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1

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

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.

4

Experimental study on thermodynamics of Cu-Pb-Ti and Cu-Pb-V alloys

Romanowska J.

Advances in Manufacturing Science and Technology

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2016

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Vol. 40, nr 2

79--86

EN

The thermodynamic activity of Pb in liquid Cu-Pb-Ti and Cu-Pb-V alloys has been determined by the equilibrium saturation method at T=1473K. The Cu-Pb alloy was accepted as a reference mixture. The interaction parameters of titanium and vanadium on the lead activity, εTiPb> and εVPb, were calculated on the basis of experimental results. Negative values of these parameters suggest that titanium and vanadium decrease lead activity in the studied alloys.

PL

Aktywność termodynamiczną ołowiu w ciekłych stopach Cu-Pb-Ti oraz Cu-Pb-V wyznaczono metodą równowagowego nasycania. Badania prowadzono w temperaturze 1473 K. Roztworem wzorcowym był ciekły stop Cu-Pb. Na podstawie wyników wykonanych doświadczeń obliczono wartości parametrów oddziaływania tytanu i wanadu na aktywność ołowiu εTiPb oraz εVPb. Ujemne wartości parametrów oddziaływania sugerują, że tytan i wanad zmniejszają aktywność termodynamiczną ołowiu w badanych stopach Cu-Pb-Ti i Cu-Pb-V.

5

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.

6

Właściwości termodynamiczne i mikrostruktura stopów Bi-Cu-Ni-Sn-Ti

Romanowska J.

Mechanik

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2014

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R. 87, nr 1

52--54

PL

Przedstawiono wyniki badań termodynamicznych i mikroskopowych stopów Bi-Cu-Ni-Sn-Ti. Aktywność bizmutu w ciekłych, rozcieńczonych stopach w temperaturze 1373 K wyznaczono metodą równowagowego nasycania. Współczynnik aktywności bizmutu opisano równaniem Wagnera. Metodą najmniejszych kwadratów wyznaczono wartości parametrów oddziaływania poszczególnych składników stopu na aktywność bizmutu. Badania mikroskopowe i analizę składu fazowego stopów przeprowadzono metodą SEM/EDS. Analiza morfologii składników fazowych potwierdza wyniki badań termodynamicznych. Stwierdzono na ich podstawie, że cyna, nikiel i tytan podwyższają aktywność bizmutu.

EN

The results of investigations of thermodynamic and microscopic alloys Bi-Cu-Ni-Sn-Ti. The activity of bismuth in the liquid, dilute alloys at a temperature of 1373 K was determined by equilibrium saturation. Bismuth activity coefficient equation describes Wagner. The least squares method, values of the parameters of the individual components influence the activity of bismuth alloy. Microscopic examination and analysis of the phase composition of alloys was performed by SEM / EDS. Analysis of the morphology of the phase components confirms the results of thermodynamic. It has been found on the basis of the tin, nickel and titanium increase the activity of bismuth.

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

Numerical prediction of the thermodynamic properties of ternary Al-Ni-Zr alloys

Romanowska J., Kotowski S.

Inżynieria Materiałowa

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2014

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Vol. 35, nr 2

187--190

EN

The thermodynamic properties of ternary Al-Ni-Zr system, such as exGAlNiZr, μAl(AlNiZr), μNi(AlNiZr) and μZr(AlNiZr) at 1273 K were predicted on the basis of thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting exGAlNiZr values was regarded as calculation of values of the exG function inside a certain area (the Gibbs triangle) unless all boundary conditions, that is values of exG on all legs of the triangle are known (exGAlNi, exGAlZr, exGNiZr). This approach is contrary to finding a function value outside a certain area, if the function value inside this area is known. exG and Lijk ternary interaction parameters in the Muggianu extension of the Redlich-Kister formalism are calculated numerically using the Excel program and Solver. The accepted values of the third component xx differed from 0.01 to 0.1 of mole fraction. Values of L parameters in the Redlich- Kister formulas are different for different xx values, but values of thermodynamic functions: exGAlNiZr, μAl(AlNiZr), μNi(AlNiZr) and μZr(AlNiZr) do not differ significantly for different xx values. The choice of xx value does not influence the accuracy of calculations.

PL

Właściwości termodynamiczne trójskładnikowych stopów Al-Ni-Zr, takie jak exGAlNiZr, μAl(AlNiZr), μNi(AlNiZr) i μZr(AlNiZr) w temperaturze 1273 K zostały wyznaczone numerycznie na podstawie właściwości termodynamicznych stopów dwuskładnikowych tworzących badany stop trójskładnikowy. Wartości exGAlNiZr wyznaczono jako wartości funkcji exG wewnątrz obszaru (trójkąta składów Gibbsa), gdy są znane wszystkie wartości brzegowe, czyli wartości exG na bokach trójkąta (exGAlNi, exGAlZr, exGNiZr). Prezentowane podejście jest odwrotne do szukania wartości funkcji na zewnątrz obszaru, dla znanych wartości funkcji wewnątrz danego obszaru. Wartości funkcji exGijk i parametrów Lijk równania Redlicha-Kistera wyznaczono numerycznie, korzystając z programu Excel i dodatku Solver. Do obliczeń przyjęto wartości zawartości trzeciego składnika xx od 0,01 do 0,1. Wartości parametrów L zmieniają się w zależności od przyjętej wartości xx, ale nie wpływa to w istotny sposób na wyznaczone wartości funkcji termodynamicznych exGAlNiZr, μAl(AlNiZr), μNi(AlNiZr) i μZr(AlNiZr).

9

A study of thermal diffusivity of carbon-epoxy and glass-epoxy composites using the modified pulse method

Terpiłowski J., Piotrowska-Woroniak J., Romanowska J.

Archives of Thermodynamics

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2014

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Vol. 35, no. 3

117--128

EN

Transient heat transfer is studied and compared in two plane-parallel composite walls and one EPIDIAN 53 epoxy resin wall acting as a matrix for both composites. The first of the two walls is made of carbon-epoxy composite; the other wall is made of glass-epoxy composite, both with comparable thickness of about 1 mm and the same number of carbon and glass fabric layers (four layers). The study was conducted for temperatures in the range of 20-120 °C. The results of the study of thermal diffusivity which characterizes the material as a heat conductor under transient conditions have a preliminary character. Three series of tests were conducted for each wall. Each series took about 24 h. The results from the three series were approximated using linear functions and were found between (0.7-1.35) x 10-7m2/s. In the whole range of temperature variation, the thermal diffusivity values for carbon-epoxy composite are from 1.2 to 1.5 times higher than those for the other two materials with nearly the same thermal diffusivity characteristics.

10

Thermodynamics and microstructure of the Cu-Ni-Sn-Ti-Zn alloys

Romanowska J.

Inżynieria Materiałowa

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2013

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Vol. 34, nr 4

367--369

EN

The urgent need of ﬁnding new, non toxic, high temperature solders induced the research of multicomponent systems, in order to find new materials that could substitute lead-containing solders. This work presents results of thermodynamic research of Cu-Ni-Sn-Ti-Zn system regarding Zn activity measurements by means of the vapour saturation method and the microstructure investigation by means of scanning electron microscopy. Results of these investigations compared with results for Cu-Ni-Sn-Zn alloys revealed a signiﬁcant inﬂuence of Ti on the Zn activity and microstucture ofthe analyzed alloys.

PL

Zapotrzebowanie na nowe, nietoksyczne materiały lutownicze, które będą mogły pracować w wysokiej temperaturze spowodowało intensyﬁkację badań właściwości stopów wieloskładnikowych w celu znalezienia materiałów, które będą mogły zastąpić lutowia zawierające ołów. W pracy przedstawiono wyniki badań termodynamicznych stopu Cu-Ni-Sn-Ti-Zn. Wyznaczono aktywność cynku metodą równowagowego nasycania i analizy mikrostruktury oraz składu fazowego metodą elektronowej mikroskopii skaningowej. Porównanie wyników prowadzonych badań z wynikami badań stopów Cu-Ni-Sn-Zn wskazują na znaczny wpływ tytanu na aktywność cynku i mikrostrukturę badanych stopów.

11

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.

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.

13

Determination of the thermodynamic properties of liquid Ag-Sb-Sn system by equilibrium saturation method

Romanowska J., Bencze L

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 48, nr 1

41--51

EN

Purpose: The interaction of lead-free solders with a copper substrate is an essential issue for the reliability of solder joints. In order to understand this interaction, the knowledge of thermodynamic and other physical properties of several ternary systems such as Ag-Sb-Sn system is necessary. The aim of this work was to determine the activities of all components in Ag-Sb-Sn alloy. Design/methodology/approach: The investigation of this system was carried out using the equilibrium saturation (ES) method. The ES measurements were performed at 1273, 1373 and 1473 K. As the latter method is a comparative one, a Sn-Sb alloy was accepted as a reference alloy, where a formula for the Sb activity proposed by Jonsson and verified by Vassiliev was accepted. Findings: In the frame of the presented experiments the activity of Sb was determined by ES method. Research limitations/implications: The activity of Sb was obtained by ES and fitted to the Redlich-Kister-Muggianu (RKM) model. Practical implications: A knowledge of multi-component phase equilibrium can provide the alloy developer with specific data enabling finding alloys that meet certain criteria. Phase diagrams are built on the basis of experimental data and the reliability of phase diagrams depends on the reliability of the experimental data used for the optimisation. Hence it is advantageous to use various source of data obtained by several methods and when the data of different source agree (like the ones presented in this paper) it proves their reliability. Data presented in this paper will be used for Ag-Sb-Sn phase diagram optimisation in the frame of the COST Action MP0602. Originality/value: Sb activity values in Ag-Sb-Sn alloys obtained by ES and activity values of Sb, Ag and Sn calculated using the RKM model.

14

Numerical approach to predicting thermodynamic properties of ternary alloys

Romanowska J.

Inżynieria Materiałowa

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2011

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Vol. 32, nr 6

929-932

EN

This paper presents a new numerical approach to the modelling of ternary systems on the basis of the thermodynamic properties of binary systems included in the investigated ternary system. The idea of predicting exGfi ijk values is regarded as the calculation of the values of an exGfi function inside a certain area (a Gibbs triangle) unless all boundary conditions, that is values of exGfi on all arms of the triangle are known (exGfi ij, exGfi ik, exGfi jk). This approach is contrary to finding a function value outside a certain area, if the function value inside this area is known. exGfi ijk and Lfi ijk ternary interaction parameters in the Muggianu extension of Redlich-Kister formalism are calculated numerically by use of the Excel program and Solver. The results of the calculations were compared to the data for the Cu-Sn-Zn and Bi-Cu-Ni systems obtained by means of the CALPHAD method.

PL

W pracy przedstawiono numeryczną metodę prognozowania właściwości termodynamicznych stopów trójskładnikowych na podstawie danych termodynamicznych stopów dwuskładnikowych, tworzących badany stop trójskładnikowy. Wartości exGfi ijk wyznaczono jako wartości funkcji exGfi wewnątrz obszaru (trójkąta składów Gibbsa), gdy są znane wszystkie wartości brzegowe, czyli wartości exGfi na bokach trójkąta (exGfi ij, exGfi ik, exGfi jk). Prezentowane podejście jest odwrotne do szukania wartości funkcji na zewnątrz obszaru dla znanych wartości funkcji wewnątrz danego obszaru. Wartości funkcji exGfi ijk i parametrów Lfi ijk równania Redlicha-Kistera wyznaczono numerycznie, korzystając z programu Excel i dodatku Solver. Wyniki obliczeń dla stopow Cu-Sn-Zn i Bi-Cu-Ni porównano z danymi uzyskanymi metodą CALPHAD.

15

Experimental study on thermodynamics of the Bi-Cu-Sn system

Romanowska J.

Archives of Metallurgy and Materials

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2011

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Vol. 56, iss. 1

87-91

EN

Bismuth thermodynamic activities in Bi-Cu-Sn liquid alloys were measured by means of the vapour saturation method at 1373K, 1423K and 1473K. These results were coupled with literature data for binary systems Bi-Cu, Bi-Sn and Cu-Sn in order to obtain a thermodynamic description of the ternary liquid by use of the geometrical Muggianu approach.

PL

Metodą równowagowego nasycania wyznaczono aktywność bizmutu w stopach Bi-Cu-Sn w temperaturze 1373, 1423 I 1473K. Na podstawie uzyskanych wyników i danych literaturowych dotyczących stopów dwuskładnikowych Bi-Cu, Bi-Sn i Cu-Sn i stosując model Muggianu uzyskano opis termodynamiczny ciekłego stopu trójskładnikowego.

16

Thermodynamics of Cu-Sn-X (X = Bi, Nb, Sb, Zn) liquid alloys

Romanowska J.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 3

724-727

EN

This paper presents the results of experimental investigations of Cu-Sn-X (X = Bi, Nb, Sb, Zn) alloys and the comparison of X activity calculated on the basis of experimentally obtained formulas with the values that could have been obtained by the use of the symmetric model.

PL

W pracy porównano wartość aktywności składnika X w stopach Cu-Sn-X (X = Bi, Nb, Sb, Zn) obliczone na podstawie doświadczalnie wyznaczonych równań z wartościami, które mogą być określone z zastosowaniem modelu symetrycznego.

17

Thermodynamic properties of liquid Cu-Sb-Sn alloys by equilibrium saturation and Knudsen effusion mass spectrometric methods

Romanowska J.

Archives of Materials Science and Engineering

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2009

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Vol. 39, nr 2

69-74

EN

Purpose: The interaction of lead-free solders with a copper substrate is an essential issue for the reliability of solder joints. In order to understand this interaction, knowledge of thermodynamic and other physical properties of several Cu-containing ternary systems such as Cu-Sb-Sn system is necessary. The aim of this work was to determine Sb activity in Cu-Sb-Sn alloy. Design/methodology/approach: Investigation of this system was carried out using the equilibrium saturation (ES) method and Knudsen effusion mass spectrometry (KEMS). The ES measurements were performed in 1373 K temperature. As the latter method is comparative one, a Sn-Sb alloy was accepted as a reference alloy, where a formula for Sb activity proposed by Jönsson and verified by Vassiliev was accepted. The Sb activity measurements by KEMS method were performed in a temperature range from 793 to 1323 K. Findings: In the frame of presented experiments, Sb activity was determined by ES and KEMS methods. Research limitations/implications: The Sb activities obtained by ES and KEMS agree well - Sb(KEMS)/Sb(ES) = 1.04 š 0.14. Practical implications: Knowledge of multi-component phase equilibrium can provide the alloy designer with specific data enabling finding alloys that meet certain criteria. Originality/value: The measured activity of antimony in the Cu-Sb-Sn alloys both by ES and KEMS method are comparable and they will be used for phase equilibria calculations of the Cu-Sb-Sn system.

18

Numerical approach to precipitate growth and dissolution calculation

Romanowska J.

Archives of Metallurgy and Materials

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2008

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Vol. 53, iss. 4

1127-1131

EN

Different aspects of precipitates formation, growth and dissolution have been thoroughly studied and many factors influ-encing it such as diffusion, thermodynamic properties and kinetics have been taken into consideration. The aim of this work is to present numerical approach to precipitates growth and dissolution processes, considering them as diffusion controlled ones, described by the first Fick's law. There have been solved differential eąuations with two variables (time and space) by the means of finite difference method. As a result, there have been obtained dependences of precipitate radii on time in processes of coagulation and dissolution. Results calculated in such a way have been compared with the values obtained by the means of other methods.

PL

Tworzenia się wydzieleń było wielokrotnie analizowane, przy czym bramo pod uwagę wiele czynników mających wpływ na ten proces np. dyfuzję, kinetykę oraz właściwości termodynamiczne. W pracy przedstawiono numeryczne podejście do procesu rozrostu i rozpuszczania się wydzieleń, przy założeniu że są to procesy kontrolowane przez dyfuzję, opisane pierwszym prawem Ficka. Rozwiązano równania różniczkowe z dwoma zmiennymi (czas i przestrzeń) metodą różnic skończonych. Uzyskano zależności promienia wydzielenia od czasu w procesie wzrostu wydzieleń i rozpuszczania. Rezultaty obliczeń porównano z wartościami uzyskanymi innymi metodami.

19

Experimental study on thermodynamics of the Cu-Ni-Sn-Zn system

Romanowska J., Wnuk G., Romanowski P.

Archives of Metallurgy and Materials

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2008

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Vol. 53, iss. 4

1107-1110

EN

The urgent need of finding new, non toxic, high temperaturę solders caused the abundance of research of multicomponent systems, as to find new materials that could substitute lead-containing solders. This work presents the results of thermodynamic research of Cu-Ni-Sn-Zn system, that is the Zn activity measurements by the means of the vapour saturation method and interaction parameters calculations. These experimental results enable phase diagram calculation in the frame of the COST action MP0602.

PL

Konieczność znalezienia nowych bezołowiowych materiałów na wysokotemperaturowe stopy lutownicze spowodowała znaczny rozwój badań nad stopami wieloskładnikowymi w celu znalezienia materiału, który mógłby zastąpić dotychczas stosowane stopy zawierające ołów. W pracy przedstawiono wyniki badań termodynamicznych stopów Cu-Ni-Sn-Zn. Metodą równowagowego próżniowego nasycania zmierzono aktywność cynku i obliczono parametry oddziaływania. Uzyskane dane eksperymentalne umożliwią obliczenie diagramu równowagi fazowej w ramach programu COST MP0602.

20

Influence of Cu and Sn on the activity of Bi in Cu-Sn-Bi liquid alloys

Wnuk G., Romanowska J.

Archives of Metallurgy and Materials

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2006

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Vol. 51, iss. 4

593-597

EN

The activies of Bi in liquid dilute Cu-Sn-Bi alloys were determined by the method of equilibrium saturation with metal vapour, at T= 1373K. As the method of equilibrium saturation is a comparative one, it is necessary to have an appropriate reference solution. The Cu-Bi alloy was accepted as the reference one. The interaction parameters [...] and [...] were determined by the least squares method. The experimental data of [...] and [...] were compared with data calculated on the basis of the “central atom” theory.

PL

Metodą równowagowego nasycania wyznaczono aktywność bizmutu w ciekłych, rozcienczonych stopach Cu-Sn-Bi w temperaturze 1373 K. Jako że metoda równowagowego nasycania jest metodą porównawczą, konieczne jest stosowanie roztworu wzorcowego. Jako roztwór wzorcowy przyjęto stop Cu-Bi. Metodą najmniejszych kwadratów wyznaczono parametry oddziaływania miedzi i cyny na aktywność bizmutu w stopie Cu-Sn-Bi, a wartości eksperymentalne porównano z wartościami obliczonymi na podstawie modelu atomu centralnego.