Abstract: A process for preparing a zirconia-alumina base composite ultra-fine powder is described, including the steps of: mixing an aluminum salt or an alumina hydrate with an aqueous zirconium oxychloride solution, with or without metal salt acting as a stabilizer; mixing urea or a substance capable of generating ammonia by hydrolysis with the resulting mixture; and allowing the mixture to react at a temperature of 140.degree. to 300.degree. C. and a pressure of 4 to 150 kg/cm.sup.2 in a high-temperature and -pressure vessel. The reaction product is further dried, calcined and crushed to obtain an ultra-fine powder.

Abstract: The cement compositions according to the invention are designed for cementing wells, in particular oil and gas or geothermal wells, and for withstanding very high temperatures.A combination of styrene-butadiene latex and a polyoxyethylenated nonylphenol stabilizer of this latex is provided. Cement sets at a right angle and gas migration in the annulus is prevented.

Abstract: A voltage-dependent ceramic resistance (varistor) based on ZnO and other addition elements, mostly in the form of oxides, is prepared, in that the addition elements are added to a suspension of ZnO powder in H.sub.2 O as chemical substances in the form of aqueous, mutually compatible, non-separating solutions of organic salts, acids, complex compounds and/or colloids, the suspension/aqueous solution formed in this manner is dried in the presence of air in a spray dryer, the free-flowing powder/granules prepared in this manner are pressed to a body and the pressed body is subjected to heat treatment, in order to decompose the organic substances, convert them into oxides, remove the decomposition products, and is finally sintered by successive heating to 650.degree. C., 900.degree. C. and 1100.degree. to 1300.degree. C. The water-soluble chemical substances to be used are preferably organic salts such as formates, acetates, lactates, tartrates, citrates, ammonium citrates and ammonium tartrates.

Abstract: In the cooling and further treatment of hot white cement clinker wherein the cooling must be protected against exposure to oxygen so that it retains its white color, it is proposed in accordance with the invention that the hot white cement clinker departing the clinker calcining kiln be sprayed with water in an oxygen-free atmosphere and subsequently conducted in counter-current flow relative to a warm drying gas steam which is withdrawn together with the vapors picked up from the cement clinker, being withdrawn separated from the cooled, dried, white cement clinker. The manufacture of white cement clinker upon application of the clinker cooling and clinker drying of the invention requires a considerably lower overall thermal outlay than the manufacture of white cement clinker utilizing previously known clinker cooling methods employing a water bath.

Abstract: The present invention is directed to a method for manufacturing a concrete which comprises the steps of mixing 20 to 100% of the total weight of cement used with water in an amount of 20 to 50% of this cement weight in order to prepare a stiff-consistency cement paste, afterward mixing the thus prepared cement paste with a coarse aggregate, further mixing 80 to 0% of the total amount of the cement and sand therewith in the order of the cement and the sand or at one time, and then mixing therewith the remaining water necessary to harden the total cement; or the present invention is directed to a method for manufacturing a concrete which comprises the steps of mixing 20 to 100% of the total weight of cement used with water in an amount of 20 to 50% of this cement weight and a coarse aggregate, so that a stiff-consistency cement paste is caused to adhere to the coarse aggregate, afterward mixing 80 to 0% of the total weight of cement and sand therewith in the order of the cement and the sand or at one time, and

Abstract: Disclosed herein is a ceramic shape memory element containing zirconia. A ceramic article is also disclosed which contains at least one of tetragonal zirconia and monoclinic zirconia, and is subjected to plastic deformation through phase transformation caused by maintaining the article at a given temperature, and/or imposing a given stress thereupon. Methods of processing and joining the ceramic article by utilizing the shape memory phenomenon peculiar to such a ceramic article are also disclosed.

Abstract: An aluminum nitride-based sintered body having a high thermal conductivity and a total oxygen content of 0.01 to 20% by weight which is prepared by mixing a main component of aluminum nitride powder containing 0.001 to 7% by weight of oxygen with 0.01 to 15% by weight of at least one of the group consisting of a powder of a rare earth element and/or a powder of a material containing the rare earth element (said 0.01 to 15% by weight being counted on the basis of the content of the rare earth element), and sintering said powder mixture.

Abstract: Disclosed is a process for preparation of a sintered silicon nitride. The process comprises the steps of:mixing a powder of silicon nitride with a powder of a sintering agent;compacting the obtained mixture; andsintering the compacted mixture in a non-oxidizing atmosphere.The feature of the process is that the powder of the sintering agent includes a powder mixture of oxide and/or hydroxide of at least two kinds of metals which has been prepared by co-precipitation.Due to the use of the co-precipitated powder as the sintering agent, it is possible to obtain a sintered silicon nitride having an excellent strength and uniformity in quality. The obtained sintered silicon nitride is preferably used as an engineering ceramic.

Abstract: A process for the preparation of micro inorganic foamed granules chracterized in that amorphous particles having particle size of not greater than 150 .mu.m recovered from particles of an amorphous residue produced by partial oxidation of coal is heated by introducing the same into a flame or gas at a high temperature, whereby foaming the amorphous particles.

Abstract: A coating composition is disclosed consisting essentially of sodium silicate, magnesium oxide or magnesium hydroxide, titanium oxide and mica. Coatings from this composition are useful as electrically insulating coatings, particularly as applied to electrical steel sheets for magnetic cores, or to other metal products or substrates. The coating may be cured at temperatures within the range of 400.degree. to 500.degree. F. and provides reduced die wear of electrical steel sheet during punching operations. It also is tightly adherent and retains excellent electrical insulating properties after annealing at temperatures within the range of 1350.degree. to 1550.degree. F.

Abstract: A refractory composition capable, when mixed with water, of forming a hydraulic-setting castable refractory resistant to aluminum penetration and adhesion and with good load bearing properties consisting essentially of a refractory aggregate, a binder for said refractory aggregate, and an aluminum anti-adhesive agent; said agent consisting of a fine powder barium sulfate and a powdered zinc borosilicate frit in a weight ratio of 1.5:1 to 5:1.

Abstract: A thixotropic cement-based paint composition and method wherein the composition is formed by combining Portland cement with presized filter particles having a predetermined relationship by weight to the cement. Water is combined in a volumetric proportion to form an average viscosity of about 3,000 to 8,000 centipoise.

Abstract: A method of preparing and molding a hydraulic cement-containing composition such as concrete or mortar is disclosed, which can be extensively utilized in the fields of civil engineering, construction projects, or the like. In the preparation of a hydraulic cement-containing composition, cement and water, and sand, gravel or the like, if necessary, are kneaded together to cause the hydration reaction. A feature of the present invention resides in preparing a mortar or the like containing water necessary for the hydration reaction in the form of ice pieces and causing the hydration of cement and water to result from the melting of the ice pieces.

Abstract: The hardened volume change of concrete, grout, patching material, and water-proof material made from blends of Calcium Sulfate Hemihydrate, Portland Cement and Calcium Aluminate Cement can be reduced by using Portland Cement containing low levels of iron oxide. By lowering the normal level of iron oxide in the Portland Cement used in the above composition, it was also discovered that the compressive strengths dramatically increase as well as the bond to old concrete.

Abstract: A process is provided for using silicious sludge (filter cake), obtained by precipitation of silica from silica-rich geothermal brine, to make a concrete material (geocrete). The process includes combining the sludge with a cementing material, such as portland cement and/or flyash and activating the cementing material with an activating media. When portland cement is used as the cementing material, the activating media is water. In such case, the sludge is preferably dewatered and the residual water content is determined, the entrapped brine adding to the water content of the mixture. Preferably, the dry weight ratio of sludge to cementing material is about 2:1 to about 3:1; although, ratios as high as 9:1 can be used when high strength of the geocrete is not required. The preferred amount of water used is about 40 weight percent, including water content of the sludge, which may typically be between about 10 and about 30 weight percent.

Abstract: A hydraulic cement composition is effectively dispersed with the use as a dispersion agent of a reaction product obtained by oxidizing and polymerizing a condensate of formaldehyde with a naphthalenesulfonic acid salt and/or an alkylnaphthalenesulfonic acid salt to produce a constitutional unit which is derived by elimination of a methylene group, hydroxyzation and condensation polmerization, or oxidation and ring-opening of the naphthalene ring.

Abstract: A storable magnesium oxide/phosphate based cement having a delayed set time is provided by heating iron-containing magnesium oxide particles at an elevated temperature to provide magnesium ferrate in a gradient that increases to a maximum at the external particle surface.

Abstract: A foamed ceramic body comprising at least 90% by weight of a ceramic composed of 60 to 80% by weight of SiO.sub.2, 5 to 15% by weight of Al.sub.2 O.sub.3, 8 to 14% by weight of an alkali metal oxide, and 1 to 10% by weight of CaO; and a process for producing the said foamed ceramic body, which comprises mixing 100 parts by weight of a powdery mixture composed of 75 to 90% by weight of a volcanic material, 5 to 15% by weight of an alkali metal oxide or compound which forms an alkali metal oxide on heating and 2 to 10% by weight of CaO or a compound which forms CaO on heating, uniformly with 0.1 to 1 part by weight of a blowing agent, and heating the mixture to a temperature of 800.degree. to 1100.degree. C.

Abstract: Methods for producing cementitious compositions from waste products, such as non-ferrous slags, or fossil fuel combustion residue, or ferrous slags, whereby the CaO and alumina contents of the waste products are adjusted as necessary to enable them to combine with a sulphate additive at elevated pH and so couple the faster reactions of the mineral Ettringite with the slower ones of the calcium silicates.

Abstract: Sealing and/or stabilizing and/or binding preparations comprising modified alkali metal silicate solutions having a molar ratio of SiO.sub.2 to Me.sub.2 O of from 2 to 4.5 wherein Me represents sodium or potassium; sodium metaborate and/or potassium metaborate in a molar ratio of SiO.sub.2 to B.sub.2 O.sub.3 of from 5 to 400; and glyoxal, and to the use of these preparations.