Search results for "Titanium"
showing 10 items of 878 documents
Alumina particle reinforced TiO2 composite films grown by direct liquid injection MOCVD
2014
Abstract The use of a liquid injection delivery system to form composite films containing nanoparticles was investigated. Al 2 O 3 –TiO 2 films were grown on silicon substrates by direct liquid injection MOCVD (DLI-MOCVD) at 400 °C. The α-Al 2 O 3 nanoparticles (α-Al 2 O 3 NPs) dispersed in TiO 2 films resulted from co-deposition using colloidal α-Al 2 O 3 solution and titanium tetraisopropoxide as titanium precursor. Scanning electron microscopy coupled with EDS as well as Raman spectroscopy confirmed the presence of α-Al 2 O 3 NPs aggregates embedded in the TiO 2 matrix. The liquid injection system coupled with CVD technique can be promising to form composite films containing preformed na…
Correlation Between the Electrical Properties and the Morphology of Low-Pressure MOCVD Titanium Oxynitride Thin Films Grown at Various Temperatures
2000
Titanium oxynitride (TiN x O y ) thin films were deposited by low-pressure metal-organic CVD (LP-MOCVD) on (100) silicon, sapphire, and polycrystalline alumina substrates. Titanium isopropoxide (TIP) and ammonia were used as precursors. The influence of the growth temperature, ranking from 450°C to 750°C, was investigated by scanning electron microscopy (SEM), and electrical DC measurements. Rutherford back-scattering (RBS) measurements were used to determine the N/O ratio in the films. The surface observations of the deposited films showed two morphological transitions. The resistivity decreased with the growth temperature, while the nitrogen content increased. Moreover, for the highest de…
Spinel-mullite composites with optical properties
1997
The aim of this paper was to study the synthesis and characterization of spinel-containing mullite based materials, using sol-gel techniques. Several gels were prepared, with nominal compositions 3(Al2−2xMx TixO3)·2SiO2 and 3(Al2−xMxO3)·2SiO2, with M=Ni+2 or Co+2 and 0.0≤x≤0.2, by hydrolysis and condensation of mixtures of aluminum, silicon and titanium alkoxides and nickel chloride. Dried gels were homogeneous and displayed a glass transition at around 750°C, which indicated that the system could be described as an amorphous silicoaluminate network.
Aluminum oxide/titanium dioxide nanolaminates grown by atomic layer deposition: Growth and mechanical properties
2017
Atomic layer deposition (ALD) is based on self-limiting surface reactions. This and cyclic process enable the growth of conformal thin films with precise thickness control and sharp interfaces. A multilayered thin film, which is nanolaminate, can be grown using ALD with tuneable electrical and optical properties to be exploited, for example, in the microelectromechanical systems. In this work, the tunability of the residual stress, adhesion, and mechanical properties of the ALD nanolaminates composed of aluminum oxide (Al2O3) and titanium dioxide (TiO2) films on silicon were explored as a function of growth temperature (110-300 C), film thickness (20-300 nm), bilayer thickness (0.1-100 nm),…
Initial stages of TiO2 thin films MOCVD growth studied by in situ surface analyses
2005
Abstract In situ chemical surface analyses using X-ray photoelectron spectroscopy (XPS) were performed to understand the initial stages of TiO 2 thin-film MOCVD growth. Deposits on Si (1 0 0), a few nanometres thick, were obtained at a fixed temperature of 650 °C and for two different pressures, 2.9 and 0.05 mbar, using titanium tetraisopropoxide (TTIP) as precursor. Pressure lowering led to a higher deposit growth rate. Reduction of titanium with respect to stoichiometric titanium dioxide and oxidation of the wet-cleaned silicon substrate are observed from decomposition of the Ti 2p and Si 2p peaks. The formation of a TiSi x O y mixed oxide is also pointed out and confirmed by the presence…
Anti-bacterial activity of graphene oxide as a new weapon nanomaterial to combat multidrug-resistance bacteria.
2016
Antibiotic resistance in microbial pathogens has become a serious health problem in the world. The increasing spread of hospital acquired infections especially in immunocompromised and cancer patients caused by multidrug-resistant (MDR) microbial pathogens is restricting the choices for impressive antibiotic therapy. So many efforts have been made to develop new compounds with antimicrobial activity. In recent years, nanoparticles, particularly graphene oxide (GO) nanoparticles have found many applications in various fields, including antibacterial action, pathogens bio detection, cancer therapy, and drug and gene delivery. The use of graphene oxide as an antibacterial agent for the treatme…
The role of angiogenesis in implant dentistry part I: Review of titanium alloys, surface characteristics and treatments
2015
Background: Angiogenesis plays an important role in osseointegration process by contributing to inflammatory and regenerative phases of surrounding alveolar bone. The present review evaluated the effect of titanium alloys and their surface characteristics including: surface topography (macro, micro, and nano), surface wettability/ energy, surface hydrophilicity or hydrophobicity, surface charge, and surface treatments of dental implants on angiogenesis events, which occur during osseointegration period. Material and Methods: An electronic search was performed in PubMed, MEDLINE, and EMBASE databases via OVID using the keywords mentioned in the PubMed and MeSH headings regarding the role of …
Immobilization of BMP‐2, BMP‐7 and alendronic acid on titanium surfaces: Adhesion, proliferation and differentiation of bone marrow‐derived stem cells
2019
This study analyzed the influence of titanium (TiO2 ) surface modifications with two osteogenic proteins (BMP-2, BMP-7) and an anti-osteoclastic drug (alendronic acid [AA]) on sandblasted/acid-etched (SLA) and plain TiO2 (PT) on cell adhesion, proliferation and differentiation (alkaline phosphatase [AP] and osteocalcin [OC]) of bone-marrow derived stem cells (BMSCs) after 1, 3 and 7 days in-vitro. Initially, AA surfaces showed the highest cell number and surface coverage. At day 3 and 7, BMP and AA-modified surfaces exhibited a significantly enhanced cell growth. For proliferation, at days 3 and 7, an enhancement on BMP-2, BMP-7 and AA-surfaces was seen. At day 7, SLA also showed a higher p…
Vertical osteoconductivity and early bone formation of titanium-zirconium and titanium implants in a subperiosteal rabbit animal model.
2013
Objectives The aim of this pilot study was to evaluate the vertical osteoconductive and osteointegrative dynamics around titanium–zirconium (TiZr) implants compared to titanium (Ti) implants. Materials and methods In a split-leg design, 12 TiZr-SLActive and 12 Ti-SLActive implants were inserted 3 mm above bone level in the proximal tibia of 12 rabbits. Full periosteal flaps were repositioned to cover the site. Specimens were obtained after 10, 20 and 30 days (each n = 4 per group). Histomorphometric measurements included percentage of linear bone fill (PLF; %), new marginal vertical bone height (VBH; mm) and vertical bone-to-implant contact (vBIC; %). Statistical analysis was performed with…
Interactions between cells and titanium surfaces.
2002
The interaction between cells and implant materials is determined by the surface structure and/or surface composition of the material. In the past years, titanium and titanium alloys have proved their superiority over other implant materials in many clinical applications. This predominant behaviour is caused by a dense passive oxide layer which forms within milliseconds in oxidizing media. Titanium dioxide layers of 100 nm thickness were produced on the surface of cp-titanium grade 2, and on an experimental alloy of high vanadium content (Ti1.5Al25V) as a harmful control. The layers were produced by thermal and anodic oxidation and by coating by means of the sol-gel process. The resulting o…