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Microstructure and positron lifetimes of zirconium modified aluminide coatings

Romanowska J., Dryzek E., Morgiel J., Siemek K., Kolek Ł., Zagula-Yavorska M.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1150--1155

EN

The microstructure of the zirconium modified and non-modified aluminide coatings was examined by the EDS, XRD, TEM and the positron annihilation spectroscopy methods. Both coatings have a double layer structure: β-NiAl phase on the top and γ′-Ni3Al below. Small zirconium nanoparticles were found along grain boundaries in the β-NiAl phase. The positron lifetime in both coatings is the same. The formation of zirconium precipitates neither affects, the number of defects nor the volume diffusion. Zirconium nanoparticles that precipitate along grain boundaries stand against the outward diffusion of Al ions through the coating to the coating/oxygen interface. This “blocking effect” may be responsible for the reduction of the alumina scale growth rate and may delay pore formation on the coating/oxygen interface.

2

Effect of Pd and Hf co-doping of aluminide coatings on pure nickel and CMSX-4 nickel superalloy

Romanowska J., Morgiel J., Kolek Ł., Kwolek P., Zagula-Yavorska M.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1421--1429

EN

Microstructure of palladium and hafnium co-doped aluminide coatings deposited on pure nickel and CMSX4 nickel super alloy by the CVD method was examined by the SEM and TEM methods. Both coatings have a double layer structure: additive and interdiffusion zones. The additive zone is formed by the hafnium doped β-(Ni,Pd)Al phase. The interdiffusion zone on pure nickel contains the palladium and hafnium doped γ′-Ni3Al phase, whereas that on CMSX-4 superalloy the hafnium doped β-(Ni,Pd)Al phase with precipitations of Topologically Closed-Pack phases (μ and σ) and Al2O3 at adhesive/interdifusion zones interfaces. Palladium is distributed uniformly in whole coatings. Hafnium forms precipitates that are situated in a Hf-rich belt. In both coatings this belt is in the additive layer, near the line of porosity and Al2O3 precipitates. Palladium and hafnium modified aluminide coatings show better oxidation resistance than those modified only with palladium.

3

Cyclic oxidation of palladium modified and nonmodified aluminide coatings deposited on nickel base superalloys

Zagula-Yavorska M., Sieniawski J.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 1

130--139

EN

Palladium layer (7 μm thick) was deposited on the surface of the Inconel 713 LC, Inconel 625 and CMSX 4 Ni-base superalloys by the electroplating method. Electroplated samples were annealed at 1050 °C for 2 h in the argon atmosphere. The aluminide coatings were deposited by the CVD method. The nonmodified aluminide coating consists of the NiAl phase. Palladium modification let to formation of the (Ni,Pd)Al phase in coatings. The palladium modified as well as nonmodified coatings were oxidized at 1100 C in the air atmosphere. For both Inconel 713 LC and CMSX 4 superalloys palladium modified coatings show better oxidation resistance than nonmodified ones. Palladium inhibits the outward diffusion of substrate elements (cobalt and chromium) during oxidation of the aluminide coating. Moreover, it stabilizes the β-NiAl phase, keeps the higher content of aluminum in the β-NiAl phase for a long time and thus increases the lifetime of the coated substrate.

4

The Ni-Al-Hf Multiphase Diffusion

Romanowska J., Wierzba B., Markowski J., Zagula-Yavorska M., Sieniawski J.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

587--592

EN

The generalized Darken method was applied to simulate the diffusion between γ-Ni| γ’-Ni3Al and γ’-Ni3Al|β-NiAl interfaces. The results of calculations were compared with the experimental concentration’s profiles of nickel, aluminum and hafnium in aluminide and hafnium doped aluminide coatings deposited by the CVD and PVD methods on pure nickel. The method deals with the Wagner’s integral diffusion coefficients and thermodynamic data - activities of components. The experimental results agree with the simulated ones.

5

Adhesion investigation of rhodium electroplated layers on nickel substrate

Zagula-Yavorska M., Krupa K., Sieniawski J.

Advances in Manufacturing Science and Technology

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2016

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Vol. 40, nr 2

67--77

EN

The paper presents the evaluation of the quality and adherence of rhodium layers deposited on the nickel substrate. Rhodium layers (0.2 and 0.5 mm thick) were deposited by the electroplating method on the surface of the nickel substrate. The scratch test method (REVETEST R) was applied to determine the adhesion of layers. The increase of test force from 0.9 to 5 N and from 0.9 to 10 N did not lead to the rhodium layers detachment. Some microcracks were observed in the nickel substrate. The increase of load from 0.9 to 10 N leads to nested cohesive microcracks formation in the nickel substrate. Microcracks formed in the tensile stress field as a result of moving of the stylus. Good adherence of rhodium layers to the nickel substrate was observed.

PL

Prowadzono analizę wyników badań przyczepności powłoki rodu do podłoża niklu. Powłoki rodu (o grubości 0,2 i 0,5 mm) wytwarzano metodą elektrochemiczną. Przyczepność tych powłok określono metodą zarysowywania. Stwierdzono, że liniowa zmiana wartości siły dociskającej wgłębnik od 0,9 do 5 N oraz od 0,9 do 10 N nie powoduje oderwania powłoki od podłoża. Zwiększenie obciążenia siły dociskającej wgłębnik od 0,9 do 10 N prowadzi natomiast do powstawania mikropęknięć w podłożu niklu.

6

The microstructure and oxidation resistance of the aluminide coatings deposited by the CVD method on pure nickel and hafnium-doped nickel superalloys

Zagula-Yavorska M., Romanowska J., Pytel M., Sieniawski J.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 4

862--872

EN

Aluminide coating were deposited on pure nickel and hafnium-doped nickel superalloys Mar M247, Mar M200 and CMSX 4 by means of the CVD method. All coatings consisted of two layers: an outer, comprising the β-NiAl phase and the interdiffusion one. The interdiffusion layer on pure nickel consisted of the γ′-Ni3Al phase and of the NiAl phase on superalloys. MC and M23C6 carbides besides the NiAl phase were found in the interdiffusion zones on Mar M247 and Mar M200, whereas topologically close-packed phases, such as the TCP σ-phase and the R phase were found in the interdiffusion zone on CMSX 4. Coatings on substrates containing more hafnium (Mar M247 and Mar M200) were more resistant to degradation during the cyclic oxidation. The amount of 1.5–1.8 wt.% hafnium in the substrate let to the HfO2 ‘pegs’ formation in the oxide scale during oxidation of aluminized Mar M247 and Mar M200 superalloys. The improvement of lifetime of coated CMSX 4 superalloy was obtained by platinum modification. Platinum decreased diffusion of alloying elements such as Ti and Ta from the substrate to the coating and oxide scale, stabilized the NiAl phase and delayed the NiAl → Ni3Al phase transformation.

7

Kształtowanie warstwy aluminidkowej wytworzonej metodą CVD z uprzednio naniesioną powłoką cyrkonu na podłożu niklu

Zagula-Yavorska M., Kubiak K., Markowski J., Romanowska J.

Mechanik

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2014

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R. 87, nr 3

192--198

PL

Warstwy aluminidkowe modyfikowane cyrkonem na podłożu nadstopów niklu charakteryzują się dwukrotnie większą żaroodpornością w porównaniu z warstwami niemodyfikowanymi. W pracy nanoszono powłokę cyrkonu o grubości 1 i 3 μm metodą parowania wiązką elektronową (EBE) na podłoże niklu. Warstwę aluminidkową wytwarzano metodą chemicznego osadzania z fazy gazowej (CVD) w temperaturze 1050 ºC w czasie 8 h. Proces CVD umożliwia tworzenie się warstwy o budowie trzystrefowej. Strefa zewnętrzna warstwy aluminidkowej składa się z kryształów fazy NiAl, a strefa wewnętrzna – z fazy Ni3Al. Obecność kryształów fazy Ni(Al) stwierdzono na granicy strefa wewnętrzna–podłoże. Twardość warstwy aluminidkowej wynosi ok. 500 HV. Proces aluminiowania podłoża niklu z naniesioną powłoką cyrkonu o grubości 1 μm prowadzi do wydzielenia się cząstek kryształów faz międzymetalicznych NiZr(NiZr2) oraz Ni5Zr na granicy strefa zewnętrzna– strefa wewnętrzna oraz strefa wewnętrzna–podłoże. Zwiększenie grubości powłoki cyrkonu do 3 μm powoduje zwiększenie objętości względnej kryształów fazy Ni5 Zr w warstwie aluminidkowej.

EN

Zirconia modified aluminide layers on a substrate of nickel superalloy characterized by twice the heat resistance in comparison with unmodified layers. The paper zirconium coating was applied with a thickness of 1 and 3 mm using electron beam evaporation (EBE) on a nickel substrate. An aluminide layer is produced by chemical vapor deposition (CVD) at 1050 ° C for 8 h. The CVD process allows the formation of the layer of three-zone structure. The outer zone aluminide layer consists of crystal NiAl phase and the inner zone - Ni3Al phase. The presence of the crystal phase of Ni (Al) was found on the border of the inner-surface zone. Aluminide layer hardness approx. 500 HV. Aluminizing process nickel substrate with the coating zirconium 1 micron thickness leads to a separation of the crystals of intermetallic particles NiZr (NiZr2) and Ni5Zr zewnętrzna- zone on the border of the inner zone and the inner-surface zone. Increasing the zirconium coating thickness of 3 Pm increases the relative volume of the crystal phase Ni5 Zr aluminide layer.

8

The effect of diffusion treatment of double (Al/Zr and Zr/Al) coatings on the microstructure of the system coating/Ni substrate

Zagula-Yavorska M., Romanowska J., Markowski J., Krupa K., Sieniawski J.

Inżynieria Materiałowa

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2013

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Vol. 34, nr 4

397--400

EN

Double layers of aluminum (1 um thick) and zirconium (1 um thick) or zirconium (1 um thick) and aluminum (1 um thick) were deposited by the EB-PVD method. Adhesion evaluation of the layers was made using the scratch test. The layers were subjected to diffusion treatment at 1050°C for 2 h in the argon atmosphere. The linear and microarea chemical composition on the cross-section was made. Layers obtained by the EB-PVD method have good adhesion to the substrate. Diffusion treatment of Zr/Al layers leads to formation of Ni5Zr phases on the distance of 5 17 um from the surface, whereas the diffusion treatment of Al/Zr layers leads to the fonnation ofNi5Zr phases near the surface.

PL

Powłoki Zr/Al o grubości (1+1) um oraz Al/Zr o grubości (1+1) um wytworzono na podłożu niklowym metodą EB-PVD. Przyczepność powłok do podłoża niklowego oceniano metodą zarysowywania (scratch-test). Wygrzewanie dyfuzyjne powłok prowadzono w temperaturze 1050°C przez 2 h. Analizę składu chemicznego na przekroju warstwy wykonano metodą mikroanalizy rentgenowskiej EDS. Uzyskane powłoki wykazały dobrą przyczepność do podłoża. Wygrzewanie powłok Zr/Al powodowało uzyskanie faz Ni5Zr w odległości ok. 5÷7 um od powierzchni, natomiast po wygrzewaniu powłok Al/Zr fazy Ni5Zr obserwowano w pobliżu powierzchni.

9

Microstructure and oxidation resistance of an aluminide coating on the nickel based superalloy Mar M247 deposited by the CVD aluminizing process

Zielińska M., Zagula-Yavorska M., Sieniawski J., Filip R.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 3

697--701

EN

An investigation was conducted to synthesize βNiAl coating on the nickel based superalloy Mar M247 in a chemical vapor deposition process (CVD). The low activity process of aluminizing was carried out for 8 hours at the temperature 1050°C. Surface morphology and cross-section microstructure of the diffusion coating were studied and compared by using an optical microscope, a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy and an X-ray diffractometer. It was found that aluminide coating with the thickness of 37 μm consisted of two layers: an outer one and the inner interdiffusion one. The outer layer consists of single phase βNiAl. The inner one, consisted of βNiAl phase and carbides: MC and M23 C6 types which were originally present in the substrate. Cyclic oxidation test was performed at 1000°C for 1000h in the air atmosphere. The aluminized samples exhibited a small mass increase and the α- Al2 O3 oxide formed during oxidation test had a good adherence to the coating. The decrease of aluminum content in the coating with the prolongation of the oxidation time and the phase transformation of βNiAl to γ’ Ni3 Al and to γNi solid solution were observed. The samples without the coating showed a strong mass decrease in comparison to the coated samples.

XX

Niskoaktywny proces aluminiowania prowadzono w temperaturze 1050°C i w czasie 8 h. Badania mikrostruktury na przekroju oraz powierzchni warstwy dyfuzyjnej prowadzono za pomoca mikroskopu optycznego oraz skaningowego mikroskopu elektronowego wyposażonego w detektor EDS. Skład fazowy określano metodą rentgenowskiej analizy fazowej. Uzyskano warstwę aluminidkową o grubości 37 μm składająca się z dwóch stref: zewnętrznej oraz wewnętrznej (dyfuzyjnej). Strefa zewnętrzna składa się z fazy βNiAl. Natomiast wewnętrzna - z fazy βNiAl oraz węglików typu MC oraz M23C6. Badania cyklicznego utleniania prowadzono w temperaturze 1000°C i w czasie 1000 h w atmosferze powietrza. Podczas utleniania warstwy aluminidkowej powstaje tlenek α-Al2O3 o dobrej przyczepności do warstwy dyfuzyjnej. Zwiększenie czasu utleniania od o do 1000 h powoduje zmniejszenie zawartości aluminium oraz przemianę fazową β-NiAl do γ’-Ni3Al i do stałego roztworu γ-Ni. Materiał bez warstwy aluminidkowej charakteryzuje się większą szybkością utleniania w porównaniu do materiału z warstwą aluminidkową.

10

Oxidation behaviour of palladium modified aluminide coatings deposited by CVD method on nickel-based superalloys under air atmosphere

Zagula-Yavorska M., Kubiak K., Sieniawski J.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

848--854

EN

Purpose: In this paper the oxidation resistance of palladium modified aluminide coatings deposited by CVD method on nickel-based superalloy was evaluated. Design/methodology/approach: Palladium coatings 3 and 7 μm thick were deposited by the electroplating process. The heat treatment of electroplating coatings at the temperature 1050 °C for 2 h under argon atmosphere was performed. Low activity CVD aluminizing process of palladium heat treated coatings (3 and 7 μm thick) at the 1050°C for 8 h using IonB ond equipment was performed. Oxidation resistance was evaluated at 1100°C for 1000 h in air atmosphere using furnace of Czylok company. The microstructure investigations of palladium modified aluminide coatings were conducted by the use of optical microscope (Nikon Epiphot 300) and a scanning electron microscope (Hitachi S-3400N) equipped with an Energy Dispersive Spectroscope EDS (VOYAGER of NORAN INSTRUMENTS). The phase composition was identified by X-ray (ARL X’TRAX) diffractometer. The surface roughness parameter - Ra of modified aluminide coatings was evaluated by Perthometer S2 MAHR equipment. Findings: The microstructure of palladium modified aluminide coatings (3 and 7 μm thick) consists of (Ni,Pd)Al phase and two zones: outer and internal one. Low activity CVD aluminizing at 1050 °C for 8 h causes the increase of surface roughness parameter of modified coatings. The increase of platinum thickness from 3 to 7 μm causes a greater surface roughness of aluminide coatings. On the ground of the obtained results, it was found that palladium modification of aluminide coatings to increases the oxidation resistance of CMSX 4 Ni-base superalloy. Practical implications: The palladium modified aluminide coatings are used as an alternative for platinum modified aluminide coatings in turbine blades of aircraft engines. Originality/value: It was proved that palladium modification of aluminide coatings has a positive effect on the oxidation resistance of CMSX 4 Ni-base substrate.

11

Some properties of platinum and palladium modified aluminide coatings deposited by CVD method on nickel-base superalloys

Zagula-Yavorska M., Sieniawski J., Gancarczyk T.

Archives of Metallurgy and Materials

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2012

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Vol. 57, iss. 2

503-509

EN

In the paper some functional properties (hardness and oxidation resistance) of platinum and palladium modified aluminide coatings deposited by the CVD method on a nickel-based superalloy were determined. The platinum and palladium microlayers, 3 μm thick were deposited by electroplating process. The heat treatment of electroplating microlayers was performed for 2h at the temperature 1050 degree Celsjus in an argon atmosphere as to increase adhesion between the coating and the substrate. The low activity CVD aluminizing process of platinum heat treated coatings 3 μm thick at the 1050degree Celsjus for 8h using IonBond equipment was performed. The effects of aluminizing process were verified by the use of an optical microscope (microstructure and coating thickness); a scanning electron microscope and an energy dispersive spectroscope (chemical composition of the surface and cross-section of the modified aluminide coating). The hardness measurements on the cross-section of nonmodified and platinum or palladium modified aluminide coatings were performed. Oxidation tests of modified aluminide coatings at the 1100 degree Celsjus for 1000 h in the air atmosphere were carried out. On the grounds of the obtained results it was found that the main phase of the platinum modified aluminide coating is β-(Ni,Pt)Al. Consequently, the palladium modification of aluminide coating causes the formation of β-(Ni,Pd)Al phase. The platinum modified aluminide coating has better oxidation resistance than nonmodified and palladium modified aluminide coating. The XRD analysis of the surface of oxidized platinum modified aluminide coating confirmed the presence of the thermodynamically stable oxide layer Al2O3, that has good protective properties. The oxides of NiAl2O4, Al1:98Cr0:02O3 and TiO2 were found on the surface of the palladium modified aluminide coating after 1000 h oxidation at the 1100 degree Celsjus the in the air atmosphere.

PL

W pracy określono niektóre właściwości użytkowe (twardość oraz żaroodporność) warstwy aluminidkowej modyfikowanej platyną i palladem wytworzonej metodą CVD na podłożu nadstopów niklu, polikrystalicznym Inconel 713 LC i monokrystalicznym - CMSX 4. Powlokę platyny i palladu (grubość - 3μm) wytworzono metodą galwaniczną. Poprawę przyczepności powłoki galwanicznej do podłoża uzyskano przez wygrzewanie w temperaturze 1050 stopni Celsjusza w czasie 2 h w atmosferze argonu. Warstwę aluminidkowa wytworzono w procesie niskoaktywnym CVD (temperatura - 1050 stopni Celsjusza, czas - 8h). Efekty procesu aluminiowania weryfikowano w badaniach mikroskopowych (mikrostruktura i głębokość warstwy) oraz w analizie składu chemicznego na powierzchni i przekroju warstwy modyfikowanej. Pomiary twardości prowadzono na przekroju niemodyfikowanej warstwy aluminidkowej oraz warstwie modyfikowanej platyna i palladem. Próbę zmęczenia cieplnego wykonano w temperaturze 1100 stopni Celsjusza i w czasie 1000 h w atmosferze powietrza. Analiza uzyskanych wyników badan pozwała stwierdzić, ze głównym składnikiem fazowym mikrostruktury modyfikowanej platyną warstwy aluminidkowej są kryształy fazy &beta ;-(Ni,Pt)Al. Modyfikowanie palladem warstwy aluminidkowej prowadzi do tworzenia się kryształów fazy &beta ;-( -(Ni,Pd)Al jako głównego składnika fazowego mikrostruktury warstwy. Warstwę aluminidkowa modyfikowaną platyną charakteryzuje większa żaroodporność w porównaniu do warstwy aluminidkowej modyfikowanej palladem lub niemodyfikowanej. Analiza składu fazowego na powierzchni warstwy aluminidkowej modyfikowanej platyna po próbie zmęczenia cieplnego wykazała obecność zgorzeliny składającej sie z termodynamicznie stabilnego tlenku Al.2O3: Tlenek NiAl2O4; Al1:98Cr0:02O3 oraz rutyl TiO2 zaobserwowano na powierzchni warstwy aluminidkowej modyfikowanej palladem po 1000 h utleniania w temperaturze 1100 stopni Celsjusza w atmosferze powietrza.

12

Oxidation behaviour of zirconium-doped NiAl coatings deposited on pure nickel

Zagula-Yavorska M., Sieniawski J., Romanowska J.

Archives of Materials Science and Engineering

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2012

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Vol. 58, nr 2

250--254

EN

Purpose: In this paper the oxidation behaviour of zirconium-doped NiAl coatings deposited on a pure nickel was investigated. Design/methodology/approach: The zirconium-doped NiAl coatings were deposited by the chemical vapour deposition method on the pure nickel. The microstructure investigations of zirconium-doped aluminide coatings were performed by the use of an optical microscope (Nikon Epiphot 300) and a scanning electron microscope (Hitachi S-3400N) equipped with an Energy Dispersive Spectroscope EDS (VOYAGER of NORAN INSTRUMENTS). Oxidation behaviour at 1100ºC for 500 h in the air atmosphere in the furnace manufactured by Czylok company was evaluated. The phase composition of oxidized coatings were identified by the X-ray (ARL X’TRAX) diffractometer. Findings: The microstructures of zirconium-doped aluminide coatings consist of the β-NiAl, γ’-Ni3Al and γ-Ni(Al) phases. EDS analysis results of elements distribution indicate that zirconium is located at the distance of 13-16 μm from the surface after 1.5 h of aluminizing and randomly distributed in the whole coating after 5 h of aluminizing. Zirconium (less than 1% at) could contribute to a faster reduction of Al vacancies through fast diffusion towards the metal/oxide interface and increases adhesion of the oxide layer to the coating and this why the oxidation resistance improves. Research limitations/implications: The research involve microstructure, phase composition and oxidation behaviour investigation of zirconium doped aluminide coatings. Practical implications: The zirconium-doped aluminide coatings may be used as the cheaper alternative to platinum and palladium modified aluminide coatings for turbine blades of aircraft engines. Originality/value: The range of investigation includes microstructure, phase composition and oxidation behaviour of zirconium doped aluminide coating.