Showing papers on "Titanium published in 1977"

Internal stresses in titanium, nickel, molybdenum, and tantalum films deposited by cylindrical magnetron sputtering

Abstract: Measurements of internal stresses in thin sputtered films of Ti, Ni, Mo, and Ta confirm the onset of compression at low working pressures, as reported earlier for Cr [D. W. Hoffman and J. A. Thornton (in press) Thin Solid Films (Jan. 1977)]. Deposition from cylindrical magnetron sputtering sources gives access to a wide range of low working gas pressures with minimal substrate heating. The transition to compressive film stress at low sputtering pressures is abrupt, and occurs at threshold pressures that increase markedly with the atomic mass of the coating material. Moreover, the electrical resistivity and optical reflectance exhibit transitions in their sputtering‐pressure dependence that shift to higher pressures for the heavier elements. It appears therefore that the transitions in film stress, resistivity, and reflectance are general phenomena caused by an underlying change in the deposition process. A peening mechanism due to energetic particle bombardment is suggested. Data are presented for Ti, Ni, Mo, and Ta films, up to 0.4 μm thick, sputtered onto glass substates at a nominal deposition rate of 1 nm/s, over the pressure range 0.13–4.0 Pa of argon.

Electrical conductivity and charge compensation in Nb doped TiO2 rutile

Abstract: The electrical conductivity of rutile doped with 0.04–3 at.% niobium is reported as a function of oxygen pressure in the temperature range 1273–1623 K. The charge compensation is discussed in terms of a point defect model, under the assumption of a substitutional incorporation of niobium into the titanium rutile sublattice. Two kinds of charge compensation occur according to the temperature and the oxygen pressure, via an electronic or a lattice defect, in a Ti1−yNbyO2 or a Ti1−yNbyO2+y/2 solid solution, respectively. In the overstoichiometric range of the oxide, the data, when applied to undoped rutile, allow some conclusions about the atomic or electronic transport properties, both in the high and low temperature regimes.

Beam effects in Auger electron spectroscopy analysis of titanium oxide films

Abstract: Auger spectra of TiO2,Ti2O3, TiO, and Ti were determined as a function of sputter time to study ion‐beam and electron‐beam effects in AES depth profile analysis of titanium oxides. The value of the oxygen–titanium peak amplitude ratio for a given titanium oxide depends on ion‐beam energy, electron‐beam current density, and oxide composition. Both ion and electron beam give rise to an apparent reduction effect and their combined action stimulates the formation of carbide at the sample surface. The latter effect is more pronounced at an ion‐beam energy of 0.5 keV than at 2 keV. Depth resolution characterized by the width of the transition region between oxide and metal decreases with increasing ion‐beam energy and with increasing thickness of the sputtered layer.

Defect Structure of α-Al2O3 Doped with Titanium

Abstract: Titanium-doped α-Al2O3 exhibits a high-temperature conductivity which is ionic at high oxygen pressures and electronic at low oxygen pressures. Both are isotropic. The temperature dependence of conductivity under conditions where equilibrium with the atmosphere is not maintained indicates both the position of the energy level of titanium (TiAlx) in the forbidden gap and the temperature dependence of the mobility of the native ionic defects (Al vacancies, VAlm). Optical absorption responsible for the pink color of the reduced crystals is measured as a function of po2 and is used to determine concentrations of Ti3+ and Ti4+. Parameters for the equilibrium constants of the reactions involving electrons by which the composition of Al2O3:Ti and undoped Al2O3 is varied are determined. The chemical diffusion data by Jones et al. are described quantitatively.

Deposition method and products

Abstract: A method of depositing a hard metal alloy is described wherein a volatile halide of titanium is reduced off the surface of a substrate and then reacted with a volatile halide of boron, carbon or silicon to effect the deposition on a substrate of an intermediate compound of titanium in a liquid phase. The liquid compound on the substrate is then reacted in the presence of hydrogen to produce a hard deposit containing titanium and boron, carbon or silicon. Also described are products which may be produced by the above method.

Titanium as a metal for implantation. Part 2: biological properties and clinical applications.

Abstract: The first part of this article on the physical properties of titanium was published in the July issue of this journal.

Diffusion of titanium in copper

Abstract: Interdiffusion coefficients in copper-titanium alloys have been determined by Matano's method in the temperature range between 973 and 1283 K on (pure Cu)-(Cu-1.98 at. pct Ti alloy) and (pure Cu)-(Cu-2.91 at. pct Ti alloy) couples. Temperature dependence of the impurity diffusion coefficient of titanium in copper, determined by extrapolation of the concentration dependence of the interdiffusion coefficient to zero mole fraction of titanium, is expressed by the following Arrhenius equation along with the probable errors:D Ti/Cu=(0.693 −0.135 +0.169 )×10−4exp[−(196±2)kJ mol−1/RT] m2/s. The difference in the activation energies for the impurity diffusion of the 3d-transition metals and self-diffusion in copper has been calculated by applying LeClaire's model with the oscillating potential of the impurity atom in copper. The calculated values agree well with the experimental values including the present one.

Nitrogen solution and titanium nitride precipitation in liquid Fe-Cr-Ni alloys

Abstract: The solubility of nitrogen in liquid Fe-Cr, Fe-Ni, Ni-Cr, and Fe-Cr-Ni alloys up to 20 wt pct Ni and 40 wt pct Cr was measured by the Sieverts’ method The first and second order interactions in iron between nitrogen and chromium, and nitrogen and nickel were determined Chromium increases the nitrogen solubility at lower chromium concentrations but the second order interaction term which is of the opposite sign becomes significant at higher chromium levels and compensates partly for the effect of the first order interaction term Nickel decreases the nitrogen solubility in iron Titanium nitride formation in liquid Fe-Cr, Fe-Ni, and Fe-Cr-Ni alloys also was investigated The first and second order interactions between titanium and chromium or nickel were determined at 1600°C Chromium increases the solubility product of TiN, principally by decreasing the activity of nitrogen in the melt Nickel decreases the solubility product of TiN by increasing the activities of nitrogen and titanium

Shape memory alloys

Abstract: A shape memory alloy is provided, having a base of nickel and titanium, and additionally comprising up to 30 wt.% copper, and from 0.01 to 5 wt.% of at least one element selected from the group consisting of aluminum, zirconium, cobalt, chromium and iron. A method of making the above alloys is provided, and articles made therefrom are exemplified.

The reason for the loss of activity of titanium anodes coated with a layer of RuO 2 and TiO 2

Abstract: The galvanostatic method has been employed for following the time change of the ATA potential in 0.5 N H2SO4. On the basis of the experimental data it is proposed that the loss of ATA activity results from the formation of a non-conductive oxide film at the titanium-active layer interface.

Novel Semiconducting Electrodes for the Photosensitized Electrolysis of Water

Abstract: The preparation of novel semiconducting electrodes, based on polycrystalline titanium dioxide having exceptionally good current-voltage characteristics, is reported. These electrodes are formed by mixed oxide TiO/sub 2/-M/sub x/O/sub y/ deposits on metallic titanium substrates, M being a divalent or trivalent element. The mixed oxide coatings were prepared by spraying a solution containing, for example, chlorides of both metals (elements) entering the film composition on Ti metal and heating at approximately 450/sup 0/C in air to decompose the chlorides. Several layers, generally between 6 and 12, were deposited on each substrate. The electrodes were finally activated in argon at 600 to 800/sup 0/C during 30 to 60 min. The current-potential characteristics of the mixed oxide electrodes (area 0.9 cm/sup 2/) were measured in a two compartment cell using 1N sodium hydroxide solution. Results are presented and discussed.

Titanium and titanium alloys ion plated with noble metals and their alloys

Abstract: Components fabricated from titanium and titanium alloys are subjected to an ion plating with noble metals or their alloys. The structures so treated are highly resistant to oxidation at elevated temperatures and possess improved mechanical properties.

Strengthening of titanium steels by carbide precipitation

Abstract: Three simple high-purity steels containing between 0.10 and 0.55 wt.-% titanium and 0.02–0.11% carbon have been examined after direct transformation of austenite to ferrite by subcritical isothermal transformation in the range 600–800°C and by continuous cooling. Electron microscopy has shown that titanium carbide occurs in a fine banded form during the γ→α transformation, the dispersion parameters being very dependent on the transformation temperature. The finer dispersions were measured by field ion microscopy. The mechanical properties in tension at room temperature were determined as a function of transformation temperature for the three alloys and compared with the properties obtained by quenching and tempering in the, same temperature range. Fracture toughness measured by a COD test was determined on two titanium steels with 0.26% and 0.48%Ti. The results emphasize the importance of transformation temperature or rate of cooling through the transformation in determining the fracture toughness...

Bipolar system electrolytic cell

Abstract: A bipolar system electrolytic cell having a partition wall made of explosion-bonded titanium plate and iron plate which is electrically connected to anode of titanium substrate at its titanium side and to cathode of iron at its iron side, space is preferably given between anode and the partition wall and also between cathode and the partition wall. An assembly having a number of such unit cells arranged in series is useful for electrolysis of sodium chloride which can be performed under a low voltage per unit cell.

Nitriding of titanium in a radio frequency discharge

Abstract: The nitriding of titanium in a nitrogen or nitrogen-hydrogen plasma prepared with a radio frequency discharge was studied. Power was supplied from an inductively coupled 13.56 MHz 500 W generator. The reaction kinetics obeyed a parabolic relationship and the reaction constants were 10−12 - 10−10 g2 cm−4s−1 under various conditions. The surface of the nitrided metal was hardened by the formation of TiN. The rate-determining steps may be the absorption of ions and the diffusion of nitrogen in the metal.

Titanium as a metal for implantation

Abstract: (1977). Titanium as a metal for implantation. Journal of Medical Engineering & Technology: Vol. 1, No. 4, pp. 202-202.

Zirconium-titanium alloys containing transition metal elements

Abstract: Zirconium-titanium alloys containing at least one of the transition metal elements of iron, cobalt, nickel and copper are disclosed. The alloys consist essentially of about 1 to 64 atom percent titanium plus at least one element selected from the group consisting of about 15 to 27 atom percent iron, about 15 to 43 atom percent cobalt, about 15 to 42 atom percent nickel and about 35 to 68 atom percent copper, balance essentially zirconium plus incidental impurities, with the proviso that when the iron is present, the maximum amount of titanium is about 25 atom percent, when cobalt is present, the maximum amount of titanium is about 54 atom percent and when nickel is present, the maximum amount of titanium is about 60 atom percent. The alloys in polycrystalline form are capable of being melted and rapidly quenched to the glassy state. Substantially totally glassy alloys of the invention evidence unusually high electrical resistivities of over 200 μΩ-cm.