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1

Influence of Heat Treatment on Properties of Ni-B/B Composite Coatings

Mazurek A., Bartoszek W., Cieślak G., Gajewska-Midziałek A., Oleszak D., Trzaska M.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

839--844

EN

The results of research on preparations of alloy Ni-B/B composite coatings produced by chemical reduction method on a carbon steel substrate are collected in this paper. The alloy Ni-B coatings were also investigated for comparative purposes. The produced coatings were subjected to a heat treatment process. The boron powder with the particles size below 1 μm was used as the dispersion phase. The structure of the coatings was examined by X-ray diffraction method. Boron powder particles as well as surface morphology and topography were characterized by scanning electron microscopy. The roughness test, microhardness and corrosion resistance by potentiodynamic method and surface wettability tests were carried out. Analysis of the chemical composi-tion by the EDS method showed that the boron powder particles were evenly embedded in the entire volume of the coating. Ni-B/Bcomposite coatings are characterized by higher hardness than alloy Ni-B coatings. As a result of heat treatment, the Ni3 B phase crystallized, which increased the hardness of the coating material. The incorporation of boron powder particles and heat treatment reduce the corrosion resistance of coatings. All produced coatings exhibited hydrophobic properties.

2

Towards cubic modification of Li7La3Zr2O12 compound by mechanical milling and annealing of powders

Oleszak D., Kurowski B., Pikula T., Pawlyta M., Senna M., Suzuki H.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

13--16

EN

The aim of these studies was to obtain single phase cubic modification of Li7La3Zr2O12 by mechanical milling and annealing of La(OH)3, Li2CO3 and ZrO2 powder mixture. Fritsch P5 planetary ball mill, Rigaku MiniFlex II X-ray diffractometer, Setaram TG-DSC 1500 analyser and FEI Titan 80-300 transmission electron microscope were used for sample preparation and investigations. The applied milling and annealing parameters allowed to obtain the significant contribution of c-Li7La3Zr2O12 in the sample structure, reaching 90%. Thermal measurements revealed more complex reactions requiring further studies.

3

The Application of Deep Cryogenic Treatment to Improve the Properties of Nitrided Layers Formed on X153CrMoV12 Steel

Wach P., Ciski A., Babul T., Kapuścińska A., Oleszak D.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

303--309

EN

Deep cryogenic treatment (DCT) is gaining popularity as a treatment used to modify structures obtained during heat or thermo-chemical treatment. The article presents the influence of DCT, carried out during heat treatment before and after gas nitriding processes, on the formation of gas nitrided layers on X153CrMoV12 steel. It was found that the use of DCT between quenching and tempering performed prior to gas nitriding processes, increases the hardness, thickness and wear resistance of the nitrided layers. At the same time, if we apply cryogenic treatment during post-heat treatment of nitrided layers, we also get very high wear resistance and increased thickness of nitrided layers, in comparison with conventional gas nitriding of X153CrMoV12 steel. In this case, DCT significantly increases also the hardness of the core by the transformation of retained austenite and the precipitation of fine carbides of alloying elements.

4

Spin reorientation process in Tm2–xHoxFe14B : analysis of conical arrangement based on Mössbauer spectra

Kurzydło P. M., Pędziwiatr A. T., Bogacz B. F., Przewoźnik J., Oleszak D.

Nukleonika

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2017

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Vol. 62, No. 2

123--127

EN

The spin reorientation process in the Tm2–xHoxFe14B series of compounds was studied using 57Fe Mössbauer spectroscopy over the temperature range 5.2–320 K with a focus on the analysis of conical spin arrangement. Each compound was studied by precise Mössbauer scanning in the vicinity of the transition and during the transition. By applying computer simulations based on the simplified Yamada-Kato model, as well as on some literature data for R2Fe14B (R = Tm, Ho) compounds, the above series was selected for studies as it contains compounds with different spin arrangements (axial, planar, conical). It was a crucial requirement for obtaining unambiguous angular dependences when applying a simultaneous fitting procedure of Mössbauer spectra. Such an extended procedure was applied which allowed the temperature dependence of the angle describing the position of the magnetization vector to be obtained. The results were compared with those from theoretical simulations. The spin arrangement diagram was constructed. A conical spin arrangement was confirmed over a wide temperature range.

5

Effect of BaTiO3 concentration on structural and magnetic properties of mechanically activated BiFeO3-BaTiO3 system

Malesa B., Pikula T., Oleszak D., Jartych E.

Nukleonika

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2017

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Vol. 62, No. 2

149--152

EN

In this research, the mechanical activation method is proposed as an alternative process of preparation of the (BiFeO3)1–x-(BaTiO3)x solid solutions with various concentrations of barium titanate (x = 0.1÷0.9). However, mechanical milling itself does not allow obtaining the desired products and additional thermal treatment is needed to complete the solid-state reaction. In the present studies, X-ray diffraction and 57Fe Mössbauer spectroscopy were applied as complementary methods in order to study the structural and magnetic properties of materials. The investigations revealed that an increase of BaTiO3 concentration causes changes in the crystalline and hyperfine magnetic structure of the studied (BiFeO3)1–x-(BaTiO3)x system.

6

Structure and Magnetic Properties of Bi5Ti3FeO15 Ceramics Prepared by Sintering, Mechanical Activation and Edamm Process. A Comparative Study

Jartych E., Pikula T., Mazurek M., Franus W., Lisinska-Czekaj A., Czekaj D., Oleszak D., Surowiec Z., Aksenczuk A., Calka A.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

869--874

EN

Three different methods were used to obtain Bi5Ti3FeO15 ceramics, i.e. solid-state sintering, mechanical activation (MA) with subsequent thermal treatment, and electrical discharge assisted mechanical milling (EDAMM). The structure and magnetic properties of producedBi5Ti3FeO15 samples were characterized using X-ray diffraction and Mössbauer spectroscopy. The purest Bi5Ti3FeO15 ceramics was obtained by standard solid-state sintering method. Mechanical milling methods are attractive because the Bi5Ti3FeO15 compound may be formed at lower temperature or without subsequent thermal treatment. In the case of EDAMM process also the time of processing is significantly shorter in comparison with solid-state sintering method. As revealed by Mössbauer spectroscopy, at room temperature theBi5Ti3FeO15 ceramics produced by various methods is in paramagnetic state.

7

Structure and Mössbauer spectroscopy studies of mechanically activated (BiFeO3)1-x-(BaTiO3)x solid solutions

Malesa B., Antolak-Dudka A., Oleszak D., Pikula T.

Nukleonika

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2015

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Vol. 60, No. 1

109--114

EN

(BiFeO3)1-x-(BaTiO3)x solid solutions with x = 0.1–0.4 and 0.7 were investigated. The ceramics were prepared by mechanical activation technology and subsequent heat treatment. As was proved by X-ray diffraction, increase of BaTiO3 concentration causes a change in the crystalline structure from the rhombohedral structure characteristic of BiFeO3 to a cubic one. 57Fe Mössbauer spectroscopy allowed observation of a gradual transformation from an ordered spin structure of Fe3+ ions to the paramagnetic state with an increase of x.

8

Search for canted spin arrangement in Er2-xTbxFe14B with Mössbauer spectroscopy

Kurzydło P. M., Bogacz B. F., Pędziwiatr A. T., Oleszak D., Przewoźnik J.

Nukleonika

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2015

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Vol. 60, No. 1

93--96

EN

The materials studied were polycrystalline compounds Er2-xTbxFe14B (x = 0.1, 0.2, 0.3, 0.4) which crystallize in a tetragonal lattice and display a variety of spin arrangements. The compounds have been measured with 57Fe Mössbauer spectroscopy over the temperature range 80–320 K in order to investigate the spin reorientation processes. Each compound was studied in a wide temperature range, with precise Mössbauer scanning in the vicinity of the transition. The set of spectra obtained for a given compound was analyzed using simultaneous fi tting procedure to investigate the infl uence of the transition on the shape of the spectra. The fi tting program was specifi ed to analyze the transition according to the ‘two state model’: spins fl ip abruptly from initial angle to fi nal arrangement (90° angle). Obtained results suggest that spin reorientation process cannot be described using only the mentioned above model. Additional computer simulations based on the Yamada–Kato model were conducted to determine temperature range and the type of spin alignments in the vicinity of the transition. These theoretical results supported by spectra analysis suggest the existence of intermediate (canted) spin arrangements in the studied compounds. The spin arrangement diagram was constructed.

9

Charakterystyka kompozytów WCCo–cBN otrzymanych metodą PPS

Zieliński R., Wachowicz J., Michalski A., Oleszak D.

Inżynieria Materiałowa

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2015

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Vol. 36, nr 5

224--228

PL

Węglik wolframu w osnowie kobaltu jest jednym z najczęściej wykorzystywanych materiałów na narzędzia skrawające. W celu zwiększenia jego odporności na ścieranie wprowadza się rozproszone cząstki cBN, które mają kilkakrotnie większą odporność na ścieranie niż węgliki spiekane w osnowie kobaltu. W pracy przedstawiono wyniki badań otrzymywania kompozytu WC6Co–20% cBN metodą PPS (Pulse Plasma Sintering) na Wydziale Inżynierii Materiałowej Politechniki Warszawskiej. Spieki zostały wykonane w temperaturze 1050, 1100, 1200°C, były spiekane przez 300 s, ich gęstość wynosi odpowiednio 98,2%, 100% oraz 99,7% gęstości teoretycznej. Twardość spieku o 100% gęstości teoretycznej wynosi 2197 HV5. Dyfrakcja rentgenowska wykonana dla próbki spiekanej w temperaturze 1100°C przez 300 s nie ujawnia przejścia twardej odmiany cBN w niepożądaną i miękką strukturę hBN. Zdjęcia wykonane na skaningowym mikroskopie elektronowym w próbkach otrzymanych w temperaturze 1050°C ujawniają niepełne ukształtowanie ziarna węgliku wolframu, ponadto w strukturze obserwuje się występowanie porów. Obraz mikrostruktury próbki spiekanej w 1100°C przez 180 s przedstawia dobrze ukształtowane ziarno WC, występuje porowatość. Wydłużenie czasu spiekania do 300 s korzystnie wpływa na mikrostrukturę próbki, ziarno jest dobrze ukształtowane o charakterystycznych ostrych krawędziach, z dobrym umocowaniem ziaren cBN oraz brakiem zauważalnej porowatości. Zwiększenie temperatury spiekania do 1200°C sprzyja zjawisku powierzchniowej degradacji cząstek cBN (przemianie w niepożądaną strukturę hBN).

EN

One of the most widely used cutting tool materials is a tungsten carbide cobalt. Dispersed cBN particles are introduced in order to enhance abrasion resistance of this material and in the result it achieved several times greater wear resistance than cemented carbides in the matrix cobalt. In this paper the results of WC6Co–20% cBN composite, which are produced using PPS (Pulse Plasma Sintering) method at the Department of Materials Science and Engineering Warsaw University of Technology. The samples which were sintered at 1050, 1100, 1200°C during 300 s, their densities are 98.2%, 100% and 99.7% of the theoretical density. The hardness of the sinter of 100% (GT) is 2197 HV5. The X-ray diffraction carried out for a sample of 1100°C and sintering time was not revealed that passage of hard cBN in undesirable variations and soft structure hBN. The pictures, taken with an scanning electron microscope, of samples prepared at 1050°C discloses incomplete formation of tungsten carbide grain in addition to the structure observed in the presence of pores. Figure 9d of the microstructure of the sample which was sintered under temperature 1100°C during 180s shows a well-evolved is a porosity. With extending of a sintering time to 300 s the positive effect of the microstructure of sample was observed. A grain has well formation with sharp-edged with a good fastening of cBN grains moreover a lack of porosity was notice. Increasing of the sintering temperature to 1200°C is favorable for the phenomenon of surface degradation cBN particles (transformed to the undesired structure hBN).

10

Structure and hyperfine interactions in multiferroic Aurivillius Bi m+1Ti3Fe m−3O3m+3 compounds prepared by mechanical activation

Mazurek M., Oleszak D., Czekaj D.

Materials Science Poland

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2014

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Vol. 32, No. 4

676--681

EN

The aim of the study was to determine the structure and hyperfine interactions of Bim+1Ti3Fem−3O3m+3 multiferroic Aurivillius compounds prepared by mechanical activation process. X-ray diffraction and Mössbauer spectroscopy were applied as complementary methods. After the process of mechanical milling, desired Aurivillius phases were not formed, thus, thermal treatment needed to be applied. Heating the product of mechanical activation up to 993 K allowed to obtain Aurivillius phases with relatively large amount of non-reacted hematite. However, after the material was annealed at an elevated temperature of 1073 K, the content of not fully synthesized hematite was significantly reduced. Mössbauer spectroscopy confirmed that Aurivillius compounds remain in paramagnetic state at room temperature.

11

Structure and hyperfine interactions of multiferroic Bim+1Ti3Fem-3O3m+3 ceramics prepared by mechanical activation

Mazurek M., Jartych E., Oleszak D.

Nukleonika

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2013

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Vol. 58, No. 1

143-147

EN

The structure and hyperfine interactions in the Bi5Ti3FeO15, Bi6Ti3Fe2O18 and Bi7Ti3Fe3O21 multiferroic ceramics were studied using X-ray diffraction and Mössbauer spectroscopy. Samples were prepared by mechanical activation process in a high-energy ball mill from a mixture of TiO2, Fe2O3 and Bi2O3 oxides as polycrystalline precursor materials. The mechanical milling process was completed by thermal processing. A pure single-phased material was obtained in the case of Bi7Ti3Fe3O21 compound. The proposed mechanical activation technology allows to produce the Aurivillius compounds at lower temperature, by about 50 K, as compared to the solid-state sintering method.

12

Mössbauer investigation of some bcc, Fe - based, multicomponent alloys

Olszewski W., Szymański K., Satuła D., Oleszak D.

Nukleonika

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2013

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Vol. 58, No. 1

165-168

EN

Mössbauer measurements of a Fe-based, bcc multicomponent alloys with concentration of non-ferrous element x = (0.1, 0.3 and 0.6) were performed. The effective thickness parameters and the second order Doppler shifts were determined as a function of temperature. The results indicate an apparent decrease of the recoilless fraction with x. The observed trends are consistent with theoretical results indicating modifications of phonon density of states by bond disorder.

13

Comparative X-ray diffraction and Mössbauer spectroscopy studies of BiFeO3 ceramics prepared by conventional solid-state reaction and mechanical activation

Jartych E., Lisinska-Czekaj A., Oleszak D., Czekaj D.

Materials Science Poland

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2013

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Vol. 31, No. 2

211--220

EN

The aim of this work was to prepare BiFeO3 by modified solid-state sintering and mechanical activation processes and to investigate the structure and hyperfine interactions of the material. X-ray diffraction and Mössbauer spectroscopy were applied as complementary methods. In the case of sintering, BiFeO3 phase was obtained from the mixture of precursors with 3 and 5 % excess of Bi2O3 during heating at 1023 K. Small amounts of impurities such as Bi2Fe4O9 and sillenite were recognized. In the case of mechanical activation, the milling of stoichiometric amounts of Bi2O3 and Fe2O3 followed by isothermal annealing at 973 K resulted in formation of the mixture of BiFeO3, Bi2Fe4O9, sillenite and hematite. After separate milling of individual Bi2O3 and Fe2O3 powders, mixing, further milling and thermal processing, the amount of desired BiFeO3 pure phase was significantly increased (from 70 to 90 %, as roughly estimated). From Mössbauer spectra, the hyperfine interaction parameters of the desired BiFeO3 compound, paramagnetic impurities of Bi2Fe4O9 and sillenite were determined. The main conclusion is that the lowest amount of impurities was obtained for BiFeO3 with 3 % excess of Bi2O3, which was sintered at 1023 K. However, in the case of mechanical activation, the pure phase formed at a temperature by 50 K lower as compared to solid-state sintering temperature. X-ray diffraction and Mössbauer spectroscopy revealed that for both sintered and mechanically activated BiFeO3 compounds, thermal treatment at elevated temperature led to a partial eliminating of the paramagnetic impurities.

14

Mössbauer studies of Bi5Ti3FeO15 electroceramic prepared by mechanical activation

Mazurek M., Jartych E., Oleszak D.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

256-258

EN

The present work involves the structure analysis and the determination of hyperfine interactions parameters of multiferroic Bi5Ti3FeO15 electroceramic, prepared by high-energy ball milling of polycrystalline precursors (mixture of the Bi2O3, TiO2 and Fe2O3 simple oxides). This analysis was performed by X-ray diffraction and Mössbauer spectroscopy.

PL

W pracy przedstawiono wyniki badań dla multiferroicznej elektroceramiki Bi5Ti3FeO15 otrzymanej podczas procesu aktywacji mechanicznej (mielenie wysokoenergetyczne polikrystalicznych proszków Bi2O3, TiO2 i Fe2O3). Badania struktury i oddziaływań nadsubtelnych przeprowadzono metodami dyfrakcji promieniowania X oraz spektroskopii efektu Mössbauera.

15

Hyperfine interactions in multiferroic mechanically activated BiFeO3 compound

Jartych E., Oleszak D., Mazurek M.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

242-244

EN

In this work the results of structural and magnetic investigations for multiferroic BiFeO3 compound prepared by mechanical activation are presented. The structural analysis and hyperfine interactions investigations were performed by X-ray diffraction and Mössbauer spectroscopy, respectively.

PL

W pracy przedstawiono wyniki badań strukturalnych i magnetycznych dla multiferroicznego związku BiFeO3 otrzymanego w procesie aktywacji mechanicznej. Badania struktury i oddziaływań nadsubtelnych przeprowadzono odpowiednio metodami dyfrakcji promieniowania X oraz spektroskopii efektu Mössbauera.

16

Amorphous Al-Fe and Al-Nb powders processed by mechanical alloying

Dąbrowska S., Oleszak D., Świerczyńska M. B., Kulik T.

Inżynieria Materiałowa

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2012

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Vol. 33, nr 6

543--545

EN

The results on fabrication and characterization of Al-based amorphous alloyed powders are presented. For powders manufacturing mechanical alloying technique has been applied, starting from the mixture of powders of pure crystalline elements. Al80Fe20 and Al60Nb40 (at. %) powder mixtures have been subjected to milling in a ball mill. Phase transformations taking place during milling have been analysed by X-ray diffraction studies (Fig. 1 and 2). In both compositions an amorphous alloy was a final product of the process. The density of the obtained alloyed powders has been measured as 3,33 and 5,01 g·cm–3 for Al80Fe20 and Al60Nb40, respectively. The shape of the particles and their size have been estimated by light microscopy method (Fig. 3 and 4). The manufactured powders have revealed a globular morphology, without tendency for agglomeration. The particle size has been estimated as 10÷20 μm for Al80Fe20 alloy and below 10 μm for Nb-containing alloy. Calorimetric studies correlated with X-ray diffraction technique have allowed for thermal stability determination of the synthesized Al60Nb40 amorphous alloy (Fig. 5 and 6). This alloy has revealed high thermal stability and its crystallization temperature has been measured as 908°C (heating rate 40°C·min–1). The performed microhardness measurements have shown that Nb-containing alloy has significantly higher microhardness (1130 HV0,02) than Fe-containing one (600 HV0,02).

PL

W pracy przedstawiono wyniki badań dotyczących wytworzenia i scharakteryzowania amorficznych proszków stopowych na osnowie aluminium. Do ich wytworzenia zastosowano metodę mechanicznej syntezy, wychodząc z mieszaniny krystalicznych proszków czystych pierwiastków. Mieleniu w młynku kulowym poddano mieszaniny o składzie Al80Fe20 i Al60Nb40 (% at.). Przemiany fazowe towarzyszące procesowi mechanicznej syntezy śledzono za pomocą dyfrakcyjnych badań rentgenowskich (rys. 1 i 2). Produktem finalnym w obu procesach był stop o strukturze amorficznej. Wytworzone proszki stopowe charakteryzowały się gęstością odpowiednio 3,33 oraz 5,01 g·cm–3. Wykorzystując technikę mikroskopii świetlnej określono kształt i oszacowano wielkość cząstek badanych proszków stopowych (rys. 3 i 4). Zsyntezowane proszki charakteryzowały się morfologią globularną i nie wykazywały tendencji do aglomeracji. Wielkość cząstek proszku Al- 80Fe20 wynosiła 10÷20 μm, natomiast dla proszku Al60Nb40 było to poniżej 10 μm. Badania kalorymetryczne w połączeniu z dyfrakcyjnymi badaniami rentgenowskimi posłużyły do określenia stabilności termicznej stopu zawierającego niob (rys. 5 i 6). Stop ten wykazywał wysoką stabilność termiczną, bowiem jego temperatura krystalizacji wynosiła 908°C (przy szybkości nagrzewania 40°C·min–1). Przeprowadzone pomiary mikrotwardości wykazały, że stop zawierający niob cechuje się większą mikrotwardością (1130 HV0,02) niż stop z żelazem (600 HV0,02).

17

Application of mechanical activation in synthesizing multiferroic Pb(Fe1/2Nb1/2)O3 powders

Bochenek D., Dercz G., Oleszak D.

Archives of Metallurgy and Materials

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2011

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Vol. 56, iss. 4

1015-1015

EN

In the study, the method of high-energy powder milling - mechanical activation (MA) was used for synthesizing Pb(Fe1/2Nb1/2)O3 (PFN) powders. For the purpose of comparing the influence of high-energy milling on PFN synthesis, two groups of powder samples were used. The first mixture consisting of simple oxide powders; the second one consisting of compound oxide powders. The obtained powders were subjected to structural analysis with the use of XRD and Mőssbauer spectroscopy. Tests revealed that during the process of high-energy milling of initial constituents a partial synthesis of PFN material phases occurs. By comparing the two methods of PFN synthesizing it may be stated that mechanical activation in the case of a simple oxide mixture (PFN1) is equally effective as for a compound oxide mixture (PFN2).

PL

W pracy, w procesie technologicznym, wykorzystano metodę wysokoenergetycznego mielenia proszków – mechanicznej aktywacji (MA) do syntezowania proszków Pb(Fe1/2Nb1/2)O3 (PFN). Do porównania wpływu wysokoenergetycznego mielenia na synteze PFN wykorzystano dwie grupy próbek proszkowych. Pierwsza mieszanine stanowiły proszki prostych tlenków (jednoetapowa metoda otrzymywania – PFN1), druga stanowiły proszki złozonych tlenków (dwuetapowa metoda otrzymywania – PFN2). Otrzymane proszki poddano analizie strukturalnej przy użyciu XRD i spektroskopii Mossbauera. Badania potwierdziły, ze podczas procesu wysokoenergetycznego mielenia składników wyjsciowych zachodzi czesciowa synteza faz materiału PFN. Porównujac dwie metody syntetyzowania PFN można stwierdzić, że mechaniczna aktywacja jest jednakowo skuteczna w przypadku mieszaniny prostych tlenków (PFN1) jak i dla mieszaniny złożonych tlenków (PFN2).

18

Proszki kompozytowe metaliczno-ceramiczne na osnowie faz Cu-Al umocnione Al2O3 wytworzone metodą reaktywnego mielenia

Oleszak D., Wieczorek-Ciurowa K.

Kompozyty

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2010

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R. 10, nr 1

59-63

PL

Celem pracy było wytworzenie metodą mechanochemicznej syntezy proszków kompozytowych Cu-Al/Al2O3 oraz określenie ich składu fazowego. Obok metalicznego glinu jako reagenty do syntezy mechanochemicznej proszków zastosowano sól (hydroksowęglan miedzi) i tlenek miedzi. Praca obejmowała przeprowadzenie procesów wysokoenergetycznego mieleniakilku serii mieszanin różniących się składem jakościowym i ilościowym uwarunkowanym założeniem wytworzenia proszków kompozytowych, składających się z Al2O3 i faz międzymetalicznych CuAl2 lub Cu9Al4. Wykazano, że niezależnie od wydajności energetycznej użytego młynka i rodzaju reagentów (sól, tlenek) nie tworzy się zamierzona zgodnie ze stechiometrią reagentów faza Cu9Al4 , lecz powstaje roztwór stały glinu w miedzi Cu(Al) i Al2O3 . Zamierzoną fazę Cu9Al4 jako metaliczną osnowę proszku kompozytowego uzyskano jedynie w przypadku mechanochemicznej syntezy tlenku miedzi z nadmiarową ilością Al w stosunku do stechiometrycznego zapisu reakcji. Natomiast w przypadku zamierzonej stechiometrii do fazy CuAl2 uzyskano tę fazę, zarówno w procesie sól-Al, jak i tlenek-Al, lecz w finalnym produkcie obserwowano także występowanie innych faz z układu Cu-Al. Taki stan rzeczy spowodowany może być małymi wartościami entalpii tworzenia faz CuAl2 i Cu9Al4, wynoszącymi odpowiednio -4 i -8 kJmol-1. Przedstawione wyniki reaktywnego mielenia badanych mieszanin soli lub tlenku miedzi z aktywnym metalem, jakim jest Al, dowodzą, że z mieszanin Cu2(OH)2CO3-Al oraz CuO-Al można wytwarzać metaliczno-ceramiczne proszki kompozytowe do konsolidacji kompozytów typu Cu-Al/Al2O3.

EN

The aim of this work was to fabricate by reactive milling Cu-Al/Al2O3 composite powders and determination of their phase composition. Copper oxide CuO and copper salt Cu2(OH)2CO3 (hydroxycarbonate) were used as reagents for mechanochemical processes. Various high energy ball milling processes were performed in order to obtain composite powders consisting of Al2O3 and CuAl2 or Cu9Al4 intermetallic compounds. It was shown that independently on the milling energy and reagents used (salt, oxide), the formation of Cu9Al4 is not observed, but instead of it Cu(Al) solid solution and Al2O3 are formed. Cu9Al4 phase as a metallic matrix of the composite powder was synthesized in the case of milling of CuO with excess amount of Al only. On the other hand, in the case of CuAl2 compound, its formation was observed in both milling processes, i.e. salt-Al and oxide-Al. Simultaneously, other compounds from the Cu-Al system were observed in the final product of mechanosynthesis. This fact can be attributed to low values of enthalpy of formation for CuAl2 and Cu9Al4 intermetallic compounds, -4 and -8 kJmol-1, respectively, and their low thermodynamic stability. However, the presented results of reactive milling of different powder mixtures containing copper oxide or copper salt with Al confirm the possibility of metallic-ceramic composite powders fabrication.

19

Natryskiwanie powłok detonacyjnych - niektóre procesy im towarzyszące

Babul T., Oleszak D.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 4

846-851

PL

W pracy przedstawiono charakterystyczne zjawiska występujące w procesach udarowych, mające istotne znaczenie oraz wpływ na jakość formowania powłok detonacyjnych. Dotyczą one stanu materiału w warunkach działania wysokiego ciśnienia i jednocześnie dużych odkształceń plastycznych (płynięcia materiałów), mechanizmu odkształcania poślizgowego po granicach ziaren w materiale o silnie rozdrobnionych ziarnach, roli strumienia odwrotnego i wzajemnego przenikania się zderzających się materiałów i formowania strefy pośredniej.

EN

In a work description of a key physical processes which occur during percussive processes is presented. The processes are related to a state of a substrate and coating material in high pressure and high plastic strains conditions. Slip strains on grain boundaries in highly fragmented material occur in the production of coatings. Grain size is in order of nanometers. Inverse stream of material and mutual penetration of materials in formed gradient layer play a substantial role in the coatings production process.

20

Influence of Sn, Fe and Ag addition on amorphization and thermal stability of mechanically alloyed CuTiZrNi alloys

Oleszak D., Dąbrowska S., Kulik T.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 3

499-501

EN

The influence of chemical composition on the amorphization and thermal stability of mechanically alloyed CuTiZrNi elemental powder mixtures was studied. The basic Cu47Ti34Zr11Ni8 composition was modified by replacing Ni by Sn and replacing Zr by Fe or Ag. In all cases, except the last one, the alloys characterized by amorphous structure have been synthesized. When Ag replaces Zr, the formation of Cu based solid solution has been observed. For amorphous alloys, the strong influence of the added element on the crystallization temperature and activation energy of crystallization have been observed. The obtained results confirm, that the differences in atomic radii between the elements and the negative values of enthalpy of mixing for the corresponding pairs of elements, promote the amorphization of the powder mixtures subjected to mechanical alloying.

PL

Z powodzeniem przeprowadzono procesy mechanicznej syntezy wybranych stopów na osnowie miedzi, badając wpływ składu chemicznego (dodatek Sn, Fe i Ag) na ich zdolność do amorfizacji i stabilność termiczną. Zastąpienie w amorficznym stopie bazowym o składzie Cu47Ti34Zr11Ni8 niklu cyną, nie pogorszyło jego zdolności do amorfizacji, jednocześnie znacznie zwiększyło stabilność termiczną. Wprowadzenie do stopu 11% at. Fe lub Ag w miejsce cyrkonu spowodowało zróżnicowany skutek. Dodatek żelaza nie wpłynął na możliwość amorfizacji, obniżył jednak stabilność termiczną stopu (temperaturę krystalizacji i energię aktywacji procesu krystalizacji). Natomiast zastąpienie cyrkonu srebrem skutkowało uzyskaniem w procesie mechanicznej syntezy stopu o strukturze roztworu stałego na osnowie miedzi. Uzyskane wyniki potwierdziły, że zróżnicowanie wielkości promieni atomowych i ujemne wartości entalpii mieszania poszczególnych par pierwiastków, silnie wpływają na proces amorfizacji stopów.