Polarization Resistance Method Research Articles

冷却水系における軟鋼の腐食モニター法としての直線分極抵抗法の適用

冷却水系における軟鋼の腐食モニター法としての直線分極抵抗法の適用

Quantitative measurements of corrosion rate of reinforcing steels embedded in concrete using polarization resistance measurements

AbstractUp to this time all the methods to measure the corrosion rate of reinforcing steels embedded in hardened concrete have been of the destructive type, which requires much time and materials and makes the full scale study of the phenomenon difficult. The authors have applied the polarization resistance method to bars embedded in hardened mortar and immersed in Ca(OH)2‐saturated solution, and have found an acceptable agreement between the gravimetric and the electrochemical weight loss data.

Determination of the instantaneous rate of atmospheric corrosion

AbstractAn attempt has been made to determine the applicability of Stern's (or polarisation resistance) method for obtaining a reliable evaluation of the instantaneous rate of atmospheric corrosion.The tests carried out so far have revealed a good agreement between electrochemically obtained information on the influence of various corrosion factors and their real effect on the attack of metals when exposed to the atmosphere.

分極抵抗法による化学銅めっきの析出速度

The rate of plating of copper in an iminodiacetate bath for electroless plating use was measured with the polarization resistance method for the monitoring of aging of the bath. The polarization resistance method well accepted in the field of corrosion study has been applied to the electroless plating. The rate of copper deposition estimated from the polarization resistance method was compared with that obtained from the gravimetric method in various concentrations of copper ion and formaldehyde, at different pH values and plating time. Results showed that the polarization resistance was inversely proportional to the average plating rate estimated from weight gain, as expected from the equation of polarization resistance;Rp=babc/2.3ipl(ba+bc)=K/iplwhere Rp is the polarization resistance, ipl the plating rate, ba and bc are the Tafel slopes of anodic and cathodic polarization curves respectively, and K a constant. The iminodiacetate bath yielded 0.12 for K, the value of which depends on the species of metallic ions, reductants and ligands. It is concluded that in laboratory tests the polarization resistance method can be used for the measurement of the rate of plating of copper in the electroless plating bath as well as for the monitoring of the aging of the electroless plating bath.

An Evaluation of Polarization Resistance Measurements

AbstractThe linear polarization, polarization resistance, threepoint and CORFIT method have been used to determine polarization resistance values for 4130 Steel in inhibited HCl. From the three‐point and the CORFIT method the corrosion current and the Tafel slopes are obtained directly. A comparison of the results obtained by the four methods and an application to on‐line monitoring of inhibitor levels in pickling baths are given.

Problems arising in the determination of accurate corrosion rates from polarization resistance measurements

The Stern-Geary polarization resistance method is a fast, sensitive electrochemical method for the evaluation of instantaneous corrosion rate. This paper outlines the general theory and usefulness of the method, identifies the main sources of error and suggests how these can be minimised. Topics covered are: advantages and disadvantages, theory and development of the method and main sources of error. This latter section is subdivided into: time dependence of the electrode's response to polarization; use of Transient Linear Polarization modification for measurement of low corrosion rates; separation of mass transfer effects from the response; different methods of polarization; effect of resistance polarization and its elimination; errors caused by neglect of curvature in polarization curves near the corrosion potential; methods for measuring Tafel slopes for conversion of polarization resistance to corrosion rate; problems occurring when the corrosion potential approaches equilibrium potentials; correlation of results with those obtained by other methods, and non uniform corrosion.

Theoretical Basis for the Determination of Corrosion Rates from Polarisation Resistance: Report prepared for the European Federation of Corrosion Working Party on ‘Physicochemical Testing Methods of Corrosion—Fundamentals and Application’

The polarisation resistance method is extensively used for corrosion rate measurement. This paper considers the theoretical conditions which must be satisfied in the measurement of polarisation resistance and the limitations of the applicability of the method in relation to the properties of the electrolyte, the kinetics of the anodic and cathodic processes, and the surface condition of the corroding metal.

Application of the Polarization Resistance Method to the Study of Lead Corrosion in Sulphuric Acid

AbstractThe corrosion rates and their evolution with time of lead alloys in hot‐concentrated sulphuric acid have been evaluated through polarization resistance measurements. For the case of alloys capable of being self‐passivated and of retaining the passive state under the exposure conditions, accurate corrosion rates can be predicted from the electrochemical data. On the other hand, some special problems are associated with the application of the polarization method to lead alloys with exhibit alternating changes of corrosion potential between an active and a passive state. Nevertheless, the method, with some slight modifications, continues to be effective for determining corrosion rates although to a lesser degree of accuracy than with stable alloys. On the basis of the results obtained, the different mechanisms of lead alloy corrosion in sulphuric acid are outlined.

硫酸溶液中におけるチタンの腐食挙動と腐食速度の測定

The nature of corroding titanium surfaces and the meaning of polarization resistance were discussed based on the dual barrier model, and electrochemical measurements of titanium corrosion in sulfuric acids were carried out. It was confirmed from the experimental results that titanium dissolved in acid solution as trivalent ion. The corrosion potential of titanium was in a potential region which, although belonging to the active dissolution region, was close to the passive region, indicating a strong resistivity of the metal to corrosion. Analyses were made for the corrosion rate of titanium using various electrochemical methods. Among them, the polarization resistance measurement gave a fairly good estimation of the corrosion rate. A polarization resistance method was also proposed, which enabled small potential jumps produced by small current steps to be measured in a very short time interval without causing any significant changes of the surface conditions of titanium.

高温脱気塩水中における軟鋼の腐食速度測定法としての分極抵抗法の適用 (第1報)

高温脱気塩水中における軟鋼の腐食速度測定法としての分極抵抗法の適用 (第1報)

The Polarization Resistance Method for Corrosion Testing

AbstractThe measurement of the polarization resistance using AC enables the corrosion losses to be determined with certain difficulties only, Despite that the AC methods are of technical interest because they allow the determination of corrosion rate/time curves without difficulties and enable potentiel fluctuation to be easily compensated; beyond that they offer certain advantages with respect to the construction of the measuring instruments.

Applications of electrochemistry in corrosion science and in practice

In an introduction, a statement is made on the influence of electrochemistry during the last 30 or 40 y on corrosion research and technology, with reference to opinions expressed by U. R. Evans, R. Piontelli and C. Edeleanu. A section on Fundamentals and Electrochemical Testing Methods describes the action of CITCE in developing electrochemical thermodynamics and kinetics, and their applications. It mentions the pioneer work of C. Wagner and W. Traud and the statement of F. L. LaQue on the links connecting electrochemical research and corrosion research. The author recalls the statement of M. G. Fontana on the relative practical usefulness of corrosion education and corrosion research. The practical usefulness of three series of electrochemical methods is emphasized: the polarization resistance methods, the anodic and cathodic polarization methods, and the zero-current electrode potential measurements. A third section reviews some of the most important applications of electrochemistry in anticorrosion practice. The following topics are examined: Cathodic protection Historical Hydrogen embrittlement of pipe-lines; bi-adhesive wrapping material Cathodic protection by perfect passivation: general. Protection of carbon steels in solutions containing chloride. Protection of cast iron drying cylinders in the paper industry. Protection of stainless steels in chloride containing environments. Protection of copper in the presence of waters. Protection of aluminium in sea-water Sacrificial anodes Corrodible anodes for impressed currents Non-corrodible anodes for impressed currents Anodic protection Inhibitors: general. Water treatment. Engine coolants for automobiles. Passivation of galvanized iron. Vapour-phase inhibitors Protection of metals Iron and carbon steels: electrolysis of water. Boilers. Reinforcing bars and steel pipes embedded in concrete Weathering steels Titanium Developments of alloys: general. Titanium-palladium alloys. Copper-nickel alloys. Alloys for surgical implants Chemical surface treatments: prepassivation of brasses for heat-exchangers. Thermochemical protection of stainless steels and of refractory alloys Protective coatings: general. Wash-primers and other phosphate coatings on steel. Zinc-rich paints. Benzotriazole coatings. Rust-transformers. Electroplating. Anodized aluminium Design and miscellaneous High-temperature corrosion: fused salts. Solid electrolytes. In his conclusions, the author pays tribute to those to whom we are indebted for what is now corrosion science, and to those who have put this science into practice. He expresses opinions on the future of corrosion research. However, he agrees with M. G. Fontana in believing that what is presently most needed in the struggle against corrosion is not so much research as teaching, education and common sense.

The application of the polarization resistance method to the study of the corrosion behaviour of CuNi10Fe in sea-water

Alloys of the CuNiFe type owe their good corrosion qualities in sea-water to the formation of a protective layer that forms gradually. The formation of this protective film as a function of time can be followed by the polarization resistance method. The influence of the flow velocity on the formation rate can be deduced. When the protective film is damaged, for instance by the action of sulphide ions, this is easily detected by polarization resistance measurements. The methods by which the measurements are made, as well as the test loops, are shown.

Corrosion Rates off Mild Steel in Alkaline Lithium Bromide Solutions by the Polarization Resistance Method

Abstract This is an electrochemical evaluation of a chemical inhibitor on the corrosion behavior of mild steel (ASTM A-414) in solutions containing 54 percent lithium bromide and 0.2 percent lithium hydroxide at 25 C (77 F). Inhibiting effects of lithium chromate at concentrations up to 3000 ppm were studied Results are analyzed in terms of corrosion current determined from polarization resistance measurements and cathodic and anodic polarization slopes. These are compared with weight loss measurements. The system inhibited with lithium chromate behaved as expected. Corrosion current, determined from polarization resistance, decreased steadily with increasing inhibitor concentration to a limiting value above 1000 ppm. Relative corrosion rates (ratio of corrosion rate of steel in the inhibited solution to that in the uninhibited solution) agree reasonably well with weight loss measurements. Extrapolations of Tafel slopes from cathodic and anodic polarization curves to the corrosion potential suggest that in the lithium chromate inhibited system, the anodic reaction controls; whereas in the uninhibited solution, cathodic and anodic processes are equally important and lead to mixed control. Severe pitting of the steel and gel formation have been observed in a number of experiments involving lithium chromate. Hence, proper chemistry involving inhibitor concentration and alkalinity control is very critical.

Electrochemical Techniques for Measurement And Interpretation of Corrosion

Abstract Corrosion of metals proceeds by electrochemical processes in most aqueous environments. Hence, electrochemical techniques can be used to study and interpret corrosion phenomena and, in certain instances, to measure the rate of corrosion. Corrosion-potential measurements furnish information on whether the anodic or cathodic process, or both, are controlling corrosion. They may also furnish useful information on film breakdown or film repair. Measurement of the potential distribution in solution by the probe method is laborious but does afford a means of determining corrosion rate and distribution of corrosion. Some of the difficulties of the probe method can be overcome by using a rotating-electrode technique that permits direct observation of the distribution of anodic and cathodic areas. Divided-cell experiments, in which pitted areas are separated from unpitted areas, permit determination of local-cell polarization diagrams as well as rate of corrosion. The polarization behavior of corroding metal electrodes can be used in several different ways to measure the rate of corrosion. A promising recent development in this area is the polarization-resistance method, in which the initial slope of a polarization curve can be used to obtain a reliable estimate of the rate of corrosion.

Use of Polarization Methods in the Determination of the Rate of Corrosion of Aluminum Alloys in Anaerobic Media

Tafel‐type cathodic polarization curves were obtained for aluminum alloys corroding in anaerobic acid and food media. The overvoltage‐intercept method was found to give corrosion currents equivalent to the measured rates of hydrogen evolution. Tafel‐type anodic polarization curves could not be obtained. Anodic polarization curves calculated from cathodic polarization data in the vicinity of the corrosion potential gave Tafel slopes which were identical to the cathodic Tafel slope, within 20%, in each individual case. On using suitable values for the Tafel slopes in the Stern and Geary equation, the polarization resistance method likewise gave corrosion currents in good agreement with measured rates of hydrogen evolution.