Abstract: A method of producing composites of micro-engineered, coated particulates embedded in a matrix of metal, ceramic powders, or combinations thereof, capable of being tailored to exhibit application-specific desired thermal, physical and mechanical properties to form substitute materials for nickel, titanium, rhenium, magnesium, aluminum, graphite epoxy, and beryllium. The particulates are solid and/or hollow and may be coated with one or more layers of deposited materials before being combined within a substrate of powder metal, ceramic or some combination thereof which also may be coated. The combined micro-engineered nano design powder is consolidated using novel solid-state processes that prevent melting of the matrix and which involve the application of varying pressures to control the formation of the microstructure and resultant mechanical properties.

Abstract: In one aspect of the present invention, a cartridge assembly for connection to the frame of a high-pressure, high-temperature press comprises a front end comprising a back-up intermediate and coaxial with an anvil and a piston, the anvil comprising a proximal end in contact with the back-up and a distal end that forms part of a pressurized chamber within the frame, the back-up comprising a proximal end comprising a first diameter proximate an interface with a distal end of the piston, and a distal end comprising a second diameter proximate an interface with the proximal end of the anvil, the back-up comprising one or more circumferential reliefs disposed on the first diameter.

Abstract: A method for preparing highly dense functional oxides with crystallite size in the range of 10-20 nm. Using a high pressure modification of a the Spark Plasma Sintering (SPS) technique, rapid thermal cycles (<10 min) coupled with very rapid pressure increase up to 1 GPa can be obtained allowing high degree of compaction and very limited grain growth. This combination of techniques was employed to produce the finest-grained ceramics ever prepared in bulk form in the case of fully stabilized zirconia and Sm-doped Ceria.

Abstract: In one aspect of the invention, a cartridge assembly is adapted for connection to a frame of a high pressure, high temperature press having a front end with a back up intermediate and coaxial with an anvil and a piston. The back up has an anterior end proximate the anvil and posterior end proximate the piston. The cartridge assembly has a hydraulic system adapted to apply axial pressure to the back-up through the piston to axially move the front end with respect to a cartridge body. The assembly also has a centralizing assembly with a rod rigidly attached to the cartridge body at a first end and a second end adapted to slide within a peripheral bore formed in the front end.

Abstract: In one aspect of the invention, a cartridge assembly is adapted for connection to a frame of a high pressure, high temperature press having a front end with a back up intermediate and coaxial with an anvil and a piston. The back up has an anterior end proximate the anvil and posterior end proximate the piston. The cartridge assembly has a hydraulic system adapted to apply axial pressure to the back-up through the piston to axially move the front end with respect to a cartridge body. The assembly also has a centralizing assembly with a rod rigidly attached to the cartridge body at a first end and a second end adapted to slide within a peripheral bore formed in the front end.

Abstract: In one aspect of the present invention, a high-temperature, high-pressure press apparatus has a cartridge assembly adapted for connection to a unitary frame. An anvil is attached at a front end of a cylindrical body of the cartridge and a hydraulic chamber within the body is adapted to apply axial pressure to the anvil. A threaded end of the anvil is adapted for mating with a threaded inside diameter of a borehole disposed within a wall of the frame. A radial compression element disposed around an outer diameter of the body is adapted to limit radial expansion of the body proximate the hydraulic chamber. At least one mechanism is attached to the radial compression element; the at least one mechanism being adapted to preload the threaded connection between the cartridge assembly and the frame.

Abstract: A cartridge assembly for connection to a frame of a high temperature, high pressure press, having an anvil at a front end of a cylindrical body of the cartridge and a hydraulic chamber within the body adapted to apply axial pressure to the anvil. A radial compression element is disposed around an outer diameter of the body and is adapted to limit radial expansion of the body proximate the hydraulic chamber.

Abstract: Solid reaction products with a dense nanocrystalline structure are formed from reactant particles with diameters in the nano-scale range by compacting the particles into a green body, then passing an electric current through the body causing Joule heating sufficient to initiate the reaction to form the reaction product while simultaneously applying pressure to the reacting body to density it to a density approaching the theoretical density of the pure product. Surprisingly, this process results in a reaction product that retains the nanocrystalline structure of the starting materials, despite the fact that a reaction has occurred and the materials have been subjected to highly stringent conditions of electric current, heat and pressure.

Abstract: A method of bonding a particle material to near theoretical density, includes placing a particle material in a die. In the first stage, a pulsed current of about 1 to 20,000 amps., is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a shear force of about 5-50 MPa is applied. In the second stage, an axial pressure of about less than 1 to 2,000 MPa is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a steady current of about 1 to 20,000 amps, is applied. The method can be used to bond metallic, ceramic, intermetallic and composite materials to near-net shape, directly from precursors or elemental particle material without the need for synthesizing the material. The method may also be applied to perform combustion synthesis of a reactive material, followed by consolidation or joining to near-net shaped articles or parts.

Abstract: A method of forming a refractory die, and a method for forming a metal article using a refractory die. The refractory die is formed of a ceramic material by casting a slurry containing particles of the ceramic material onto a mold. Then the mold is vibrated while excess liquid medium from the slurry is simultaneously removed, whereby ceramic particles continue to flow into surface details of the mold. The present method of forming a refractory die minimizes drying and firing shrinkage, and even adjusts for drying and firing shrinkage by inclusion of kyanite in the refractory die. According to the method of forming a metal article, a particulate material containing powdered metal is compressed on a refractory die at an elevated temperature and pressure. The consolidated particulate material is differentially cooled, wherein a first, low mass portion contacting the refractory die is cooled more quickly than an opposing, high mass portion of the consolidated body.

Abstract: A plurality of blanks divided at a division end face 5 or a blank-bonded product comprising a plurality of blanks sintered and bonded together are or is compressed in the same mold, so that they are plastically deformed until the division end faces 5 are cohered. Thereafter, a load is applied to the plastically worked product in a direction of breaking of the division end faces 5 to break the division end faces 5 and divide the plastically worked product into a plurality of members. In this manner, a split type mechanical part having irregularities meshed with each other on mating faces and easily positionable relative to each other can be produced with a good dimentional accuracy.

Abstract: A method for preparing a highly dense product from a powdered mixture of reactants, whereby simultaneous application of a high current and pressure enables synthesis and densification of a variety of high temperature materials. The combination of field-activated combustion synthesis and the application of mechanical pressure was employed to produce dense MoSi.sub.2.

Abstract: There is provided a process for producing titanium composite, comprising the steps of: molding titanium powder, titanium alloy powder, or powder comprising titanium into a certain shape by a cold isostatic press or cold press; reacting the shape with hydrocarbon gas at its decomposition temperature or higher, to form TiC therein; and providing the shape with high density by vacuum sintering, hot isostatic pressing, hot forging, hot rolling and/or the combinations thereof. TiC a reinforcing material, is in-situ formed by reacting a cold-pressed body of the powder with hydrocarbon gas and cleaner than the externally added one and distributed more uniformly and finely in the Ti matrix, leading to a significant improvement in wear resistance and high temperature property.

Abstract: The invention relates to a neutron-absorbing material and to its production process.This material comprises a homogeneous, boron carbide matrix 1 in which are dispersed e.g. pseudospherical, 150 to 500 .mu.m , calibrated clusters 3 of boride such as HfB.sub.2, in order to prevent the propagation of cracks F in the material and improve its thermal shock resistance.

Abstract: A composite jet engine compressor ring is made by casting a tape reinforced with ceramic fibers, winding the cast tape around a mandrel to form an unconsolidated ring, heating the ring to drive off binder, and pressing at a high temperature to form a unitary composite ring. Compression of the ring in an axial direction during hot pressing results in a desired axial spacing between adjacent fibers. The tape is preferably cast from a mixture of titanium base metal particles and a polyisobutylene binder dissolved in an organic solvent.

Abstract: The invention relates to a process for pressing electrically conductive powders to high-density compacts in dimensionally stable pressing molds, whereby the achievable compression density is greater than 96% and, in many cases, amounts to almost 100% of the theoretical density of suitable materials. For said purpose, static pressing of the powders according to conventional methods is superimposed by a second process step, in which from 1 to 3 electric current pulses of from 5.times.10.sup.-5 to 5.times.10.sup.-2 s duration and high electric power are applied to the punches of the press. As opposed to known methods, no notable sintering of powder of particles occurs in such process. The process is especially suitable for the manufacture of high-density and high-strength, sintered mass-produced components, where compacts are produced on automatic presses with high cycle frequencies.

Abstract: To manufacture a reflector formed by a reflective metallic layer on a metallic matrix composite support, a metallic layer having a reflective surface whose shape is at least approximately identical to the required geometrical shape is disposed on a mold surface having a geometrical shape complementary to the required geometrical shape of the reflector. Fibers to constitute the composite support are draped on the metallic layer. They are metallized by the metallic or intermetallic material to form the metallic matrix. This layer and the metallized fibers are subjected to temperature and pressure conditions adapted to press the reflective surface strongly against the mold surface and to cause diffusion welding of the layer with the metallized fibers and of the metallized fibers with themselves so as to integrate the layer to the composite support during consolidation of the latter.

Abstract: Supported polycrystalline compacts having improved shear strength, impact, and fracture toughness properties, and methods for making the same under high temperature/high pressure (HT/HP) processing conditions. The method involves a HT/HP apparatus formed of a generally cylindrical reaction cell assembly having an inner chamber of predefined axial and radial extents and containing pressure transmitting medium, and a charge assembly having axial and radial surfaces and formed of at least one sub-assembly comprising a mass of crystalline particles adjacent a metal carbide support layer. The charge assembly is disposed within the chamber of the reaction cell assembly, with the pressure transmitting medium being interposed between the axial and radial surfaces of the charge assembly and the extents of the reaction cell chamber to define an axial pressure transmitting medium thickness, L.sub.h, and a radial pressure transmitting medium thickness, L.sub.r, the ratio of which, L.sub.h /L.sub.

Abstract: A plunger charged as an electrode is received in a trough charged as a counter-electrode in order to heat material in the trough above the annealing temperature of metal material or the sintering temperature of ceramic-material. The trough and plunger are situated in a vacuum chamber separated from a condenser and pump stand by a valve. The plunger can be retracted into a cover of the chamber by a hydraulic drive on the cover. The cover, drive, and plunger are removable from the lower part of the chamber as a unit.

Abstract: A magnet is formed as a ring magnet and magnetized by radial application of a magnetic field while the intensity of the magnetic field is changed periodically along the circumference of the ring magnet to give a circumferentially sinusoidal waveform distribution of magnetic flux density to the ring magnet in the magnetized state of the magnet.

Abstract: A silicon carbide material is made following a procedure including hot pressing to provide a finished product having a microstructure with an optimal grain size of less than 7 micrometers. The material exhibits a dominant failure mode of intergranular fracture requiring significant energy for crack propagation. The method of manufacturing is cost-effective by allowing the use of "dirty" raw materials since the process causes impurities to segregate at multi-grain boundary junctions to form isolated pockets of impurities which do not affect the structural integrity of the material. End uses include use as protective projectile-resistant armor.

Abstract: A sintered product useful for abrasion- and impact-resistant tools and the like is provided comprising an iron-group metal binder and refractory metal carbide particles, e.g. tungsten carbide, formed in situ during sintering by the exothermic reaction of a carbide-forming refractory metal powder with a carbon source mixed therewith. The sintering is carried out at an elevated temperature and at a pressure at which diamond is stable in the presence of a liquid phase comprised substantially of an iron-group binder metal, refractory metal, and dissolved carbon. The product may optionally contain diamond, up to about 95% in volume, enabling its properties to be tailored for a wide range of applications.

Abstract: A method for producing titamium alloy articles having a desired microstructure which comprises the steps of:(a) providing a prealloyed gamma titanium aluminide alloy powder;(b) filling a suitable die or mold with the powder;(c) consolidating the powder in the filled mold at a pressure of 30 Ksi or greater and at a temperature of about 70 to 95 percent of the alpha-2+gamma eutectoid temperature of the alloy, in degrees C.

Abstract: A composite material comprising a metal matrix containing tungsten grain is roduced from tungsten powders formed by plasma rapid solidification. The powders comprise tungsten and up to 20 weight percent of a metal selected from the group consisting of molybdenum, tantalum, niobium, rhenium, and chromium. The surfaces of the powders are cleaned to reduce the surface oxide thereon, and the powders are coated with at least one metal selected from the group consisting of copper, nickel, cobalt, hafnium and tantalum. The coated powders are formed into a sintered preform which is less than fully dense, and the sintered preform is further consolidated to full density by a technique selected from hot isostatic pressing, rapid omin-directional compaction, and hot extrusion.

Abstract: A method of joining two porous bodies of silicon carbide is disclosed. It entails utilizing an aqueous slip of a similar silicon carbide as was used to form the porous bodies, including the sintering aids, and a binder to initially join the porous bodies together. Then the composite structure is subjected to cold isostatic pressing to form a joint having good handling strength. Then the composite structure is subjected to pressureless sintering to form the final strong bond. Optionally, after the sintering the structure is subjected to hot isostatic pressing to further improve the joint and densify the structure. The result is a composite structure in which the joint is almost indistinguishable from the silicon carbide pieces which it joins.

Abstract: Apparatus and methods for compressing a mass utilizing a plurality of interfitting anvils mounted for movement relative to one another along co-planar paths and include faces which, when the anvils are operatively moved relative to one another, exert compression on a mass positioned between the faces in at least two directions in a plane simultaneously. The faces of the apparatus can be so shaped that the cross section of the mass being compressed is urged toward a shape other than that of a regular polygon. Methods of the invention include the consolidation of a mass of compactable material enclosed within a hollow tube having deformable walls, the extraction of juice or oil from fruit or seeds and the internal fracturing of solids so as to swell materials such as solid rocket propellants.

Abstract: The invention provides an aluminum base bearing alloy which is excellent in both lubricating capability and fatigue resistance and is useful, e.g. in automotive engines. The bearing alloy consists essentially of at least one lubricating element such as Pb and/or Sn the total amount of which is more than 0.04 and not more than 0.07 by sectional area ratio to the aluminum matrix, Si the amount of which is in the range from 0.01 to 0.17 by sectional area ratio to the aluminum matrix, 0.2-5.0 wt % of at least one reinforcing element such as Cu and/or Cr, 0-3.0 wt % of at least one refining element such as Ti and/or B and the balance of Al. The grain size of the lubricating element(s) is not larger than 8 .mu.m, and the grain size of Si is not larger than 12 .mu.m and preferably not smaller than 6 .mu.m.

Abstract: Waste material such as toxic compounds, radioactive waste materials and spent nuclear fuel rods are encapsulated in a container system which is subjected to a hot pressure process to cause a protective powder material located around the waste material to form a dense matrix and function as a highly corrosion resistant and protective shroud. Embodiments include hot isostatic pressing and hot uniaxial pressing, the use of metal powder such as copper powder for the protective powder material or alternatively ceramic powder and, depending upon the embodiment chosen, the use of a single container or dual container system in which a first container is located within an outer container. Either or both of such containers may be cylindrical with a bellows-like side wall to facilitate compression thereof in an axial direction.

Abstract: A compressible bellows type metal canister is used in a hot pressing process for immobilizing high level radioactive nuclear waste material in the form of synthetic rock, the canister comprises a base wall and a corrugated bellows side wall of generally circular cross-section, concentrically arranged within the corrugated side wall is a cylindrical liner. In the center of the base wall a conically-tapered aperture is provided with a filter plug. Diametrically opposed apertures are provided in the base wall and are connected by an outlet pipe for removal of waste gases.

Abstract: A dry, pourable particulate mixture of nuclear waste and synthetic rock-forming components is produced by supplying the rock forming components in dry particulate form to a mixer, supplying the nuclear waste in liquid phase and operating the mixer to distribute the waste substantially uniformly through the synthetic rock components; the mixture is calcined to produce a precursor powder which is adapted to be used in a hot pressing process to form synthetic rock throughout which the radioactive nuclear waste is distributed and immobilized. A reducing gas atmosphere is preferably maintained in the calcining process stage, the gas being for example pure hydrogen or a mixture of hydrogen in nitrogen in proportions which are non-explosive. A screw type or paddle type conveyor can be used for the mixing and calcining stages although the calcining can be effected in a vertically downwardly directed tube device having associated heating means such as microwave heating.

Abstract: Form-locking means and process for joining same to a subcaliber projectile in a peripheral region thereof. The form-locking means consists of a material in the form of a n-phase sintered alloy having a high content of at least one heavy metal, wherein n.gtoreq.2. The material forming the form-locking means in the peripheral region of the subcaliber projectile form at least one further alloy phase. The form-locking means includes interlocking lands and grooves, and are joined to the periphery of the subcaliber projectile in the form of a layer of predetermined thickness which can be joined to the projectile surface by means of explosion welding.

Abstract: A method for forming a high density body from a powder material of metallic and non-metallic compositions and combinations thereof comprising confining a quantity of the powder material in a flexible mold structure, subjecting the powder material in the mold structure to a predetermined pressure along one axis while confining the material against movement in directions normal to the axis so as to form a compact body of the powder material and subsequently heating the compact body to a predetermined temperature so as to further compact the body. A quantity of glass is heated so that it will flow and transmit pressure following which the heated body is immersed in the heated glass and the flowable glass is subjected to a pressure high enough to further compact the body. The resulting densified body is uniformly compressed in the directions of three mutually perpendicular axes extending through the body.

Abstract: Amorphous alloy shaped articles having excellent magnetic properties, high hardness and strength, or high corrosion resistance can be obtained by a method, wherein amorphous alloy or atomized alloy raw material powder layer is laminately arranged adjacently to a metal powder layer having a shock impedance a little different from that of the raw material powder layer, and a shock pressure is applied to the raw material powder layer.

Abstract: A method for synthesizing low density cermets of boron carbide and a metal binder, using decomposition of a metallic compound at controlled temperature and pressure.

Abstract: A method of manufacture of objects by consolidation of powdered metals, alloys, ceramics, or their mixtures is disclosed. The method comprises the steps of preparing a shaped, preferably ceramic, shell, placing it inside a metal or ceramic can, filling both the shell and space between the shell and the can with powder, outgassing and sealing the can if necessary, heating the full can and pressing it to consolidate the powder into a dense form; and separating the densified object within the shell from the densified shapes between the shell and the can. During pressing, the ceramic shell does not consolidate or bond to the surrounding powder, thus acting as an easy parting surface as well as being a shape defining container for the object being consolidated. The method permits easy definition of desired shell shape and permits manufacture of complex shaped, fully densified objects in near-net-shape form.

Abstract: Particulate material is poured into a container which is decay and heat resistant, the container is sealed and subjected to axial compression at elevated temperature to cause densification of the material, there being an arrangement for preventing substantial radially outward deformation of the container during compression. An important application is to immobilization of nuclear reactor waste in a synthetic rock structure formed during the high temperature compression step, and advantageously the containers are secured within an outer metal cannister for subsequent safe handling and disposal. An important embodiment includes a bellows container which advantageously is upwardly pressed into an inverted metal cannister restrained by an upper abutment, the bellows container becoming an interference fit within the metal cannister during the final portion of compression, but the bellows container wall itself being substantially sufficient to prevent gross outward deformation of the bellows container.

Abstract: A powder-metallurgy method for producing tubular product having at least one surface and preferably an internal surface thereof clad with an alloy different from and preferably more resistant to destructive media than the material from which the remainder of the tubing is constructed. An assembly is constructed of a metal tubing having an internal surface to be clad and a tubular insert mounted generally axially within the tubing in spaced-apart relation to the internal surface thereof, which provides a generally annular cavity between the internal surface of the tubing and the tubular insert. This cavity is filled with metal particles of a composition to be clad on the tubing internal surface. The cavity is sealed and the assembly is heated to an elevated temperature at which it is forged to compact the metal particles introduced to the cavity to substantially full density and metallurgically bond the particles to the internal surface of the tubing to provide a desired destructive-media resistant cladding.

Abstract: A method is described for the manufacture of articles in defect immunized materials in which the defects are eliminated, or broken up and oriented in such manner as to minimize their harmful effects on the article. Referring to FIG. 1e, a rotor disc for a gas turbine engine is formed to an approximate shape by stacking together "sticks" 5 of material in an evacuated container and bonding them together by a hot isostatic pressing process. The "sticks" 5 are produced by extruding a starting body, for example, of powder material, to produce an elongation of up to twenty times and then cutting them to the appropriate length. By this means any non-metallic inclusions in the powder are broken up, inspection of the sticks and rejection of defective ones becomes easier, and the sticks can be oriented so that the effects of any remaining defects can be minimized.

Abstract: Amorphous metal powders or ribbons are fabricated into solid shapes of appreciable thickness by the application of compaction energy. The temperature regime wherein the amorphous metal deforms by viscous flow is measured. The metal powders or ribbons are compacted within the temperature range.

Abstract: A green compact (17) preheated to a predetermined temperature in a heating furnace (16) is inserted into a container comprising a press table (20) and a hollow cylinder (25), and molten glass (33) is then placed into the container. The green compact (17) is uniformly pressed by a press rod (29) through the molten glass (33). The molten glass (33) is cooled by a coolant flowing through channels (22) and (26) formed in the press table (20) and the cylinder (25), whereby a solidified shell (34) is formed at the outer peripheral portion of the mass of glass. Finally, the shell (34) is taken out from the container, and the molten portion of glass (33) is transferred into a ladle (31) through a grating (30), leaving the compressed sintered product on the grating (30).

Abstract: The method of producing a metallic, ceramic, or metal ceramic, part, employing powdered material, that includes:(a) forming two or more oversize powder material preforms respectively corresponding to two or more sections of the ultimate part to be produced,(b) placing said preforms in side-by-side relation, and(c) consolidating said preforms at elevated temperature and pressure to weld said sections together and to reduce the sections to ultimate part size.

Abstract: A method of consolidating metallic body means comprises(a) applying to the body means a mixture of:(i) metallic powder(ii) fugitive organic binder(iii) volatile solvent(b) drying the mixture, and(c) burning out the binder and solvent at elevated temperature,(d) and applying pressure to the powdered metal to consolidate same on said body means.

Abstract: Sintering method and apparatus. A pre-sintered or compacted mass of particulate material is densified by loading the mass into a substantially closed three-dimensional space defined by three pairs of punches juxtaposed thereacross in three respective directions, and then by multi-axially compressing the mass by advancing the punches of each pair toward each other while energizing the mass with thermal energy. The axes of action of pressures applied thereto by the three pairs of punches intersect substantially at a point substantially constituting the center of the three-dimensional space.

Abstract: A method for producing metal alloys with improved properties such as a high modulus of elasticity, includes:(a) mixing fine metal powders and blending and milling said mix to a homogeneous condition,(b) forming the mix to a preliminary powder shape, said forming including exerting pressure on the mix,(c) and heating and transferring said powder shape to a hot refractory particle matrix and pressurizing said matrix so as to consolidate and densify the powder shape and to diffusion bond the powders into a solid body,(d) whereby the body may be subjected to a subsequent heat treatment serving to develop the uniformity, the grain structure, and the properties required in the alloy body.

Abstract: A powder metallurgical method of consolidating iron-based alloy powder, particularly white cast iron, to form a body of high density in which the powder is thermally cycled above and below the alpha-gamma transformation temperature of below 800.degree. C., and a stress of between 1.7 MPa and 34.5 MPa is simultaneously applied to the powder to form a high density consolidated body.

Abstract: A method for the implosive consolidation into a solid body of a mass of free particles, which mass consists, selectively, entirely of amorphous particles, or a mixture of amorphous and nonamorphous particles. During the consolidation act, pressure and temperature are controlled in a manner which assures that the consolidated amorphous particles in the solid body exhibit substantially the same amorphous characteristics as those displayed by the unconsolidated, free amorphous particles.

Abstract: A process and a product produced thereby, for forming rod or bar or tube stock or strip, comprising a sheath and a densified dispersion strengthened metal core. Powdered dispersion strengthened copper is put into a metal can and compressively reduced to size and density. The relationship between the tensile strength of the core when fully densified and the cold worked tensile strength of the can is important to the nature of the product.

Abstract: A method is provided for producing a fully dense high temperature powdered metal component. This process comprises the steps of filling a centrally located mold cavity with a high temperature powder, heating the filled mold to a temperature greater than half the melting temperature of the powder in degrees centigrade and less than the melting temperature of the powder, while the cavity is maintained in a vacuum level of at least twenty microns of mercury, axially compressing the heated mold while maintaining the vacuum at a pressure of at least 345 megapascals, while restricting the mold about its lateral periphery holding the mold in a compressed state for at least 20 seconds after attaining maximum pressure, and separating the mold materials from the component. The mold is composed of a material having substantially the same flow stress throughout, and the material is able to maintain its dimensional stability in a viscoelastic state at a temperature of between approximately 950.degree. to 1300.degree. C.