Hybrid Ti Research Articles

INFLUENCE OF ABUTMENT MATERIAL, CEMENT THICKNESS, AND CROWN TYPE ON THE FINAL COLOR OF IMPLANT-SUPPORTED RESTORATIONS.

To evaluate the influence of abutment material, cement thickness, and crown type on the esthetics of implant supported restorations. In total, 60 specimens were prepared to represent six abutment groups: Group PA &#61; pink-anodized Ti; Group GA &#61; gold-anodized Ti; Group T &#61; nonanodized Ti; Group H &#61; hybrid (Ti &#43; zirconia); Group P &#61; PEEK (Ti &#43; PEEK); and Group C &#61; composite resin (control). Crown specimens (n &#61; 120) were obtained from Vita Enamic (VE) and Vita Suprinity (VS). Two cement thicknesses (0.1 and 0.2 mm) were used. The color values of crown configura:ons were measured and ΔE00* values were calculated. Statistical analyses included were Shapiro Wilk, three-way ANOVA, and Tukey HSD tests (P ≤ .05). Abutment (P < .001) and crown materials (P &#61; .001) had a significant effect on ΔE00* values, while cement thickness did not. Groups PA and H resulted in significantly lower mean ΔE00* values than other abutments, whereas Group T revealed the highest. Unlike VS, cement thicknesses created a significant difference on the ΔE00* values for VE (P ≤.05). Pink-anodized Ti or hybrid abutments for VE and pink- or goldanodized Ti for VS seem to be better options, in terms of color change. Cement thickness of 0.1 mm resulted in higher ΔE00* value than 0.2 mm for VE (P ≤ .05).

Development of TiB and nanocrystalline Ti-reinforced novel hybrid Ti nanocomposite produced by powder metallurgy

Titanium monoboride (TiB) whisker-reinforced titanium (Ti) matrix composites were produced by powder metallurgy, through vacuum sintering. TiB is formed by thermal decomposition of TiB2 precursor. In addition, a new hybrid composite was developed by admixing nanograined and nanocrystalline (more important) Ti to enhance the transformation mechanism of TiB2 to TiB phase. The morphology and particle size of the initial powders, mixtures and the microstructure of the composites have been studied by scanning electron microscopy (SEM). The phase analysis and transformation monitoring were performed by X-ray diffraction (XRD). The sintered composites were also subjected to compressive strength and hardness measurements. According to XRD results, through the addition of nanocrystalline Ti, a probable enhancement of the TiB2 → TiB transformation occurred producing more TiB whiskers in the hybrid composites. All samples of the hybrid composites exhibited improved yield strength (1365 MPa) and hardness (358 HV) compared to the non-hybrid ones 927 MPa and 254 HV, respectively.Graphical abstract

Determination of H+ ion diffusion in Ti3C2-rGO glucose sensor

• The hybrid Ti 3 C 2 -rGO film is fabricated by electrostatic self-assembly method. • The optimal interlayer spacing may modify the effective H + ion diffusion channels. • H + ion diffusion in low frequency range plays a key role in the sensing process. • H + ion diffusion is regarded as the dominant origin of enhanced glucose sensitivity. The diffusion of generated H + ions in glucose sensing process is critical for the sensitivity of sensor. Although many glucose sensors assembled by two dimensional (2D) materials (MXene, graphene, MoS 2 et al.) have been extensively studied, the detailed analyses about the diffusion of H + ions are still rarely reported. Herein, hybrid Ti 3 C 2 -rGO film is fabricated by electrostatic self-assembly utilizing the 2D Ti 3 C 2 and graphene sheets to focus on the H + ion’s diffusion dynamic properties related to the sensing performance. Through controlling the graphene content, this hybrid Ti 3 C 2 -rGO film provide the effective H + ion diffusion channels. Based on the comprehensive analyses of cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS), the corresponding localized conduction and enzymatic reaction at interfaces between the Ti 3 C 2 -rGO electrodes and glucose solution were investigated. According to the Warburg impedance in Nyquist plot from EIS, it is certified that the H + ion diffusion in low frequency range may play a significant role in the sensing mechanism of the glucose sensor. Moreover, the relationship derived from the interaction including interlayer spacing, H + ion diffusion and the sensing performance further reveal the H + ion diffusion as the dominant origin of the enhanced glucose sensitivity. This analysis will provide fundamental insight into the electrode structures assembled with 2D materials to optimize the sensor design in terms of ion transport dynamics.

Review of nonlinear effects under TW-power PS pulses amplification in GARPUN-MTW Ti:sapphire-KrF laser facility

Investigations were carried out at the multistage hybrid Ti:sapphire–KrF laser facility GARPUN-MTW on the direct amplification of TW-power picosecond UV laser pulses in e-beam-pumped KrF amplifiers and propagation along a 100 m laboratory air pass. The experiments identified the main nonlinear effects and their impact on the amplification efficiency, amplifier optics degradation, beam quality and focusability, and the evolution of radiation spectra. The research was performed towards an implementation of the shock-ignition concept of inertial-confinement fusion using krypton fluoride laser drivers.

RETRACTED: Hybridisation of microstructures from three classes of titanium alloys

A ternary hybrid Ti alloy (HYTA) was produced by selective laser melting (SLM), combining all three classes of the titanium system. The hybridisation of the α CP Ti, α-β Ti-64 and β Ti-5553 gave rise to a highly heterogeneous microstructure encompassing all the possible phases and structures which do not co-exist in conventional monolithic Ti alloys. The details of the complex microstructure were comprehensively characterised, revealing the roles played by such important factors as the distribution of the ingredient alloy particles, the Marangoni convection and diffusion of solute during melting, and microsegregation of solute during solidification. The ternary HYTA exhibited an excellent combination of high tensile yield strength of 1000 MPa and enhanced ductility with uniform elongation of ∼15% and total elongation of ∼20%, superior to conventional Ti alloys of various types. Such exceptional performance is attributed to the high-degree heterogeneity and the operation of most major deformation mechanisms which coordinate effectively and transfer smoothly between various parts with a wide range of hardness (4–6 GPa). The outcome has further demonstrated the potential of hybridisation of microstructures as a new strategy for future alloy development.

Facile preparation of mussel-inspired antibiotic-decorated titanium surfaces with enhanced antibacterial activity for implant applications

Titanium implants (Ti) have been widely used in several medical fields. In clinical practice, Ti can become contaminated with bacteria through a variety of mechanisms. This contamination can lead to implant failure and serious infections. In this study, we aimed to develop a new, hybrid Ti with good biocompatibility and antibacterial properties by immobilizing ceftazidime (CFT) onto the Ti surface through polydopamine (PDA) and polyethyleneimine (PEI) chemistry. Hybrid Ti was confirmed by assessing the cell proliferation of human adipose-derived stem cells using a cell counting. The biofilm formation across the Ti surface of two bacterial strains associated with nosocomial infections, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus, was evaluated by scanning electron microscopy. The viability of the bacteria exposed to Ti surface was evaluated by cell counting. Our results clearly demonstrate that the bacterial biofilm formation as well as bacterial viability was significantly reduced on the hybrid Ti as compared to the control, Ti alone. Collectively, the Ti surface was successfully modified to form the hybrid Ti exhibiting good biocompatibility and antibacterial properties through PDA, PEI, and CFT grafting. Within the limitations of this in vitro study, we conclude that the hybrid Ti may be useful for successful implant treatment.

Superior titanium from hybridised microstructures – A new strategy for future alloys

A new strategy for future alloys by hybridising microstructures of existing alloys using selective laser melting was introduced. In particular, two existing Ti alloys were hybridised, leading to a new Ti, referred to as HYbrid Ti Alloy (HYTA). An excellent combination of high strength, work hardening and ductility was achieved, superior to conventional Ti. Further, individual properties of HYTA were manipulated via simple heat treatments, revealing great versatility. This novel approach can be applied to a vast variety of metals beyond Ti and contributes significantly to the coming era of microstructure-by-design.

Hybrid Ti matrix composites with TiB2 and TiC compounds

Spark plasma sintering method was utilized to produce monolithic Ti and four composite samples with different amount of TiB2 and TiC as additives. The Sintering conditions of 1200 °C for 5 min under 50 MPa external pressure was employed for SPS process. The effect of different amount of additives was studied on the relative density, microstructure and mechanical characterizations of as-sintered samples. Microstructural investigations, thermodynamic assessments and XRD analysis revealed the formation of in-situ TiBw phase in the Titanium matrix composites (TMCs). However, thanks to the short dwell time and existence of coarse TiB2 particles, some semi reacted titanium diboride surrounded by TiBw phase remained into the samples specially the ones with high TiB2 contents. On the other hand, Titanium also diffuse into the TiC phase and the new phase of TiC1-x was produced. The best relative density of 99.77 was obtained for monolithic sample. Adding additives decreased the UTS, elongation and bending strength of as-sintered samples whilst the hardness of specimens increased with addition of more TiB2/TiC. The fractographs shown the role of additives on obtaining a finer microstructure by hindering the extensive grain growth. Predominant fracture mode was brittle and adding more additives rose up the transgranular fractures.

Effects of adding CNTs on the thermo-mechanical characteristics of hybrid titanium nanocomposites

Feasibility of using carbon nanotubes (CNTs) for improving the thermo-mechanical properties of titanium (Ti) matrix composites (TMCs) is studied by means of a multi-stage micromechanical approach. The hybrid Ti matrix nanocomposite (HTMNC) system consists of Ti-6Al-4 V alloy reinforced by unidirectional SiC fibers and randomly dispersed CNTs. An efficient micromechanics procedure is proposed to investigate the CNT aggregation encountered frequently in real engineering situations. The effects of the SiC fiber volume fraction, off-axis angle, aspect ratio and arrangement type as well as the CNT volume fraction, waviness, aspect ratio and non-uniform dispersion are examined on the HTMNC effective properties. Owing to their high Young's modulus and low coefficient of thermal expansion (CTE), the CNT use into the conventional TMCs is revealed to be effective at improving the resulting HTMNC thermo-mechanical properties. Also, the HTMNC elastic moduli and CTEs tend to further improvement by the use of straight CNTs. However, it is demonstrated that the CNT aggregation has a deterioration effect on the effective properties. Generally, the model predictions agree well with the experimental measurements. The results could be actually useful to guide design of general metal matrix composites containing CNTs with superior thermo-mechanical properties.

The use of heparin chemistry to improve dental osteogenesis associated with implants

In this study, we designed a hybrid Ti by heparin modifying the Ti surface followed by Growth/differentiation factor-5 (GDF-5) loading. After that, products were characterized by physicochemical analysis. Quantitative analysis of functionalized groups was also confirmed. The release behavior of GDF-5 grafted samples was confirmed for up to 21days. The surface modification process was found to be successful and to effectively immobilize GDF-5 and provide for its sustained release behavior. As an in vitro test, GDF-5 loaded Ti showed significantly enhanced osteogenic differentiation with increased calcium deposition under nontoxic conditions against periodontal ligament stem cells (PDLSc). Furthermore, an in vivo result showed that GDF-5 loaded Ti had a significant influence on new bone formation in a rabbit model. These results clearly confirmed that our strategy may suggest a useful paradigm by inducing osseo-integration as a means to remodeling and healing of bone defects for restorative procedures in dentistry.

Effect of hybrid oxidation on the titanium oxide layer's properties investigated by spectroscopic methods

In this work the study of hybrid Ti Grade 2 during oxidation using FADT – fluidized bed atmospheric diffusive treatment and PVD – magnetron sputtering have been investigated. Additionally, the influence of the oxidation method on the change in the mechanism of oxygen transport to the substrate have been discussed (phenomenon responsible for the improvement of bioactivity). Presented method consists in forming the titanium surface layer saturated with oxygen due to the diffusion and deposition of a thin homogeneous oxide coating on the Ti surface. Discussed processes diminish the surface roughness and increase bio-compatibility of the surface, which results in easier hydroxyapatite cluster deposition. The diffusion process was conducted on Al2O3 fluidized bed, with air as the fluidizing factor at 913 K for 8 h. The deposition of the oxide coatings were carried out with magnetron sputtering, with the use of a TiO2 target at a pressure of 3 × 10−2 mbars and power of 350 W. To evaluate the effects of hybrid oxidation and to determine the mechanism of oxygen transport, the following research methods have been applied: spectroscopy (GDOS, SIMS, RS), microscopic methods (SEM-EDS, SEM-EBSD, TEM-EFTEM), X-ray tests (μ-XRD, GID). Obtained test results were used to identify the type of oxide coatings, to assess the thickness of the layers and to study the influence of crystallographic orientation on oxygen transport and concentration in the surface layer and in the oxide coating. It has been found that the formation of oxide coatings created by using the hybrid method (FADT + PVD leads to a change in oxygen concentration in the substrate due to introduced defects. This phenomenon is in opposition to the conventional methods such as: electrochemical or laser oxidation. In contrast, forming a tight homogeneous oxide coating on Ti surface improves the biocompatibility, which is particularly important in the context of biomedical applications.

Extended plasma channels created by UV laser in air and their application to control electric discharges

Results are presented from a series of experimental and theoretical studies on creating weakly ionized extended plasma channels in atmospheric air by 248-nm UV laser radiation and their application to control long high-voltage discharges. The main mechanisms of air ionization by UV laser pulses with durations from 100 fs to 25 ns and intensities in the ranges of 3×1011–1.5×1013 and 3×106–3×1011 W/cm2, respectively, which are below the threshold for optical gas breakdown, as well as the main relaxation processes in plasma with a density of 109–1017 cm−3, are considered. It is shown that plasma channels in air can be efficiently created by amplitude-modulated UV pulses consisting of a train of subpicosecond pulses producing primary photoelectrons and a long UV pulse suppressing electron attachment and sustaining the density of free electrons in plasma. Different modes of the generation and amplification of trains of subterawatt subpicosecond pulses and amplitude-modulated UV pulses with an energy of several tens of joules were implemented on the GARPUN-MTW hybrid Ti:sapphire-KrF laser facility. The filamentation of such UV laser beams during their propagation in air over distances of up to 100 m and the parameters of the corresponding plasma channels were studied experimentally and theoretically. Laser initiation of high-voltage electric discharges and control of their trajectories by means of amplitude-modulated UV pulses, as well as the spatiotemporal structure of breakdowns in air gaps with length of up to 80 cm, were studied.

Directed transfer of microwave radiation in sliding-mode plasma waveguides produced by ultraviolet laser in atmospheric air.

Experiments have been performed at hybrid Ti:sapphire/KrF laser facility GARPUN-MTW to develop a novel technique to create a hollow-core sliding-mode plasma-filament waveguide for directed transfer of microwave radiation. Efficient multiphoton air ionization was produced by a train of picosecond 1-TW UV pulses at 248nm wavelength, or by amplitude-modulated 100ns pulse combining a short-pulse train with a free-running 1-GW pulse, which detached electrons off O2- ions. Multiple filamentation of UV laser radiation in air was observed, and filamentation theory based on resonance-enhanced ionization was developed to explain the experimental results.

Anticorrosive ultrathin film derived from bio-based urushiol–Ti by layer-by-layer self-assembly

Abstract Urushiol–metal polymers, obtained by the reaction between metal and urushiol (an extraction of natural Chinese lacquer sap), are a heavy anticorrosive coating used in chemical industry because of their excellent resistance against chemical medias. Herein, through layer-by-layer (LBL) self-assembly of n-butyl titanate and urushiol, a stable anticorrosive multilayer inorganic–organic hybrid Ti/ polyurushiol (Ti/PU)n ultrathin film was constructed after UV irradiation. The formation of the (Ti/PU)n ultrathin film was monitored by Fourier transform infrared (FT-IR) spectroscopy and UV–vis spectroscopy, while the microstructure of the film was analyzed by X-ray photoelectron spectroscopy (XPS), X-ray reflectometry (XRR), atomic force microscopy (AFM) and scanning electron microscopy (SEM) . The anticorrosion property of the (Ti/U)n film with number n (n = 1, 3, 5, 7, 9, 11) and (Ti/PU)n (n = 3, 5, 7, 9, 11) film was investigated in concentrated salt aqueous solution using potentiodynamic polarization measurement. Due to the compact and defectless three-dimensional cross-linking network structure through the coordinate bonding between urushiol and Ti by LBL technique and subsequent photo-induced polymerization, the resultant (Ti/PU)7 film showed pronounced protective efficiency with inhibiting efficiency (IE) of greater than 99%. The morphology of (Ti/PU)7 film remained integrated and defect-free after immersion in 3.5 wt.% NaCl and 1 mol/L HCl solution for 24 h.

Effects of picosecond terawatt UV laser beam filamentation and a repetitive pulse train on creation of prolonged plasma channels in atmospheric air

Amplitude-modulated UV laser pulse of up to 30J energy was produced at hybrid Ti:Sapphire/KrF GARPUN-MTW laser facility when a preliminary amplified train of short pulses was injected into unstable resonator cavity of the main e-beam-pumped KrF amplifier. The combined radiation consisted of regeneratively amplified picosecond pulses with subTW peak power overlapped with 100-ns pulse of a free-running lasing. The advantages of combined radiation for production of long-lived prolonged plasma channels in air and HV discharge triggering were demonstrated: photocurrent sustained by modulated pulse is two orders of magnitude higher and HV breakdown distance is twice longer than for a smooth UV pulse. It was found that in contrast to IR radiation multiple filamentation of high-power UV laser beam does not produce extended nonlinear focusing of UV radiation.

Development and application of cathodic vacuum arc plasma for nanostructured and nanocomposite film deposition

A cathodic vacuum arc plasma (CVAP) system was constructed at Chiang Mai University to be used for the deposition of nanostructured and nanocomposite thin films. Various CVAP sources were developed, such as with a single or dual-rod cathode. A range of features were implemented including “triggerless” arc initiation, macroparticle filters, and negative substrate bias, which can be pulsed. In our experiments, various kinds of conductive materials were used as cathode in modes of single- or multi-element film deposition. The film deposition could be done under several types of gas atmospheres with various pressures. These technical developments allowed us to produce diverse types of thin and nanostructured films. Examples of applications include Mo-containing tetrahedral amorphous carbon films, diamond-like carbon (DLC) films, nano-structured carbon films and C–Mo nanocomposite films, C–Ti and C–Pt hybrid films, Ti-nitride films, hybrid Ti–Ni films, etc. The films were applied to wafers used in microelectronics, and to components in fuel cells.

Triggering and guiding electric discharge by a train of ultraviolet picosecond pulses combined with a long ultraviolet pulse

Non-self-sustained electric discharge and electric breakdown were triggered and guided by a train of picosecond UV pulses overlapped with a long free-running UV pulse of a hybrid Ti:Sapphire-KrF laser facility. Photocurrent sustained by this train is two orders of magnitude higher, and electric breakdown distance is twice longer than those for the discharge triggered by the long UV pulse only.

Multiterawatt Ti:Sapphire/KrF laser GARPUN-MTW as a test bench facility for verification of combined amplification of nanosecond and subpicosecond pulses

The possibility of the same large-aperture KrF laser driver to amplify simultaneously both nanosecond pulses for thermonuclear target implosion and picosecond ones for fuel ignition is discussed relative to KrF-based Fusion Test Facility. In this way experiments were performed at hybrid Ti:Sapphire/KrF GARPUN-MTW facility on amplification of subpicosecond pulses. 2-TW, 330-fs pulses were produced with beam divergence 20 μrad in direct double-pass amplification scheme. Peak power as high as 30–40 TW can be achieved in 50-fs pulses, being combined with long pulses (of a few ns to 100 ns) of ∼1 GW power.

A 5 Hz flashlamp pumped Cr:LiSAF multipass amplifier for ultrashort pulses

We report here the operation, at 5 Hz, of a multipass flashlamp pumped Cr:LiSAF ultrashort pulse amplifier, presenting peak powers over 0.3 TW. This unusual high repetition rate was obtained by using a two-flashlamp pumping scheme, aiming at the minimization of the thermal load on the gain medium by the use of intracavity absorption filters. This cavity was used as a four-pass multipass amplifier in a hybrid Ti:sapphire/Cr:LiSAF system. The maximum amplification factor was 150, and the compressed pulse duration was 60 fs.

GARPUN-MTW: A hybrid Ti:Sapphire/KrF laser facility for simultaneous amplification of subpicosecond/nanosecond pulses relevant to fast-ignition ICF concept

The first stage of the petawatt excimer laser project started at the P.N. Lebedev Physical Institute, implements a development of multiterawatt hybrid GARPUN-MTW laser facility for generation of ultra-high intensity subpicosecond ultraviolet (UV) laser pulses. Under this project, a multi-stage e-beam-pumped 100-J, 100-ns GARPUN KrF laser was upgraded with a femtosecond Ti:Sapphire front-end, to produce combined subpicosecond/nanosecond laser pulses with variable time delay. Attractive possibility to amplify simultaneously short and long pulses in the same large-scale KrF amplifiers is analyzed with regard to the fast-ignition, inertial confinement fusion problem. Detailed description of hybrid laser system is presented with synchronized KrF and Ti:Sapphire master oscillators. Based on gain and absorption measurements at GARPUN amplifier and numerical simulations with a quasi-stationary code, we are predicting that 1.6 J can be obtained in a short pulse at hybrid GARPUN-MTW Ti:Sapphire/KrF laser facility, combined with several tens of joules in nanosecond pulse. Amplified spontaneous emission, which is responsible for the pre-pulse formation on a target, was also investigated: its acceptable level can be provided by properly choosing staged gain or loading the amplifiers by quasi-steady laser radiation. Fluorescence and transient absorption spectra of Ar/Kr/F2 mixtures conventionally used in KrF amplifiers were recorded to find out the possibility for femtosecond pulse amplification at the broadband Kr2F (42Γ → 1,2 2Γ) transition, which benefits in 100 times higher saturation energy density than for KrF (B → X) transition.