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1

Otrzymywanie i termiczna modyfikacja warstw kompozytowych Ni+Al

Napłoszek-Bilnik I., Budniok A.

Kompozyty

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2002

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R. 2, nr 3

52-57

PL

Badano wpływ zawartości proszku glinu w kąpieli galwanicznej na skład chemiczny warstw kompozytowych Ni+Al, otrzymywanych elektrolitycznie w warunkach galwanostatycznych (1170 C x cm-2) na podłożu stalowym. Kąpiel galwaniczna zawierała proszek glinu w ilości: 20, 40, 60, 80, 100 g/dm3. Stwierdzono, że wraz ze wzrostem zawartości Al w kąpieli jego zawartość w warstwie osiąga 16%, po czym maleje do około 11%. Dla optymalnego składu kąpieli galwanicznej zapewniającego otrzymanie warstw o zawartości 16% Al określono wpływ wartości gęstości prądowej na ilość wbudowywanego Al do warstwy. Następnie warstwy te były wygrzewane w piecu elektrycznym, do którego doprowadzany był argon. Badania składu fazowego przeprowadzono za pomocą rentgenowskiej analizy fazowej, a analizę składu chemicznego metodą atomowej absorpcji. Przeprowadzone badania wykazały możliwość otrzymywania warstw kompozytowych na osnowie Ni z zabudowanymi ziarnami Al. Warstwy poddane modyfikacji termicznej w temperaturze 873 K, obok obecności krystalitów niklu i glinu, wykazują obecność związków międzymetalicznych Ni2Al3 i Ni3Al4.

EN

Electrolytic nickel layers are typified by good corrosion resistance and electrochemical activity in the processes of cathodic hydrogen evolution and anodic oxygen evolution. In order to improve of utilizable properties of the nickel layers, the coatings were co-deposited from baths containing metal oxides (Al2O3, Al3O4, NiO). Incorporating into a metallic matrix of composite component as metallic powder and its embedding into the matrix structure follows to obtain a new kind of composite material. Therefore, the present study was undertaken in order to obtain the electrolytic composite layers containing embedded aluminum grains into a nickel matrix. The structure and properties of Ni+AI alloys were determined using different methods. Composite Ni+AI layers were prepared by simultaneous electrodeposition of nickel and aluminum on a steel substrate in which 20, 40, 60, 80, 100 g/dm3 of Al powder were suspended. The electrodeposition was carried out under galvanostatic conditions at a temperature of 293 K and the current density of jD = 300 mA/cm2 for 1 h. The phase composition of the layers was investigated by the X-ray diffraction method. The surface morphology of the coatings was examined by means of a stereoscopic microscope Nicon. The obtained Ni+AI layers are of mat, rough metallic surface. There are a visible Al grains on the layer surface (Fig. 1). X-ray analysis of Ni+AI layers revealed their two phase composition (Fig. 2a). It was found that the phase structure of obtained layers depends on phosphorous content in the layer only. Atomic absorption spectroscope was used for chemical characterization of the layers. The influence of aluminum powder content in an electroplating bath on the chemical composition of Ni+AI layers was examined. Chemical analysis of the Ni+AI layers confirms the co-deposition of Ni and Al. It was ascertained that the increase aluminum powder amount in the bath causes the rise in Al content embedded into the composite layers. In the layers of Ni+Al-a linear increase of Al content in the layer from 15% to about 20% was observed (Tab. 1). It was assumed that mechanism of Al embedding into the layer based on the adsorption phenomena and migration of the charged suspension-micelles towards the cathode. The chemical composition of the layers depends also on current density deposition (Tab. 2). It was showed that from the bath containing 40 g Al/dm3 at the current density equal 320 mA/cm2 composite layer containing about 16% Al was obtained. In this case the average mass increment has also maximal value. The result of that process is possibility to obtain considerable thickness and good adhesivity of those composite layers. The thickness of composite layers increase linearly with the increasing of Al content in the bath. It is equal 120 and 150 micrometers for Ni+AI. The heat treatment of the layer at 873 K was done. It was ascertained that after the thermal treatment the obtained layers are of mat, rough metallic surface (Fig. 3). Depending on time of heat treatment the different surface morphology are obtained. This indicates on chemical reaction in solid state of the layer. Markedly different X-ray spectra were obtained for the electrocoatings heated in the argon atmosphere. The main peaks corresponding to the Ni and Al coexist with the new ones corresponding to new phases: Ni2jAl3, Ni3Al4 (Fig. 2b). Such phases can take part in hydrogen electroevolution.

2

Obróbka termiczna warstw kompozytowych Ni-P+TiO2+Ti

Łosiewicz B., Budniok A., Wykpis K., Łągiewka E., Rówiński E., Cybo J., Służałek G.

Kompozyty

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2002

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R. 2, nr 3

47-51

PL

Amorficzne warstwy kompozytowe Ni-P+TiO2+Ti były otrzymywane przez jednoczesne elektroosadzanie niklu z TiO2 (anataz) i Ti na podłożu miedziowym z roztworu, w którym cząstki tlenku i metalicznego proszku tytanu utrzymywano w zawiesinie, stosując ciągłe mieszanie. Elektroosadzanie prowadzono w warunkach galwanostatycznych w temperaturze 293 K. W celach porównawczych otrzymano w tych samych warunkach warstwy Ni-P. Do fizycznej i chemicznej charakterystyki warstw użyto dyfraktometru rentgenowskiego, mikroskopu metalograficznego i stereoskopowego, profilografometru, spektrometru elektronów Augera oraz spektrometru atomowej absorpcji. Wykazano, że obróbka cieplna w atmosferze argonu badanych warstw prowadzi do otrzymania warstw kompozytowych zawierających niestechiometryczne tlenki tytanu, które wspólobecne w materiale kompozytowym z TiCh mogą stanowić pary utłeniająco-redukujące przydatne przy zastosowaniu tych warstw jako materiały elektrodowe w elektrochemii.

EN

Amorphous Ni-P+TiO2+Ti composite layers were prepared by co-deposition of nickel with titanium dioxide (anatase) and titanium powder on a copper substrate from a solution in which TiO2 and Ti particles were suspended by stirring. In order to obtain composite Ni-P+TiO2+Ti layers the following nickel plating bath was prepared (g/dm3): 51 NiSO4 x 7H2O, 10,7 NH4CI, 29 NaH2PO2 x H20,10 CH3COONa, 8 H3BO3 with addition of: 99 TiO2 and 10 Ti. The mean surface area of TiO2 and Ti grains were measured and calculated to be respectively: 12 and 25 um2. Reagents from POCh Gliwice (Poland) and Merck (Germany) of analytical purity and deionized water were used for the solution. The suspension had a pH of 4.8:5.1. The electrodeposition was carried out under galvanostatic conditions at the current density of j = 250 mA/cm2 at a temperature of 293 K. The vessel diameter was 8 cm. The copper plates of one-sided area 1 cm2 were placed parallel to the bottom of the vessel. Electrodeposition was conducted in the electrolytic cell containing 250 cm3 of the solution. The other side of the plates was covered with non-conducting resin. The distance between the plates and the surface of the solution was 5 cm. The counter electrode was made of platinum mesh with the geometric area of 1 dm2. Under these conditions the solution mixing rate of 300 rev/min was applied. For comparison the Ni-P layers were also obtained and investigated in the same manner. The thickness of the deposited layers was found to be about 100-250 um. Heat treatment of the layers was carried out at a temperature of: 400°C for 8 h, 500°C for 10 h, 800°C for 12 h in argon atmosphere. X-ray diffractometer, Auger electrons spectrometer, atomic absorption spectroscope, metallographic and stereoscopic microscope, and surface analyser were used for physical and chemical characterization of the layers. It was found that the heat treatment of the composite Ni-P+TiO2+Ti layers leads to the production of Ni-P + titanium oxides layers with a new qualitative chemical composition. The layers obtained after heat treatment are of a compact composite structure and contain new phases as products of an amorphous nickel matrix crystallization, NiTi intermetallic compound and nonstoichiometric titanium oxides. There are nonstoichiometric titanium oxides after heat treatment at the temperature of: 400°C - Ti10O19, 500°C - Ti7O13 and 800°C - Ti4O7 in the layers. Under proposed conditions of the heat treatment of composite Ni-P+TiO2+Ti layers is possible to obtain composite materials containing different red-ox pairs as TiO2-Ti10O19, TiO2-Ti7O13 or TiO2-Ti4O7. Such pairs of titanium dioxide and nonstoichiometric titanium oxides can influence the electrolytic hydrogen evolution reaction.

3

Obróbka cieplno-chemiczna warstw kompozytowych zawierających tytan

Serek A., Budniok A.

Kompozyty

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2002

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R. 2, nr 3

58-62

PL

Elektroosadzanie warstw Ni+Ti oraz Ni-P+Ti przeprowadzono z kąpieli niklowej zawierającej 40 g Ti w 1 dm3 roztworu. Otrzymane warstwy poddano obróbce cieplno-chemicznej w temperaturze 1093 K w czasie 6:48 godzin. Otrzymane w ten sposób materiały kompozytowe poddano badaniu składu fazowego metodą dyfrakcji promieni rentgenowskich, analizie morfometrycznej, wykorzystując mikroskop stereoskopowy Nikon. Stwierdzono, że oba rodzaje warstw kompozytowych są podatne na obróbkę cieplno-chemiczną w atmosferze azotu, co prowadzi do otrzymania dwu nowych rodzajów warstw kompozytowych. Różnią się one ilością powstałego azotku tytanu. Jego ilość w warstwach jest zależna od początkowej zawartości tytanu. Ponadto w obu rodzajach warstw tworzą się związki międzymetaliczne typu Ni3Ti oraz NiTi. W warstwach zawierających dodatkowo fosfor następuje także krystalizacja fosforków niklu Ni5P2 z amorficznej osnowy. Te przemiany fizykochemiczne są podstawą do podwyższenia wartości mikrotwardości powierzchniowej warstw w porównaniu do podłoża stalowego, jak i czystego niklu.

EN

In order to improve of utilitarian properties of the nickel layers, the layers were co-deposited from baths containing solid metal particles of different oxides (TiO2, Sc2O3, NiO), carbides, nitrides or PTFE. Incorporating into a metall matrix the component in powder form and its embedding into a matrix structure allows to obtain a new kind of composite material. Therefore, the present study was undertaken in order to obtain the galvanic composite layers containing embedded titanium grains into crystalline or amorphous matrix. Electrodeposition of Ni+Ti and Ni-P-t-Ti composite was carried out in the nickel galvanic bath to which 40 g/dm3 of titanium powder was added. Electrodeposition process was carried out on a steel substrate (018 A1IT). Thermo-chemical treatment of obtained composite layers was conducted at nitrogen atmosphere at a temperature of 1093 K for 6:48 hours. After treatment the structural analysis, the surface morphology, microhardness and the percentage volume fraction of selected TiN phase was investigated. The phase composition of the layers was studied by the X-ray diffraction method. It was ascertained that the thermal treatment of the Ni+Ti layers leads to production of a new kind of composite layers containing TiN, Ni3Ti and NiTi phases (Fig. 1a), where the thermal treatment of the Ni-P+Ti layers produces layers containing TiN, Ni5P2, Ni3Ti and NiTi phases in the nickel matrix (Fig. 1b). The quantity of those phases depends on time of the thermal treatment. The surface morphology after thermal treatment was investigated by Nikon stereoscopic microscope and Svistmet computer system. Obtained layers show the mat, rough metallic surface with places of gold colour (Fig. 2a, b). Depending on thermal treatment time at 1093 K the different surface morphology are produced. This indicates that chemical reaction in solid state in the layer took place. It allows to determine the percentage of volume fraction of selected TiN phase. It was proved that the composite layers Ni+Ti and Ni-P+Ti contain about 46 and 30% TiN respectively (Fig. 3). Additionally the micro-hardness of the obtained coatings was calculated. The micro-hardness of the Ni+Ti and Ni-P+Ti layers after thermal treatment is higher then the values before the thermal treatment. The highest micro-hardness are observed after 48 hours of nitridation. The micro-hardness of the Ni+Ti and Ni-P+Ti layers depends on time of thermal treatment (Fig. 4). Using the microscopic observation the thickness of the diffusion layers obtained after thermal treatment from cross-sections were evaluated (Figs 5, 7). The thickness of those diffusion layers increase non linearly with annealing time (Fig. 6). It means that in the layers the different chemical reaction and phase transformations occur. In conclusion it is stated that after thermo-chemical treatment obtaining of the Ni+Ti and Ni-P+Ti layers are possible in new kind of composite which contains TiN, Ni3Ti and NiTi or additionally Ni5P2 phases embedded in the nickel matrix. These layers exhibit that their structure is based on a nickel matrix.