Showing papers on "Mixed oxide published in 1977"

Studies on the Oxide‐Coated Metal Anodes for Chlor‐Alkali Cells

Abstract: Formation of the mixed oxide consisting of and was studied by the DTA/TGA technique and x‐ray diffraction. The coating agent containing and tetra‐n‐butyl titanate converted into the mixed oxide of and at about 400°C on the Ti substrate, and the reaction was exothermic. The electric resistance through the oxide film depends much on the fire temperature, and an optimum condition arises between 450° and 500°C. The solution composition and the time of preparation are also important factors. The anodic polarization behavior in the solution was also affected by the material or the condition of preparation of the oxide‐coated Ti electrode.

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.

Bonding mechanism evidence in a ceramic–nonprecious alloy system

Abstract: Bonding between porcelain and dental ceramic alloys is thought to be dependent upon the establishment of a continous electron structure across the ceramicmetal interface (Pask, Proc. Procelain Enamel Inst., 33, 1, 1971). Such a structure most likely results from the compatibility of metal ions at the metal surface saturated in an oxide form with the complex oxide structure of the ceramic matrix. Reaction zone compounds are expected to play a prominent role in the strength of the ceramic–metal bonds but thus far none have been detected or identified. The present study was centered on the determination of possible adherence zone compounds in four composite ceramic–metal couples examined by x-ray energy analysis. Elemental analysis of four couples revealed the presence of a predominant AlCr interaction resulting from the formation of an AlCrO compound or mixed oxide complex. The Cr ions were supplied by the Cr2O3 oxide layer at the metal surface and the Al was provided by the initial bonding-agent coating.

Production of maleic anhydride and catalysts therefor

Abstract: Catalysts for the oxidation of hydrocarbons to maleic anhydride comprise a phosphorus/vanadium mixed oxide promoted by tungsten antimony, niobium, and/or molybdenum, having a surface area of at least 10m 2 /g.

Oxidation Activity and Acid-base Properties of Mixed Oxide Catalysts Containing Titania. II. The TiO2–V2O5–P2O5 System

Abstract: The acidity and basicity of a series of TiO2–V2O5–P2O5(atomic ratio Ti : V : P=9 : 1 : x) catalysts with different P2O5 contents (x=0–18), were measured by studying the adsorption of the basic and acidic molecules in the gas phase, using both the static and pulse methods. TiO2–V2O5(V/Ti=1/9) is rather basic, but this catalyst can be modified from basic to acidic by the introduction of P2O5. The vapor-phase oxidation of butadiene and 1-butene, which were chosen as electron-donor-type reactants, and that of acetic acid, as an acidic reactant, were carried out in the presence of an excess of air, and then the relationship between the catalytic behavior and the acid-base properties was investigated. The results support an earlier proposal that the activity and selectivity in mild oxidation can be interpreted in terms of the acid-base properties of the catalyst and the reactant.

Oxidation reduction catalyst for the treatment of combustion gases and method for making the catalyst

Abstract: A catalyst which is capable of carrying out simultaneously the oxidation of hydrocarbons and of carbon monoxide and the reduction of nitrogen oxides which are present in the exhaust gases of internal combustion engines comprises a support of inert material coated with lanthanum oxide and a catalytic phase constituted by ruthenium combined with lanthanum in the form of mixed oxide of the perovskite type, by platinum or palladium and by rhodium.

Method for forming zinc oxide-containing ceramics by hot pressing and annealing

Abstract: Zinc oxide powder and a single phase mixed oxide glass powder including bismuth oxide are mixed and then simultaneously heated and pressed to form a consolidated ceramic body of linear electrical characteristics. Subsequent annealing transforms the body to one of non-linear characteristics.

Process for preparing maleic anhydride

Abstract: Activated catalyst for oxidation reactions on the basis of mixed oxides of vanadium and phosphorus, characterized in that the vanadium has an average valence of less than +3.9. The activated catalyst is produced using a process wherein a mixed oxide, in which the vanadium has an average valence of +3.9 to more than +4, is activated at temperatures of 300° to 500° C. by passing over it a gaseous hydrocarbon component having 2 to 6 carbon atoms with the exclusion of molecular oxygen. The activated catalyst is used for the production of maleic anhydride from straight-chain C 4 -hydrocarbons in the gaseous phase.

Oxidation Activity and Acid-base Properties of Mixed Oxide Catalysts

Abstract: In this article it is described that the oxidation activity and selectivity can be well interpreted in connection with the acid-base properties of metal oxide catalysts and that the interpretation holds well for various kinds of mixed oxide catalysts and oxidation reactions.The following subjects are dealt with ;1) Acid-base properties of various kinds of mixed metal oxides, 2) The correlation between catalytic property and acid-base properties, 3) The role of each component in the catalytic actions of mixed oxide catalysts.

Mixed oxide compounds for casting advanced superalloy materials

Abstract: Mixed oxide compounds La 2 O 3 . 11Al 2 O 3 , NdAlO 3 and nonstoichiometric MgAl 2 O 3 are suitable for making cores and molds for casting advanced superalloy materials such as NiTaC-13.

Studies on the oxide-coated metal anodes for chlor-alkali cells

Abstract: Formation of the mixed oxide consisting of and was studied by the DTA/TGA technique and x‐ray diffraction. The coating agent containing and tetra‐n‐butyl titanate converted into the mixed oxide of and at about 400°C on the Ti substrate, and the reaction was exothermic. The electric resistance through the oxide film depends much on the fire temperature, and an optimum condition arises between 450° and 500°C. The solution composition and the time of preparation are also important factors. The anodic polarization behavior in the solution was also affected by the material or the condition of preparation of the oxide‐coated Ti electrode.

Catalyst for manufacturing maleic acid anhydride

Abstract: Catalysts for the oxidation of hydrocarbons to maleic anhydride comprise a phosphorus/vanadium mixed oxide promoted by tungsten antimony, niobium, and/or molybdenum, having a surface area of at least 10m2/g.

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.