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Yayınlar
- MakaleAçık Erişim2016Investigation of structural and tribological properties of duplex surface treated pure titanium
Çelik, I.; Karakan, M.
Commercial pure titanium (CP-Ti) is used in many engineering fields because of its superior properties such as excellent corrosion resistance, high strength/weight ratio, and biocompatibility. However, it is not available at the desired rate, since the CP-Ti has poor wear resistance. For this reason, many surface treatments have been applied to improve the poor tribological properties of the CP-Ti. In this study, duplex surface treatments, which are the combination of treatments of electroless Ni-B coating and plasma nitriding, were applied on the surfaces of the CP-Ti. Structural properties of the different surfaces of the treated materials were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Microhardness measurements were made for the determination of mechanical properties and the pin-on-disk wear tests were made to determine the tribological properties. It was observed that poor wear resistance of the CP-Ti was improved with duplex surface treatments. The results showed that surface hardness, friction coefficient, and surface roughness of coated samples were better than of uncoated CP-Ti.
- MakaleAçık Erişim2015Preparation and characterization of electroless Ni-B/nano-SiO2, Al2O3, TiO2 and CuO composite coatings
Ekmekci, Dursun; Bülbül, Ferhat
Ni-B/SiO2, Al2O3, TiO2 and CuO composite coatings were successfully obtained by the electroless plating technique. Dispersible SiO2, Al2O3, TiO2 and CuO nanoparticles were co-deposited with electroless Ni-B coating onto AISI-304 steel substrates. Deposits were characterized for its structural properties by X-ray diffraction (XRD). XRD results showed a broad peak of Ni-B and low intensity composite nanoparticle peaks. The surface and cross-section morphology of samples were analysed using a scanning electron microscope (SEM). Surface analysis showed that the incorporation in Ni-B matrix of nano-SiO2, Al2O3, TiO2 and CuO particles increases the nodularity of composite coatings. The deposits are composed of a columnar structure grown along the vertical direction of the substrate surface. The results also show that electroless nanocomposite coatings tend to have greater microhardness compared with the coating without nanoparticles. The increase in the microhardness of the nanocomposite coatings reported in this study is attributed to an effect of dispersion strengthening of ceramic particles in the Ni-B matrix.
- MakaleYalnız künye2014EFFECT OF HEAT TREATMENT ON STRUCTURE OF ELECTROLESS Ni-B COATED PURE TITANIUM
Bülbül, Ferhat; Çelik, Ilhan
Pure titanium has a very large potential for use industrially due to its low weight, however, its usage continues to be limited because it possesses some disadvantages such as low hardness and wear resistance, weak corrosion resistance in high temperatures and high cost. In order to strengthen these weaknesses of pure titanium, electroless Ni-B deposition process, may be an alternative solution. In this study, the Ni-B coatings were deposited on pure titanium and annealed at the temperatures of 450 degrees C, 650 degrees C and 850 degrees C. The non-heat treated and heat treated coatings were structurally characterized via SEM (scanning electron microscope) and XRD (x ray diffraction). These coatings transformed from amorphous structure to a pronounced crystalline structure depending on heat treatment.