Showing papers on "Oxide published in 1973"

Conduction Characteristics of the Lithium Iodide‐Aluminum Oxide Solid Electrolytes

Abstract: The conduction characteristics of the polycrystalline lithium iodide containing aluminum oxide were studied. It was found that the incorporation of aluminum oxide substantially increased the conductivity of lithium iodide. Lithium iodide containing 33–45 mole per cent (m/o) aluminum oxide exhibited conductivities in the order of 10−5 ohm−1 cm−1 at 25° ± 2°C. Inasmuch as no substantial amount of aluminum oxide was found soluble in the lithium iodide under the experimental conditions, the increase in conductivity could not be explained by the classical doping mechanism. The electronic conductivity of the lithium iodide‐aluminum oxide solid was negligible compared to the ionic conductivity. Therefore, it is suitable as a solid electrolyte in solid‐state battery systems.

Direct calculation of Young's moidulus of glass

Abstract: An equation has been derived for the direct calculation of the Young's modulus of oxide glasses from their chemical compositions. The method is based on a consideration of dissociation energy of the oxide constituents per unit volume and the packing density. For borate glasses, the ratio of four-coordinated to three-coordinated borons must be taken into consideration. Excellent agreement is obtained between calculated and measured values of Young's modulus for over thirty different glasses.

Defect structure and electronic donor levels in stannic oxide crystals

Abstract: By measuring the conductivity of stannic oxide crystals as a function of oxygen partial pressure at elevated temperatures, it is shown that the dominant native defect in SnO2 is a doubly ionizable oxygen vacancy. Both donor levels of this defect, the first 30 meV deep and the second 150 meV deep, are identified and a model is presented that explains previous results. The behavior in hydrogen is contrasted to that in oxygen, and preliminary results are presented indicating that hydrogen introduces a donor 50 meV deep.

Mechanisms for the hot corrosion of nickel-base alloys

Abstract: The Na2SO4-induced accelerated oxidation of nickel-base alloys containing elements such as Cr, Al, Mo, W, and V has been studied in 1.0 atm O2 in the temperature range of 650° to 1000°C. It has been found that the hot corrosion behavior of these alloys can usually be characterized according to one of two types of attack: 1) Na2SO4-induced accelerated oxidation; 2) Na2SO4-induced catastrophic oxidation. In both types of hot corrosion, accelerated oxidation occurs as a result of the formation of a liquid flux based on Na2SC>4 which dissolves the normally protective oxide scales. Catastrophic, or self-sustaining rapid oxidation can occur in alloys which contain Mo, W, or V, because solutions of oxides of these elements with Na2SO4 decrease the oxide ion activity of the molten salts, producing melts which are acidic fluxes for oxide scales. The accelerated oxidation type of attack which was observed with most alloys which did not contain Mo, W, or V, was more severe than for normal oxidation, but much less severe than catastrophic oxidation. Na2SO4-induced accelerated oxidation occurs because the oxide ion activity of the Na2SO4 increases to the point where oxide scales can partially dissolve in the basic melt. Generally, this basic fluxing results from the diffusion of sulfur from the Na2SO4 into the alloy. In some alloys, the formation of sulfides during basic fluxing is a sufficient condition to cause accelerated oxidation. In other alloys, changes in the oxidation mechanism occur because of depletion of the alloy surface, concomitant with basic fluxing, of those elements needed for protective oxide scales, such as aluminum and chromium.

Anodic oxidation of titanium and its alloys

Abstract: This review deals with the procedures used in the anodic oxidation of titanium and its alloys, the nature and properties of the oxide films, their uses, and the trends in research and development.

The Use of Rutherford Backscattering to Study the Behavior of Ion‐Implanted Atoms During Anodic Oxidation of Aluminum: Ar, Kr, Xe, K, Rb, Cs, Cl, Br, and l

Abstract: It is shown that from the energy spectra of He ions backscattered from aluminum, recorded before and after anodic oxidation, the thickness of the oxide films and the positions of ion‐implanted foreign atoms within the films can be determined. Information on the composition and uniformity of the films is also obtained. The scope, limitations, and precision of the method are predictable and are discussed. As model experiments the behavior of ion‐implanted noble gases was studied. The results agree with previous work and can be interpreted to show that, as expected, both aluminum and oxygen are mobile during the oxidation. The behavior of ion‐implanted alkali metals and halogens was also studied. These species were found to be mobile during oxidation and behaved in a manner consistent with their expected ionic charges.

Acidic properties of Binary Metal Oxides

Abstract: Eighteen binary metal oxides consisting of TiO2–MmOn, ZnO–MmOn and Al2O3–MmOn (MmOn: metal oxide) were prepared by the usual co-precipitation method, their acid amounts and strengths being determined by n-butylamine titration using various acid-base indicators. The acid strengths of fourteen of the tested binary oxides of molar ratio 1 : 1 were found to be remarkably higher than those of the component single oxides. High acid strengths were as follows: H0≤−8.2 for TiO2–SiO2, H0≤−5.6 for TiO2–Al2O3 and Al2O3–ZrO2 and H0≤−3 for TiO2–CdO, TiO2–SnO2 and ZnO–SiO2. The acid amounts of sixteen binary oxides were larger than those of the component oxides. The effect of the composition of binary oxides on acidity was examined for TiO2–Al2O3, ZnO–Al2O3 and Al2O3–ZrO2. The acidity maxima appearing for TiO2–Al2O3 and ZnO–Al2O3 were found to be of molar ratio\simeq9:1 and for Al2O3–ZrO2\simeq3:2. A fairly good correlation has been demonstrated between the observed highest acid strengths and the average electronegativi...

Poly(perfluoroalkylene oxide) derivatives

Abstract: Polyfunctional poly(perfluoroalkylene oxide) compounds, such as compounds of the formula A--CF.sub.2 O(CF.sub.2 CF.sub.2 O).sub.m (CF.sub.2 O).sub.n CF.sub.2 --A' where A and A' are reactive radicals containing a polymerizable functional group, e.g., hydroxyl, are provided, such compounds being useful as monomers in the preparation of polymeric materials, e.g., polyurethanes, possessing unusual low temperature stability and resistance to solvents.

Steam reforming catalysts

Abstract: A catalyst for steam reforming of hydrocarbons comprises a refractory support, a catalytic metal or compound thereof reducible upon heating to the metal, and alkali or alkaline earth metal compound, wherein the refractory support which contains one or more acidic or amphotoic constituents is reacted at above 500 DEG C. with an alkaline compound to form a less water soluble or less easily water leachable compound and the so-treated support material is mixed with the catalyst metal constituent. The refractory support is preferably Al2O3 or SiO2 or mixtures thereof e.g. china clay but TiO2, ZrO2, V2O5, WO3, or mixtures of chromia with Al2O3 or SiO2 may also be used. The alkali or alkaline earth metal compound is one which at least when heated is basic and is preferably alkaline aqueous solution or convertible to the carbonate or oxide on heating. It may be an oxide, hydroxide, carbonate, bicarbonate, nitrite, nitrate, or aluminate, silicate or carboxylate e.g. acetate. If SiO2 forms the support and a alkali metal compound is present then an oxide which can form complex i.e. insoluble silicates should be added e.g. G2O3 or Al2O3. The support and the alkaline compound may be heat treated at 600-900 DEG C The catalytic metal may be Ni, Co, Ru, Rh, Pd, Os, Ir, Pt or mixtures thereof e.g. Ni + 0.001%-0.1% Rh, Ru or Pt. The preferred Ni or Co p content is 12-31% as NiO. In specific embodiments, china clay is mixed with (a) KOH solution or (b) Ca(NO3)2 solution to form a paste, the mass dried and then heated to 700 DEG C1. Basic nickel carbonate is then mixed with a slurry of the treated china clay together with (a) MgO or (b) soda ash and an aluminous cement and graphite added to the composition. The composition can be modified after manufacture by adding chloroplatinic acid solution and heating. Uncombined alkaline compound may be washed from the composition.

Crystalline silicates and method of preparing the same

Abstract: A crystalline metal organosilicate having the composition, in its anhydrous state, as follows: 0.9 ± 0.2 [xR.sub.2 O + (1-x) M.sub.2/n O]: <.005 Al.sub.2 O.sub.3 :>1SiO 2 where M is a metal, other than a metal of Group IIIA, n is the valence of said metal, R is an alkyl ammonium radical and x is a number greater than 0 but not exceeding 1, said organosilicate being characterized by a specified X-ray diffraction pattern. Said organosilicate is prepared by digesting a reaction mixture comprising (R 4 N) 2 O, sodium oxide, an oxide of a metal other than a metal of group IIIA, an oxide of silicon and water. The crystalline organosilicates are useful as adsorbents and in their catalytically active form as catalysts for organic compound conversion.

Structural studies of polyethers. IX. Planar zigzag modification of poly(ethylene oxide)

Abstract: A new crystal modification was found in poly(ethylene oxide) stretched about two-fold after necking at room temperature. An x-ray diffraction analysis indicated that the planar zigzag molecule passes through a triclinic unit cell with parameters α = 4.71 A, b = 4.44 A, c (fiber axis) = 7.12 A, α = 62.8°, β = 93.2°, and γ = 111.4°. The space group is P1−Ci1. Packing of the molecule is very similar to that of monoclinic polyethylene.

Discharge of MNOS structures

Abstract: The discharge of MNOS memory devices at zero or low gate voltages is studied theoretically and experimentally. A theory based on direct tunneling of charge carriers from traps in the silicon nitride layer into the silicon describes the experiments quite well. The discharge process is found to be logarithmic in time, starting at a certain time, ift d , which is exponentially dependent on the oxide thickness, and ending at another time, extrapolated to much larger than 10 years. Some implications of the discharge model are discussed.

Production of stable lubricating oils by sequential hydrocracking and hydrogenation

Abstract: A process is disclosed for producing a lubricating oil having good UV stability from a hydrocarbon feedstock boiling in the range 700* to 1,200*F., which comprises: A. catalytically hydrocracking in a hydrocracking zone said feedstock at a per pass conversion of at least 20 volume percent to materials boiling below the initial boiling point of said feedstock; B. catalytically hydrogenating in a hydrogenating zone at least a substantial portion of the effluent from said hydrocracking zone boiling in the range 550*-1,200*F. at hydrogenation conditions, in the presence of a hydrogenation catalyst comprising 1. A REFRACTORY OXIDE, AND 2. A HYDROGENATING COMPONENT COMPRISING A NOBLE METAL; AND C. recovering as a product of the hydrogenating step a lubricating oil having good UV stability.

Transport Numbers of Metal and Oxygen during the Anodic Oxidation of Tantalum

Abstract: An oxide film on a metal surface will thicken only if metal, or oxygen, or both, migrate across it. The relative magnitude of the metal and oxygen migrations can be determined using markers, and the possible results are reviewed for the ideal case of a homogeneous oxide grown to uniform thickness on a plane metal surface. Such experiments require markers that are both inert and immobile; criteria are developed to establish that these requirements have been met. Experimentally, it has been shown that the anodic oxidation of tantalum is a system close to the ideal, and that the radioisotope of a noble gas is a good approximation for the required marker. Radioactive noble gases were implanted by means of a mass separator into thin films of anodic tantalum oxide, and the transport numbers of the tantalum and oxygen measured after thickening by further anodization. The transport numbers were found to be 0.243 and 0.757, respectively, for anodizing conditions of . The noble gas concentration profiles were observed to broaden on further anodizing, and this was interpreted as being due to the simultaneous movement of tantalum and oxygen atoms during the charge transfer event.

Spheroidal composite particle and method of making

Abstract: Composite abrasive granules, in which fine, hard abrasive grains are distributed throughout a relatively softer metal oxide matrix, can be substituted for conventional abrasive grains. In a preferred method of manufacture, the abrasive grains are dispersed in a metal oxide gel, the gel dehydrated to leave spheroidal composite granules, and the granules heated to drive off the remaining water. The temperature of heating is low enough that temperature-unstable abrasive grains, like diamonds and cubic boron nitride, can be used.

The Anodic Oxide Film on Iron in Neutral Solution

Abstract: The composition of the anodic passive oxide film on iron in neutral solution has been investigated by cathodic reduction, chemical analysis and ellipsometry. The cathodic reduction using a borate solution of pH 6·35 containing arsenic trioxide as inhibitor estimates iron in the film to be all iron (III), indicating that no magnetite layer is present. Oxygen in the film is estimated from the ellipsometric thickness to be in excess of the stoichiometric ferric oxide, suggesting the presence of bound water. The average composition is represented as Fe2O3.0·4H2O, in which hydrogen may be replaced partly with iron-ion vacancy. The anodic oxide film is composed of an inner anhydrous ferric oxide layer, which thickens with the potential and an outer layer of hydrous ferric oxide whose thickness depends on the condition of passivation and environment. The anodic oxide film formed in the oxygen-potential region has also been measured by cathodic reduction, and it is found that the film retains nearly constant thickness above a critical potential where transpassive dissolution begins to occur.

A model for mild steel oxidation in CO2

Abstract: A model for the oxidation of mild steel in CO2 is proposed, which is an extension of the ideas of Bruckman, Romanski, and Mrowec. A single layer of magnetite forms initially by short-circuit solid-state transport of cations. Lattice vacancies are injected into the underlying metal and eventually cause loss of scale-metal adhesion in some areas. Microchannels develop in the overlying oxide and the scale continues to grow at both oxide-metal and oxide-gas interfaces. In this duplex stage of growth, inner layer oxide nodules form in the vacancy condensation volume produced by departing metal. Their growth is restricted by a build-up of CO released by the oxidation reaction, so that a microporous structure is perpetuated. Breakaway oxidation is the result of local destruction of CO when a catalyst for the Boudouard reaction eventually forms. The inner layer crystals then grow in an atmosphere of higher oxygen potential, and deposited carbon produces a very porous structure.

Generalized Model for Anion and Cation Adsorption at Oxide Surfaces

Abstract: A model of ion adsorption on variable charged surfaces is presented and discussed. Comparison with experiment suggests that the model explains most principal features.