Adsorption of Polyions on Flat TiO2 Surface

In this study, the surface properties of Ti/TiO2 substrate before and after the adsorption of polyelectrolytes were investigated. As model polyelectrolytes, strongly charged polycation poly(diallyldimethylammonium) (PDADMA) and strongly charged polyanion poly(4-styrenesulfonate) (PSS) were used. Initially, the bare titanium substrate was characterized by means of ellipsometry, atomic force microscopy (AFM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and measurements of inner surface potential using crystal electrode (CrE). It was shown that the substrate surface is very smooth with the roughness of 3.5 nm and oxide layer thickness of 3.8 nm. After the adsorption of PDADMA and PSS, polyelectrolyte-coated titanium surface was examined using the above-mentioned methods under the same conditions. It was found that both PDADMA cations and PSS anions form a stable polymeric nanofilm on Ti/TiO2 surface that partially covers the surface, without significant impact on the surface roughness. The corrosion protection effectiveness values indicate that the corrosion properties were greatly enhanced upon polyion adsorption and polyelectrolyte coating formation on the flat TiO2 surface. The obtained results were additionally confirmed by inner surface potential measurements. According to the methods employed, PDADMA nanofilm modification offers enhanced corrosion protection to the underlying titanium material in sodium chloride electrolyte solution.

RECONSTRUCTION OF MANDIBULAR DEFECTS USING INDIVIDUAL VASCULARIZED AUTOGRAFTS COMBINED WITH MACROPOROUSTITANIUM FIBER MA

— The choice of donor material poses a problem for surgeons handling reconstruction of large combined bone defects or limited maxillofacial bone defects. Restoration methods, applicable in reconstructive microsurgery are based on materials of non-biological origin and musculoskeletal autogenous transplants which have complications and may inhibit the processes of osseointegration. Our study aimed to improve the efficiency of surgical treatment and rehabilitation of patients with mandibular defects using vascularized autograft in combination with macroporous titanium fiber material. The reconstruction of the defective mandible caused by chronic osteomyelitis, trauma, benign tumors was performed in 107 patients either by means of conventional methods (titanium plates, free and vascularized bone autografts), or by a novel engineered bone substitute. Our novel vascularized bone autotransplant combines a macroporous fiber titanium material and spiral bone autochips. For its fabrication we applied digital 3D technologies and methods of rapid prototyping, whereas its vascularization was harvested in iliac crest. Unlike the standard methods of reconstruction, the use of the engineered vascularized implant showed a significant reduction in stages, volume and invasiveness of surgical procedures and an improvement of esthetic and functional outcomes in patients with mandibular defects.

Influence of ZrO2 and TiO2 Nano Particles in P(VDF-TrFE) Composite For Energy Harvesting Application

Zirconium and Titanium material are used for making PZT piezoelectric ceramic composite. In this article, Zirconium dioxide (ZrO2) and Titanium dioxide (TiO2) ceramic fillers with, ferroelectric polymer PolyVinyliDene fluoride-Tri Fluoro Ethylene( P(VDF-TrFE)) forms the ZrO2/P(VDF-TrFE) and TiO2 /P(VDF-TrFE) nano-composite. The scanning electron microscope (SEM) with EDS examine the TiO2, ZrO2 fillers presents in composite. The ceramic fillers molecules Ti 2p and Zr 3d binding energy are confirmed by X-Ray photoelectron spectroscopy (XPS). Each composite reaches their piezoelectric β- phase are confirmed by Fourier Transform - Infrared Spectroscopy (FT-IR). The low surface roughness of the thin-film reaches more flexibility and deformation of cantilever. The ZrO2/P(VDF-TrFE) composite is obtained low average surface value of 10nm in the region of 50µm is measured from Gwyddion software. Natural resonance frequency of ceramic composite reaches 100Hz low frequency is measured by Lased Doppler Vibrometer. The cantilever beam structure energy harvester produces peak to peak output voltage 8.2 V. The harvested output voltage used for electronics devices and sensor applications.

Linear analysis of parameters in Arrhenius model for Ti-6Al-4V at superplastic forming

Purpose With the discussion on the linear relationship of determined material parameters, this study aims to propose a new method to analyze the deformation mechanism. Design/methodology/approach A modified constitutive model based on the hyperbolic sine Arrhenius equation has been established, which is applied to describe the flow behavior of Ti-6Al-4V alloy during the superplastic forming (SPF). Findings The modified constitutive model in this work has a good ability to describe the flow behavior for Ti-6Al-4V in SPF. Besides, a deformation map of titanium material is obtained based on the parameters. As the supplement, finite element models of high-temperature tensile tests are carried out as the application of the constitutive model. Originality/value The relationship between constitutive model parameters and forming mechanism is established, which is a new angle in rheological behavior research and constitutive model analysis.

Mekanisme Pembentukan Burr pada Pemesinan Frais Mikro Ti 6Al- 4V ELI dalam Keadaan Kering

One of the ingredients that are popular now is titanium, but titanium is a material that is difficult to process using conventional milling machining because of the poor thermal conductivity of the material so that the high-temperature machining process produced in the cutting zone causes plastic deformation in cutting tools and increased chemical reactivity in titanium. High-speed micro-milling machining can be used for micromachining of hard metals or alloys that are difficult to achieve at low speeds. Micro milling machining in titanium material 6Al-4V ELI with variations in milling knife diameter 1 and 2 mm, spindle speed 10.000 and 15.000 rpm, feed 0,001 and 0,005 mm / rev, depth of cut 100 and 150 μm, which then do data processing using the method Taguchi full factorial and theoretical analysis. The results showed that the diameter of the tool and into the cut had the greatest effect on burr formation, the greater the diameter of the milling blade resulted in the formation of shorter and smaller burrs, the use of a 1 mm diameter milling blade and a 150 μm depth cut gave rise to long burr formations and tight, while the use of a 2 mm diameter milling blade and a cutting depth of 100 μm give rise to a short and slight burr formation.

Kekasaran permukaan pada pemesinan frais mikro Ti 6Al- 4V ELI (extra low intertitial)

One of the ingredients that are popular now is titanium, but titanium is a material that is difficult to process using conventional milling machining because of the poor thermal conductivity of the material so that the high-temperature machining process produced in the cutting zone causes plastic deformation in cutting tools and increased chemical reactivity in titanium. High-speed micro-milling machining can be used for micro machining of hard metals or alloys that are difficult to achieve at low speeds. Micro milling machining in titanium material 6Al-4V ELI with variations in milling tool diameter 1 and 2 mm, spindle speed 10.000 and 15.000 rpm, feed 0,001 and 0,005 mm/rev, depth of cut 100 and 150 μm, which then do data processing using the method taguchi full factorial and theoretical analysis. The results showed that the diameter of the tool and into the depth of cut the most effect on surface roughness, the greater the tool diameter of the milling produced a smaller roughness value, this is inversely proportional to the depth of the cut. The lowest roughness value is 0,26 and the highest roughness value is 0,9. Keywords: Micro milling machining, titanium 6Al-4V ELI, surface roughness.