Czestochowa University of Technology, Faculty of Production Engineering and Materials Technology,
Al. Armii Krajowej 19, 42-200 Czestochowa, Poland
The influence of copper(I) oxide on electrochemical properties of a composite electrode, obtained on the basis of LaNi5 intermetallic compound, was studied in the paper. Discharge capacities and kinetic parameters of hydride electrodes were measured during electrochemical cycling. The electrochemical measurements were carried out by means of the chronopotentiometric method in 6M KOH solution at 25oC. During discharging of studied hydride electrodes it is not possible to prevent oxidation of both lanthanum and nickel. Copper particles obtained in the first charging cycle, as a result of Cu2O reduction, do not oxidise in the next discharging cycles. SEM images and EDS analysis confirmed the presence of the formed copper particles deposit at surface of the electrode. Modification of hydrogen-absorbing LaNi5 powder particles surface by mixing it with copper(I) oxide leads to changes of electrode’s electrocatalytic properties. The existence of copper(I) oxide in the hydrogen-absorbing LaNi5 alloy clearly improves the process of hydride electrode activation and accelerates the hydrogen absorption/desorption reaction. No influence of 5 wt.% of Cu2O on the hydrogen diffusivity was found in the studied electrodes.
Keywords: LaNi5 intermetallic compound; copper(I) oxide; redox reactions; electrochemical properties
2018, Vol. 61, nr 5, pp. 114-118
SZAT KOWSKA E.
Wydział Budowy Maszyn i Informatyki, Akademia Techniczno-Humanistyczna, ul.Willowa 2, 43-309 Bielsko-Biała
The aim of the undertaken research is to improve the mechanical and functional properties of hot-dip zinc coating deposited on Fe-C alloys (industrial conditions, acc. PN-EN ISO 10684). In the study the influence of heat treatment on the hardness of zinc coating, applied to the surface of steel and cast iron were examined. The results presented in the paper are the first stage of the experiment. The aim of the experiment is to determine the range of changes of heat treatment parameters (time, temperature, heating rate, etc.), which in the next stage will be used to optimize this process. The article contains the results of: microscopic examinations, microhardness measurements of heat treated coatings and corrosion resistance test in the salt chamber (acc. PN-EN ISO 9227). Analysis of microhardness changes confirmed the efficiency of heat treatment as a method of increasing the hardness of the coating. The results of surface tests showed that the complex properties of the coating (its possible degradation, discontinuities caused by heat treatment, reduction of corrosion resistance) are determined not only by the values of individual parameters, but their mutual relation. The changes observed in the structure of the heat-treated coating in the upper temperature range resulted in decreased corrosion resistance.
Keywords: hot-dip zinc coating, corrosion resistance, heat treatment
2018 Vol. 61, nr 5, pp.119-123
CORROSION PROTECTION IN PRACTICE
„ENERGOPOMIAR” Sp. z o.o., Division of Chemistry and Diagnostics
The application of protective rubber linings on surfaces of elements of flue gas desulphurization installations is mainly imposed by economic aspects. Proper operation and constant diagnostic supervision enable extension of effective service life of installations. Moreover, constant diagnostic supervision allows reduction or elimination of failures and defects in protective rubber linings and also service life extension while maintaining protective properties of the lining. The paper presents defects in protective rubber linings detected during diagnostic tests.
Keywords: flue gas desulphurization installation, rubber lining, absorbe surface protection, damage to the absorber shell, service life of rubber linings, durability of rubber linings, damage to rubber linings, diagnostics of rubber linings.
2018, Vol. 61, nr 5, pp. 124-129