Journal KOM

Research Articles

The corrosion-resistant Ni-based coatings and their tribological properties / Korózne odolné povlaky na báze Ni a ich tribologické vlastnosti
Zdravecká E., Tkáčová J.
2020, 64 (2), 38–44

Citace (ACS): Zdravecká, E.; Tkáčová, J. The corrosion-resistant Ni-based coatings and their tribological properties / Korózne odolné povlaky na báze Ni a ich tribologické vlastnosti. Koroze a ochrana materiálů 2020, 64 (2), 38–44.

Citace (ISO): Zdravecká, E.; Tkáčová, J. The corrosion-resistant Ni-based coatings and their tribological properties / Korózne odolné povlaky na báze Ni a ich tribologické vlastnosti. Koroze a ochrana materiálů 2020, vol. 64, no. 2, p. 38–44.

Ni-based coatings can be successfully applied under abrasive and adhesive conditions as a substitute for environmentally harmful chrome coatings. The research has been carried out for thermally flame sprayed Ni-based coatings with remelting (so-called the two-step process) with the different chemical composition of starting powders. The structure of coatings was evaluated by optical and scanning electron microscopy. Both the three-body abrasive wear test, according to ASTM G65-4 (Dry-Sand Rubber Wheel Test) and dry sliding wear test by the Falex tester, were performed. The results show the influence of the effective chemical composition of the metal powders on improving the properties of the coating. The higher hardness of the coatings leads to a lower tendency for the creation of adhesive bonds, and as a result, leads to a lower tendency to scuffing. A similar trend shows the influence of higher coating hardness on the increasing of abrasive wear resistance.

Povlaky na báze Ni je možné úspešne aplikovať pre abrazívne a adhézne podmienky ako náhradu za environmentálne škodlivé chrómové povlaky. Výskum bol uskutočnený pre žiarovo plameňom striekané povlaky na báze Ni s pretavením (tzv. dvojkrokový proces) s rôznym chemickým zložením východiskových práškov. Štruktúra povlakov bola vyhodnotená optickou a skenovacou elektrónovou mikroskópiou. Realizovaný bol test abrazívneho opotrebenia pri trojbodovom dotyku podľa ASTM G65-4 (Dry-Sand Rubber Wheel Test) a test na opotrebenie kĺzaním pomocou Falex testera. Výsledky ukazujú vplyv chemického zloženia kovových práškov na vylepšenie vlastnosti povlakov. Vyššia tvrdosť povlakov vedie k nižšej tendencii vytvárania adhéznych spojov a v dôsledku toho k nižšej tendencii k odieraniu. Podobný trend ukazuje vplyv vyššej tvrdosti povlaku na zvýšenie odolnosti proti abrazívnemu opotrebeniu.

 

Corrosion-fatigue failure of tractor trailers metal materials in aggressive environments
Popovych P., Poberezhny L., Shevchuk O., Murovanyi I., Poberezhna L., Hrytsanchuk A. and Koval Y.
2020, 64 (2), 45–51

Citace (ACS): Popovych, P.; Poberezhny, L.; Shevchuk, O.; Murovanyi, I.; Poberezhna, L.; Hrytsanchuk, A. Corrosion-fatigue failure of tractor trailers metal materials in aggressive environments. Koroze a ochrana materiálů 2020, 64 (2), 45–51.

Citace (ISO): Popovych, P.; Poberezhny, L.; Shevchuk, O.; Murovanyi, I.; Poberezhna, L.; Hrytsanchuk, A. Corrosion-fatigue failure of tractor trailers metal materials in aggressive environments. Koroze a ochrana materiálů 2020, vol. 64, no. 2, p. 45–51.

The processes of corrosion-fatigue failure of materials in contact with mineral fertilizers are insufficiently studied. As a result of joint influence of atmospheric corrosion and mechanical loads, about 70 to 80 % of mаchine parts get out of order, 20 to 25 % of which are failures caused by operating overload due to the strength loss because of atmospheric corrosion. A large part of metal structures of agricultural vehicles used to transport mineral fertilizers is under the direct influence of aggressive environments and dynamic loads that occur during the motion by field roads. Saturated solutions of the most aggressive working environments used in agricultural production, in particular ammonium sulphate and nitrophosphate are investigated to reduce fatigue resistance of ordinary steels groups – St3 and St5 and quality steels – 10 Steel, 15 Steel, 20 Steel, 25 Steel when loaded at all levels. The fatigue endurance limit decreases in comparison with air up to 2.02 times in a solution of ammonium sulphate, and to 2.32 times in a solution of nitrophosphate. In organic fertilizer environments, compared to distilled water, the conditional fatigue endurance limit increased to 9 %. The properties of the given materials as an inhibitor of corrosion-fatigue failure were discovered and proved. 

Use of non-destructive eddy current technique to detect simulated corrosion of aircraft structures / Zisťovanie simulovanej korózie leteckých konštrukcií metódu vírivých prúdov
Janovec M., Čerňan J., Škultéty F.
2020, 64 (2), 52–58

Citace (ACS): Janovec, M.; Čerňan, J.; Škultéty, F. Use of non-destructive eddy current technique to detect simulated corrosion of aircraft structures / Zisťovanie simulovanej korózie leteckých konštrukcií metódu vírivých prúdov. Koroze a ochrana materiálů 2020, 64 (2), 52–58.

Citace (ISO): Janovec, M.; Čerňan, J.; Škultéty, F. Use of non-destructive eddy current technique to detect simulated corrosion of aircraft structures / Zisťovanie simulovanej korózie leteckých konštrukcií metódu vírivých prúdov. Koroze a ochrana materiálů 2020, vol. 64, no. 2, p. 52–58.

The article deals with the issue of non-destructive testing of riveted joints. In the article, the authors used a non-destructive eddy current array technique, which was applied to detect simulated corrosion in the field of aircraft riveted joints of aluminum sheets. In aircraft maintenance, the eddy current method is used to control the outer surface of the aircraft skin, especially the areas around the riveted joints. This method makes it possible to detect hidden cracks and corrosion that may occur during aircraft operation. Especially hidden are hidden cracks and corrosion of aircraft structures, which cannot be detected during a visual inspection of the aircraft. The aim of the experimental measurements was to reveal simulated corrosion in the area of riveted joints formed on the experimental sample. Corrosion was simulated by gluing aluminum powder to the surface of the aluminum sheets from which the sample was made. The simulated corrosion in the second and third layers of the riveted sample was reliably detected. The settings, the method of control and the results of measurements are given in the article in the experimental part and the results of measurements. Measurements were performed using a defectoscope with an ECA measurement module, with appropriate measuring probes suitable for this type of inspection.

 

Článok sa zoberá problematikou nedeštruktívneho testovania leteckých nitovaných spojov. V článku autori využili nedeštruktívnu techniku vírivých prúdov, ktorá bola aplikovaná na zistenie simulovanej korózia v oblasti leteckých nitovaných spojov hliníkových plechov. V údržbe lietadiel sa metóda vírových prúdov používa na kontrolu vonkajšieho poťahu plášťa lietadla, hlavne teda oblastí v okolí nitovaných spojov. Táto metóda umožňuje odhaliť skryté trhliny a koróziu, ktoré môžu vzniknúť počas prevádzky lietadiel. Nebezpečné sú hlavne teda skryté trhliny a korózia leteckých konštrukcií, ktoré nie je možné odhaliť pri vizuálnej prehliadke lietadla. Cieľom experimentálnych meraní bolo odhalenie simulovanej korózie v oblasti nitovaných spojov, vytvorených na experimentálnej vzorke. Korózia bola simulovaná nalepením hliníkového prášku na povrch hliníkových plechov, z ktorých bola vzorka vyrobená. Simulovaná korózia v druhej a tretej vrstve nitovanej vzorke, bola spoľahlivo odhalená. Nastavenia, spôsob kontroly, výsledky meraní sú v článku uvedené v experimentálnej časti a výsledkoch meraní. Merania boli vykonané pomocou defoktoskopu s modulom pre meranie ECA, s príslušnými meracími sondami, vhodnými na takýto typ kontroly.

Corrosion inhibition of mild steel using novel pyridine derivative in 1 M hydrochloric acid
Al-Amiery A.A., Shaker L.M.
2020, 64 (2), 59–64

Citace (ACS): Al-Amiery, A.; Shaker, L. Corrosion inhibition of mild steel using novel pyridine derivative in 1 M hydrochloric acid . Koroze a ochrana materiálů 2020, 64 (2), 59–64.

Citace (ISO): Al-Amiery, A.; Shaker, L. Corrosion inhibition of mild steel using novel pyridine derivative in 1 M hydrochloric acid . Koroze a ochrana materiálů 2020, vol. 64, no. 2, p. 59–64.

A novel pyridine derivative was synthesized, and its corrosion inhibition effects on mild steel in a 1M hydrochloric acid environment were investigated by gravimetric techniques, The results demonstrated that the inhibitive performance increased with the increasing of inhibitor concentration. At 303, the inhibition efficiency of pyridine derivative 4-hydroxy-3-(pyridin-2-ylaminomethyl)toluene accomplished 96.2% at the inhibitor concentration of 0.005 M. The mechanism of inhibition implicated the forming of a protective layer from inhibitor molecules on the surface of mild steel by a Langmuir adsorption isotherm. The presence of nitrogen and oxygen atoms in the structure of 4-hydroxy-3-(pyridin-2-ylaminomethyl)toluene confirmed by CHN-analysis revealed the adsorption of inhibitor molecules on the surface of mild steel surface.

Technology and developement

Chemical resistance of NR/SBR rubber blends for surfaces corrosion protection of metallic tanks in petrochemical industries
Braihi A. J., Jawad A. J., Kadhum A. A. H., Aljibori H. S. S., Al-Amiery A. A.
2020, 64 (2), 65–71

Citace (ACS): Braihi, A.; Jawad, A.; Kadhum, A.; Aljibori, H.; Al-Amiery, A. Chemical resistance of NR/SBR rubber blends for surfaces corrosion protection of metallic tanks in petrochemical industries . Koroze a ochrana materiálů 2020, 64 (2), 65–71.

Citace (ISO): Braihi, A.; Jawad, A.; Kadhum, A.; Aljibori, H.; Al-Amiery, A. Chemical resistance of NR/SBR rubber blends for surfaces corrosion protection of metallic tanks in petrochemical industries . Koroze a ochrana materiálů 2020, vol. 64, no. 2, p. 65–71.

In this work, a series of Natural Rubber (NR)/Styrene Butadiene Rubber (SBR) blends were formulated to protect metallic petrochemical storage tanks from corrosive media. Therefore, these blends tested against a 10% HCl solution for 72 hr at room temperature. Blends series were prepared with different ratios of NR/SBR; 25/75, 30/70, 35/65, 40/60, 45/55, 50/50, and 55/45. Three types of carbon black (N-330, N-660, and N-762) were added individually to the 45/55 blend. Hardness, tensile strength, modulus, and elongation properties were tested before and after immersion in the 10% HCl attack media. All these mechanical properties decreased after immersion action accept hardness property. Up to 45 phr NR content, the hardness increased linearly independent on immersion action, but HCl immersion gives higher hardness values. Tensile strength increased up to 40 phr NR content with and without immersion and the immersion action decreased tensile values. The highest elongation value obtained with 35/65 blend with and without immersion. The 45 phr NR content gives the higher modulus, while the lowest value obtained with the 30 phhr content. For 45/55 blend, the hardness increased as the carbon black particle size decreased and immersion action gives higher hardness values. The tensile strength decreased linearly with the carbon black surface area, while with the medium surface area, the highest modulus and lowest elongation obtained.