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Article
Publication date: 1 February 2000

K. Darowicki and S. Krakowiak

Performed investigations by cyclic thermometry in a solution containing 1 per cent H2SO4 by weight admixed with chloride ions in 0.2 per cent quantity by weight at 553K have shown…

363

Abstract

Performed investigations by cyclic thermometry in a solution containing 1 per cent H2SO4 by weight admixed with chloride ions in 0.2 per cent quantity by weight at 553K have shown that 654SMO steel is not susceptible to pitting, while 316L steel is intensively attacked in investigation conditions. On cyclic thermograms for 316L steel three temperature zones can be distinguished. The first zone is the zone of resistance to pitting. In the third temperature zone rapid development of pits is observed. The second intermediate temperature range includes the process of initiation and formation of pits. The temperature of pitting corrosion of 316L steel depends linearly on the applied polarisation. The temperature determined by extrapolation for a polarisation equal to zero is the measure of resistance to pitting corrosion. The pitting corrosion temperature determined in this way is related to stationary conditions, with no polarisation.

Details

Anti-Corrosion Methods and Materials, vol. 47 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 April 2002

Stefan Krakowiak and Kazimierz Darowicki

Results have been presented of investigations on the effect of the temperature change rate on the critical temperature of pitting corrosion. Investigations of 316L stainless steel…

510

Abstract

Results have been presented of investigations on the effect of the temperature change rate on the critical temperature of pitting corrosion. Investigations of 316L stainless steel have been conducted by cyclic thermometry. An increase has been stated of the critical pitting temperature with increase of the temperature change rate. The dependence of the pitting critical temperature is linear in character for all investigated temperature change rates. Values of the critical temperature of pitting corrosion for stationary conditions (E−ES=0) were obtained by using the extrapolation procedure. The critical pitting temperature obtained by extrapolation practically does not depend on the temperature change rate in the investigated range and is equal to 336.9 K (63.9°C).

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Anti-Corrosion Methods and Materials, vol. 49 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 2 November 2012

Stefan Krakowiak, Kazimierz Darowicki and Kacper Jurak

The purpose of this paper is to examine the passive layer on 1050A aluminium alloy in non‐stationary conditions of linearly raised and lowered temperatures by means of dynamic…

151

Abstract

Purpose

The purpose of this paper is to examine the passive layer on 1050A aluminium alloy in non‐stationary conditions of linearly raised and lowered temperatures by means of dynamic electrochemistry impedance spectroscopy (DEIS).

Design/methodology/approach

The oxide passive layer on aluminium was examined using DEIS under non‐stationary conditions of linearly raised and lowered temperatures. In total, five heating‐cooling cycles were performed.

Findings

A significant change of impedance was observed only during the first cycle, which was called the forming one. During the subsequent cycles, the impedance of the system changed in a reversible manner.

Originality/value

The analysis using a equivalent circuit allowed us to determine a change of electric parameters of the circuit in the temperature function. Obtained changes of the electric parameters were correlated with layer structure.

Details

Anti-Corrosion Methods and Materials, vol. 59 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 February 1999

Kazimierz Darowicki and Stefan Krakowiak

Results of DC electrochemical measurements of four Ni‐base alloys are presented. The tests were conducted in 1 percent sulphuric acid, containing 0.2 percent chlorides at…

310

Abstract

Results of DC electrochemical measurements of four Ni‐base alloys are presented. The tests were conducted in 1 percent sulphuric acid, containing 0.2 percent chlorides at temperature 353K. Gravimetric test, performed in the same conditions, revealed excellent properties of alloy signed A3. Pitting corrosion of alloy A4 at the test conditions after long exposure at 353K was observed and was confirmed by the applied tests. The multiple anodic polarization (MAP) method is proposed to control alloys’ susceptibility to pitting corrosion.

Details

Anti-Corrosion Methods and Materials, vol. 46 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 December 2001

Stefan Krakowiak, Kazimierz Darowicki and Jacek Bordzilowski

A method has been proposed for testing rubber linings in industrial conditions based on a proposed model of coating penetration. The depth of penetration of rubber lining by water…

432

Abstract

A method has been proposed for testing rubber linings in industrial conditions based on a proposed model of coating penetration. The depth of penetration of rubber lining by water has been determined on the basis of investigation results by electrochemical impedance spectroscopy. Verification of the proposed procedure has been performed by comparing the obtained results of electrochemical investigations with determination of the water content in rubber by the gravimetric method. It has been confirmed that the values calculated in accordance with the penetration model correlate with the water content in rubber. Investigation results confirm views on the corrosion aggressiveness of media in different zones of a scrubber working as part of the flue gas desulphurisation installation.

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Anti-Corrosion Methods and Materials, vol. 48 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 12 January 2010

S. Krakowiak and K. Darowicki

The purpose of this paper is to present the investigation of aluminum alloy by means of dynamic electrochemical impedance spectroscopy (DEIS), which is simultaneous method of AC…

509

Abstract

Purpose

The purpose of this paper is to present the investigation of aluminum alloy by means of dynamic electrochemical impedance spectroscopy (DEIS), which is simultaneous method of AC impedance and DC polarization measurements.

Design/methodology/approach

A method of DEIS has been applied. Changes in equivalent circuit (EC) parameters versus potential for both investigated aluminium alloys are evaluated.

Findings

On the basis of obtained results, it is unambiguously demonstrated that the addition of 4.5 percent magnesium degraded the anticorrosive properties of the test alloys. It is difficult to define unequivocally the range of passive state and a moment of passive layer breakdown on the basis of current/voltage dependencies. However, application of the DEIS method and analysis of the evolution of particular elements of an electrical EC allowed identification of the instant of corrosion process initiation.

Practical implications

The presented method is only suitable for laboratory evaluation of metal alloys because it requires sophisticated measuring equipment and is a difficult and time‐consuming way to obtain final results.

Originality/value

In one experiment, both polarization (DC) data and impedance (AC) measurements can be obtained. This allows the electrochemical properties of very similar aluminum alloys to be compared precisely with one other.

Details

Anti-Corrosion Methods and Materials, vol. 57 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 February 2002

A. Zielinski, J. Smulko, A. Krakowiak and K. Darowicki

The results of the electrochemical noise observations in 0H18N9 steel are presented. Current noise was obtained by potentiostatic measurements in aqueous solution of 0.1M H2SO4

429

Abstract

The results of the electrochemical noise observations in 0H18N9 steel are presented. Current noise was obtained by potentiostatic measurements in aqueous solution of 0.1M H2SO4 and 0.06M Cl. The recorded noise had an evident trend and peaks that are typically observed during pitting corrosion. The trend was removed by means of the third order polynomial approximation. The statistical hypothesis, i.e. the difference between the approximation and the observed noise, was tested. The results confirmed that current noise caused by pitting corrosion has nonstationary or weakly stationary character. The recorded noise was analysed using the Joint Time‐Frequency Analysis method, which is appropriate for nonstationary signals. The derived results confirmed the presence of pitting corrosion. It was usual for a few pits to form on the surface of the electrodes in distinct phases, and these were observed as peaks in current fluctuations.

Details

Anti-Corrosion Methods and Materials, vol. 49 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 December 1997

K. Darowicki and S. Krakowiak

Presents the results of direct current polarization and exposure measurements of alloy steels, used as construction materials for flue‐gas desulphurization units. Ascertains that…

533

Abstract

Presents the results of direct current polarization and exposure measurements of alloy steels, used as construction materials for flue‐gas desulphurization units. Ascertains that in some cases there is unconformity between results of classic anodic cyclic polarization and results of laboratory exposure. Proposes a modified methodology for the evaluation of the susceptibility of alloy steels to pitting (multiple anodic polarization). Discusses results on the basis of the tested steels’ composition analysis and results of polarization measurements. Determines the conditions in which the pitting resistance equivalent should be used. Tests have been carried out in electrolyte‐simulating conditions in the purified gas zone of the wet flue‐gas desulphurization units. On the basis of the experimental data, determines flexibility for pitting corrosion of investigated materials.

Details

Anti-Corrosion Methods and Materials, vol. 44 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 17 March 2012

Jian Li, Gang Du, Chen Jiang and Shijiu Jin

The purpose of this paper is to classify and identify the acoustic emission (AE) signals of 304 stainless steel during stress corrosion process.

396

Abstract

Purpose

The purpose of this paper is to classify and identify the acoustic emission (AE) signals of 304 stainless steel during stress corrosion process.

Design/methodology/approach

The corrosion behavior of a specimen during slow strain rate testing (SSRT) in acidic NaCl solution was studied. The AE signals during the corrosion process were classified based on K‐means cluster algorithms; meanwhile, the characteristics of different AE sources were analyzed.

Findings

The results indicated that the AE characteristics of different AE sources, such as pitting, cracking, and bubble break‐up, differ significantly. The 304 stainless steel was prone to the occurrence of stress corrosion cracking under the SSRT condition in acidic NaCl solution.

Originality/value

The characteristics of different AE sources during corrosion process were gained for the first time, which could be of much help in analyzing and judging the corrosion situation.

Details

Anti-Corrosion Methods and Materials, vol. 59 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Available. Content available
Article
Publication date: 1 February 2000

248

Abstract

Details

Anti-Corrosion Methods and Materials, vol. 47 no. 1
Type: Research Article
ISSN: 0003-5599

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