Wyniki wyszukiwania - BazTech

1

Efficiency of a coating with a Y2O3 thermal barrier deposited on 733E831 superalloy exposed to hot corrosion in a vapor of sodium chloride and sodium sulfate

Salah Kheder A., Hamood Mahmood A., Abed Mazin A., Ahmed Samir M.

Ochrona przed Korozją

|

2025

|

nr 1

12--17

EN

Superalloy 733E831 was subjected to cyclic oxidation and hot corrosion with a mixture of salt vapors (NaCl + Na2SO4) at 1080°C. The alloy samples were coated with aluminum alone and aluminum with a thermal barrier of yttrium oxide (Y2O3). They were examined using a scanning electron microscope (SEM), X-ray spectroscopy and energy dispersive X-ray EDS. X-ray spectra revealed the formation of phases saturated by aluminum, SEM showed grain aggregation and growth, while EDS indicated a different concentration of each element within the alloy as a result of the variation in the diffusion process. The oxidation and hot corrosion test for 324 h showed better stability of the samples coated by aluminum alone than the samples coated by aluminum with a thermal barrier.

PL

Nadstop 733E831 został poddany cyklicznemu utlenianiu i korozji wysokotemperaturowej w obecności mieszaniny oparów soli (NaCl + Na2SO4) w temperaturze 1080°C. Próbki stopu zostały pokryte samym aluminium i aluminium z barierą termiczną z tlenku itru (Y2O3). Zostały zbadane za pomocą skaningowego mikroskopu elektronowego (SEM), spektroskopii rentgenowskiej i rentgenowskiej dyspersji energii EDS. Widma rentgenowskie ujawniły tworzenie się faz nasyconych aluminium, SEM wykazał agregację i wzrost ziaren, a EDS – różne stężenie każdego pierwiastka w stopie w wyniku zmienności procesu dyfuzji. Test utleniania i korozji wysokotemperaturowej, prowadzony przez 324 h, dowiódł lepszej stabilności próbek pokrytych samym aluminium niż próbek pokrytych aluminium z barierą termiczną. Słowa kluczowe: powłoka bariery termicznej, tlenek itru (Y2O3), utlenianie, korozja wysokotemperaturowa, tlenek glinu (Al2O3).

2

Cyclic oxidation of 304L and 316L stainless steel coated and uncoated with Cr3C2–NiCr at elevated temperatures

Kumar Naveen, Alam Md Sarfaraz, Mishra Nagendra Kumar, Kumar Sujeet, Giri Jayant, Aly Ayman A., Gupta Gaurav Kumar

Materials Science Poland

|

2025

|

Vol. 43, No. 1

103--114

EN

Failure of the boiler, gas turbine, incinerator, and other power-producing machines is mainly caused by the metals’ oxidation and alloys at high temperature service environment. It is a common practice to apply thermal barrier coating to increase the resistance to oxidation of metal alloys when subjected to high temperatures. In the current research, an effort has been made to apply a coating of Cr3C2–NiCr using the detonation gun (D-gun) technique on stainless steel (SS) 304L and SS 316L. The characteristics of coatings have been studied at 750 and 850°C. A cyclic oxidation process was carried out in a muffle furnace for 50 cycles. For each cycle, 304L and 316L SS, both bare and coated, are heated for 1 h in a muffle furnace and cooled for 20 min in ambient air. Under the investigated conditions, the Cr3C2–NiCr coating sprayed with a D-gun exhibited outstanding adhesion to the substrate alloy. A weight change/area versus the number of cycles plot has been drawn to understand the kinetics of oxidation. SS 304L coating has shown approximately 26.54 and 21.93% improvement in oxidation resistance at 850 and 750°C, respectively. For SS, 316L coating has shown approximately 27.67 and 25.92% improvement in the oxidation resistance, respectively, at 850 and 750°C. The oxide-scale-generated Cr3C2 phase demonstrated notable resistance to oxidation throughout the 50 cycles of cyclic oxidation at 750 and 850°C. The weight change/area shows that 316L has much better oxidation resistance than 304L at both temperatures of 750 and 850°C. The application of such coatings at high temperatures may reduce the formation of oxide scale which attacks and corrodes exhaust valves, turbocharger nozzles, and blade.

3

Evaluation of cyanide removal processes on water effluents from gold ore processing and industrial scale up

Freitas Juliana, Bellido Jorge

Journal of Sustainable Mining

|

2025

|

Vol. 24, iss. 3

369--376

EN

Gold extraction goes through different steps, from research to physical-chemical processing, which uses chemical reagents for extraction, such as cyanide. In literature, there are presented many ways to remove cyanide from this effluent on a bench scale, although on an industry scale it is not very often analysed. In this study, seeking innovation on an industrial scale for cyanide removal from real effluent generated by gold processing was analysed through oxidation with H2O2 and Fenton process. It was proven that these processes can remove cyanide at the levels required for recirculation of the effluent in the process, which is 1.0 mg/L of free cyanide, reaching 99% of removal. Applying the treatment on an industrial scale, it was possible to obtain the removal of 89% of free cyanide and 90% of total cyanide. A statistical study was carried out using a DOE tool to evaluate the dosages of H2O2 and FeCl2 at different pH values to reduce the operational costs of this decontamination process. The results indicated that it is possible to remove cyanide to reuse the effluent, with results higher than 96% of removal, using 88% less H2O2 and 70% less FeCl2, monitoring pH at 3, resulting in less waste operation for the treatment of the effluent.

4

Research of the possibility of removing organic pollutants from water by membrane methods and purification of the obtained concentrate by chemical methods

Piekutin Janina, Bolińska Marta Iwona, Kotowska Urszula, Koszelnik Piotr, Puchlik Monika

Economics and Environment

|

2025

|

No. 1

art. no. 1105

EN

Reverse osmosis (RO) and nanofiltration (NF) stand out for their versatility in terms of applicability to a wide range of contaminants, including personal care product (PCP) residues and endocrine disrupting chemicals (EDCs). The aim of the research was to analyse the efficiency of the removal of dosed PCPs and EDCs from model water with the use of RO and NF membranes. A study was also undertaken on the oxidation of the resulting concentrate after the membrane process - the efficiency of oxidation with ultraviolet-activated peracetic acid - UV/PAA system was analysed. Analysis of samples after each stage of the study showed that reverse osmosis was more effective in purifying water of EDCs than nanofiltration, while the UV/PAA oxidation system has a high potential for neutralising the concentrate formed after membrane processes, and points in the right direction for further in-depth research.

PL

Odwrócona osmoza (RO) i nanofiltracja (NF) wyróżniają się wszechstronnością pod względem możliwości zastosowania do szerokiego zakresu zanieczyszczeń, w tym pozostałości środków higieny osobistej (PCP) i związków endokrynnie czynnych (EDC). Celem badań była analiza skuteczności usuwania dozowanych PCP i EDC do wody modelowej przy użyciu membran RO i NF. Podjęto również badania nad utlenianiem powstałego koncentratu po procesie membranowym – analizowano skuteczność utleniania za pomocą aktywowanego promieniowaniem ultrafioletowym kwasu nadoctowego – układ UV/PAA. Analiza próbek po każdym etapie badań wykazała, że odwrócona osmoza była bardziej skuteczna w oczyszczaniu wody z EDC niż nanofiltracja, natomiast system utleniania UV/PAA ma duży potencjał do neutralizacji koncentratu powstałego po procesach membranowych i wskazuje właściwy kierunek dalszych pogłębionych badań.

5

Uszkodzenia korozyjne wysokotemperaturowe w kolektorze rurowego wymiennika ciepła wynikające z niekorzystnych warunków przepływu i miejscowego przegrzania : analiza CFD

Parol Filip, Pawlicki Jakub

Przemysł Chemiczny

|

2024

|

T. 103, nr 12

1473--1478

PL

Przedstawiono wyniki analiz przepływowo-strukturalnych CFD kolektora wraz z początkowym odcinkiem rurek wymiennika ciepła konstrukcji ALSTOM. Analizy termiczno-przepływowe są częścią kompleksowych badań nad przyczynami uszkodzeń rurek wewnętrznych, spowodowanych szybko postępującą korozją od strony przestrzeni wodnej w okolicy połączenia z dnem sitowym. Przeprowadzono je na podstawie wcześniej wykonanych analiz materiałowych i procesowych. Badania materiałowe wykazały, że przyczyną uszkodzenia rur kotła była wysokotemperaturowa korozja w środowisku woda-para. Na podstawie analizy procesów technologicznych stwierdzono prawdopodobieństwo niewystarczającego odgazowania w deaeratorze oraz możliwe nagromadzenie osadów korozyjnych. Analizy termiczno-przepływowe wskazały na występowanie zastojów przepływu za częścią rurek wymiennika i pokrywanie się ich obszarów z typowymi miejscami uszkodzeń. Wykonano symulację uwzględniającą obecność warstwy korozyjnej na części powierzchni rurki i zaobserwowano znaczący wzrost temperatury w miejscach korozji.

EN

CFD flow-structural anal. of the manifold along with the initial section of the heat exchanger tubes, designed by ALSTOM were carried out to det. the causes of internal tube damage caused by rapidly progressing corrosion from the water side near the connection to the tube sheet. Flow-thermal anal. showed the occurrence of flow stagnation behind some of the heat exchanger tubes. Material tests showed that the cause of the boiler tube damage was high-temperature corrosion in a water-steam environment. A simulation was carried out taking into account the presence of a corrosion layer on part of the tube surface, revealing a significant increase in temp. in the corrosion areas.

6

Opracowanie nowego procesu otrzymywania kwasu adypinowego

Lisicki Dawid, Orlińska Beata, Peckh Kamil, Martyniuk Tomasz, Dziuba Krzysztof

Przemysł Chemiczny

|

2024

|

T. 103, nr 10

1114--1123

PL

Współpraca jednostek naukowych z sektorem przemysłowym to istotna ścieżka rozwoju gospodarki. Opracowane na polskich uczelniach nowe technologie lub rozwiązania są szansą na zwiększenie bazy produktowej polskich przedsiębiorstw. Przedstawiono wybrane aspekty współpracy Politechniki Śląskiej z Grupą Azoty Zakłady Azotowe Puławy SA w ramach opracowania nowej technologii otrzymywania kwasu adypinowego, która ma w możliwie małym stopniu obciążać środowisko naturalne. Kwas adypinowy stanowi ważny półprodukt chemiczny stosowany w produkcji m.in. poliamidów, poliestrów i plastyfikatorów.

EN

Adipic acid market was presented and processes for its prodn. were reviewed and evaluated. Scientific university-industry cooperation in this area was exemplified on case Silesian Univ. of Technol. and a Polish enterprise (Grupa Azoty Zakłady Azotowe Puławy SA). The parameters and flow-sheet of the developed process as well as properties of the product were presented.

7

Problematyka starzenia estru naturalnego - hydroliza

Szcześniak Dominika, Przybyłek Piotr, Marcinkowska Agnieszka

Przegląd Elektrotechniczny

|

2024

|

R. 100, nr 11

229--232

PL

Pomimo wielu zalet estrów naturalnych ich stosowanie w transformatorach energetycznych może przysparzać problemów wynikających z toczących się w nich procesów utleniania oraz hydrolizy. Oba mechanizmy starzenia różnią się pod względem generowanych produktów rozkładu estru, co powoduje, że procesy te w inny sposób zmieniają jego właściwości. Autorzy artykułu przedstawili wpływ procesu hydrolizy na właściwości fizykochemiczne, elektryczne oraz strukturę chemiczną estru naturalnego.

EN

Despite the many advantages of natural esters, their application in power transformers can pose problems due to the oxidation and hydrolysis processes taking place within them. The two ageing mechanisms differ in terms of the generated decay products of ester, which cause that these processes change its properties in another way. The authors of this article presented the influence of the hydrolysis process on the physicochemical, electrical and chemical properties of natural ester.

8

Coupled action of ozone and UV radiation towards obtaining adipic acid from cyclohexane/one

Marek Adam A., Lisicki Dawid

Polish Journal of Chemical Technology

|

2024

|

Vol. 26, nr 1

97--101

EN

A lot of research is constantly underway in the world to develop new or improve the current processes of the chemical industry to make them more effective and environmentally friendly. The described research on the oxidation of cyclohexane or cyclohexanone to adipic acid with a coupled action of UV radiation and oxygen–ozone mixture, instead of the currently used oxidation with HNO3, is part of this trend. Gas chromatography was used to determine process indicators, such as cyclohexane conversion and selectivity to AA, which exceeded 50% at 25°C, after 16 h. This method can also be used for the preparation of other dicarboxylic acids from cycloalkanes, which proves its universal character.

9

Protective layers of zirconium alloys used for claddings to improve the corrosion resistance

Sartowska Bożena, Starosta Wojciech, Sokołowski Paweł, Wawszczak Danuta, Smolik Jerzy

Nukleonika

|

2024

|

Vol. 69, No. 2

125--128

EN

Zirconium alloys are used as a cladding material for fuel elements in nuclear reactors. In the case of severe accident conditions, the possible rapid oxidation of zirconium in steam or/and air may result in intense hydrogen generation and hydrogen–oxide mixture explosion. Advanced technologies for increasing the corrosion resistance of claddings are being investigated in two directions: (a) protective coatings on Zr alloys and (b) the use of new materials for claddings. Coatings with silicon may provide a more protective barrier than the ZrO2 films formed on an alloy cladding during nuclear plant operations. These coatings may also serve as a protective barrier during high-temperature accidents. The current work aimed at developing protective coatings with silicon on zirconium alloys. Multielemental Zr–Si–Cr coatings were formed on Zry-2 alloy using the physical vapor deposition (PVD) method. Long-term oxidation tests were carried out under the following conditions: 360°C/195 bar/63 days/water-simulating PWR water. Obtained results show the protective character of formed layers. The material in the form of silicon carbide grains covered with yttrium–aluminum garnet (SiC + YAG) was prepared using the sol–gel method. The formed powder is the main component for coating formation on Zr–1Nb alloy using the method of suspension plasma spraying (SPS).

10

Uncertainty Evaluation of the TGA Oxidation Data

Kang Kweonho, Hong Seokmin, Lee Changhwa

Archives of Metallurgy and Materials

|

2024

|

Vol. 69, iss. 2

407--410

EN

Thermogravimetric analysis (TGA) involves the measurement of the changes in mass that occur when a constant heat is applied to an unknown specimen as a function of time or temperature. It is used to evaluate thermal stability, oxidative stability, composition, and estimated lifetime, among other parameters. Given that accurate TGA data is important information for lifetime and stability evaluation of parts and products, an uncertainty evaluation procedure is required to ensure the reliability of the data. In this study, the uncertainty evaluation procedure was established according to the Guide to the Expression of Uncertainty in Measurement (GUM). The mathematically expression of the relationship between the measurand and the input quantities, evaluation of the standard uncertainty of each input estimate, determination of the combined standard uncertainty, and calculation of the expanded uncertainty were performed. The biggest factor affecting the uncertainty of TGA data is the uncertainty of correction factor caused by system calibration.

11

Obtaining colored oxide layers on titanium alloys with application to utility models

Mycka Emilia, Małecka Joanna

Sustainable Production, Instrumentation and Engineering Sciences

|

2023

|

nr 2

11--17

EN

Titanium and its alloys, due to their unusual properties, are widely used in many fields. This paper challenged the design of an everyday use object made of titanium alloy coated with a colored oxide layer. As the object under development, the so-called Italian moka pot was chosen, which is an interesting object due to its history and design.

12

Odzysk kobaltu i manganu ze strumieni odpadowych przemysłu petrochemicznego na przykładzie procesu produkcji kwasu tereftalowego

Kura Łukasz, Jurczakowski Rafał, Wiśniewski Piotr

Przemysł Chemiczny

|

2023

|

T. 102, nr 6

600--605

PL

Stwierdzono ilościowe wytrącanie szczawianów kobaltu(II) i manganu(II) (stężenia metali poniżej LOD: Co < 0,35 ppm, Mn < 0,27 ppm) w stężonym roztworze kwasu octowego (90% mas.), powszechnie stosowanym jako rozpuszczalnik w przemysłowych procesach utleniania p-ksylenu do kwasu tereftalowego. Obecność zanieczyszczeń typowych dla procesu utleniania p-ksylenu, czyli kwasu benzoesowego, kwasu bromowodorowego oraz jonów sodu nie miała negatywnego wpływu na powstawanie osadów. Obecność stałego kwasu tereftalowego w mieszaninie reakcyjnej miała pozytywny wpływ na proces odzyskiwania katalizatora. Zaobserwowano, że szczawiany tworzą aglomeraty na powierzchni stałego kwasu tereftalowego, co ułatwia oddzielenie osadu od cieczy macierzystej. Ponadto potwierdzono wysoką efektywność wytrącania w szerokim zakresie stężeń metali (50-1600 ppm). Wyniki pokazują, że strącanie kwasem szczawiowym jest skuteczną metodą odzyskiwania katalizatorów homogenicznych zawierających związki kobaltu(II) i manganu(II).

EN

A 1% soln. of (COOH)₂ in 90% MeCOOH was added to a 90% MeCOOH soln. contg. Co and Mn ions at concns. of 500 and 300 ppm, resp., and impurities typical of the oxidn. of p-xylene to C₆H₄(COOH)₂ (BzOH, HBr and Na ions) in amts. simulating the mother liquor compn. of a real industrial process. After mixing, the Co and Mn contents of the decanted liq. were detd. by AAS. Presence of impurities had no neg. impact on the ppt. formation. The presence of solid C₆H₄(COOH)₂ in the reaction mixt. had a pos. impact on the catalyst recovery process. Oxalates formed agglomerates on the surface of the solid C₆H₄(COOH)₂ which facilitated the sepn. of the ppt. from the mother liquor. The pptn. with (COOH)₂ is an efficient recovery method of spend Co(II) and Mn(II) homogeneous catalysts.

13

Klimat i oceanografia przełomu jury i kredy zachodniej Tetydy

Lodowski Damian Gerard

Przegląd Geologiczny

|

2023

|

Vol. 71, nr 10

514--522

EN

The key aspect for evaluation of potential effects of ongoing environmental changes is identification of their controlson one hand, and understanding of their mutual relations on other. In this context, the best source of information about medium and long term coThe key aspect for evaluation of potential effects of ongoing environmental changes is identification of their controlson one hand, and understanding of their mutual relations on other. In this context, the best source of information about medium and long term consequences of various environmental processes is the geologic record. Numerous different-scale palaeoenvironmental events took place during the Jurassic/Cretaceous transition; amongst them, the best documented so far are: long term marine regression during the Tithonian-early Berriasian, climate aridization during the late Tithonian-early Berriasian, and tectonic activity in western parts of the Neo Tethys Ocean during the late Berriasian-Valanginian. This study, which is based on the Ph Ddissertation of Damian Gerard Lodowski, attempts to reconstruct the latest Jurassic-earliest Cretaceous paleoenvironment and its evolution in the area of the Western Tethys, with special attention paid to cause-and-effect relationships between climate changes, tectonic activity and oceanographic conditions (perturbations in marine circulation and bioproductivity). Here are presented the basic results of high-resolution geochemical investigations performed in the Transdanubian Range (Hárskút and Lókút, Hungary), High-Tatric (Giewont, Poland) and Lower Sub-Tatric (Pośrednie III, Poland) series, Pieniny Klippen Belt (Brodno and Snežnica, Slovakia; Velykyi Kamianets, Ukraine) and Western Balkan (Barlya, Bulgaria) sections. The sections were correlated and compared in terms ofpaleoredox conditions (authigenic U), accumulation of micronutrient-type element (Zn) and climate changes (chemical index of alteration, CIA), providinga consistent scenario of the Tithonian-Berriasian palaeoenvironment evolution in various western Tethyan basins. Amongst the first-order trends and events, characteristic of studied sections are the two intervals recording an oxygen deficient at the seafloor: 1) the upper Tithonian-lowermost Berriasian (OD I); and 2) at the lower/upper Berriasian transition (OD II). Noteworthy, this phenomena cooccurred with elevated accumulations of nutrient-type elements (i. e. enrichment factor of Zn). Besides, collected data document the late Tithonian-early Berriasian trend of climate aridization, as well as the late Berriasian humidification. Such record is explained by a model, in which decreasing intensity of atmospheric circulation during the late Tithonian-early Berriasian was directly connected with climate cooling and aridization. This process resulted in lesser efficiency of up- and/or downwelling currents, which induced sea water stratification, seafloor hypoxia and perturbations in the nutrient-shuttle process during the OD I. On the other hand, the OD II interval may correspond to tectonic reactivation in the Neo Tethyan Collision Belt. This process might have led to physical cutoff of Alpine Tethys basins from the Neo Tethyan circulation (both atmospheric and oceanic), driving the limited stratification in the former, and limiting the effect of gradual humidification of global climate (i.e. due to increasing strength of monsoons and monsoonal upwellings). nsequences of various environmental processes is the geologic record. Numerous different-scale palaeoenvironmental events took place during the Jurassic/Cretaceous transition; amongst them, the best documented so far are: long term marine regression during the Tithonian-early Berriasian, climate aridization during the late Tithonian-early Berriasian, and tectonic activity in western parts of the Neo Tethys Ocean during the late Berriasian-Valanginian. This study, which is based on the Ph Ddissertation of Damian Gerard Lodowski, attempts to reconstruct the latest Jurassic-earliest Cretaceous paleoenvironment and its evolution in the area of the Western Tethys, with special attention paid to cause-and-effect relationships between climate changes, tectonic activity and oceanographic conditions (perturbations in marine circulation and bioproductivity). Here are presented the basic results of high-resolution geochemical investigations performed in the Transdanubian Range (Hárskút and Lókút, Hungary), High-Tatric (Giewont, Poland) and Lower Sub-Tatric (Pośrednie III, Poland) series, Pieniny Klippen Belt (Brodno and Snežnica, Slovakia; Velykyi Kamianets, Ukraine) and Western Balkan (Barlya, Bulgaria) sections. The sections were correlated and compared in terms ofpaleoredox conditions (authigenic U), accumulation of micronutrient-type element (Zn) and climate changes (chemical index of alteration, CIA), providinga consistent scenario of the Tithonian-Berriasian palaeoenvironment evolution in various western Tethyan basins. Amongst the first-order trends and events, characteristic of studied sections are the two intervals recording an oxygen deficient at the seafloor: 1) the upper Tithonian-lowermost Berriasian (OD I); and 2) at the lower/upper Berriasian transition (OD II). Noteworthy, this phenomena cooccurred with elevated accumulations of nutrient-type elements (i. e. enrichment factor of Zn). Besides, collected data document the late Tithonian-early Berriasian trend of climate aridization, as well as the late Berriasian humidification. Such record is explained by a model, in which decreasing intensity of atmospheric circulation during the late Tithonian-early Berriasian was directly connected with climate cooling and aridization. This process resulted in lesser efficiency of up- and/or downwelling currents, which induced sea water stratification, seafloor hypoxia and perturbations in the nutrient-shuttle process during the OD I. On the other hand, the OD II interval may correspond to tectonic reactivation in the Neo Tethyan Collision Belt. This process might have led to physical cutoff of Alpine Tethys basins from the Neo Tethyan circulation (both atmospheric and oceanic), driving the limited stratification in the former, and limiting the effect of gradual humidification of global climate (i.e. due to increasing strength of monsoons and monsoonal upwellings).

14

Modern materials used for environmental barrier coatings – a review

Mokrzycka Magdalena, Jopek Jakub, Słyś Anita, Góral Marek, Ochał Kamil

Ochrona przed Korozją

|

2023

|

nr 4

104--112

EN

In this article, the materials used for EBC coatings, representing next stage in the development of heat-resistant layers, and thermal barrier coatings are reviewed. In the introduction, the design of gas turbine is characterized, as well as the materials used for the hot part components and the requirements for protective coatings. Ceramic materials that can be an alternative to currently used nickel superalloys for turbine blades are also described. The requirements for EBC coatings were analyzed and then the various types of EBC coatings were characterized, as well as their degradation mechanisms.

PL

W artykule dokonano krótkiego przeglądu materiałów stosowanych na powłoki EBC (environmental barrier coatings) reprezentujących kolejny etap zaawansowania warstw żaroodpornych i powłokowych barier cieplnych (TBC – thermal barrier coatings). Opisano konstrukcję turbiny gazowej i materiały stosowane do produkcji elementów części gorącej oraz wymagania w zakresie powłok ochronnych. Opisane zostały również materiały ceramiczne, które mogą być alternatywą dla obecnie stosowanych nadstopów niklu używanych do wytwarzania łopatek turbin. Przeprowadzono analizę wymagań dotyczących powłok EBC, a następnie scharakteryzowano poszczególne rodzaje tych powłok, a także mechanizmy ich degradacji.

15

Manufacturing Cu-Pb alloys and studying efficiency in resisting oxidation

Sufian Amina, Hamood Mahmood Ahmad Al- Jiboori

Ochrona przed Korozją

|

2023

|

nr 12

388--392

EN

Binary alloys of copper and lead were produced by casting these elements in specially designed moulds with dimensions appropriate to the tests to be carried out on them. The effectiveness of these alloys in resisting oxidation was then studied in an atmosphere of a mixture of sodium chloride vapour and sodium sulphate at specific concentrations and heating the mixture to 180°C. Recently, corrosion has become a major problem in the overall performance of many engineering devices due to automotive exhaust gases produced by the internal combustion engine, which leads to corrosion of materials that make up some components of engineering industries. Copper also has good corrosion performance due to the formation of a copper oxide layer, which has made it the most important material in industrial applications. Through this research, we have achieved the desired goal as the alloys produced have shown their efficiency in resisting saline and acidic conditions and at high levels. The best sample is Cu95Pb5 and Cu90Pb10 with little difference between them in terms of efficiency. The aim of this work is to produce alloys and study their efficiency in resisting oxidation at high temperatures.

PL

Binarne stopy miedzi i ołowiu zostały wytworzone metodą odlewania w specjalnie zaprojektowanych formach o wymiarach dostosowanych do badań. Odporność stopów na utlenianie została zbadana w atmosferze mieszaniny oparów chlorku sodu i siarczanu sodu w określonych stężeniach i po podgrzaniu mieszaniny do 180°C. Korozja jest poważnym problemem, zaburza funkcjonowanie wielu urządzeń inżynieryjnych. Jej źródłem są m.in. spaliny wytwarzane przez silniki spalinowe. Miedź ma dobre właściwości antykorozyjne ze względu na warstwę tlenku miedzi, tworzącą się na jej powierzchni w wyniku utleniania. Z tego względu jest głównym materiałem stosowanym w przemyśle. Badane stopy miedzi i ołowiu wykazały wysoką odporność na działanie soli i kwasów w dużych stężeniach. Najlepsze wyniki uzyskano dla stopów Cu95Pb5 i Cu90Pb10 (różnica między nimi była niewielka). Celem pracy było zbadanie odporności wytworzonych stopów na utlenianie w wysokich temperaturach.

16

Removal of Organic Pollutants from Wastewater Using Different Oxidation Strategies

Fajri Nibras Raad, Mohammed Rusul Naseer

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 10

351--359

EN

Many countries use nontraditional methods to treat wastewater, especially those with water lacks. Among these methods, heterogeneous photocatalysis is more commonly widely used since it converts organic molecules into carbon dioxide and water. In this study, the photocatalytic degradation process of total organic carbon was investigated by TIO2/UV technique (TUT). This treatment is carried out in a batch recycle reactor using a UV light and catalyst TIO2. The optimum operating parameters were investigated regarding the best organic removal including, total organic carbon concentration, flow rate, pH, irradiation time, and photocatalysis dosage. The result showed that the TUT is affected by reducing total organic carbon (TOC) from synthetic wastewater (SW) by 61% at 50 ml/min of flow rate, 250 mg of catalyst concentration TIO2, and a concentration of TOC of 25 mg/l. Then the result of TUT was compared with a process of combining TIO2/UV and an oxidizing agent (Hydrogen peroxide H2O2). It was found that 73% of organic removal was obtained which is best than TUT when using an H2O2 dosage of 100 mg/l. Experimentally, Ozone was also added to the process of TUT and the result showed that the removal percentage increased to 80%.

17

The formation of Al-Si aluminide coatings by pack cementation method on TNM-B1 intermetallic alloy

Woźniak Mateusz, Góral Marek, Kościelniak Barbara

Advances in Mechanical and Materials Engineering

|

2023

|

Vol. 40, nr 1

79--86

EN

The TiAl intermetallics are the promising material for aerospace application. According to its insufficient oxidation resistance above 900°C the using of protective coatings is necessary. The diffusion aluminide coatings based on TiAl2 or TiAl3 phases permits to formation of alumina scale on the surface of TiAl alloys. The pack cementation with Si doping is one of the most popular method of this type of coatings production. In present article the influence of Si content in the pack, process time and temperature during pack cementation process were investigated. The thickness of obtained coating was in range 20-50 μm. When Si content was higher the formation of titanium silicides was observed using almost all analysed values of process parameters. The results showed that using of 24 wt. % Si containing pack and process parameters: 4h/950°C enables to obtain the coating characterized by optimal thickness and structure. The porosity and cracks in coatings according to TiAl phases brittleness was observed.

PL

Fazy międzymetaliczne TiAl są obiecującym materiałem do zastosowań w lotnictwie. Ze względu na niedostateczną odporność na utlenianie powyżej 900°C konieczne jest stosowanie powłok ochronnych. Dyfuzyjne powłoki aluminidkowe na bazie faz TiAl2 lub TiAl3 pozwalają na tworzenie się zgorzeliny tlenku aluminium na powierzchni stopów TiAl. Aluminiowanie metodą kontaktowo gazową z wprowadzaniem Si jest jedną z najpopularniejszych technik wytwarzania tego typu powłok. W niniejszym artykule zbadano wpływ zawartości Si w powłoce w zależności od czasu trwania procesu oraz temperatury. Grubość otrzymanej powłoki zawierała się w przedziale 20-50 μm. Gdy zawartość Si była wyższa, obserwowano powstawanie krzemków tytanu przy prawie wszystkich analizowanych wartościach parametrów procesu. Wyniki pokazały, że użycie proszku zawierającego 24% wag. % Si oraz czasu i temperatury 4h/950°C pozwala na uzyskanie powłoki charakteryzującej się optymalną grubością i strukturą. Zaobserwowano porowatość i spękania powłok.

18

Microstructural Evolution and Oxidation Behavior of Fe-4Cr-6Ti Ferritic Alloy with Fe2Ti Laves Phase Precipitates

Demirel Ahmet, Çetin Emre Can, Karakuş Ali, Ataş Mehmet Şahin, Yildirim Mehmet

Archives of Metallurgy and Materials

|

2022

|

Vol. 67, iss. 3

827--836

EN

The microstructural properties and hardness of a model ternary Fe-4Cr-6Ti ferritic alloy aged at 800°C for 8, 16 and 24 h are investigated in detail. Fine Fe2Ti Laves phase particles precipitate in the α-Fe (ferrite) matrix phase after solutionizing and subsequent aging treatments. The size and amount of Fe2Ti precipitates gradually increase with increasing aging time. The magnetic measurements of the aged samples confirm the variations in the microstructural properties including the volume fraction of the constituent phases, and Ti content of the α-Fe matrix phase. The mean Vickers microhardness value also increases from 203.5 to 238.4 with increasing aging time from 8 to 24 h. In addition, the cyclic oxidation behavior of 24 h aged sample, which contains maximum amount of Fe2Ti precipitates, is also investigated in detail. X-ray diffraction analysis reveals that scale product is α-Fe2O3 (hematite). Significant scale spallation and void formation is observed on the surfaces of 24 h aged Fe-4Cr-6Ti sample oxidized at 500°C.

19

Metody utleniania aldehydu 2-etyloheksanowego do kwasu 2-etyloheksanowego o potencjale aplikacyjnym

Czieszowic Łukasz, Orlińska Beata, Pankalla Ewa

Przemysł Chemiczny

|

2021

|

T. 100, nr 8

770--774

PL

Kwas 2-etyloheksanowy (2-EHA) znajduje szerokie zastosowanie m.in. w przemyśle chemicznym, farmaceutycznym i kosmetycznym. Na skalę przemysłową jest otrzymywany w procesie utleniania aldehydu 2-etyloheksanowego (2-EHAL). W pracy dokonano przeglądu literaturowego i przedstawiono dane dotyczące metod utleniania 2-EHAL z uwzględnieniem tych o potencjalnym zastosowaniu przemysłowym.

EN

A review, with 46 refs., of BuEtCCHO oxidn. methods using greener catalysts, solvents and oxidizing agents, including those with potential industrial application. An alternative to the processes currently used in the chem. industry may be reaction systems using N-hydroxyphthalimide as a catalyst.

20

Selective flotation separation of chalcopyrite and sphalerite by thermal pretreatment under air atmosphere

Zhou Hepeng, Geng Liang, Zhang Yongbing, Yang Zhizhao, He Kunzhong, Xie Fanxin

Physicochemical Problems of Mineral Processing

|

2021

|

Vol. 57, iss. 1

305--314

EN

Thermal pretreatment was performed to enhance the flotation separation of chalcopyrite and sphalerite under the air atmosphere for the first time. Microflotation experiment showed that the floatability of chalcopyrite vanished after thermal pretreatment at above 170℃. By contrast, the floatability of sphalerite was well maintained with a flotation recovery of 90%. In artificial mixed mineral flotation experiments, the separation of sphalerite and chalcopyrite was successfully realized by thermal pretreatment. Results of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses indicated that the chalcopyrite surface was oxidized dramatically at 170℃, and hydrophilic species such as sulfate (SO42-), oxides (CuO and Fe2O3), and hydroxyl species (Fe(OH)3) were formed on the surface. Hence, the adsorption of potassium butyl xanthate on chalcopyrite decreased significantly after thermal pretreatment. The reason for the higher oxidation speed of chalcopyrite than that of sphalerite was also analyzed.