Influence of Alkali Treatment on Anodized Titanium Alloys in Wollastonite Suspension

The surface modification of titanium alloys is an effective method to improve their biocompatibility and tailor the material to the desired profile of implant functionality. In this work, technologically-advanced titanium alloys—Ti-15Mo, Ti-13Nb-13Zr and Ti-6Al-7Nb—were anodized in suspensions, followed by treatment in alkali solutions, with wollastonite deposition from the powder phase suspended in solution. The anodized samples were immersed in NaOH or KOH solution with various concentrations with a different set of temperatures and exposure times. Based on their morphologies (observed by scanning electron microscope), the selected samples were investigated by Raman and X-ray photoelectron spectroscopy (XPS). Titaniate compounds were formed on the previously anodized titanium surfaces. The surface wettability significantly decreased, mainly on the modified Ti-15Mo alloy surface. Titanium alloy compounds had an influence on the results of the titanium alloys’ surface modification, which caused the surfaces to exhibit differential physical properties. In this paper, we present the influence of the anodization procedure on alkali treatment effects and the properties of obtained hybrid coatings

Wear resistance and biocompatibility of dental tools upgraded by different coatings

Narzędzia stomatologiczne ulegają zniszczeniu, zarówno w procesie ich użytkowania, jak i podczas sterylizacji oraz dezynfekcji. Celem zwiększenia trwałości wierteł stomatologicznych i pincet oraz zwiększenia zgodności biologicznej podjęto próbę ulepszenia ich powierzchni poprzez wytworzenie powłok z TiN i TiAlN. Powłoki zostały naniesione technologią PAPVD (Plasma Assisted Physical Vapour Deposition). Przeprowadzono dwuletnie badania eksploatacyjne wierteł stomatologicznych i pincet oraz obserwacje metalograficzne powierzchni zużytych po 3, 6, 9, 12 i 24 miesiącach. Wyniki badań zostały przedstawione w niniejszym artykule.Dental tools are sometimes damaged as a results of exploitation or during sterilization and desinfection. The aim of durability improving of dental borers and tweezers and increasing of the biocompatibility was modification of the surface of tools by TiN and TiAlN coatings. The coatings were made by PAPVD technology (Plasma Assisted Physical Vapour Deposition). The dental borers and tweezers were observed after the operation time of 3, 6, 9, 12 and 24 months. The results of investigation are presented in this article

Manufacturing, Microstructure and Corrosion Resistance of Electrophoretically Deposited SiO2 and Ni/SiO2 Coatings On X2CrNiMo17–12–2 Steel

The SiO2 and Ni/SiO2 coatings were electrophoretically deposited on X2CrNiMo17-12-2 steel using ethanol-based suspensions of the SiO2 and Ni powders. The influence of the zeta potential and concentration of the suspensions, the applied voltage and deposition time on the quality of the coatings was studied. Microstructure of the plan-view and cross sections of the coatings was investigated using scanning electron microscopy. The plan-view images revealed the uniform microstructure of the coatings with sporadically observed cracks, pores as well SiO2 and Ni agglomerates. On the cross-sections, the Cr2O3 layer, resulted from oxidation of the substrate during sintering of the coatings was observed. The polarization tests have shown that SiO2 and Ni/SiO2 coatings improve the corrosion resistance of the X2CrNiMo17-12-2 steel in 3.5% NaCl aqueous solution

Investigations of friction stir welds between 5083 and 7075 aluminum alloys using EBSD and X-ray techniques

Microstructure and texture of the friction stir welded 5083 and 7075 aluminum alloys were characterized by means of the electron backscatter diffraction and X-ray techniques. A complex vortex-like microstructure with distinctive bands of the both joint materials was found in the centre of the weld. The alternating bands filled roughly equiaxed dynamically recrystallized grain volumes. The grain size was slightly smaller in bands of the alloy 7075 than in bands of the alloy 5083. Grains in the thermomechanically affected zone were elongated, especially on the retreating side of the weld (7075 alloy). On the other hand, the grain shape in the heat affected zone was similar to that for the base material

Starzenie naturalne złączy stopów aluminium Al-Zn-Mg-Cu wykonanych metodą zgrzewania tarciowego z mieszaniem materiału

The long term natural aging behavior of friction stir welded aluminum 7136-T76 and 7042 T6 extrusions was investigated. The microstructural characteristics and mechanical properties in the as-welded and six years naturally aged conditions were studied and correlated to a coupled thermal/material flow model of the joining process. Hardness profiles for the 7136 alloy taken along the mid-plane thickness of the workpiece displayed the characteristic W-shape. With natural aging, hardness recovery occurred on both sides of the weld, but the position of the hardness minima, particularly on the advancing side, shifted away from the weld centerline. The hardness profile for the 7042 alloy displayed U-shape in the as-welded condition and W-shape after natural aging. The hardness behavior upon natural aging correlated to the temperature profile developed during welding and the degree to which phase dissolution occurred in the regions adjacent to the stir zone.W artykule przedstawiono wyniki badań dotyczące długoterminowego starzenia naturalnego złączy stopów aluminium 7136-T76 i 7042-T6 wykonanych metodą zgrzewania tarciowego z mieszaniem materiału. Złącza w stanie po zgrzewaniu oraz po 6 latach starzenia naturalnego scharakteryzowano pod względem mikrostrukturalnym oraz mechanicznym. Wyniki badań skorelowano z modelem termicznym i modelem płynięcia materiału podczas zgrzewania. Profil twardości złącza stopu 7136 wykazuje charakterystyczny kształt litery „W”. Starzenie naturalne powoduje wzrost twardości, przy czym minimum twardości, szczególnie po stronie natarcia, odsuwa się od środka złącza. Profil twardości złącza stopu 7042 przyjmuje kształt litery „U” po zgrzewaniu i kształt litery „W” po starzeniu naturalnym. Takie zachowanie twardości po starzeniu naturalnym jest związane z temperaturą podczas procesu zgrzewania oraz stopniem, w jakim rozpuszczają się fazy w obszarach sąsiadujących ze strefą mieszania

Influence of PAA on the Microstructure and Corrosion Resistance of Electrophoretically Deposited SiO2 and Ni/SiO2 Coatings on X2CrNiMo17-12-2 Steel

The effect of anionic surfactant in the form of polyacrylic acid (PAA) on the electrophoretic deposition of the SiO2 and Ni/SiO2 coatings on X2CrNiMo17-12-2 stainless steel was examined. Parameters of the process, such as chemical composition of the suspensions, voltage between the electrodes and the deposition time were experimentally selected. Zeta potential measurements showed a beneficial effect of polyacrylic acid on the SiO2 and Ni particles stability in ethanol. Scanning and transmission electron microscopy studies revealed that the microstructure of the coatings obtained from the suspensions containing polyelectrolyte is more homogenous and has less amount of desiccation cracks on the surface. The results of the polarization tests have shown that addition of anionic surfactant improves also corrosion resistance of the coatings in 3.5% NaCl solution