Showing papers on "Calcium oxide published in 1969"

Manganese-modified zinc oxide voltage variable resistor

Abstract: A VOLTAGE VARIABLE RESISTOR CERAMIC COMPOSITION CONSISTING ESSENTIALLY OF ZINC OXIDE AND, AS AN ADDITIVE, MANGANESE OXIDE. THE MANGANESE-MODIFIED ZINC OXIDE VOLTAGE VARIABLE RESISTOR HAS IMPROVED VOLTAGE NONLINEAR PROPERTIES DUE TO THE FURTHER ADDITION OF BARIUM OXIDE, STRONTIUM OXIDE, LEAD OXIDE, URANIUM OXIDE, COBALT OXIDE, BISMUTH OXIDE AND CALCIUM OXIDE.

Preparation of Massive Plutonium Metal Directly from Its Oxides

Abstract: This report details a technique for the rapid production of massive Pu metal directly from its oxides. Salient features of this single unit process are as follows: the reduction of plutonium oxides with Ca metal; the extraction, by dissolution, of the calcium oxide reaction product with molten calcium chloride; and a quantitative separation of the two immiscible molten metal phases by the immiscible salt solution. Reduction, separation and massive metal yield efficiencies are in excess of 99.96%. The purity of the metal produced is equal to that of the initial feed material. The batch cycle time is 15 min. The single waste product is far below recovery level and is discardable as a small volume solid waste.

Anodic behaviour of aluminium and its alloys in alkaline media in the presence of inhibitive and complexing substances

Abstract: In order to find out the suitability of four different grades of aluminium, namely 2S, 3S, 57S, and unalloyed aluminium for use as a galvanic anode in 1M-sodium hydroxide solution containing calcium oxide and sodium citrate, the potential-time variation, the anodic polarisation, the anode efficiency and corrosion/behaviour of these grades have been investigated. It has been found that all the above mentioned grades of aluminium behave in a similar manner, and self-corrosion can be reduced by more than 75% by the joint addition of calcium oxide and sodium citrate. However, on the basis of anode efficiency in inhibited 1M-sodium hydroxide solution, 28 grade and unalloyed aluminium seem to be the materials of choice since maximum efficienciesof 93–94% can be obtained by the use of appropriate current densities. Even in these cases, high anode efficienciesof the order of 80–94% are attained only at current densities of 9–12 mA/cm2 but the results are less encouraging at lower current densities, and at...

Conditions of preparation of calcium and barium hexaboride powders

Abstract: 1. A study was made of the conditions of preparation of barium and calcium hexaborides by the boroncarbide and borothermic techniques and by the reaction of barium carbonate with boron in a vacuum. 2. It was established that a barium hexaboride with a composition approaching theoretical can be obtained by the borothermic techniques at a temperature of 1600°C from a charge with a 40% excess of barium oxide. It is more economical to prepare BaB6 by the reaction of barium carbonate with boron in two stages (30 min at 900°C and 60 min at 1500°C). 3. The optimum conditions for the preparation of calcium hexaboride by the borothermic and boroncarbide techniques are a temperature of 1600°C and a holding time of 60 min; the charge should contain a 10% excess of calcium oxide. 4. The results obtained have been analyzed in terms of the electronic structure of atoms of the alkaline-earth metals and their oxides.

Uranium-modified zinc oxide voltage variable resistor

Abstract: A VOLTAGE VARIABLE RESISTOR CERAMIC COMPOSITION CONSISTING ESSENTIALLY OF ZINC OXIDE AND, AS AN ADDITIVE, URANIUM OXIDE. THE URANIUM-MODIFIED ZINC OXIDE VOLTAGE VARIABLE RESISTOR HAS IMPROVED VOLTAGE NONLINEAR PROPERTIES DUE TO THE FURTHER ADDITION OF BISMUTH OXIDE, CALCIUM OXIDE AND COBALT OXIDE.

Calcium oxide-aluminum oxide-silicon dioxide ceramic substrate material for thin film circuits

Abstract: A ceramic body, having the nominal composition in percent by weight 31 CaO, 56 Al2O3 and 13 SiO2, when fired to a dense, finegrain structure, is useful as a substrate material for thin film resistors and capacitors.

Catalyst and process for the preparation of 1 3-cyclohexanedianes,3-cyclohexanediamine

Abstract: A PROCESS AND A CATALYST FOR THE PREPARATION OF 1,3CYCLOHEXANEDIAMINES ARE PROVIDED. THE PROCESS COMPRISES HYDROGENATING 1,3-PHENYLENEDIAMINES IN THE PRESENCE OF AN ALKALI-PROMOTED CATALYST CONSISTING OF COBALTOUS OXIDE, CALCIUM OXIDE, AND SODIUM CARBONATE AT ELEVATED TEMPERATURE AND UNDER MODERATE PRESSURE TO FORM 1,3-CYCLOHEXANEDIAMINES. THE ALIPHATIC DIAMINES ARE USEFUL AS INTERMEDIATES IN THE PREPARATION OF POLYURETHANE, POLYUREA, POLYURETHANE-POLYUREA AND POLYAMIDE COATINGS, SEALANTS, AND ELASTOMERS.

Silica-alumina-lithia glasses, ceramics and method

Abstract: Disclosed are new thermally crystallizable glasses in the silica-alumina-lithia system containing titanium oxide, zirconium oxide, and calcium oxide and being limited to very low percentages of ZnO, P2O5 and B2O3. Glass-ceramics of these same compositions and methods for making them by crystallizing such glasses are also disclosed, as are transparent glass-ceramic mirror blanks of low coefficients of expansion.