Wyniki wyszukiwania - Biblioteka Nauki

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Electrophoretic deposition of nc-TiO2/chitosan composite coatings on X2CrNiMo17-12-2 stainless steel

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Ledwig P. , Kot M. , Moskalewicz T. , Dubiel B.

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tom Vol. 62, iss. 1

405--410

EN

This paper presents the results of the optimization of electrophoretic deposition parameters for manufacturing of nc-TiO2/chitosan composite coatings on X2CrNiMo17-12-2 steel as well as characterization of their microstructure, electrochemical properties and adhesion to the substrate. The parameters of the deposition, such as composition, pH and zeta potential of suspensions as well as voltage and process time were investigated. The microstructure of the coatings was characterized using scanning and transmission electron microscopy. Obtained coatings were crack-free and uniform. The adhesion strength to the substrate was measured by scratch-test method. The deposited coatings improve corrosion resistance of steel, what was confirmed by the results of the potentiodynamic polarization test in Ringer’s solution.

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Electrophoretic Deposition and Characterisation of Chitosan Coatings on Near-Β Titanium Alloy

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Jugowiec D. , Kot M. , Moskalewicz T.

Archives of Metallurgy and Materials

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2016

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tom Vol. 61, iss. 2A

657--664

EN

In this study, chitosan coatings were electrophoretically deposited (EPD) on near-β Ti-13Nb-13Zr alloy. The influence of colloidal solution composition and EPD parameters on the quality of chitosan coatings was investigated. It was established that the uniformity of as-deposited chitosan coatings is highly dependent on the chemical composition of the solution used for EPD, the pH, electrophoretic mobility and zeta potential of chitosan colloidal molecules, as well as EPD parameters, such as potential difference value and deposition time. The microstructure of the coatings was investigated using electron microscopy and X-ray diffractometry. The coatings 350 nm thick were homogeneous and exhibited an amorphous structure. The coatings had low hardness and Young’s modulus. The effect of surface of the substrate preparation prior to coating deposition on the adhesion of chitosan coatings to the Ti-13Nb-13Zr alloy was also investigated. The coatings exhibited good adhesion to the non-acid-etched surface of the titanium alloy.

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Corrosion behaviour and bioactivity of electrophoretically deposited hydroxyapatite on titanium in physiological media (Hanks' solution)

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Mohamed S. G. , Abdeltawab A. A. , Shoeib M. A.

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tom Vol. 30, No. 3

231--239

EN

Hydroxyapatite (HA) coatings were developed on titanium by electrophoretic deposition at various deposition potentials from 30 to 60 V and at a constant deposition time of 5 minutes using the synthetic HA (Ca10(PO4)6(OH)2,) powder in a suspension of dimethyleformamide (DMF, HCON(CH3)2). The electrochemical corrosion behavior of the HA coatings in simulated body fluid (SBF Hanks' solution) at 37 °C and pH 7.4 was investigated by means of open-circuit potential (OCP) measurement and potentiodynamic polarization tests. The OCP test showed that the values OCP for the coated samples shifted to more noble potential than for uncoated titanium, especially after addition of dispersants. The polarization test revealed that all HA coated specimens had a corrosion resistance higher than that of the substrate, especially after addition of dispersants such as polyvinyl butyral (PVB), polyethylene glycol (PEG) and triethanolamine (TEA) to the suspension. The coating morphology after polarization, characterized by scanning electron microscopy (SEM), showed penetration of electrolyte into the HA coats. Bone bioactivity of the coatings was also studied by immersion of coated specimens in Hanks' solution for 3 and 7 days. Apatite granules growth on the surface of the HA layers was observed.

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Electrophoretic deposition of biphasic calcium phosphates on NiTi shape memory alloy

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Dudek K. , Goryczka T.

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tom R. 15, nr 4

192--195

EN

The application of NiTi shape memory alloys as long-term implants is dependent on ensuring better biocompatibility of the alloy, which is achieved by modification of the surface by protective coatings or layers. In the present work, the surface of the NiTi alloy was covered by biocompatible composite coatings. First, a thin rutile layer was formed by autoclaving. Passivation was carried out at 134°C for 30min which resulted in forming an amorphous TiO2 thin film. Next, a biphasic calcium phosphate (BCP) layer was deposited using electrophoresis (EPD). The BCP layer was composed of hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP). The deposition voltage ranged from 40 to 80 V at a constant time of 60 s. The deposited samples were vacuum-sintered at 800°C for 2 h. Observations of the surface revealed that the obtained coatings are crack-free. Measurements done with X-ray diffraction confirmed that the top layer consisted of β-TCP and HAP.

PL

Zastosowanie stopów NiTi w medycynie na długoterminowe implanty uwarunkowane jest zapewnieniem lepszej biokompatybilności, co uzyskuje się poprzez modyfikację powierzchni wyjściowej stopów odpowiednimi biozgodnymi warstwami lub powłokami ochronnymi. W prezentowanej pracy powierzchnia stopu NiTi została zmodyfikowana poprzez wytworzenie warstwy kompozytowej składającej się z rutylu (TiO2) oraz dwufazowej ceramiki opartej o fosforany wapnia (BCP), złożonej z hydroksyapatytu (HAP) oraz ceramiki whitlockitowej (β-TCP). Warstwa rutylu została wytworzona poprzez pasywację w autoklawie parowym w warunkach stosowanych do sterylizacji narzędzi chirurgicznych (134°C, 30 min). Następnie na spasywowanej powierzchni została wytworzona metodą elektroforezy powłoka składająca się z dwufazowej ceramiki CaPs. Warstwy nałożono, stosując napięcie z zakresu 40÷80 V przy stałym czasie depozycji wynoszącym 60 s. Naniesione warstwy spiekano w piecu próżniowym w temperaturze 800°C przez 2 h. Obserwacje powierzchni przy użyciu skaningowego mikroskopu elektronowego nie wykazały pęknięć na powierzchni warstw. Badania rentgenowskie potwierdziły kompozytowy skład warstwy wierzchniej.

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Polimerowe, ceramiczne i kompozytowe powłoki osadzane elektroforetycznie poprawiające wybrane właściwości materiałów metalowych

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Moskalewicz T. , Dubiel B. , Sak A. , Ratajski D. , Jugowiec D. , Ledwig P. , Cieniek Ł. , Kalemba-Rec I. , Radziszewska A. , Kopia A. , Zimowski S. , Kot M. , Łukaszczyk A.

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2016

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tom Vol. 83, nr 4

170--180

PL

W pracy przedstawiono przykłady wytwarzania różnych powłok polimerowych, ceramicznych i kompozytowych na modelowych materiałach metalowych metodą osadzania elektroforetycznego. W celu uzyskania dobrej jakości powłok dobrano optymalny skład chemiczny roztworów koloidalnych i zawiesin stosowanych do osadzania, wyznaczono ich pH i potencjał elektrokinetyczny dzeta. W oparciu o badania makroskopowe osadzonych powłok dobrano napięcie prądu i czas osadzania elektroforetycznego. Wykonano badania mikrostruktury powłok i ich wybranych właściwości, takich jak odporność na korozję, odporność na zużycie ścierne i wyznaczono współczynnik tarcia. Wykazano, że osadzanie elektroforetyczne jest perspektywiczną metodą wytwarzania powłok: polimerowych (chitozanu i polieteroeteroketonu (PEEK)), ceramicznych (SiO2), kompozytowych (szkło żelowe/chitozan, TiO2/chitozan, SiO2/HA i Ni/SiO2) oraz porowatych (szkło żelowe/PEEK).

EN

This work presents the examples of electrophoretic deposition of various polymer, ceramic and composite coatings on model metallic materials. To obtain good quality coatings, chemical composition of colloidal solutions and suspensions as well as their pH and Zeta potential were optimized. The voltage and deposition time were experimentally selected by macroscopic examination of as-deposited coatings. Investigation of the coatings comprised microstructural analysis as well as determination of their corrosion resistance, wear resistance and friction coefficient. It was demonstrated that electrophoretic deposition is a prospective method for obtaining various coatings: polymer chitosan and polyetheroetheroketone (PEEK), ceramic SiO2, composite gel glass/chitosan, TiO2/chitosan, SiO2/HA and Ni/SiO2 as well as porous sol-gel glass/PEEK coatings.