44results about How to "Uniform densification" patented technology

A gas preheater for a CVI furnace designed for the densification of annular porous substrates arranged in a plurality of vertical annular stacks of substrates, comprising: a sleeve made of heat conductive material resting upon the bottom wall of a susceptor and delimiting a gas preheating chamber, with a gas inlet opening in the gas preheating chamber; a heat exchange assembly located in the gas preheating chamber; a gas distribution plate resting upon the sleeve, covering the gas preheating chamber and provided with a plurality of passages for preheated gas; a load supporting plate for supporting stacks of annular substrates and provided with a plurality of passages in communication with respective passages of the gas distribution plate and registration with internal volumes of respective stacks of annular substrates; and nozzles inserted in passages communicating the gas preheating zone with the internal volumes of respective stacks of annular substrates for adjusting the flows of preheated gas respectively admitted in said internal volumes.

Part of the flow of reactive gas admitted into the enclosure (10) is guided to the inside of the volume defined by a concave inside face of the or each hollow-shaped substrate (S1, S2, S3) so that said concave inside face is swept in full by a fraction of the total admitted gas flow.

A known method for producing synthetic quartz glass comprises the method steps: providing a liquid SiO₂ feedstock material, which contains octamethylcyclotetrasiloxane D4 as the main component, vaporizing the SiO₂ feedstock material into a feedstock material vapor, converting the feedstock material vapor into SiO₂ particles, depositing the SiO₂ particles on a deposition surface while forming a porous SiO₂ soot body, and vitrifying the SiO₂ soot body while forming the synthetic quartz glass. Starting therefrom, to produce large-volume cylindrical soot bodies with outer diameters of more than 300 mm of improved material homogeneity, it is suggested according to the invention that the liquid feedstock material contains additional components comprising hexamethylcyclotrisiloxane D3 and the linear homolog thereof with a weight fraction mD3, decamethylcyclohexasiloxane D6 and the linear homolog thereof with a weight fraction mD6, and tetradecamethylcycloheptasiloxane D7 and/or hexadecamethylcyclooctasiloxane D8 and the linear homologs thereof with a weight fraction mD7+, wherein the weight ratio mD3/mD6 is in a range between 0.05 and 90 and the weight fraction mD7+ is at least 20 wt. ppm.

A method for producing synthetic quartz glass comprises providing a liquid SiO₂ feedstock material containing octamethylcyclotetrasiloxane D4, vaporizing the SiO₂ feedstock material into vapor, converting the vapor into SiO₂ particles, depositing the particles to form a porous SiO₂ soot body, and vitrifying the soot body, forming the synthetic quartz glass. To produce cylindrical soot bodies with outer diameters above 300 mm and improved material homogeneity, the liquid feedstock material contains additional components comprising hexamethylcyclotrisiloxane D3 and the linear homolog thereof with a weight fraction mD3, decamethylcyclohexasiloxane D6 and the linear homolog thereof with a weight fraction mD6, and tetradecamethylcycloheptasiloxane D7 and/or hexadecamethylcyclooctasiloxane D8 and the linear homologs thereof with a weight fraction mD7+, wherein the weight ratio mD3/mD6 is between 0.5 and 500 and the weight fraction mD7+ is at least 20 wt. ppm.

The invention relates to a preparation method of a tantalum-silicon alloy sputtering target material. The preparation method comprises the following steps of (1) uniformly mixing tantalum powder and silicon powder; (2) loading into a mold and sealing; (3) carrying out hot pressed sintering treatment on the sealed mold at 1130-1170 DEG C so as to obtain a tantalum-silicon alloy sputtering target crude product; and (4) machining to obtain the tantalum-silicon alloy sputtering target material. According to the preparation method, the tantalum-silicon alloy sputtering target material with the purity and density meeting the requirements can be prepared, the density reaches 99 percent or above, energy consumption and cost can be reduced, and the preparation method is suitable for large-scale popularization.

The invention discloses a super-large-size carbon/carbon composite material sheet and equipment for preparing the same. The invention discloses a super-large-size carbon/carbon composite material sheet. A preparation method of the super-large-size carbon/carbon composite material sheet comprises the following steps: (1) designing and constructing a reactor; (2) clamping and loading a carbon fiberpreform; (3) performing carbon source component regulation and flow field control setting; (4) performing chemical vapor deposition densification; and (5) discharging and dismounting the tool. The invention further designs equipment matched with the process, the super-large-size carbon/carbon composite sheet with high straightness, uniform densification and small deformation can be obtained through cooperation of the equipment and the process, and a feasible method is provided for near-net forming preparation of the super-large-size carbon/carbon composite sheet.

A densifying apparatus including: a reaction chamber; a fixed heater is disposed close to the inner wall of the reaction chamber and generating heat; a detachable heater detachably coupled to the reaction chamber and generating heat; and a gas supply unit supplying a gas into the reaction chamber. It is possible to minimize energy consumption when densifying a small amount of preforms or a large amount of preforms and uniformly densify disc preforms having the shape of a thick ring. Further, it is possible to reduce time to density those preforms.

The invention relates to aluminum oxide ceramic, a preparation method thereof and a ceramic bearing. The preparation method of the aluminum oxide ceramic comprises the following steps: mixing the following raw materials in percentage by mass: 35%-99% of aluminum oxide, 0.5%-60% of zirconium oxide and 0.5%-5.0% of a sintering aid to obtain ceramic powder, wherein the particle sizes of the raw materials are nanoscale, and the sintering aid comprises magnesium oxide, calcium oxide, sodium oxide, hafnium oxide and potassium oxide, molding the ceramic powder to obtain a ceramic green body, carryingout normal pressure sintering on the ceramic green body at 1400-1500 DEG C, and then carrying out hot isostatic pressing sintering at 1300-1350 DEG C under 100-200 MPa to obtain the aluminum oxide ceramic. The preparation method of the aluminum oxide ceramic can be used for breaking the aluminum oxide ceramic with relatively high toughness.

The invention provides a titanium based cathode material with a uniform and dense TiB2 layer and a preparation method of titanium based cathode material, and belongs to the technical field of cathodematerial preparation. The preparation method comprises the following steps that (1) a titanium substrate with the surface being completely treated is subjected to boronizing treatment, a boronizing agent is prepared from anhydrous borax, anhydrous potassium carbonate and B4C, a graphite crucible serves as an anode, a metal titanium plate serves as a cathode, and thus a TiB2-TiB/Ti gradient composite material is obtained; (2) the surface of the TiB2-TiB/Ti gradient composite material is completely cleaned; and (3) the completely treated composite material is subjected to TiB2 molten salt electrode position, and the TiB2-TiB/Ti gradient composite material with the surface electrodeposited with a TiB2 cladding material is obtained. According to the preparation method, the cathode TiB2-TiB/Tigradient composite material for aluminum electrolysis with the uniform and dense TiB2 outermost layer can be obtained, the TiB2 layer is thickened at the same time, and the service life of the cathodematerial is prolonged.

The invention relates to a carbon/carbon composite material as well as a preparation method and application thereof. The preparation method of the carbon/carbon composite material comprises the following steps: sequentially carrying out carbon deposition and silicon carbide deposition on a carbon fiber preform by adopting a chemical vapor deposition method to obtain a silicon carbide-containing carbon/carbon composite rough blank, dipping the carbon/carbon composite rough blank in a molybdenum source solution, baking the carbon/carbon composite rough blank, carrying out reduction reaction in areducing atmosphere to obtain a carbon/carbon composite precursor containing elemental molybdenum, and finally, carrying out melt siliconizing treatment on the carbon/carbon composite precursor to obtain the carbon/carbon composite material containing silicon carbide and molybdenum silicide. The internal components of the carbon/carbon composite material prepared by the preparation method are uniform and stable, the difference between the internal and external layer components is small, the difference between the internal thermal expansion coefficients of the material is small, and the carbon/carbon composite material has excellent high-temperature oxidation resistance and mechanical properties.

The invention relates to a method for producing a household appliance component (1), in which a base part (2) of the household appliance component (1) is provided, which is formed of plastic at least one a top side (3) and a mark (5) is generated with a laser (4) on the top side (3), wherein a plastic foam area (6) is formed on the top side (3) by means of the laser (4) for the mark (5), wherein the plastic foam area (6) is reduced in thickness (d) and/or increased in density afterwards. The invention also relates to a household appliance component (1).

The invention discloses a high-purity gadolinium hexaboride polycrystal and a preparation method thereof. The gadolinium hexaboride polycrystal does not contain gadolinium tetraboride impurities; andpreferably, the density of the gadolinium hexaboride polycrystal exceeds 80%, and the diameter of the gadolinium hexaboride polycrystal is 15 mm or above.

The invention relates to the technical field of chemical vapor infiltration of carbon-carbon composite materials, and discloses a deposition device for densification of a preform and a charging structure. A flow limiting channel is formed between the preform to be densified and the side wall of an inner flow limiting cylinder, and an overflowing opening is formed in the top of the preform to be densified; and a flow limiting path which sequentially leads to the flow limiting channel, the overflowing opening and the furnace cavity outlet from the furnace cavity inlet is formed in the furnace cavity. In the deposition process, the temperature of a thermal field in a furnace chamber is gradually reduced from outside to inside, the deposition speed is increased exponentially along with temperature increase, carbon source gas permeates from the inner surface to the outer side with the high temperature for deposition densification, the temperature in the prefabricated body to be densified is continuously increased, and the deposition surface is continuously pushed inwards during deposition; and the whole to-be-densified prefabricated body is completely deposited, so that the surface crusting of the to-be-densified prefabricated body is avoided, and the densification density of the to-be-densified prefabricated body is uniform. In addition, through the flow limiting path, the carbon source gas activity space can be effectively compressed, the active group collision probability is increased, and therefore the deposition efficiency is greatly improved.

A process for densifying annular porous substrates by chemical vapour infiltration, includes providing a plurality of unit modules including a support plate on which is formed a stack of substrates, the support plate including a central gas inlet opening communicating with an internal volume formed by the central passages of the stacked substrates and gas outlet openings distributed angularly around the central opening, and a thermal mass cylinder disposed around the stack of substrates having a first end integral with the support plate and a second free end, forming stacks of unit modules in the chamber of a densification furnace, and injecting into the stacks of unit modules a gas phase including a gas precursor of a matrix material to be deposited within the porosity of the substrates.

The invention relates to a method for establishing a connection between an electric connection element for a motor vehicle electrical system and a cable of the motor vehicle electrical system, in which method: the cable (2) is provided with a metal stranded conductor (4); then the metal stranded conductor is mechanically compressed such that a planar region is formed, an integral connection beingformed between strands of the stranded conductor (4) during said compression; and subsequently the connection element is integrally bonded to the planar region.