Showing papers on "Titanium published in 1980"

Thin film interaction between titanium and polycrystalline silicon

Abstract: The low resistivity of the titanium disilicide makes this material attractive for gate and interconnect metallizations. TiSi2 has been formed by reacting Ti films with polycrystalline and monocrystalline silicon in the temperature range 400–1100 °C. The interaction is investigated by use of sheet resistance, x‐ray diffraction, and stress measurements. It has been found that Ti and Si react very rapidly to form both TiSi and TiSi2 at temperatures ? 700 °C and only TiSi2 at temperatures ≳ 700 °C. The TiSi2 films are associated with a very low resistivity (∼15 μΩ cm), high tensile stress [∼ (1–2) ×1010 dyn/cm2)], and a rough surface. Silicided structures are mechanically stable. It is proposed that the silicon, as the predominant diffusing species, first diffuses into titanium to completely convert titanium into TiSi and then into TiSi to form TiSi2.

The wetting of alumina by copper alloyed with titanium and other elements

Abstract: The wettability of alumina by ternary alloys of copper, titanium and aluminium, gallium gold, indium, nickel or silver has been investigated using sessile drop tests conducted in vacuum at 1050–1250° C. Substantial additions of titanium are known to induce copper to wet alumina due to the formation of a titanium rich reaction product at the alloy/ ceramic interface, but the present work has shown that the concentration of titanium can be reduced by the addition of ternary alloying elements. Additions of indium are very beneficial, of aluminium, gold or silver are moderately beneficial, and of gallium or nickel are of negligible benefit or detrimental. These observations, and previous work with copper-tin-titanium alloys [1] can be interpreted in terms of effects on the activity of titanium which it is argued will be enhanced if the ternary alloying element has a low surface energy and is readily saturated by titanium. The correlation of the experimental wetting observations with the surface energy and titanium solubility data for the ternary alloying elements provides a basis for the rational development of reactive metal brazes for joining unmetallized ceramics.

Reactions of trimethylsilylcyclopentadiene derivatives with titanium, niobium, and tantalum halides

Abstract: The use of trimethylsilyl derivatives as effective reagents for the new or improved syntheses of complexes of the early transition metals is described. Improved routes, involving the use of trimethylsilylcyclopentadiene, are described for the syntheses of [TiCl3(cp)], [TiBr3(cp)], [Til3(cp)], [NbCl4(cp)], and [TaCl4(cp)](cp = cyclopentadienyl). Routes, involving the use of bis(trimethylsilyl)cyclopentadiene, are described for the syntheses of the analogous complexes [TiX3(Me3Si-η-C5H4)], where X = Cl, Br, or l. The reactions of [TiCl3(cp)], [TiBr3(cp)], and [TiCl3(Me3Si-η-C5H4)] with a variety of bidentate ligands are described. The Lewis acidity of these titanium compounds is much reduced from that of the parent tetrahalides and only two adducts have been positively identified: these are [TiCl3(cp)]·phen (phen =o-phenanthroline) and [TiCl3(Me3Si-η-C5H4)]·pdma (pdma =o-phenylenebisdimethylarsine).

Silicide formation in thin cosputtered (tantalum + silicon) films on polycrystalline silicon and SiO2

Abstract: Formation of the silicides of titanium has been investigated by cosputtering titanium and silicon on polycrystalline silicon and oxidized silicon wafers. Alloys with as‐deposited Si/Ti atomic ratios of 0.5–8 were sintered in vacuum or hydrogen ambient in the temperature range 400–1000 °C. The Ti‐Si interaction in such films was studied by the use of sheet resistance, x‐ray diffraction, and stress measurements. It was found that in cases of silicon deficient alloys (e.g., the case of alloys sputtered on oxide with Si/Ti ratio <2) intermetallics Ti5Si3 and TiSi were formed. These intermetallics were stable up to 900 °C. In the presence of polycrystalline silicon and for alloys with Si/Ti ratio ?2, the only intermetallic formed was TiSi2. TiSi2 was responsible for very low resistivity (as low as ∼25 μΩcm) in the films. The volume change associated with silicide formation led to high tensile stresses in the films. It is suggested that in cosputtered films metallurgical interaction occurs locally which leads t...

Interference-Enhanced Raman Scattering of Very Thin Titanium and Titanium Oxide Films

Abstract: The Raman spectra of very thin evaporated films (\ensuremath{\sim}6 nm thick) of metallic titanium and oxidized titanium are obtained with a new technique called interference-enhanced Raman scattering. The results indicate that titanium films exhibit a crystalline hcp structure while the titanium oxide has an amorphous structure with local atomic bonding configurations similar to those in crystalline ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$.

Anodic Polarization Behavior of Ti-Ni and Ti-6A 1-4 V in Simulated Physiological Solutions

Abstract: Anodic polarization measurements made in Hanks' physiological solution at 37 degrees C and a pH of 7.4 show titanium materials to be the most passive of the following metals: titanium, Ti-6A1-4V, Ti-Ni (memory alloy), MP35N (Co-Ni-Cr-Mo), Co-Cr-Mo, 316L stainless steel, and nickel. The influence of the amino acids, cysteine, and tryptophan on the corrosion behavior of Ti-Ni and Ti-6A1-4V was studied. Cysteine caused a lower breakdown potential for Ti-Ni, but it did not affect the breakdown of Ti-6A1-4V, although an increase in current density for Ti-6A1-4V was observed. Tryptophan produced no significant effects.

Titanium halide catalyst system

Abstract: A novel catalyst system for the polymerization of alpha-olefins is provided. The catalyst system comprises: (a) an organoaluminum containing component, e.g. triethyl aluminum, and (b) a titanium halide containing component. The titanium halide containing component is obtained by co-pulverizing a halogen containing magnesium compound, e.g. MgCl2, with an electron-donor compound, e.g. ethyl benzoate, to produce a co-pulverized product. The co-pulverized product is then reacted with an organic phosphite, e.g. triphenyl phosphite, to produce a reaction product. The reaction product is then reacted with a titanium halide compound, e.g. TiCl4. A novel titanium halide containing component is provided as well as a process for producing said component. A process for the polymerization of alpha-olefins is also provided.

Process for producing highly porous thermoplastic films

Abstract: There is disclosed a novel process for the cold stretching at high stretch tension and at low stretch ratios of a film of a blend of synthetic orientable thermoplastic polymer and at least 50 weight percent of a coated inorganic filler selected from the group consisting of calcium carbonate, clays and titanium oxide and coated with a fatty acid ester of silicon and titanium to form a highly porous thermoplastic film (ie 10,000 to 100,000 surface ruptures/mm 2 ) exhibiting paper-like properties

Photocurrent spectroscopy of anodic oxide films on titanium

Abstract: Photocurrent spectroscopy has been used to examine the early stages of anodic film growth on titanium. Analysis of the photocurrent conversion efficiency as a function of wavelength for films formed at different potentials has shown that the film is essentially pure TiO2 above ca.1.5 V vs. SCE (at pH 0). Photocurrent spectroscopy has also been used to follow changes in the structure and thickness of the anodic film during breakdown at higher voltages.

Endemic isotopic anomalies in titanium

Abstract: Abundances of the titanium isotopes were determined using a new high-precision technique that shows terrestrial, lunar, and bulk meteorite samples to be indistinguishable Ca-Al-Ti-rich inclusions in the Allende meteorite are found to contain Ti of widely varying isotopic composition reflecting the presence of at least three nucleosynthetic components The anomalies in Ti appear to be relatively widespread and, when correlated with Ca data, provide a clue to nucleosynthesis in the neighborhood of the iron peak and to the late-stage nucleosynthetic processes which immediately preceded formation of the solar nebula

Coated cemented carbide bodies

Abstract: A process for increasing the resistance to wear of the surface of hard metal parts subject to wear, such as a cutting blade of metal cutting tools, and the product which results from the process, which includes coating the surface of the hard metal, for example, cemented carbide articles with a first layer comprised of one or more layers of a metallic carbide or nitride in a total thickness ranging from 0.01 to 10 μm, a second layer comprised of one or more layers of a refractory oxide, such as an oxide of aluminum, zirconium, silicon, calcium, magnesium, titanium, and hafnium, and stabilized zirconium oxide in a total thickness ranging from 0.5 to 10 μm, and depositing over the refractory oxide coating a third layer comprised of one or more layers of a nitride, carbonitride, oxynitride, oxycarbide or oxycarbonitride and boride of such metals as titanium, zirconium, hafnium, aluminum and silicon in a total thickness ranging from 1 to 10 μm. The process may include transitional layers to optimize the adherence of the various layers.

Polymerized solutions for depositing optical oxide coatings

Abstract: A clear solution is prepared by reacting metal alkoxide with a mixture of critical amounts of water and/or acid in an alcohol diluted medium. Alkoxides may be Ti(OR) 4 or Ta(OR) 5 , or another metal alkoxide such as Si(OR) 4 in admixture with these alkoxides. Acids may be HCl or HNO 3 . Quarter wave inorganic optical coatings are deposited by applying the alkoxide solution to a substrate then heating the coating at over 350° C. The coatings reduce reflectivity on silicon solar cells. The index of refraction of the coating can be varied by several techniques, including altering the proportion of titanium and silicon in the coating firing temperature, firing atmosphere. Thicknesses of the coating can be controlled by varying the rpm in spin application, withdrawal rate in dipping application, by concentration of the solution, by the type of solvent or the degree of polymerization of the titanium complexes.

A Titanium Dioxide Hydrogen Detector

Abstract: Sputtered films of titanium dioxide several thousand angstroms thick and sandwiched between a layer of titanium and a layer of platinum are highly selective detectors of hydrogen. The resistance of the device decreases on exposure to hydrogen. At concentrations above 0.5% in air, the response is rapid and limited by lead resistance. At lower concentrations the response is proportional to concentration but relatively slow at room temperature. Moderate increases in temperature quicken the response. The detectors may be used as effective alarm devices at room temperature, with a‐c or d‐c circuitry that requires negligible power in the absence of hydrogen.

Low-expansion ceramics and method of producing the same

Abstract: The present invention relates to low-expansion ceramics essentially consisting of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al2 O3), 24 to 80% by weight of titanium in terms of titanium oxide (TiO2), and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe2 O3), that major component of crystalline phase thereof is a solid solution of magnesium oxide-aluminum oxide-titanium dioxide-iron oxide, and that the ceramics has a coefficient of thermal expansion of not more than 20×10-7 (1/° C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure 1,100° C. for 1,000 hours, and a method of producing low-expansion ceramics comprising steps of preparing a batch of compounds so as to provide a chemical composition of 1.5 to 20% by weight of magnesia (MgO), 8 to 68% by weight of alumina (Al2 O3), 24 to 80% by weight of titanium in terms of titanium oxide, and 0.5 to 20% by weight of iron in terms of ferric oxide (Fe2 O3); plasticizing the batch if necessary and shaping the batch; drying the body thus formed and firing the formed body at 1,300° C. to 1,700° C. for 0.5 to 48 hours, thereby having a coefficient of thermal expansion of less than 20×10-7 (1/° C.) in a temperature range of 25° C. to 800° C. and a melting point of not lower than 1,500° C., said coefficient of thermal expansion being maintained even after exposure at 1,100° C. for 1,000 hours, wherein the shape of ceramics is a honeycomb structure.

Methyl‐triisopropoxy‐titanium, a highly selective nucleophilic methylating reagent. Preliminary Communication

Abstract: Replacement of lithium or magnesium by titanium can furnish nucleophilic organometallic reagents of high selectivity as exemplified by the title compound 1 (see Tables 1–3).

Carbon-induced amorphous surface layers in Ti-implanted Fe

Abstract: Titanium implantation into high‐purity Fe is shown to produce a ternary amorphous surface layer consisting of not only Fe and Ti, but also C. The amorphous layer forms at the surface and grows inward with increasing Ti fluence. The amount of C present also increases with Ti fluence and is believed to be deposited on the surface from the vacuum during implantation and to subsequently diffuse into the sample to produce the amorphous layer. For Ti concentrations ≲10 at.%, the amorphous layer thickness is less than the depth of the implanted Ti, but agrees with C diffusion distances, thus demonstrating that C is an essential constituent of the amorphous phase.

Method of depositing hard wear-resistant coatings on substrates

Abstract: A method of depositing hard, wear-resistant coatings on workpieces and utility articles by evaporating a metal such as titanium in a reactive atmosphere. To make the coating hard as far as possible, wear resistant, and less susceptible to oxidation, the deposition is effected in an atmosphere containing nitrogen, oxygen and carbon, with the atomic number proportion of O to C ranging between 0.5 and 1.5. An evaporation by means of a low voltage arc discharge and the use of CO as the residual gas atmosphere are particularly advisable.

Olefin polymerization catalyst component and composition and method of preparation

Abstract: An olefin polymerization catalyst composition comprising: (a) a reaction product of an organo aluminium compound and an electron donor, and (b) a product obtained by contacting a solid component comprising a magnesium halide in which the atomic ratio of chlorine to magnesium is at least 1.2, a titanium halide and an electron donor, with a halohydrocarbon and with a tetravalent titanium compound.

Hydrogen absorption in some A2B intermetallic compounds with the MoSi2-type structure (C11b)

Abstract: Hydrogen absorption was studied for the MoSi2-type phases Zr2Cu, Hf2Cu, Ti2Cu, Ti2Pd, Zr2Pd, Hf2Pd, Pd2Zr and Pd2Hf. In all but the last two compounds substantial hydrogen absorption was observed. Hydrogen favors the tetrahedral sites in the lattice where it is surrounded by four zirconium, titanium or hafnium metal atoms. At the composition A2BH2 all these sites are occupied; on further hydrogen absorption additional sites, possibly octahedral, are occupied. The intermetallic compound hydrides which contained copper decomposed at relatively low temperatures (approximately 200 °C) whilst no decomposition was observed in the palladium compounds at substantially higher temperatures (400–500 °C). The difference in behavior is predominantly due to the difference in the stability of the intermetallic compounds. The copper compounds have low stability, as evidenced by their small enthalpies of formation, whilst the palladium compounds, with estimated enthalpies of formation in excess of 100 kJ (g atom) −1, are among the most stable intermetallic compounds known.

The influence of grain orientation on the mode and rate of fatigue crack growth in α -titanium

Abstract: The high cycle fatigue crack growth characteristics of coarse grainedα-titanium have been studied in vacuum, air, water and brine. Tests were carried out on single-edge-notch tension test-pieces at anR ratio of 0.35, a frequency of 130 Hz, and a ΔK range of 5 to 25 MPa-√m. The use of channelling patterns in the SEM permitted detailed crystallographic information to be correlated with fatigue fracture morphologies. Three distinct modes of fatigue crack growth were identified. Cleavage-like facets on the basal planes (0002); the formation of which was encouraged by increasing severity of environment and increasing stress normal to (0002), striations on planes normal to (0002) consistent with a mechanism involving intersecting prism slip systems, and furrows in the [0001] direction associated with fine lines parallel to the 1123 direction. It is shown how the relationships between grain orientation, stress geometry and testing environment may be presented in the form of Grain Orientation Control Maps. The rate of fatigue crack growth in individual grains was dominated by the mode of growth; below a ΔK of 10 MPa√m the cleavage-like mode was up to 10 times more rapid than the other modes of growth.

Correlation between the oxidation mechanism of titanium under a pure oxygen atmosphere, morphology of the oxide scale, and diffusional phenomena

Abstract: The oxidation behavior of titanium was studied over the temperature range of 600 to 800°C in a pure oxygen atmosphere. A parabolic kinetics period is made up of a succession of short parts whose weight gain is nearly constant and whose beginning is characterized by an alteration of the oxidation rate. The kinetics curve is closely correlated with the morphology of the oxide scale which contains several layers separated by short cracks. These cracks decrease the diffusional flows of oxygen and titanium and alter the oxidation rate. A parabolic-linear kinetics transition is attributed to the formation of a continuous crack between the oxide scale and the matrix. The oxide scale then forms a porous barrier of constant thickness which induces a linear rate law due to the steady-state oxygen diffusion. Titanium cannot diffuse across the continuous crack. During the linear kinetics period several layers of constant thickness, separated by a continuous crack, spread out.