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.

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.

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.

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.

A chemical study of thermally activated chromic titanate on silica ethylene polymerization catalysts

Abstract: Thermally activated ethylene polymerization catalysts which contain chromium and titanium on silica differ from those catalysts which contain only chromium on silica. The characteristics of chromium-titanium catalysts vary with the method of incorporating the titanium and the thermal activation procedure. Titanated catalysts of the kind examined in this article have faster initiation and a higher polymerization rate per unit catalyst weight than corresponding catalysts without titanium. High-density polyethylene produced by this type of titanium-chromium catalyst tends to have a higher melt index and a broader molecular weight distribution than polyethylene made with chromium on silica catalysts. Iodometric titration showed that reduction from the initial hexavalent chromium to trivalent occurs when the dry, catalyst starting material is treated with titanium tetraisopropoxide. A study of the reaction between chromium trioxide and titanium tetraisopropoxide in carbon tetrachloride revealed that (1) it is not necessary to have a reaction between surface silanols and titanium tetraisopropoxide for the reduction to occur, and (2) the reaction product has an absorption near 660 nm in the visible range. Comparison of spectra showed that chromium trioxide on silica reduced by isopropyl alcohol has a shifted absorption, i.e., 600 nm. These findings are interpreted to mean that titanium atoms come sufficiently close to chromium atoms to change their electron density in the starting material and remain close neighbors in the activated catalysts. The interpretation is further supported by ESCA data and leads to the proposal that in this case the activated catalysts contain titanium chromate structures.

Fused aluminum oxide abrasive grain containing reduced titanium oxide

Abstract: A fused abrasive grain, useful for inclusion in coated abrasives and bonded abrasives, consists essentially of alumina; titanium oxide containing from about 0.42 to about 0.84% titanium, by weight of the abrasive grain, present as a reduced titanium oxide having an average oxidation state lower than in Ti2 O3 ; from about 0.05 to about 0.3% by weight carbon; from about 0.02 to about 0.1% by weight Na2 O; and from 0 to about 0.1% by weight total of calcium and silicon oxides. The grain before roasting has a gain on ignition of from about 0.4 to about 0.7% by weight, and is produced in an electric furnace by fusing high-purity titania, alumina containing Na2 O as the only significant oxide impurity, and carbon, followed by crushing and roasting the fused grain.

Heat recoverable nickel/titanium alloy with improved stability and machinability

Abstract: Nickel/titanium alloys containing less than a stoichiometric quantity of titanium, which are capable of having the property of heat recoverability imparted thereto at a temperature above the boiling point of liquid nitrogen, may be stabilized by the addition of from 1.5 to 9 atomic percent copper. These stabilized alloys also possess improved workability and machinability.