Abstract: The invention relates to powder metallurgy. The invention involves deforming combustion products by extrusion at an extrusion temperature chose in the range from 0.3T.sub.1 to T.sub.2, wherein T.sub.1 is the melting point of a hard phase of the combustion products and T.sub.2 is the melting point of a binder material in a container (5) made up of vertically extending segments (12) defining spaces (13) with one another and having a die (14) and a heat insulated sizing member (17) the temperature conditions of extrusion being controlled by a unit (21) having a temperature sensor (22) and a member (23) receiving information from the sensor (22) and sending a command for moving the punch (10).

Abstract: The present invention relates to preparing refractory chromium-containing material and resides in local initiation of an exothermal reaction in a mixture of the following composition: a chromium-containing component, 8-20 mass % of a reducer selected from the group consisting of aluminium, magnesium, silicon, titanium, zirconium, or the alloys thereof, and 0.1-50 mass % of a filler, wherein as the filler use is made of periclase, sand, clay, refractory oxide, refractory scrap, wastes of blast-furnace processes, wastes of graphite or silicon carbide production, or an inorganic salt taken separately or in a mixture.

Abstract: The invention relates to the production of a new ceramic composite material containing molybdenum disilicide in the form of 20-60 .mu.m grains.The method involves preparation of an exothermic mixture containing silicon, molybdenum (VI) oxide, aluminium and molybdenum with the following ratio of the components (wt %):______________________________________ silicon 29-38 molybdenum (VI) oxide 7-42 aluminium 3-16 molybdenum 13-52 ______________________________________its heat treatment in a combustion mode, followed by compaction of the obtained combustion products by way of at least two-stage compression with a degree of deformation from 0.75 to 0.90 at each stage, at a temperature within 1500.degree. to 1900.degree. C.

Abstract: The method relates to inorganic chemistry.Pursuant to the method, a powder mixture comprising a transition metal, a nonmetal, an inert filler and an activator is prepared; a workpiece to be coated is embedded in the powder mixture and this is placed, integrally with the workpiece, into an oxygen-free medium for a subsequent heat treatment which is accomplished by a locally-initiated combustion of the powder mixture.

Abstract: The invention relates to production of superconductors, more particularly, LnM.sub.2.sup.II M.sub.3.sup.I O.sub.y compounds where y=6-8; Ln=Y, Sc or lanthanide; M.sup.II =Ba, Ca or Sr; M.sup.I =Cu, Cu+Ag or LnM.sub.2.sup.II M.sup.I O.sub.y-x F where x=1-2. It comprises local initiation of an exothermic reaction in a stoichiometric mixutre of source constituents chosen to provide for production of the afore-mentioned compounds. An exothermic mixture of corresponding constituents includes a non-combustible component and a combustible component comprising at least one metal from the group composed of a rare-earth metal of the periodic system chosen from scandium, yttrium and lanthanide, a metal of group II of the periodic system, a metal of group I of the periodic system or hydride of at least one of said metals.

Abstract: The invention relates to the powder metallurgy. The invention involves deforming combustion products by extrusion at an extrusion temperature chosen in the range from 0.3T.sub.1 to T.sub.2, wherein T.sub.1 is the melting point of a hard phase of the combustion products and T.sub.2 is the melting point of a binder material in a container (5) made up of vertically extending segments (12) defining spaces (13) with one another and having a die (14) and a heat insulated sizing member (17) the temperature conditions of extrusion being controlled by means of a unit (21) having a temperature pick-up (22) and a member (23) receiving information from the pick-up (22) and sending a command for moving the punch (10).

Abstract: The invention relates to preparing refractory inorganic compounds, particularly, to methods of preparing silicon nitride with a high a -phase content.The method of preparing silicon nitride with a high .alpha.-phase content is accomplished by means of self-propagating high-temperature synthesis. The method includes contacting the charge containing a silicon-reagent with an additive in a nitrating medium. The silicon-reagent is metallic silicon and at least one ammonium halide is used as an additive in the amount of 1-60% of the mass of metallic silicon. The synthesis is carried out at a pressure of 4-30 MPa.

Abstract: The proposed invention is used for the manufacture from the obtained composite of cutting tools, hard alloy tooling, dies and other products. A method according to the invention involves preparing a mixture, compacting it, placing the mixture into a synthesis zone, igniting the mixture, with subsequent reaction of components of the mixture under combustion conditions. Then cure is carried out during a period ranging from about 0.1 seconds to about 0.5 hours, and the hot combustion products are compacted under pressure at an average pressure rise rate ranging from about 10 to about 2000 kgf/cm.sup.2.s, with subsequent cure of the compacted product under isobaric conditions to complete homogenization of the composite, with subsequent cooling thereof to obtain an end composite.

Abstract: The metal composition and the process for producing same relate to the art of alloy metallurgy.The metal composition based on metals of VIII Group and nitrides of metals of III-VII Groups is characterized in that at least one alloy containing at least one metal of VIII Group and at least one metal of III-VII Groups are disintegrated to powder, placed into a nitrogen-containing atmosphere with an excess of nitrogen, burning is initiated by way of a local ignition of the mixture at any point thereof and the excess of nitrogen is maintained till completion of the reaction.The metal composition and process for producing same according to the present invention are useful in the manufacture of hard alloys based on refractory or high-melting compounds.

Abstract: A tungsten-free hard alloy consists of titanium diboride, titanium carbide and a binder. As the binder the tungsten-free hard alloy contains at least one of metals of subgroup IB of the periodic system inactive relative to boron or an alloy based on one of such metals. The components of the tungsten-free hard alloy are present in the following proportions, percent by mass:titanium diboride--40 to 60binder--3 to 30titanium carbide--the balance.The tungsten-free hard alloy of the above-specified composition has a porosity of below 1%.A process for producing a tungsten-free hard alloy comprises preparation of the starting charge by intermixing powders of titanium, boron and carbon, compression of the charge local ignition thereof to initiate the exothermal reaction of titanium with boron and carbon which further proceeds spontaneously under burning conditions being propagated through the charge at the account of the heat transfer from a heated layer of the charge to a cold one.

Abstract: A process for preparing propylene oxide and acetic acid which comprises oxidation of propylene and acetaldehyde with an oxygen-containing gas in a liquid phase at a temperature of from 70.degree. to 100.degree. C. under a pressure of from 40 to 50 atm in the presence of a catalyst, viz. a boron compound of the formula BE, wherein E is a metal of IV,V,VI Groups of the periodic system, and nitrogen. The process according to the present invention makes it possible to increase selectivity of the formation of propylene oxide as calculated from the reacted acetaldehyde.

Abstract: A method for the production of two-layer pipe casting is carried out in the following manner. First, a reaction chamber is filled with an initial mixture. Then, the reaction chamber with the initial mixture is set in rotation about its longitudinal axis whereupon the centrifugal acceleration of the reaction chamber is brought up to about 300 to about 1000 g. The initial mixture is then inflamed and centrifugal acceleration is gradually brought down to about 50 to about 100 g for a time period sufficient to enable combustion of the initial mixture as well as subsequent separation of the resultant melt into two layers, external and internal, until their solidification. The separation of the melt composed of the final products of combustion into two layers takes place under the action of centrifugal forces due to the difference in specific weights of said layers.

Abstract: A process for preparing titanium carbide in accordance with the present invention comprises ignition of a mixture consisting of 80-88% by weight of a powder of commercial titanium and 20-12% by weight of finely divided carbon followed by an exothermal reaction of said mixture under the conditions of layer-by-layer combustion with the formation of gaseous by-products; the process is conducted in a porous casing which prevents the mixture from scattering in the course of its intensive cooling, and removing the gaseous products therethrough.The process according to the present invention makes it posible to produce titanium carbide with a content of combined carbon approaching the stoichiometric value (19.5-19.8% by weight), the content of free carbon of 0.08% by weight and oxygen 0.1% by weight. The process according to the invention makes it also possible to use, as the starting materials, commercial products, i.e. products containing impurities.