Abstract: Ceramic pellets, which may have, or not, nuclear fuel materials embedded therein, are formed by first preparing a gel by precipitation of metallic salts from solutions of their compounds at a concentration of at least 10 grams per liter, said solutions being added dropwise to a coagulation bath which contains, for example, ammonium or sodium hydroxide, whereafter the precipitated gel are fired, in one or two stages, to precondition them prior to the compaction to form the final pellets which are subsequently sintered at an appropriate temperature.

Abstract: Sintering and gas hot isostatic pressing are used to prepare polycrystalline yttria-gadolinia ceramic scintillator bodies. Multicomponent powder compacts, formed by cold pressing and cold isostatic pressing, are sintered to the closed porosity stage. The density of the sintered compacts is then increased by gas hot isostatic pressing. The finished scintillator includes Y.sub.2 O.sub.3, Gd.sub.2 O.sub.3, and one or more of Eu.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Yb.sub.2 O.sub.3, Dy.sub.2 O.sub.3, Pr.sub.2 O.sub.3, and Tb.sub.2 O.sub.3 rare-earth activator oxides. At least one of the oxides of elements Zr, Th, and Ta is included as a transparency promoting densifying agent. At least one of CaO and SrO may be included as a light output restorer.

Abstract: Ceramic materials suitable for use in varistors, enabling the same to function both as such and as capacitors. The ceramic compositions comprise a major proportion of SrTiO.sub.3, the balance being (1) one or more of Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, WO.sub.3, La.sub.2 O.sub.3, CeO.sub.2, Nd.sub.2 O.sub.3, Pr.sub.6 O.sub.11, Dy.sub.2 O.sub.3, Y.sub.2 O.sub.3, and Sm.sub.2 O.sub.3, for making the compositions semiconductive, and (2) one or more of V.sub.2 O.sub.5, Cr.sub.2 O.sub.3, CuO, Cu.sub.2 O, MoO.sub.3, and MnO.sub.2, for improving the nonlinear volt-ampere characteristic of the compositions. If desired, for improving the coherency of bodies molded from the composition, there can be added one or more of GeO.sub.2, ZnO, B.sub.2 O.sub.3, and PbO. For use as varistors the mixture of the above ingredients, all in finely divided form and made coherent with a binder, is molded into desired shape under pressure.

Abstract: A brick-forming vacuum press is provided with a die and top and bottom plungers which are disposed along the same vertical central axis as the die. Spaces which extend from the die and surround the top and bottom plungers are enclosed by chambers formed of sealing cylinders, flexible bowl-like skirts and sealing flanges. A horizontal table is provdided on the die to support a mix-filling charger and a compact-discharging pickup device. A wiper is carried by the pickup device to clean the table when the pickup device is shifted away from the vertical central axis of the press. Controls are provided to automate the filling of the die, press-forming and discharging of the resultant compact.

Abstract: A process for producing a silicon carbide sintered body is disclosed, which comprises the steps of charging a sintering raw material consisting mainly of silicon carbide fine powder and sintering aid into a dispersion medium together with, if necessary, at least one substance of a molding assistant and a deflocculating agent to form such a uniform suspension that a volume ratio of solid content composed of said silicon carbide fine powder and sintering aid in said suspension is not more than 15%; spray freezing said suspension in an atmosphere held at a temperature lower than a melting point of said dispersion medium to obtain a granular frozen body; freeze drying said granular frozen body for sublimation of said dispersion medium to obtain a powdery dried mixture; shaping said powdery dried mixture into a green body of an optional form; and sintering said green body without pressing.

Abstract: A method of manufacturing construction products which involves feeding dry or substantially dry constituents including a liquid-setting powder and a reinforcement therefor into a molding zone. At least a part of the mold is vibrated to effect compacting of the constituents in the molding zone to such a degree that the constituents will stand and be self-sustaining upon removal of an upstanding portion of the mold. At least a portion of the mold is removed from contact from the compacted constituents, thereby exposing at least one upstanding surface of of the compacted constituents. A quantity of setting liquid is applied to substantially the full extent of the surface. The quantity of setting liquid is sufficient to wet all of the compacted constituents in the molding zone so as to initiate a chemical setting reaction but not sufficient to completely saturate the compacted constituents and to cause the associated effect of structural collapse of the compacted constituents in the region of the exposed surface.

Abstract: Construction products are moulded by mixing the dry constituents, including a proportion of fine particulate material, feeding (1, 2) the mixture into a mould (5), compacting the mixture, removing part (6) of the mould (5), lightly spraying (9) an exposed upstanding surface of the product with setting liquid, removing the product from the mould (5) and allowing it to set. Sufficient fine particulate material to surround the coarse particles and compaction, using vibration (7) of the mould (5) and compression of the mixture, to cause the fine particles to fill the interstices between the coarse particles, provide sufficient support of the exposed surface to prevent collapse or erosion thereof during wetting even though no fibre reinforcement is included in the mixture. Sufficient liquid to wet the product but not to saturate it is applied by the spray (8, 9).

Abstract: A method of producing decorative ceramic ware is disclosed. In the first step, a flocculant is added to an aqueous suspension containing as main solid components a fibrous material and a ceramic raw material clay, followed by preparing ceramic raw material sheets from the suspension by the ordinary paper-making method. Prepared are at least two kinds of ceramic raw material sheets differing from each other in color after firing. Then, the stacking-cutting operation of the sheets is performed at least once, in which the different kinds of sheets are alternately stacked, followed by cutting the stacked mass in a direction not parallel with the surface of the raw material sheet. The cut piece is formed into the desired shape and, then, dried and fired to produce a striped or checkered decorative ceramic ware. This particular method permits industrial production of ceramic ware.

Abstract: In a process for making refractory articles, such as cores and moulds for use in casting metals, the articles are formed from dies using a refractory material mixed with a thermosetting resin. The articles are formed with the mixture heated to a softened state and the resin is cured. Thereafter the article has to be fired and problems have arisen with deformation of the articles during the firing process.With the present invention, the articles, 8, which as can be seen in FIG. 2 are mould segments, are bound into an assembly with a flexible refractory tape (15) which shrinks on firing to a greater extent than the articles, and thus pulls the assembly tightly together whereby each article provides support for the adjacent article and prevents distortion. The joint faces between the mould segments are thus held in tight abutment and for pouring metal into the mould, the firing cup is fitted and a coating of refractory slurry is brushed on without removing the tape to seal the assembly.

Abstract: An apparatus for constructing a unitary pre-cast concrete modular building unit comprising: a collapsible outer form having a rigid rectangular base and rigid walls pivotally connected thereto and collapsible to the plane of said base; a hydraulically retractable inner form thus providing with the outer form, a mold for said building unit; and an extruder for removing said inner form from said building unit.

Abstract: A three-dimensional work piece, such as an interior part for a car, is manufactured by keeping the blank, such as a sheet of plastic on or in the same primary mold (24) for the initial shaping step, for the foaming step, for the curing step and for the final trimming step. The primary mold (24) shuttles back and forth in a given direction for sequential cooperation with two secondary molds (75 and 31 or 48 and 31) arranged for reciprocation in a direction extending perpendicularly to said given direction. Preferably, two primary mold members (66, 67) are arranged for horizontal back and forth shuttling in unison so that each primary mold member may cooperate with two out of three vertically reciprocable secondary molds. The efficiency is substantially doubled when each of two primary mold members (66, 67) cooperates with two out of three secondary molds.

Abstract: A method for preparing high density yttria-gadolinia ceramic scintillators by cold-pressing multicomponent powder to form powder compacts and then sintering the compacts to form transparent-to-translucent ceramic scintillator bodies. The powder compacts are formed by either die pressing or die pressing followed by isostatic pressing to further increase green density. The powder compacts are sintered in vacuum or a reducing atmosphere at a temperatue of between 1800.degree. C. and 2100.degree. C. The preferred heating sequence includes a holding period at a temperature lower than the final sintering temperature. The finished scintillator includes Y.sub.2 O.sub.3, Gd.sub.2 O.sub.3, and one or more of Eu.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Yb.sub.2 O.sub.3, Dy.sub.2 O.sub.3, Pr.sub.2 O.sub.3, and Tb.sub.2 O.sub.3 rare earth activator oxides. At least one of the oxides of elements Zr, Th, and Ta is included as a transparency promoting densifying agent.

Abstract: Sintering and gas hot isostatic pressing are used to prepare polycrystalline yttria-gadolinia ceramic scintillator bodies. Multi-component powder compacts, formed by cold pressing cold isostatic pressing, are sintered to the closed porosity stage. The density of the sintered compacts is then increased by gas hot isostatic pressing. The finished scintillator includes Y.sub.2 O.sub.3, Gd.sub.2 O.sub.3, and one or more of Eu.sub.2 O.sub.3, Nd.sub.2 O.sub.3, Yb.sub.2 O.sub.3, Dy.sub.2 O.sub.3, Pr.sub.2 O.sub.3, and Tb.sub.2 O.sub.3 rare earth activator oxides. The finished scintillator may also include at least one of SrO and CaO as afterglow reducers.

Abstract: The invention relates to synthetic, non-fused, aluminum oxide-based abrasive mineral having a microcrystalline structure of randomly oriented crystallites comprising a dominant continuous phase of .alpha.-alumina and a secondary phase, to a method of making the same employing chemical ceramic technology, and to abrasive articles made with the abrasive mineral.

Abstract: This invention relates to a pointed heat-generating device for molds of injection molding machines. It comprises a metal casing, a pointed projectile heat-generating means fixed with the metal casing, and a gate formed at the pointed heat-generating means and communicated to a cavity of the molds, characterized in that a heat-generating wire is penetrated wholly into a passage which is bored in a non-processed cylindrical material and an alloy portion is formed in an inert gas between an end of the heat-generating wire and the non-processed cylindrical material, thereby the alloy portion being formed as a pointed part of the heat-generating means by machining.

Abstract: A release and carry-out apparatus is disclosed for removing a mold from a molding such as a concrete panel, and carrying out the molding to a predetermined position. This release and carry-out apparatus comprises: a base frame; an erectable frame erectably supported by this base frame; and a carrier for receiving only the molding disposed on a mold bed firmly, which bed is secured to this erectable frame when the erectable frame is erect, and carrying the molding to the predetermined position.

Abstract: Continuous inorganic fibers consisting substantially of Si, Zr and C and optionally of O, said fibers being composed of (1) an amorphous material consisting substantially of Si, Zr and C and optionally of O, or (2) an aggregate consisting substantially of ultrafine crystalline particles of .beta.-SiC, ZrC, a solid solution of .beta.-SiC and ZrC and ZrC.sub.1-x wherein 0<x<1 and having a particle diameter of not more than 500.ANG., in which amorphous SiO.sub.2 and ZrO.sub.2 sometimes exist in the neighborhood of these ultrafine crystalline particles, or (3) a mixture of said amorphous material (1) and said aggregate (2) of ultrafine crystalline particles. The aforesaid continuous inorganic fibers can be produced by the following steps: a first step of preparing a semi-inorganic block copolymer comprising polycarbosilane blocks having a main chain skeleton composed mainly of carbosilane units of the formula --Si--CH.sub.

Abstract: Refractory parts or articles, even of very large dimensions, are made with starting material of carbon particles mixed with silicon particles in a predetermined ratio which is suspended in a solution of a binder, after which the suspension is squirted into a precipitating liquid to coat the particles with the binder, the solids then being separated and dried, molded under slight pressure, and coked (at 800.degree.-1,000.degree. C.), and then rapidly raised in temperature (to 1,400.degree.-1,600.degree. C.) for formation of silicon carbide throughout the article. It is useful to add powdered silicon carbide and mix it in before the coking step and, also, to hold the heated body at a temperature somewhat below 1,400.degree. C. long enough to remove temperature gradients within it, followed by rapid heating up to a carbide-forming temperature.

Abstract: A carbon resistor and a method for producing the resistor are disclosed. The method preferably comprises the steps of preparing a uniform, finely-divided mixture by blending a glass frit with at least one temporary binder and substantially 1/4 to 4 percent of conductive carbon, pressing a longitudinally extending shape having opposed ends from the mixture, heating the shape to 450-550 degrees F. for about 30 minutes and cooling to ambient temperature, applying a silver paint containing a lead borosilicate frit composition to the cooled shape to provide electrical contacts, and firing the shape and contacts to vitrify the frit of the resistor. A preferred lead borosilicate frit composition, by weight, consists essentially of from 5 to 15 percent of AlPO.sub.4, from 1/4 to 3 percent of conductive carbon, from 15 to 30 percent of a phenyl lower alkyl silicone resin and from 65 to 80 percent of a lead borosilicate glass frit which consists essentially of substantially 20 percent SiO.sub.2, 15 percent B.sub.2 O.

Abstract: A method is disclosed for making a more densified silicon nitride comprising object under less stringent heating conditions without sacrificing physical properties. A mixture of silicon powder, 6-18% yttrium silicon oxynitride (a major proportion of which is the Y.sub.10 Si.sub.6 O.sub.24 N.sub.2 phase), 0.4-3% Al.sub.2 O.sub.3, and possibly up to 2% of an oxynitride forming oxide (Y.sub.2 O.sub.3) is compacted, nitrided, and sintered to produce a silicon nitride/YSiO.sub.2 N comprising object of relatively high density.