The aim of this paper was to investigate the corrosion resistance of Mg66Zn30Ca4 and Mg68Zn28Ca4 metallic glasses and evaluate the ability of this amorphous alloy use for medical applications as biodegradable medical implants. Taking into account the amount of Mg, Zn, Ca elements dissolved in multielectrolyte physiological fluid (MPF) from Mg66+xZn30-xCa4 (x=0.2) alloys the daily dose of evolved ions from alloys components was determined. Additional goal of the paper was determination of corrosion rate (Vcorr) and amount of hydrogen evolved from amorphous magnesium alloys in simulated environment of human body fluids during 24h immersion and during electrochemical tests. Corrosion studies were done in the multielectrolyte physiological fluid (MPF) at 37°C. The amount of hydrogen evolved [ml/cm2] and corrosion rate Vcorr [mm/year] of amorphous Mg66Zn30Ca4 and Mg68Zn28Ca4 alloys were compared. The work also presents characterization of Mg-based bulk metallic glasses structure in the form of 2 mm thickness plates. Samples structure was analyzed by means of X-ray diffraction. Fracture and surface morphology of magnesium alloy samples were identified using scanning electron microscopy.

Corrosion of Pipeline Steel in the Presence of Alternating Current and the New CP Recommendation

2010 ◽  
Author(s):  
A. Q. Fu ◽  
Y. F. Cheng
Keyword(s):  
Corrosion Rate ◽  
Current Density ◽  
Cathodic Protection ◽  
Pitting Corrosion ◽  
Pipeline Steel ◽  
Alternating Current ◽  
National Association ◽  
Ac Current ◽  
Ac Interference ◽  
Full Protection

The alternating current (AC)-induced corrosion of a cathodically protected X65 pipeline steel was studied in a high pH, concentrated carbonate/bicarbonate solution. Results demonstrated that the corrosion rate of the steel increases with the AC current density, and AC interference could increase the pitting corrosion of the steel. In the absence of AC interference or at a low AC current density, i.e., 20 A/m2, a cathodic protection (CP) potential of −950 mV(Cu/CuSO4 electrode, CSE), which is 100 mV more cathodic than −850 mV(CSE) recommended by National Association of Corrosion Engineers (NACE), provides a full protection over the steel. When the AC current density is higher than 20 A/m2, the NACE-recommended CP is incapable of protecting the pipeline from corrosion. A new CP standard is thus developed for recommendation to industry to avoid AC corrosion of pipelines.

Corrosion of Iron in an H2S-CO2-H2O System

CORROSION ◽  
1962 ◽  
Vol 18 (3) ◽  
pp. 119t-124t ◽  
Author(s):  
EDWARD C. GRECO ◽  
WILLIAM B. WRIGHT
Keyword(s):  
Hydrogen Sulfide ◽  
Corrosion Rate ◽  
Partial Pressure ◽  
Stress Cracking ◽  
Corrosion Studies ◽  
Partial Pressures ◽  
Sulfide Stress ◽  
Initial Drop ◽  
Corrosion Of Iron ◽  
Relationship Of

Abstract Corrosion studies of iron in an H2S-CO2-H2O System were made under static and dynamic conditions. The data indicated that there existed a certain hydrogen sulfide partial pressure, approximately 0.02 psia, above which hydrogen blistering occurred. Similar results with sulfide stress cracking were obtained. The hydrogen sulfide partial pressure at onset of cracking was 0.150 psia. Hydrogen sulfide became the controlling factor at very low partial pressures causing an initial drop in the corrosion rate. Apparently, the type of corrosion film formed controlled the corrosion rate. Changes in these films were observed to take place coincident with changes in corrosion rate and prevalence of hydrogen blisters. The relationship of these phenomena is discussed. 6.2.2, 8.4.3, 3.2.2, 3.5.8

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