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„Ochrona przed Korozją” (Corrosion Protection) No 04/2018

 View cover and table of contents (in Polish and English) (pdf)

 

RESEARCH ARTICLES

 

DOI: 10.15199/40.2018.4.1

The properties of zinc coatings electrodeposited on S235JR steel in choline chloride / urea deep eutectic solvent containing ZnCl2

WINIARSKI J.

BROŻYŃSKA P.

Department of Advanced Material Technologies, Faculty of Chemistry, Wroclaw University of Science and Technology,

Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland

The morphology, topography and corrosion resistance of zinc coatings deposited galvanostatically in choline chloride / urea (1:2 molar ratio) eutectic mixture were investigated. It was discovered that in this solvent containing 0.3 mol dm−3 ZnCl2, the reduction of zinc starts below −1.1 V vs. Ag wire quasi-reference electrode. The morphology and structure of the deposits are strongly affected by the temperature of plating bath (40-70 °C) and the cathodic current density (1.0-4.6 mA cm−2). Electrodeposition at lower current density and higher plating bath temperature (60 °C) results in more compact and tight zinc coating. According to EIS measurements, the calculated charge transfer resistance is higher than 2 kΩ cm2 after 24 hours exposure in 0.05 mol dm−3 solution of NaCl.

Keywords: Zn coating; Deep eutectic solvent (DES); Electroplating; SEM; EIS

2018, Vol. 61, nr 4, pp.83-85, Ref. 6

 

DOI: 10.15199/40.2018.4.2

Sodium molybdate as the corrosion inhibitor of aluminium alloys in the acidic solution

KWOLEK P.

SIENIAWSKI J.

Department of Materials Science, Faculty of Mechanical Engineering and Aeronautics,

Rzeszow University of Technology, Rzeszów, Poland

Wincentego Pola 2 Avenue, 35-959 Rzeszów,

The influence of the initial concentration of sodium molybdate on the mechanism of corrosion of the unalloyed aluminium (1050) and Al2Cu phase in 0.5 M H3PO4 was studied. Sodium molybdate is a promising alternative for chromate-containing corrosion inhibitor of aluminium alloys in the acidic media. In the studied solutions, molybdic blue species are formed. They are efficient inhibitors of corrosion of unalloyed aluminium in the acidic solution. Inhibition efficiency equals to 97%. Al2Cu phase in the acidic solution undergoes selective corrosion. Aluminium is leached, the porous copper structure remains on the surface. Sodium molybdate prevents from this process only temporarily.

Keywords: aluminium; Al2Cu intermetallic phase; sodium molybdate; corrosion inhibition; orthophosphoric acid

2018, Vol. 61, nr 4, pp.86-89

Ref. 10

 

DOI: 10.15199/40.2018.4.3

Electrochemical characteristics of LaNi4,5Co0,5 alloy composite hydrogen storage material at high discharge rates

STEFANIAK A.

BORDOLIŃSKA K.

BALA H.

Faculty of Production Engineering and Materials Technology, Department of Chemistry,

Częstochowa University of Technology, Al. Armii Krajowej 19, 42-200 Częstochowa, Poland

Electrochemical hydrogen storage behavior of LaNi4,5Co0,5 powder composite electrode cycled in 6M KOH solution at increased discharge rates is discussed. Galvanostatic charging/discharging technique has been applied to determine high rate discharge ability (HRD) after N = 15 and N = 60 cycles. The anodic plots for both tested options are typical: electrode potential nearly linearly (with very low slope) increases with electrode discharge and then sharply jumps towards Eend = –0.5V (HgO/Hg) after electrode full dehydrogenation. Maximum discharge capacity (298 mAh·g–1 at –0.5C/+0.5C i.e. –186/+186 mA·g–1) has been achieved after N = 31 cycles. The HRD markedly decreases with electrode cycling. After 15 cycles the HRD falls to 46.8 % at discharge rate of 5C. The SEM examinations reveal severe structural deterioration of the electrode, especially evident after 60 cycles at the greatest discharge rates.

Keywords: intermetallic alloy, hydride capacity, charge/discharge, HRD

2018, Vol. 61, nr 4, pp.90-92

Ref. 17

 

DOI: 10.15199/40.2018.4.4

Electrodeposition of nickel coatings in choline chloride: ethylene glycol deep eutectic solvent

WINIARSKI  J.

CIEŚLIKOWSKA B.

SZCZYGIEŁ B.

Department of Advanced Material Technologies, Faculty of Chemistry, Wroclaw University of Science and Technology,

Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland

The electrodeposition and morphology of nickel coatings deposited potentiostatically in (2-hydroxyethyl)trimethylammonium chloride : ethylene glycol (1:2 molar ratio) eutectic solvent on copper substrate were investigated. In the presence of 1 mol dm−3 NiCl2·6H2O the reduction of nickel at 25 °C takes place at potentials more negative than −0.4 V vs. Ag quasi-reference electrode. It was found that the morphology and structure of nickel coatings are strongly affected by deposition potential. In the investigated system, electrodeposition at ambient temperature and at the potentials between −0.6 and −0.8 V vs. Ag results in compact nickel coatings devoid of visible defects.

Keywords: Ni coating, deep eutectic solvent (DES), electroplating, SEM

2018, Vol. 61, nr 4, pp.93-95

Ref. 7

 

DOI: 10.15199/40.2018.4.5

Kinetics of Ti-48Al-2Cr-2Nb alloy oxidation in oxygen

PRZELIORZ R.

Wydział Inżynierii Materiałowej i Metalurgii, Politechnika Śląska, ul Krasińskiego 8, Katowice

SWADŹBA R.

Instytut Metalurgii Żelaza im. Stanisława Staszica, ul. K.Miarki 12-14, Gliwice

SWADŹBA L.

MENDALA B.

WITALA B.

Wydział Inżynierii Materiałowej i Metalurgii, Politechnika Śląska, ul Krasińskiego 8, Katowice,

MARUGI K.

Avio Aero, ul. Grażynskiego 141, Bielsko-Biała

TRACZ J.

Wydział Inżynierii Materiałowej i Metalurgii, Politechnika Śląska, ul Krasińskiego 8, Katowice

KANIA Z.

Instytut Metalurgii Żelaza im. Stanisława Staszica, ul. K.Miarki 12-14, Gliwice

SUPERNAK W.

Wydział Inżynierii Materiałowej i Metalurgii, Politechnika Śląska, ul Krasińskiego 8, Katowice

The initial period of isothermal oxidation of Ti-48Al-2Cr-2Nb alloy in oxygen in a temperature range of 800-950oC was evaluated. It was observed that in the temperature range of 800-900oC, oxidation does not

assume a parabolic characteristic. An approximately parabolic correlation between mass increase and the reaction time occurs at 950oC. Oxidation constant kp = 2,5 · 10-5, g2/(cm4·s).

Keywords: oxidation kinetics, titanium alloys on γ –TiAl phase matrix

2018, Vol. 61, nr 4, pp.96-99

Ref. 16

 

DOI: 10.15199/40.2018.4.6

Diversification of the zinc coating thickness on the grading ring for overhead power line

WOJTYNEK K.

Silesian University of Technology, Faculty of Materials Engineering and Metallurgy, Katowice

WĘGRZYNKIEWICZ S.

BELOS-PLP S.A., Bielsko- Biała

KIEŁBUS A.

Silesian University of Technology, Faculty of Materials Engineering and Metallurgy, Katowice

SOZAŃSKA M.

Silesian University of Technology, Faculty of Materials Engineering and Metallurgy, Katowice

LECLAIR A.

Preformed Line Products (France), Buchelay

The evaluation of the zinc coating thickness on the grading ring was the aim of the tests. The measurement of the zinc coating thickness was done on the different parts of the object: ring rod and ring. The weld area formed by melting the base material, S235JRH steel and different kind of welding wires (G3Si1 and G2Si) was examined as well. Measurements of the zinc coating thickness were performed by the magnetic (acc. to ISO 2178) and microscopic methods (acc. to ISO 1463). The structure was observed and the chemical composition of the obtained coatings was performed. Based on the performed tests, it was confirmed that zinc coatings formed on individual parts of the grading ring, i.e. ring rod, ring and weld, were different. According to the technology used, it is not possible to eliminate different zinc coating thickness on the ring rod and ring. However, the problem concerning to the visibility of the weld after hot-dip galvanizing may be completely eliminated. This is particularly the case for the final acceptance of the manufactured products.

Keywords: welding, hot dip galvanizing, welding wire, zinc coating thickness, zinc coating structure

2018, Vol. 61, nr 4, pp.100-105

Ref. 10

 

DOI: 10.15199/40.2018.4.7

Comparison of anticorrosion activity of aminomethylphosphonic acids at constant phosphorus concentration

BROL A.

KLAKOČAR-CIEPACZ M.

Faculty of Chemistry, Wrocław University of Science and Technology

The results of electrochemical tests carried out for active substances in industrially used anti-corrosive preparations are presented. The tests were carried out at a constant phosphorus concentration of 30 mmol P/dm3 in order to compare the effectiveness of anti-corrosive protection of compounds with different amounts of aminomethylphosphonic units. The tests confirmed that compounds with an even amount of methylphosphonic groups showed very good activity.

Keywords: corrosion inhibitors, steel, aminomethylphosphonic acids

2018, Vol. 61, nr 4, pp.106-108

Ref. 6