Showing papers on "Titanium published in 1972"

Cold‐Pressing and Low‐Temperature Sintering of Alkoxy‐Derived PLZT

Abstract: Multiorganometallic compounds were used to prepare high-purity submicron-size lead lanthanum zirconate-titanate (PLZT) powders which can be consolidated at low sintering temperatures to high-density piezoelectric and electrooptic ceramic bodies. Simultaneous hydrolytic decomposition of lead isoamyloxide, lanthanum isopropoxide, and zirconium and titanium tertiary amyloxides produced quaternary titanate powders with particle sizes of 75 to 300 A and analyzed purity of 99.92%; the major contaminant was Na from an intermediate reaction product. Homogeneity and stoichiometry of the powders before and after processing were demonstrated by electron microscopy and chemical analysis. High-temperature X-ray diffraction indicated an amorphous material up to ∼600°C, where the crystalline phase was first observed. Powders prepared in this manner sintered to high-density fine-grained transparent bodies with uniform microstructure. The experimental results suggest that less rigorous consolidation methods are required with high-purity homogeneous precursor materials with fine particle size.

The band structures of some transition metal dichalcogenides: band structures of the titanium dichalcogenides

Abstract: Band structures of the stoichiometric titanium dichalcogenides TiS2, TiSe2 and TiTe2 are calculated using a semi-empirical tight binding method. The results are fitted to optical reflectivity and absorption data and are compared with similar calculations on other group IVA dichalcogenides.

Environmental hydrogen embrittlement of an α-β titanium alloy: Effect of microstructure

Abstract: Study of environmental hydrogen embrittlement of a Ti-6 Al-4 alloy as a function of test displacement rate and of variations in alpha-beta microstructure Embrittlement in low-pressure (about 1 atm) gaseous hydrogen was inversely dependent on test displacement rate and strongly dependent on microstructure At a given displacement rate, microstructures having a continuous alpha-phase matrix were less severely embrittled than those having a continuous beta-phase matrix Further, brittle fracture occurred in the former microstructures by transgranular cleavage and in the latter microstructures by intergranular separation These observations are consistent with previous studies made on slow strain-rate embrittlement of hydrogen-charged titanium alloys and are explained in terms of relative hydrogen transport rates within the alpha-phase and beta-phase titanium

Methods of coating and surface finishing articles made of metals and their alloys

Abstract: Articles made of ferrous, non-ferrous and light metals and alloys thereof, e.g., aluminum, beryllium, magnesium, molybdenum, steel, tantalum, titanium, tungsten, vanadium and zinc and their alloys, are pretreated before coating and surface finishing in an anhydrous, inert, aprotic liquid, and subsequently electroplated with aluminum, cadmium, indium or zinc in an aprotic organo-metal electrolyte essentially free of molecular oxygen and water and, optionally, additionally finished by anodizing, chemical oxidation or diffusion. The pretreatment may be by erosion with finely-divided abrasive particles suspended in such liquid and impinged upon the surface of the article by hydraulic jetting, or with an aprotic liquid by the liquid-drop erosion method. Alternatively, the pretreatment may be by electrolytic action in a circuit where the article serves as the anode and is immersed in an anhydrous, aprotic electrolyte. Articles so pretreated and electroplated are thereafter more readily surface-finished or mechanically shaped.

Three-co-ordinated transition metal compounds. Part I. The preparation and characterization of tris(bistrimethylsilylamido)-derivatives of scandium, titanium, vanadium, chromium, and iron

Abstract: The compounds M[N(SiMe3)2]3, where M = Sc, Ti, V, Cr, and Fe, have been prepared by reactions involving metal chloride complexes and the lithium derivative of hexamethyldisilazane. The compounds have been characterized by analysis, molecular weight determination, i.r., and mass spectra. They are members of a trigonally co-ordinated transition metal series.

Stress-corrosion cracking in high strength steels and in titanium and aluminum alloys

Abstract: : Contents: Fundamentals; Stress Corrosion testing with Precracked Specimens; High Strength Steels; High Strength Aluminum alloys; Titanium alloys.

Apparatus for introducing gas into liquid metal

Abstract: The invention concerns apparatus for introducing a gas into liquid metal and provides a member formed of silicon carbide or alumina bonded with a binding material comprising the oxides and silicates of zirconium, titanium or aluminium, the member having a tubular stem portion and a diffusing portion at an angle thereto between 45 DEG and 135 DEG and preferably 90 DEG , the stem portion being made gas impermeable preferably by insertion of a gas feed tube coaxially sealed therein.

Determination of the photocatalytic activities of titanium dioxides and other white pigments

Abstract: Titanium dioxide, zinc oxide, and other white pigments are widely used in protective coatings and textile applications. An undesirable property of such pigments is their behavior as photo-oxidation catalysts. As a measure of the activities of various pigments, quantum yields were determined for the photo-oxidation of isopropyl alcohol to acetone in a system where the pigment was the only absorbing species. An absolute quantum yield of 0.5 was found for reagent-grade anatase; relative quantum yields were determined for various commercial anatase and rutile titanium dioxides, zinc oxide, barium sulfate, and barium tungstate. A good correlation was found between the photodegradation rates of pigmented polypropylenes, the photodegradation rates of the dyes in pigmented cellulose acetate butyrate, and the activities of the pigments determined by the isopropyl alcohol oxidation method.

Anodic discharge of chloride ions on oxide electrodes

Abstract: The behaviour of a mixed oxide coating thermally deposited on titanium has been examined with respect to the anodic discharge of chloride ions.

The Reactions of Titanium and Silicon with Al2O3-CaO-CaF2 Slags in the ESR Process

Abstract: The reactions of titanium and silicon with slags of the system alumina-calcium oxide-fluorspar were calculated. The calculations were confirmed by melts in a laboratory induction furnace and also through statistical calculations of 320 heats of 500 mm □ (3,6 ton) ingots for the Ti–Al2O3 reaction and of 100 ESR heats of the same ingot size for the Si–Al2O3 reaction. By statistical evaluation of all heats the dependence of the aluminum and titanium or silicon contents for different TiO2 or SiO2 contents of the slags were determined. By application of these data the losses of Ti or Si by a reaction with alumina can be prevented.

Some observations on the deformation characteristics of titanium hydride

Abstract: Deformation studies have been performed on bulk polycrystalline titanium hydride, of compositions between TiH1.53 and TiM,1.99, and at temperatures between −35 and 200° C. The yield stress increased with decreasing temperature and with increasing non-stoichiometric hydrogen vacancy content. The temperature dependence of the yield stress was enhanced with increasing vacancy content. Two-surface analysis of slip lines revealed that the slip plane was {1 1 1}. Strain-rate tests on TiH1.65 demonstrated a considerable strain-rate dependence of both yield and fracture characteristics. The effects of test temperature, non-stoichiometric defect concentration and strain-rate on the deformation and fracture characteristics are shown to be strongly related to hydrogen ion mobility.

Electrochemical Behavior of Ti-Ni Alloys in Acidic Chloride Solutions

Abstract: A study has been made of the electrochemical behavior of titanium, nickel, and various titanium-nickel alloys, containing 2, 3.5, 4.5, 28.5, 38, and 98 wt % nickel, in an acidified (pH = 1...

The mutual solubilities of titanium and boron in pure aluminum

Abstract: The mutual solubilities of titanium and boron in Al-Ti-B ternary melts were determined over the temperature range 700° to 1300°C and the results interpreted in terms of the assumption (for which there is considerable evidence1) that the solubilities of these elements are limited by their reaction together to form titanium diboride (TiB2) probably containing aluminium diboride. In the method used, ternary melts were sampled at progressively lowered temperature levels after allowing time for titanium diboride precipitated to settle out.

Lamellar crucible for induction melting titanium

Abstract: A lamellar crucible for induction melting titanium has an outer graphite shell closed at one end to form inner and outer surfaces. A first layer generally of the class of refractory metals or of beryllium oxide covers the inner surface of the shell to limit carbon contamination. A second layer is preferably oxygen deficient yttrium oxide and may also be generally of the class of rare earth metal oxides in an oxygen deficient condition. Also, the second layer may be yttrium oxide or the rare earth metal oxides. The second layer covers the first layer to limit reactivity with the molten titanium.

Method and apparatus for the production of liquid titanium from the reaction of vaporized titanium tetrachloride and a reducing metal

Abstract: Elemental titanium is produced by reducing titanium tetrachloride using an alkali or alkaline earth metal, preferably sodium. The reaction is carried out in the vapour phase, a carrier gas, preferably hydrogen, being heated by an electric arc and injected into the reaction chamber to heat the sodium and titanium tetrachloride which are injected as liquids or vapours. The reaction is carried out at a temperature above the melting point of titanium, typically between 1,800 DEG and 2,500 DEG C, the titanium falling as a liquid to the bottom of the reaction chamber and the chloride of the reducing metal and other unwanted products being removed in vapour form. The chloride of the reducing metal is passed through a heat exchanger for heating material passing into the chamber and is electrolysed to provide the required alkali or alkaline earth metal.

Carbide alloys suitable for cutting tools and wear parts

Abstract: This invention relates to refractory metal bonded carbide alloys for use as cutting tools and in other applications where high hardness and abrasion resistance are required. The desired finegrain, lamellar microstructure is obtained preferably by casting eutectic, or near-eutectic composition alloys of a Group IVa metal (titanium, zirconium, hafnium), tungsten and carbon which may contain certain alloying and inert materials. For selected applications, the composites may be fabricated by powdermetallurgical techniques.

Altering the appearance of corundum crystals

Abstract: A corundum crystal whose surface is altered by contact with a powdered metal oxide colorant at an elevated temperature within the range of 1600°C to a temperature below the fusion temperature of the said powder, said metal oxide colorant consisting essentially of an oxide of titanium and at least one metal oxide selected from the group consisting of iron, chromium, vanadium and nickel, said metal oxide colorant being sufficient to impart color to the surface of the crystal.

Nonpolarizable muscle stimulating electrode

Abstract: A nonpolarizable muscle stimulating electrode is formed of a platinum black insert in a housing of inert electrode metal, preferably titanium. It features high current density at low pulse voltage.

Appearance Potential Study of the Band Structure of Transition Metals on Transition Metal Surfaces

Abstract: Soft x-ray appearance potential spectra have been obtained for dilute coverages of transition metals on transition metal surfaces. The appearance potential spectrum of a given core level is the differential excitation probability as a function of sample potential. For transition metals this produces a strong positive threshold peak whose width is related to the unfilled portion of the d band. The titanium-nickel system is of particular interest since, in their pure form, titanium and nickel have nearly empty and nearly filled 3d bands respectively. In preliminary studies of this system, we find the 2p32 peak of nickel in dilute concentration on a titanium surface to be identical to the titanium 2p32 peak obtained from dilute coverages of titanium on a nickel surface. The width of these peaks is intermediate between the clean Ti and Ni values. This result, which suggests a common band model for an alloy of stoichiometry near that of TiNi, is contrasted with recent experimental and theoretical studies of di...

High-temperature oxidation of titanium carbide

Abstract: 1. A study was made, in experiments of 5 h duration, of the high-temperature oxidation of TiC in air at 500–1200° C. The resultant oxidation products were subjected to metallographic and x-ray diffraction examinations. It was established that, when TiC reacts with oxygen, the most probable is the reaction yielding oxides and carbon, which builds up under the scale layer. 2. Thermodynamic calculations were performed of the equilibria in the systems titanium carbideoxygen (nitrogen) in the temperature range 298–2000°K. It was found that, from a thermodyanmic point of view, TiC in oxygen and nitrogen atmospheres may be unstable right up to 1800°K. 3. The role of carbon in the TiC oxidation process was investigated, and it was established that carbon promotes the sintering of the scale layer and stabilizes oxide phases (anatase). 4. Metallographic and x-ray diffraction analyses revealed that the scale forming during the oxidation of TiC contains metallic titanium. This observation confirms the validity of a complex model of the defective structure of oxide layers, postulating preferential diffusion of interstitial cations at high temperatures.