3 results
Search Results
Now showing 1 - 3 of 3
- ItemThe Effect of Boron Content on Wetting Kinetics in Si-B Alloy/h-BN System(New York, NY : Springer, 2019) Polkowski, Wojciech; Sobczak, Natalia; Bruzda, Grzegorz; Nowak, Rafał; Giuranno, Donatella; Kudyba, Artur; Polkowska, Adelajda; Pajor, Krzysztof; Kozieł, Tomasz; Kaban, IvanIn this work, the effect of boron content on the high-temperature wetting behavior in the Si-B alloy/h-BN systems was experimentally examined. For this reason, hypoeutectic, eutectic and hypereutectic Si-B alloys (Si-1B, Si-3.2B and Si-5.7B wt.%, respectively) were produced by electric arc melting method and then subjected to sessile drop/contact heating experiments with polycrystalline h-BN substrates, at temperatures up to 1750 °C. Similar to pure Si/h-BN system, wetting kinetics curves calculated on a basis of in situ recorded drop/substrate images point toward non-wetting behavior of all selected Si-B alloy/h-BN couples. The highest contact angle values of ~ 150° were obtained for hypoeutectic and eutectic Si-B alloys in the whole examined temperature range. © 2018, The Author(s).
- ItemHigh-Temperature Interaction of Liquid Gd with Y2O3(New York, NY : Springer, 2019) Turalska, P.; Sobczak, N.; Bruzda, G.; Kaban, I.; Mattern, N.The sessile drop method combined with contact heating procedure was applied for the investigation of high-temperature interaction between liquid Gd and Y2O3 substrate. Real-time behavior of Gd sample in flowing inert gas (Ar) atmosphere upon heating to and at temperature of 1362 °C was recorded using high-speed high-resolution CCD camera. The results evidenced that molten Gd wets Y2O3 substrate (the contact angle θ < 90°) immediately after melting of metal sample observed at T = 1324 °C (Tm = 1312 °C). During the first 3 min of the sessile drop test, the contact angle dropped from θ = 52° to θ = 24° and then stabilized at the final value of θf * = 33°. The solidified Gd/Y2O3 couple was subjected to structural characterization using optical microscopy, scanning electron microscopy coupled with x-ray energy-dispersive spectroscopy. The results evidenced that the wettability in the Gd/Y2O3 system has a reactive nature and the leading mechanism of the interaction between liquid Gd and Y2O3 is the dissolution of the ceramic in the liquid metal responsible for the formation of a deep crater in the substrate under the drop. Therefore, the final contact angle θf*, estimated from the side-view drop image, should be considered as an apparent value, compared to the more reliable value of θf = 70° measured on the cross section of the solidified couple. © 2019, The Author(s).
- ItemFunctionalization of Ti-40Nb implant material with strontium by reactive sputtering(London : BioMed Central, 2017-10-10) Göttlicher, Markus; Rohnke, Marcus; Moryson, Yannik; Thomas, Jürgen; Sann, Joachim; Lode, Anja; Schumacher, Matthias; Schmidt, Romy; Pilz, Stefan; Gebert, Annett; Gemming, Thomas; Janek, JürgenBackground: Surface functionalization of orthopedic implants with pharmaceutically active agents is a modern approach to enhance osseointegration in systemically altered bone. A local release of strontium, a verified bone building therapeutic agent, at the fracture site would diminish side effects, which could occur otherwise by oral administration. Strontium surface functionalization of specially designed titanium-niobium (Ti-40Nb) implant alloy would provide an advanced implant system that is mechanically adapted to altered bone with the ability to stimulate bone formation. Methods: Strontium-containing coatings were prepared by reactive sputtering of strontium chloride (SrCl2) in a self-constructed capacitively coupled radio frequency (RF) plasma reactor. Film morphology, structure and composition were investigated by scanning electron microscopy (SEM), time of flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). High-resolution transmission electron microscopy (HR-TEM) was used for the investigation of thickness and growth direction of the product layer. TEM lamellae were prepared using the focused ion beam (FIB) technique. Bioactivity of the surface coatings was tested by cultivation of primary human osteoblasts and subsequent analysis of cell morphology, viability, proliferation and differentiation. The results are correlated with the amount of strontium that is released from the coating in biomedical buffer solution, quantified by inductively coupled plasma mass spectrometry (ICP-MS). Results: Dense coatings, consisting of SrOxCly, of more than 100 nm thickness and columnar structure, were prepared. TEM images of cross sections clearly show an incoherent but well-structured interface between coating and substrate without any cracks. Sr2+ is released from the SrOxCly coating into physiological solution as proven by ICP-MS analysis. Cell culture studies showed excellent biocompatibility of the functionalized alloy. Conclusions: Ti-40Nb alloy, a potential orthopedic implant material for osteoporosis patients, could be successfully plasma coated with a dense SrOxCly film. The material performed well in in vitro tests. Nevertheless, the Sr2+ release must be optimized in future work to meet the requirements of an effective drug delivery system.