The results of investigations applying to determination the anticorrosion properties of galvanic zinc-cobalt alloy coatings on steel substrate are presented in this paper. The corrosion resistance studies of the coatings were carried out in salt chamber by NNS (neutral salt spray) method. On the basis of the research, it was found that among all monolithic coatings the best anticorrosion properties exhibit the one fabricated in neutral bath with a higher content of cobalt (0,04 mol/dm3). The multilayer coatings deposited in the bath are characterized by much better corrosion resistance, comparable to zinc-nickel and cadmium coatings.

Low-temperature plasma carburising of stainless steels is used for improvement of tribological properties and of corrosion resistance. A study was carried out on austenitic 316L steel untreated and after carburising in the CH4/H2 atmosphere at 470 oC for 15 h which produced a surface layer with supersaturated carbon solution in austenite (6,6 % at. C). In the solution of 0.1 M Na2SO4 + 0.4 M NaCl, pH 3.0, untreated steel underwent a pitting corrosion, whereas carburised steel was fully resistant to localised corrosion and showed the enhanced resistance to general corrosion. Measurements of current transients after applying an anodic polarisation showed that in comparison with untreated steel, passivation of carburised steel was faster in the active region, but slower in the passive region. From the increased currents of cathodic reduction it was concluded that the amounts of oxide products (mainly magnetite) were on carburised steel larger than those on untreated steel. It was proposed that the enhanced corrosion resistance of carburised steel was due mainly to the formation of protective magnetite layer.

In paper the effect of milling time of Nd10Fe84B6 alloy on corrosion resistance of neodymium magnets in an environment simulating the oral cavity was carried out. The analysis of structure magnets based on Nd10Fe84B6 powder after 10, 48 and 90-hours of mechanical alloying process was performed. On the basis of X-ray analysis three phases occurring in the magnet structure were identifi ed. It was found that besides the basic ferromagnetic phase Nd2Fe14B also two phases: soft ferromagnetic α-Fe phase and Nd2Fe17 phase in the material structure are present. To evaluate the corrosion resistance of the magnets potentiokinetic polarization curves in a solution of artifi cial saliva were measured. Corrosion tests have shown that prolonged mechanical alloying (90 h), and thus the fragmentation of the structure effectively slows the rate of corrosion of the magnets.

The results of corrosion tests conducted by the potentiodynamic method for copper and brass in water containing 5 g/dm3 NaCl and selected natural organic compounds are presented. As potential corrosion inhibitors for copper and brass adenine, theophylline and inosine were tested. It was found that the effectiveness of corrosion protection of copper can achieve a value of 70%, at a concentration of adenine in water at the level 100–150 mg/dm3. Good protection against corrosion for brass provides theophylline (inhibition effi ciency more than 70% at a concentration in water 50 mg/ dm3) and adenine (inhibition effi ciency about 70% at a concentration of 100 mg/dm3). All three tested compounds exhibit primarily inhibition of cathodic corrosion processes for copper and brass.

The paper presents the study of corrosion properties of nanocomposite coatings MoS2Ti and MoS2(Ti, W) produced by magnetron sputtering method on titanium alloy Ti6Al4V. Corrosion resistances of the coatings were performed by means of voltametric measurements (polarization curves) carried out in the sodium sulfate and sodium chlorate solutions. Surfaces of the coatings were characterized using scanning electron microscopy (SEM). The paper presents the results of tribological tests. Average coeffi cient of friction and wear resistance were determined. Class of adhesion by Daimler-Benz method were identifi ed.

The kinetic oxidation of welds made of magnesium alloys has been studied. These experiments have been carried out at 450oC, in oxygen. The corrosion products were analysed with electron microscopy (SEM) and X-ray diffraction (XRD). It has been found that the weld made of alloy WE43 shows best corrosion resistance in comparison to other welds investigated. Good corrosion resistance is the result of the formation on the surface protective (YNd)2O3 scale.

Studies of the inhibition of steel corrosion by calcium nitrite were performed in solutions simulating pore liquid in concrete with different degree of carbonation. Tests were done in the condition corresponding to the initiation of steel corrosion (the inhibitor was added to solutions before the exposure of steel) as well as in the condition corresponding to developed corrosion (the inhibitor was added after a long prior exposure of steel in corrosive solution, leading to severe corrosion). The inhibiting effi ciency of calcium nitrite was estimated upon analysis of impedance and polarization data. It was found, that calcium nitrite shows high inhibition effi ciency of the initiation of steel corrosion. For developed corrosion of steel (precorroded), this inhibitor is less effective and should be applied at higher concentrations.

Diagnostic research on durability of protection coatings on water-wall tubes in lowemission boilers has been presented in the paper. Thermal spraying Al2O3/Ni-30Cr and hybrid paint coatings were evaluated. Durability of the coatings was evaluated after one and two years of service in direct action of fl ame, fl ue gas, and air fl ux from blower. It has been said that the coatings do not protect heating surface of waterwall tubes from hot corrosion, including sulfi dation under substoichiometric burning. Durability of the coatings is from one to two years of exploitation of a boiler only.

The results of the effectiveness research of the reinforcement protection against corrosion by concrete containing high calcium fl y ash from the combustion of coal in power station Bełchatów are shown. The research was done using two independent polarization methods – potentiodynamic method in concentrated water extracts from the crumbled concrete and using potentiostatic measurement on reinforcing inserts in concrete cylinder samples according to PN-EN 480-14 code. The results were compared with results gained in the similar way on samples from reference concrete without additives and with criteria including border values of electrochemical process parameters. It was shown that concrete containing 15%, 30% and 50% of high calcium fl y ash to cement mass properly protects reinforcing inserts from corrosion.

In this work, the electrochemical characterization of the LaNi3,6(Co,Mn,Al)1,2In0,2 type alloys is presented in 6M KOH environment with the use of galvanostatic charge/ discharge measurements. It is shown that partial substitution of Co, Mn or Al with indium in the tested alloys causes decrease of both exchange current density and current capacity of the electrodes.

A series of impedance spectra of three new unused rubber linings and the three used ones taken from the scrubber after several years of exposure were measured. In order to best fi t the spectra generated by these circuits to the experimental data a series of electrical equivalent circuits were used. From among tested materials the best barrier properties shows self-vulcanizing soft rubber lining system based on bromobutyl rubber marked as GBB. Behavior of this material resembles that of a real capacitor with low loss tangent. Samples of rubber linings exposed in the scrubber remained good protective properties, in spite of long time exposure to aggressive environment. Their properties are not worse than the new unused materials vulcanized two-ply soft rubber lining based on chlorobutyl rubber (GCB) and self-vulcanizing soft rubber lining based on chloroprene rubber (GCP).

Results of NiCrAlY coatings oxidation test at temperature 1100°C was presented in this article. The aim of investigations was related to characterization of oxides morphology in dependences of their localization and especially basic differences between them. The investigations showed that oxides localized in area of the roughness profi le bottom are dense and they have good adherences to basic material. Especially their thickness is much lower in comparison to oxides localized in area of the roughness profi le peak of NiCrAlY coating. There are the differences in phases constituent as well. In fi rst case basic oxides is alumina, in the second case the spinels were revealed.