Wyniki 1-4 spośród 4 dla zapytania: authorDesc:"Anna Mazurek"

The corrosion resistance of nanocrystalline composite Ni/diamond coatings produced by electrochemical method DOI:10.15199/40.2015.11.9

  The paper presents results of studies of nanocomposite nickel/diamond coatings produced by electrocrystallization method on carbon steel. For comparison purposes, the tests also included a layer of nickel exhibiting nanocrystalline structure. The nanocomposite coatings were prepared in a bath containing different amounts of diamond disperse phase. The structure of the diamond disperse phase was characterized by using a transmission electron microscope. The construction of the produced coatings and the chemical composition were investigated by optical microscopy and scanning electron microscopy with an EDS attachment. Micro-hardness of produced coatings and their corrosion resistance were studied by the Vickers method and potentiodynamic method in the environment of 0.5M NaCl, respectively. The results of corrosion testing of produced coatings are presented in the form of potentiodynamic polarization curves j = f(E) and the value of the potential and current corrosion. Damages of the coatings after tests in a corrosive environment were identified. The results of performed investigations indicate on a compact and uniform thickness of the produced coatings on the whole coated surface and good adhesion to the steel substrate. The diamond built into coating and its contents significantly affect their microhardness and corrosion resistance. Keywords: corrosion resistance, electrodeposition, Ni/diamond coatings Odporność korozyjna nanokrystalicznych powłok kompozytowych Ni/diament wytwarzanych metodą elektrochemiczną W pracy przedstawiono wyniki badań nanokompozytowych powłok nikiel/diament wytworzonych metodą elektrokrystalizacji na stali węglowej. W celach porównawczych badania obejmowały również warstwy niklowe o strukturze nanokrystalicznej. Powłoki kompozytowe wytwarzano w kąpieli o różnej zawartości diamentowej fazy dyspersyjnej. Charakterystykę struktury [...]

Corrosion properties of Ni-P and Ni-B alloy coatings produced by chemical method DOI:10.15199/40.2015.11.15

  The paper presents results of investigations reported to Ni-P and Ni-B alloy coatings produced by electroless deposition in chemical reduction process on S235JR carbon steel substrate. The coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical microscopy, Vickers microhardness measurements and electrochemical corrosion tests. Images of the surface morphology, cross-sections of the coatings and corrosion damages are presented. The results of corrosion tests for investigated coatings are presented in the forms of potentiodynamic polarization curves j = f (E) and values of corrosion potentials and currents. The results showed a compact and a good adhesion of the alloy coatings to the substrate and their good corrosion resistance in studied corrosive environments. Keywords: corrosion, Ni-P, Ni-B, alloy coatings, electroless deposition, surface layers Właściwości korozyjne powłok stopowych Ni-P oraz Ni-B wytwarzanych metodą chemiczną W pracy przedstawiono wyniki badań powłok stopowych Ni-P oraz Ni-B wytworzonych na podłożu ze stali węglowej S235JR metodą bezprądową w wyniku procesu redukcji chemicznej. Powłoki scharakteryzowano za pomocą: dyfrakcji promieniowania rentgenowskiego (XRD), skaningowej mikroskopii elektronowej (SEM), mikroskopii optycznej. Przeprowadzono badania mikrotwardości metodą Vickersa, oraz badania odporności korozyjnej metodą potencjodynamiczną. Przedstawiono obrazy morfologii powierzchni, przekrojów poprzecznych powłok oraz zniszczeń korozyjnych. Wyniki badań korozyjnych powłok zostały przedstawione w postaci potencjodynamicznych krzywych polaryzacji j = f(E) oraz wartości potencjałów i prądów korozyjnych. Wyniki badań wskazują na zwartą budowę oraz dobre połączenie wytworzonych powłok do stalowego podłoża oraz dobrą odporność korozyjną w badanym środowisku korozyjnym. Słowa kluczowe: korozja, Ni-P, Ni-B, bezprądowe osadzanie, warstwy powierzchniowe 1. Introduction One of the[...]

Corrosion properties of Ni-B/Al2O3 composites layers produced by electroless method DOI:10.15199/40.2017.7.1

  1. Introduction The rapid development of technology forces the search of new materials with more favorable mechanical and physical properties and corrosion resistance. Furthermore, due to restrictions on the use of such materials as chrome and cadmium there is a sought of alternatives much less toxic to humans and more protecting the environment, with meeting at the same time the high performance requirements. An important place in surface engineering is assigned to the surface layers deposited by electroless method. Improvement of the properties of materials by deposition on their surfaces of the metal layers by electroless methods has been known for a long time and still further is under developements. Especially interesting in this subject appears the production of composite materials whose properties significantly depend on the structure of the matrix material and of the disperse phase. The literature describes studies of Ni-P, Ni-B layers [2, 11, 7, 1] and composite materials deposited in the form of the surface layers by electroless method [10, 5, 8, 9, 6], which significantly increase the life of the pieces’ work, including the corrosion resistance. 2. Research methodology Composite layers of Ni-B/Al2O3 and alloy Ni-B layer were produced by electroless method on the DC01 carbon steel substrate. The deposition process was carried out in multicomponent bath containing: nickel chloride, sodium borohydride, ethylenediamine, sodiumhydroxide and leadnitrate. As the dispersion phase was used o powder of aluminum oxide (TAIMEI CHEMICALS co., ltd.) with its content in the bath of 5 and 10 g/dm3. Powder of Al2O3 was characterized by scanning electron microscopy (ZEISS) and X-Ray diffraction (Philips). The morphology and topography of produced layers were analyzed using a VHX 5000 Keyence optical microscope. The microhardness of the layers was examined on the probe cross-sections by the Vickers method at 25 G load (HV 0.025) [...]

Corrosion properties of Ni/Al2O3/Cgraphite hybrid composite layers DOI:10.15199/40.2018.2.2

  1. Introduction The requirements for mechanical properties and corrosion resistance of equipment components working in modern constructions are continuously increasing. To improve the performance of the final products, their surfer layers are effectivelly modified. One of the methods of modifying the useful properties of the products is the deposition of appropriate metal layer on their surface by electrodeposition method. The properties of electrodeposited layers can be formed by suitable selection of electrolyte solution composition and by current parameters control. It has to be noted that presently the composites layers made of metal matrix and dispersion phase are increasingly used in many industries. The matrix material and type of dispersion phase - especially size of particles and their percentage share in the material affect the composite layer properties. By appropriate selection of matrix material and type of dispersion phase, properties of the produced composite layers can be controlled [4, 5, 8, 9]. The new direction of concerned research is the incorporation of two types of dispersion phase into metal matrix, resulting in a hybrid layer. Production of this type of layers allows to apply dispersion phases with different properties like hard particles of Al2O3, Si3N4 or PTFE and graphite particles which improve lubricating properties [1, 6, 7]. A material with high abrasion resistance and lubricating properties what is desirable in the friction nodes can be made by appropriate selection of size and shape of particles and percentage share of both incorporated phases. The subject of realized research are hybrid composite layers Ni/Al2O3/ Cgraphite and composite layers Ni/Al2O3, Ni/Cgraphite which are made for comparative purposes. Nanostructure nickel layers made by electrodeposition method were also investigated. The purpose of the performed study was to determine the influence of incorporation of two types of dispersio[...]

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