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1

Struktura stereometryczna powierzchni powłok metalowych natryskiwanych metodą HVOF na podłoże ceramiczne Al2O3

Golański Dariusz

Przemysł Chemiczny

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2024

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T. 103, nr 11

1287--1291

PL

Przedstawiono wyniki badania chropowatości powierzchni powłok metalowych (Cu, Mo, Ni, Ti) natryskanych metodą płomieniową naddźwiękową HVOF na podłoże ceramiki konstrukcyjnej Al₂O₃. Oprócz klasycznych pomiarów 2D, wykonano także pomiary 3D, otrzymując mapy stereometryczne z obszaru badanej powierzchni metalizowanych próbek ceramicznych. Uzyskane wyniki pozwoliły na ocenę struktury stereometrycznej różnych powłok metalicznych natryskiwanych metodą HVOF oraz możliwość ich zastosowania jako warstwy metalizacyjnej przy spajaniu ceramiki Al₂O₃ z metalami za pomocą lutów nieaktywnych.

EN

Metal coatings (Cu, Mo, Ni, Ti) were sprayed onto Al₂O₃ structural ceramic substrates using the HVOF supersonic flame method. The 2D and 3D roughness of the obtained metalized surfaces was examined using a profilometer. The obtained stereometric maps of the surface of the metalized ceramic sample allowed for the assessment of the stereometric structure of various metal coatings and the possibility of their use as a layer for connecting Al₂O₃ ceramics with metals using inactive filler alloys.

2

Comparative analysis of microstructure and selected properties of WC-Co-Cr coatings sprayed by high-velocity oxy fuel on S235 and AZ31 substrates

Jonda Ewa, Myalska-Głowacka Hanna, Łatka Leszek, Szymański Krzysztof, Dziekońska Małgorzata

Materials Science Poland

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2024

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Vol. 42, No. 1

32--41

EN

The purpose of this work was to carry out comparative studies of WC-Co-Cr coatings deposited using the high velocity oxy fuel (HVOF) method onto two types of substrate material: structural steel S235 and magnesium alloy AZ31. The influence of the substrate material type on the microstructure, phase composition, crystallite size, porosity, Vickers microhardness, instrumental hardness (HIT), Young’s modulus (EIT), and fracture toughness was investigated. For both substrates, the deposited coatings deposited were characterized with fine-grained and compact microstructure. The X-ray diffraction (XRD) revealed presence of following phases: WC, W2C, Co0.9W0.1, and Co3W9C4. The WC phase was the most desirable and stable one with crystallites were below 100 nm. On the other hand, the size of the W2C crystallites was below 30 nm. The coatings obtained showed porosity values equal to 2.3 ± 0.4 vol% and 2.8 ± 0.7 vol% for AZ31 and S235, respectively. The average Vickers microhardness for both types of sample was appproximately 1200 HV0.3. The average HIT values for carbide particles and metallic matrix were around 29 GPa and 6.5 GPa, respectively. In the case of EIT, it was around 620 GPa and 190 GPa for WC and Co-Cr, respectively. The differences between coatings were negligible. The EIT value for both coatings was equal to 344 ± 11 GPa. The fracture toughness was around 4.5 MPa · m1/2 in both cases. The investigations revealed that it is possible to replace steel substrate material with a much lighter equivalent, in this case AZ31 alloy, without deterioration of the coating properties.

3

Effect of spray distance on the microstructure and corrosion resistance of WC - based coatings sprayed by HVOF

Jonda Ewa, Łatka Leszek, Maciej Artur, Godzierz Marcin, Gołombek Klaudiusz, Radziszewski Andrzej

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 2

art. no. e144610

EN

Cermet coatings provide protection against aggressive operating environment of machine and device elements, such as corrosion, wear or high-temperature conditions. Currently WC-based cermet coatings are frequently used in the different industry branches. In this work, conventional WC-based powders (WC-Co and WC-Co-Cr) were sprayed with High Velocity Oxy Fuel (HVOF) onto AZ31 magnesium alloy with different spray distances (320 and 400 mm). The aim of the research was to investigate the effect of the spray distance on the microstructure of the coatings, phase composition and electrochemical corrosion resistance. Results revealed that higher spray distance results in greater porosity, 1.9% and 2.3% for 320 mm and 2.8% and 3.1% for 400 mm in case of WC-Co and WC-Co-Cr coatings, respectively. Also the influence has been observed for coatings microhardness, c.a. 1300 HV0.3 for shorter spray distance, whereas for longer one it was less than 1100 HV0.3. The corrosion resistance estimated in potentiodynamic polarization measurements was the best for WC-Co-Cr coating deposited from the shorter spray distance, corrosion current density was equal to 2.9 µA·cm-2 and polarization resistance was equal to 8424 Ω∙cm2.

4

Investigations on the Microstructure and Corrosion Performance of Different WC-Based Cermet Coatings Deposited by High Velocity Oxy Fuel Process onto Magnesium Alloy Substrate

Jonda Ewa, Łatka Leszek, Maciej Artur, Khozhanov Aleksandr

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no. 2

25--35

EN

In the field of surface engineering, thermal spraying is very wide adopted in many branches of the industry. The main reasons of such situation are its flexibility as well as cost effectiveness. Among others, High Velocity Oxy Fuel (HVOF) technique is dedicated for spraying hardmetal and cermet coatings, especially for wear- and corrosion resistance. Such type of coating could be a promising candidate as protective layer for magnesium alloys elements. These materials need a strong improvement in the corrosion protection as well as on the field of wear resistance in order to be widely used in the industry. In this work, different WC-based coatings, namely: (i) WC-Co, (ii) WC-Co-Cr and (iii) WC-Cr3C2-Ni manufactured by HVOF spraying, were investigated. The form of all feedstock materials was agglomerated and sintered powder. All coatings were sprayed with the same technological parameters, especially spray distance which was equal to 400 mm on the AZ91 magnesium alloy substrate. The main aim of the studies was to investigate the influence of the powder material on the corrosion resistance of obtained coatings. The manufactured coatings were examined in terms of its microstructure, using scanning electron microscope (SEM) and corrosion performance, which was assessed in the electrochemical corrosion investigations in 3.5% NaCl solution by Tafel method. The study showed that the corrosion resistance increasing in such order: AZ91 < WC-Cr3C2-Ni < WC-Co < WC-Co-Cr. It should be stressed that WC-Cr3C2-Ni coating exhibits very low corrosion performance, which could be effected by relatively high porosity (c.a. 3 vol.%) and because of that the more complex composition promotes creation of many corrosion cells.

5

The effect of spray distance on porosity, surface roughness and microhardness of WC-10Co-4Cr coatings deposited by HVOF

Górnik Monika, Jonda Ewa, Nowakowska Monika, Łatka Leszek

Advances in Materials Science

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2021

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Vol. 21, nr 4(70)

99--111

EN

The paper presents the computational studies on the microstructure of WC-Co-Cr coatings deposited by High Velocity Oxy Fuel spraying (HVOF). The study covers the porosity assessment according to ASTM E2109-01 standard, carried out in ImageJ software, in terms of volume porosity, size and shape of the pores. The evaluation was preceded by scanning electron microscope (SEM) observations at magnifications of 2000x and 5000x. Additionally, topography analysis has been performed by confocal laser scanning microscope (CLSM), and the surface roughness Ra was evaluated by the contact method with use of a stylus profilometer. Finally, the influence of porosity was observed for coatings microhardness HV0.3. According to the results, the total closed porosity was found to be in the range of 5.01 vol.% and 5.38 vol.%. The dominated pores in the coatings were of size 0.1-1.0 μm. Studies showed that HVOF process enabled deposition of dense coatings, characterized by homogenous distribution of pores and low roughness.

6

Badania możliwości technologicznych metody HVOF oraz wytrzymałości materiałów na obciążenie cieplne

Krzemiński Łukasz

LAB Laboratoria, Aparatura, Badania

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2020

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R. 25, nr 3

28--31

7

Cavitation erosion and sliding wear of MCrAlY and NiCrMo coatings deposited by HVOF thermal spraying

Szala M., Walczak M., Łatka L., Gancarczyk K., Özkan D.

Advances in Materials Science

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2020

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Vol. 20, nr 2(64)

26--38

EN

The investigation into wear resistance is an up-to-date problem from the point of view of both scientific and engineering practice. In this study, HVOF coatings such as MCrAlY (CoNiCrAlY and NiCoCrAlY) and NiCrMo were deposited on AISI 310 (X15CrNi25-20) stainless steel substrates. The microstructural properties and surface morphology of the as-sprayed coatings were examined. Cavitation erosion tests were conducted using the vibratory method in accordance with the ASTM G32 standard. Sliding wear was examined with the use of a ball-on-disc tribometer, and friction coefficients were measured. The sliding and cavitation wear mechanisms were identified with the SEM-EDS method. In comparison to the NiCrMo coating, the MCrAlY coatings have lower wear resistance. The cavitation erosion resistance of the as-sprayed M(Co,Ni)CrAlY coatings is almost two times lower than that of the as-sprayed NiCrMoFeCo deposit. Moreover, the sliding wear resistance increases with increasing the nickel content as follows: CoNiCrAlY < NiCoCrAlY < NiCrMoFeCo. The mean friction coefficient of CoNiCrAlY coating equals of 0.873, which almost 50% exceed those reported for coating NiCrMoFeCo of 0.573. The as-sprayed NiCrMoFeCo coating presents superior sliding wear and cavitation erosion resistance to the as-sprayed MCrAlY (CoNiCrAlY and NiCoCrAlY) coatings.

8

Structure and Mechanical Properties of HVOF Sprayed (WC-Co+Co) Composite Coating on Ductile Cast Iron

Ksiazek Marzanna, Boron Lukasz, Tchorz Adam, Grzelka Ryszard

Welding Technology Review

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2019

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R. 91, nr 3

41--50

EN

An investigation was conducted to determine the role of Co particles in the WC-Co coating produced with the High Velocity Oxygen-Fuel (HVOF) spraying on microstructure, mechanical and wear properties in a system of type: WC-Co coating/ductlile cast iron. The microstructure of the thermal sprayed WC-Co+Co coating was characterized by scanning electron (SEM) and transmission electron (TEM) microscopes as well as the analysis of chemical and phase composition in microareas (EDS, XRD). For analysis of the quality and adhesion of coatings, the scratch-test was applied. It was found that as a result of the HVOF spray of WC-Co powders with the addition of Co particles, the coatings of low porosity, high hardness, a very good adhesion to the substrate, compact structure with partially molten Co particles and finely fragmented WC particles embedded in a cobalt matrix, coming to the size of nanocrystalline sizes were obtained. Moreover, the results were discussed in reference to examination of bending strength considering cracking and delamination in the system of (WC-Co+Co)/ductile cast iron as well as hardness and wear resistance of the coating. It was found that the addition of Co particles was significantly increase resistance to cracking and wear behaviour in the studied system.

PL

W pracy przedstawiono wyniki badań, dotyczące wpływu modyfikacji składu chemicznego powłok WC-Co (poprzez domieszkowanie cząstkami Co), wytworzonych techniką natryskiwania proszkowego naddźwiękowego z dużymi prędkościami (HVOF) na mikrostrukturę, właściwości mechaniczne i użytkowe układu typu: powłoka WC-Co/żeliwo sferoidalne. Mikrostruktura powłok WC-Co+Co była analizowana za pomocą mikroskopu świetlnego, skaningowego i transmisyjnego wraz z przeprowadzeniem badań składu chemicznego i fazowego powłok w mikroobszarach przy wykorzystaniu techniki EOS i XRO. Do analizy jakości i przyczepności powłok zastosowano test zarysowania. Stwierdzono, że w wyniku natryskiwania techniką HVOF proszków WC-Co z dodatkiem cząstek Co, powłoki charakteryzują się niską porowatością wysoką twardością bardzo dobrą przyczepnością do podłoża, zwartą budową z częściowo stopionymi cząstkami Co i silnie rozdrobnionymi cząstkami WC osadzonymi w kobaltowej matrycy, dochodzącymi do wymiarów nanometrycznych. Ponadto w pracy przedstawiono wyniki dotyczące wytrzymałości na zginanie układu WC-Co+Co/żeliwo sferoidalne w zestawieniu z analizą pękania i delaminacji powłoki w obszarze granicy rozdziału, oraz wynikami pomiarów twardości i odporności na zużycie powłoki. Stwierdzono, że dodatek cząstek Co znacznie zwiększa odporność na pękanie i zużycie w badanym układzie.

9

Spray Deposition of Mechanically Alloyed F/M ODS Steel Powder

Kang Suk Hoon, Rhee Chang-Kyu, Noh Sanghoon, Kim Tae Kyu

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 2

607--611

EN

Thermal/cold spray deposition were used for additive manufacture of oxide dispersion strengthened (ODS) steel layers. Mechanically alloyed F/M ODS steel powders (Fe(bal.)-10Cr-1Mo-0.25Ti-0.35Y2O3 in wt.%) were sprayed by a high velocity oxygen fuel (HVOF) and cold spray methods. HVOF, as a thermal method, was used for manufacturing a 1 mm-thick ODS steel layer with a ~95% density. The source to objective distance (SOD) and feeding rate were controlled to achieve sound manufacturing. Y2 Ti2 O7 nano-particles were preserved in the HVOF sprayed layer; however, unexpected Cr2 O3 phases were frequently observed at the boundary area of the powders. A cold spray was used for manufacturing the Cr2 O3 -free layer and showed great feasibility. The density and yield of the cold spray were roughly 80% and 45%, respectively. The softening of ODS powders before the cold spray was conducted using a tube furnace of up to 1200°C. Microstructural characteristics of the cold sprayed layer were investigated by electron back-scattered diffraction (EBSD), the uniformity of deformation amount inside powders was observed.

10

Cavitation erosion and sliding wear resistance of HVOF coatings

Szala M., Walczak M.

Welding Technology Review

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2018

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R. 90, nr 10

31--36

EN

The aim of the work was to investigate the resistance to cavitation erosion and sliding wear of as-sprayed HVOF coatings. M(Ni,Co)CrAlY and Cr3C2-NiCr based coatings were deposited using HVOF method onto stainless steel substrate grade AISI 304. As-sprayed coatings’ surface morphology was examined by SEM-EDS and profilometer methods. Cavitation erosion tests were conducted in distilled water with the use of vibratory rig and stationary specimen method. Cavitation erosion curves were plotted as well as cavitational wear mechanism was observed with the use of SEM microscope. Sliding wear tests were performed using the ball-on-disc tribotester with counter-specimen (ball) made of steel 100Cr6. Wear rates and coefficient of friction were computed. Normalized wear resistance with reference to stainless steel reference sample AISI 304 was calculated. In addition, comparable analysis of wear resistance results was conducted. M(Ni,Co)CrAlY coating presented the highest cavitation erosion resistance, therefore Cr3C2-NiCr coating represented the highest sliding wear resistance of all tested materials.

PL

Celem pracy było zbadanie odporności na zużycie kawitacyjne i ścierne powłok natryskiwanych metodą HVOF. Powłoki typu M(Ni,Co)CrAIY oraz Cr3CrNiCr wytworzono na podłożu ze stali odpornej na korozję gatunku AISI 304. Morfologię powłok w stanie po natryskiwaniu scharakteryzowano metodą SEM-EDS (skaningowy mikroskop elektronowy) oraz profilometrycznie. Badania kawitacyjne prowadzono w wodzie destylowanej na stanowisku wibracyjnym ze stacjonarną próbką. Wyznaczono krzywe erozyjne badanych materiałów, powierzchnię zużycia poddano obserwacjom mikroskopowym SEM. Badania odporności na zużycie ścierne przeprowadzono metodą ball-on-disc stosując przeciwpróbkę 100Cr6, wyznaczono współczynniki zużycia i tarcia. Obliczono znormalizowaną odporność na zużycie w odniesieniu do próbki referencyjnej wykonanej ze stali odporniej na korozję AISI 304 oraz dokonano analizy porównawczej odporności na zużycie. Powłoka M(Ni,Co)CrAIY charakteryzowała się najwyższą odpornością na erozję kawitacją natomiast powłoka Cr3CrNiCr wykazała najwyższą odporność na zużycie ścierne.

11

HVOF sprayed nanostructured composite coatings with a reduced friction coefficient

Żórawski W., Makrenek M., Góral A., Zimowski S.

Tribologia

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2017

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nr 4

139--147

EN

Nanostructured materials provide new possibilities, which enable creating composite structures with much better properties than composites obtained from conventional materials. Such a solution facilitates combining selected features of different nanomaterials in order to obtain a composite with the required durability, thermal, insulation, tribological, etc. properties. In the case of a composite containing a solid lubricant, it is comprised of a nanostructured matrix, providing mechanical durability, and an evenly distributed nanostructured solid lubricant. A study of the tribological properties of composite HVOF sprayed from nanostructured WC-12Co mixed with nanostructured Fe3O4, having the properties of the solid lubricant is presented. The coatings were sprayed by means of a Hybrid Diamond Jet system. A T-01 ball on disc tribological tester was used to determine the coefficient of friction on the basis of friction force obtained in the course of continuous measurement at a set load. The result of investigations was compared with properties of coatings sprayed with standard WC-12Co/ Fe3O4.

PL

Materiały nanostrukturalne stwarzają nowe możliwości, które pozwalają na tworzenie struktur kompozytowych o właściwościach znacznie lepszych niż te otrzymywane z materiałów konwencjonalnych. Takie rozwiązanie umożliwia łączenie wybranych właściwości różnych nanomateriałów w celu uzyskania kompozytu, który będzie posiadał wymagane właściwości wytrzymałościowe, tribologiczne, cieplne i inne. W przypadku kompozytów zawierających smar stały składają się one z nanostrukturalnej matrycy zapewniającej wytrzymałość mechaniczną i równomiernie rozłożonego nanostrukturalnego smaru stałego. W artykule przedstawiono badania właściwości tribologicznych płomieniowo natryskanego naddźwiękowo kompozytu będącego mieszaniną nanostrukturalnego proszku WC-12Co i nanostrukturalnego proszku Fe3O4 o właściwościach smaru stałego. Powłoki kompozytowe zostały natryskane z użyciem systemu do płomieniowego natryskiwania naddźwiękowego Hybrid Diamond Jet. Tester tribologiczny T-01 typu kulka-pierścień został użyty do zbadania współczynnika tarcia na podstawie pomiaru siły tarcia otrzymanej w wyniku ciągłego pomiaru przy ustalonym obciążeniu. Wyniki badań zostały porównane z właściwościami powłok płomieniowo natryskanymi naddźwiękowo z konwencjonalnych proszków WC-12Co/Fe3O4.

12

Effect of tribological conditions for properties thermal spraying

Landova M., Brezinova J.

Production Engineering Archives

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2017

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Vol. 14

37--39

EN

The present contribution deals with the influence of tribological conditions on coating quality. Two types of coatings were selected for analysis WC-WB-CO and WC-FeCrAl, to advise that a new type of coating - carbide green. These coatings were applied to the base material AISI 316L of technology HVOF – High velocity oxygen fuel. The aim of the experimental study was to determine the quality coatings and its resistance to abrasive wear, depending on the number of thermal cycles. It was evaluated hardness, thickness, the resistance to abrasive wear in free abrasives and firmly bonded abrasives. Results of experiments showed a higher resistance of the coating WC-Co-WB.

13

Zastosowanie nowoczesnych metod natryskiwania cieplnego jako klucz do uzyskania wysokich własności użytkowych powłok

Szymański K., Szczucka-Lasota B., Gdesz M.

Ochrona przed Korozją

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2016

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nr 11

399--401

PL

Przedstawiono podstawowe informacje o procesie natryskiwania cieplnego i jego odmianach, wskazano kierunki rozwoju nowoczesnych metod natryskiwania cieplnego oraz podano wybrane informacje o materiałach powłokowych stosowanych w procesach natryskiwania cieplnego. Wykazano również konieczność stosowania należytych procedur kontroli procesu które mogą być podstawą systemu zapewnienia jakości dla wytwarzanych powłok.

EN

Basic information about thermal spraying and its varieties has been presented. The authors have pointed out the directions for the further development of thermal spraying methods. Selected information about coating materials used in the methods has been included. The need for using proper quality control assessment methods has been emphasized.

14

Wpływ zawartości kobaltu na właściwości powłok WC-Co natryskiwanych naddźwiękowo

Olbrycht A., Pawlik S.

Inżynieria Powierzchni

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2016

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nr 3

45--53

PL

W pracy przedstawiono wyniki badań powłok WC-Co natryskiwanych metodą płomieniowa naddźwiękową z proszków o zawartości kobaltu 12 i 17%. Zbadano wpływ wielkości ziarna natryskiwanego proszku WC-Co na właściwości powłok. Opisano oraz przedstawiono wyniki badań: metalograficznych, twardości HV, metodą DSI (Depth Sensing Indentation), zarysowania (scratch test), przyczepności oraz twardości Rockwella HRC. Stwierdzono, że w wyniku natryskiwania cieplnego metodą naddźwiękową proszków WC-Co otrzymano powłoki o zwartej budowie, nieznacznej porowatości oraz dobrej przyczepności do podłoża. Powłoki natryskiwane naddźwiękowo z proszku o wyższej zawartości Co 17% mają wyższą twardość (zmierzoną metodą DSI na powierzchni powłoki), niż powłoki natryskane cieplnie z proszku o zawartości 12% Co. Najwyższą średnią wartość modułu Younga odnotowano w przypadku powłoki natryskanej z proszku WC-17Co (-20+5 µm), powłoka ta ma również najwyższe twardości mierzone metoda DSI: indentacyjną, Martensa oraz Yickersa.

EN

The paper presents the results of the examinations of WC-Co coatings sprayed by high velocity flame method with powder containing different amounts of cobalt. The impact of particle size of the sprayed WC-Co powder on the properties of the coatings was also examined. The paper describes and presents the results of the following te.sts: metallographic tests, hardness measurement HV, testing by DSI method (Depth Sensing Indentation), scratch test, adhesion test and measurement of Rockwell hardness HRC. It was found that by supersonic thermal spraying with WC-Co powders with different content of Co and with various particle sizes, the, coatings of compact structure, slight porosity and a very good adhesion to the substrate were obtained. It was also found that the thermally sprayed coatings with the powder with a higher Co content, ie. 17% have higher hardness, as measured by the DSI method, on the surface of the coating than the coatings sprayed thermally with the powder containing 12% Co. The highest average vahic of Young's modults was observed for the coating sprayed with the WC-Co83/l7 (-20-5 µm) powder, this coating has also the highest hardness measured by DSI method: indentation hardness, Martens hardness and Yickers hardness.

15

Structure and properties of the FeAl (HVOF, HVAF, DGS) coatings for power industry

Senderowski C., Durejko T., Zasada D., Napadłek W., Bojar Z.

Inżynieria Materiałowa

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2016

|

Vol. 37, nr 6

283--288

EN

Recently, some systematic studies have been conducted on microstructural changes and material properties of B2 FeAl coatings sprayed by supersonic stream metallization in HVOF (High Velocity Oxygen Fuel), HVAF (High Velocity Air Fuel) and DGS (Detonation Gas Spraying) conditions. The present paper reports the results and analysis of HVOF, HVAF and DGS supersonic spraying on the structure and properties of Fe–Al type coatings obtained from spraying the Fe40Al0.05Zr at. % +50 ppm B intermetallic feedstock powder on a C45 steel substrate. A comprehensive study of the coating performances was conducted in relation to their material parameters by taking into account technological conditions affecting the formation of a structure in the ultrasonic spraying technologies. Analysis included chemical-phase composition inheritance, morphology of the grains, and porosity as well as oxidation of the coating material, hardness and abrasive resistance. These properties were analysed to determine if, Fe–Al coatings could be used as a potential material in the elements of gas turbines and boilers.

PL

W pracy przedstawiono wyniki badań i analiz efektów wykorzystania metody HVOF (High Velocity Oxygen Fuel), HVAF (High Velocity Air Fuel) oraz DGS (D-gun Spraying) do otrzymania powłok z naddźwiękowego strumienia metalizacyjnego z użyciem proszku intermetalicznego typu Fe40Al (VIGA) osadzonego na stali 45 w stanie po ulepszaniu cieplnym. Przeprowadzono kompleksowe badania właściwości użytkowych powłok, uwzględniając ich specyfikę struktury — morfologię ziaren, skład chemiczny i budowę fazową oraz porowatość i stopień utlenienia — w powiązaniu z warunkami subtelnych zmian uwarunkowań technologicznych. Określono ich wpływ na formowanie strumienia metalizacyjnego w zastosowanych metodach natryskiwania naddźwiękowego. W ramach analizy wpływu cech strukturalnych na właściwości użytkowe powłok określono także poziom ich umocnienia i odporność na zużywanie ścierne z udziałem luźnego ścierniwa w aspekcie potencjalnego wykorzystania ich na elementy turbin gazowych i kotłów energetycznych.

16

Mechanical Properties and Corrosion Resistance of HVOF Sprayed Coatings Using Nanostructured Carbide Powders

Żórawski W., Makrenek M., Góral A.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

1839--1846

EN

Nanostructured and composite WC-12Co coatings were prepared by means of the supersonic spray process (HVOF). The microstructure and composition of WC-12Co nanostructured powder were analyzed by scanning electron microscope (SEM) and transmission electron microscope (TEM). Investigations revealed nano grains of WC with the size in the range of 50-500 nm. The nanostructured sprayed coating was analysed by SEM and phase composition was investigated by X-ray diffractometer (XRD). A denser coating structure with higher hardness was observed compared to conventional coating with a small amount of W2C, WC1−x, W and some amorphous phase. Young’s modulus and hardness were determined by depth sensing indentation in HVOF sprayed WC-12Co nanostructured coatings. Results were compared to conventional coatings and the relevance of the nanostructure was analyzed. An indentation size effect was observed on the polished surface and cross-section of both coatings. Data provided by indentation tests at maximum load allow to estimate hardness and elastic modulus. Enhanced nanomechanical properties of conventional coating in comparison to nanostructured one were observed. Nanostructured coatings WC-12Co (N) revealed significantly better corrosion resistance.

17

Study of selected properties of thermally sprayed coatings containing WC and WB hard particles

Brezinová J., Guzanová A., Draganovská D., Maruschak P. O., Landová M.

Acta Mechanica et Automatica

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2016

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Vol. 10, no. 4

296--299

EN

The paper presents results of research of the essential characteristics of two kinds of advanced coatings applied by HVOF technology. One studied coating: WB-WC-Co (60-30-10%) contains two types of hard particles (WC and WB), the second coating is ecofriendly alternative to the previously used WC-based coatings, called "green carbides" with the composition WC-FeCrAl (85-15%). In green carbides coating the heavy metals (Co, Ni, NiCr) forming the binding matrix in conventional wear-resistant coatings are replaced by more environmentally friendly matrix based on FeCrAl alloy. On the coatings was carried out: metallographic analysis, measurement of thickness, micro-hardness, adhesion, resistance to thermal cyclic loading and adhesive wear resistance (pin-on-disk test). One thermal cycle consisted of heating the coatings to 600°C, dwell for 10 minutes, and subsequently cooling on the still air. The number of thermal cycles: 10. The base material was stainless steel AISI 316L, pretreatment prior to application of the coating: blasting with white corundum, application device JP-5000.

18

Właściwości tribologiczne powłok nanoszonych techniką naddźwiękową w warunkach smarowania cieczą jonową

Madej M., Ozimina D.

Logistyka

|

2015

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nr 4

4662--4668, CD2

PL

W pracy przedstawiono wyniki badań tribologicznych powłok kompozytowych Ni/WC otrzymywanych metodą naddźwiękową HP/HVOF o dużej adhezji do elementów metalowych. Badania tribologiczne przeprowadzono przy użyciu testera tribologicznego pracującego w systemie kula – tarcza w warunkach tarcia technicznie suchego oraz tarcia granicznego. Jako substancje smarowe zastosowano ciecze jonowe - syntetyczne środki smarowe nowej generacji. Podstawowym zagadnieniem przedstawionym w pracy było określenie charakteru oddziaływań tribochemicznych różnych kationów i anionów wybranych cieczy jonowych. Powłoki na elementach po badaniach tribologicznych poddano obserwacjom mikroskopowym na elektronowym mikroskopie skaningowym SEM. Przeprowadzona analiza właściwości tribologicznych wytworzonych powłok kompozytowych, potwierdziła zróżnicowana aktywność tribochemiczną zastosowanych w badaniach cieczy jonowych. Na podstawie przeprowadzonych eksperymentów stwierdzono, że stanowiły one czynnik decydujący o efektywności tribologicznej powstających podczas tarcia warstw granicznych i przeciwzużyciowych reakcyjnych warstwach powierzchniowych.

EN

This paper discusses the tribological behaviour of HP/HVOF sprayed WC-Ni composite coatings characterized by high adhesion to metallic substrates. The tribological tests were conducted under dry friction and boundary lubricated conditions using a ball-on-disc system. Ionic liquids − new-generation synthetic lubricants − were used in the experiments. The main objective of the study was to determine the nature of the tribochemical actions of different cations and anions of the selected ionic liquids. Once the tribological tests were completed, the coatings were examined by scanning electron microscopy. The analysis of the tribological properties of the composite coatings confirmed the different tribochemical activities of the different ionic liquids used. From the experimental data it is clear that they were responsible for the tribological effectiveness of the boundary layers forming during friction and the antiwear reactive surface layers.

19

Abrasive resistance of HVOF thermally sprayed coatings based on alloys and cermets compared to nitrided stainless steel

Cesanek Z., Schubert J.

Archives of Materials Science and Engineering

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2014

|

Vol. 67, nr 1

18--23

EN

Purpose: This work is focused on the abrasion resistance comparison of alloy and cermet based coatings with nitrided stainless steel. Design/methodology/approach: The coatings deposited on the steel substrates were subjected to the abrasion test according to a modified ASTM G-65 (Rubber Wheel/Dry Sand Abrasion Test). Al2O3 abrasive sand with the granularity of 212-250 μm was used as an abrasive material. Stellite 6, NiCrBSi, Hastelloy C-276, Cr3C2-NiCr, Cr3C2-CoNiCrAlY and TiMoCN-Ni powders were used to prepare several set of samples. Findings: The obtained results show that the abrasion resistance is not directly proportional to the hardness. The difference in microstructure between cermet and alloy bases coatings in relation to their wear mechanism plays an important role. Research limitations/implications: The HVOF thermal spraying technology (High Velocity Oxygen Fuel) is commonly used as a component surface protection against abrasive wear. Alloy and cermets based coatings therefore meet the requirements for high abrasion resistance. Originality/value: The current trend in increase of operating temperature and steam parameters to improve steam turbine performance results in the operating temperatures which are close to the nitriding temperatures of steels limiting the use of this technology. For these reasons, the demand for alternative ways of functional surface protection is increasing, in particular to increase the abrasion resistance of component surfaces operating at high temperatures.

20

Combined study of wear phenomena using steel wheel abrasion test

Zdravecká E., Marton M., Tkáčová J., Trpčevská J., Kelemen M.

Tribologia

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2013

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nr 1

149--157

EN

In the present work, thermally sprayed tungsten carbide-based coatings deposited by methods of high velocity oxy-fuel (HVOF) and also flame spraying (FS) combined with surface flame melting (SFM) were studied. Different powders and spraying systems were used to evaluate abrasive wear resistance of thermally sprayed coatings. Steel Wheel Abrasion Test (SWAT) has been applied to test setup for three-body abrasion. The wear rates were sensitive to the microstructure of the coatings. Studied coatings show wear behavior depending on the bond strength of carbide particles to the binder and also the size of carbides and type of binder. Relatively uncomplicated application and good abrasive resistance of deposited coatings are the main factors that contribute to implementation of SFM method into practice.

PL

W prezentowanej pracy wykonano badania powłok na bazie węglika wolframu nanoszonych metodami termicznymi za pomocą szybkościowego napawania tlenowo-gazowego (HVOF) i metalizacji natryskowej (FS) połączonych z płomieniowym nadtapianiem powierzchni (SFM). Dla oceny odporności na zużycie ścierne powłok nanoszonych metodami termicznymi zostały użyte różne proszki i różne systemy metalizacji. Zastosowano test zużycia ściernego ze stalową rolką (SWAT) do badań ścieralności z trzecim ciałem. Wartość intensywności zużywania były zależne od mikrostruktury powłok. Na zachowania zużyciowe testowanych powłok wpływa wytrzymałość wiązań cząstek węglików z żywicą, a także rozmiar cząstek i rodzaj żywicy. Stosunkowo prosta aplikacja i dobra odporność na ścieranie są czynnikami, które przyczyniają się do praktycznego zastosowania metody SFM.