2028 results about "Hydrogen atmosphere" patented technology

A method for manufacturing a field effect transistor, includes: forming a mask of an insulating film on a semiconductor layer containing Si formed on a semiconductor substrate; forming the semiconductor layer into a mesa structure by performing etching with the use of the mask, the mesa structure extending in a direction parallel to an upper face of the semiconductor substrate; narrowing a distance between two sidewalls of the mesa structure and flattening the sidewalls by performing a heat treatment in a hydrogen atmosphere, the two sidewalls extending in the direction and facing each other; forming a gate insulating film covering the mesa structure having the sidewalls flattened; forming a gate electrode covering the gate insulating film; and forming source and drain regions at portions of the mesa structure, the portions being located on two sides of the gate electrode.

A method for manufacturing a silicon carbide semiconductor device includes the steps of: forming a trench mask on an upper surface of a semiconductor substrate; forming the trench such that the trench having an aspect ratio equal to or larger than 2 and having a trench slanting angle equal to or larger than 80 degrees is formed; and removing a damage portion in such a manner that the damage portion disposed on an inner surface of the trench formed in the semiconductor substrate in the step of forming the trench is etched and removed in hydrogen atmosphere under decompression pressure at a temperature equal to or higher than 1600° C.

An electrochemical process and apparatus for preparing metal hydride compounds from metal salts under a hydrogen atmosphere are disclosed. The electrochemical process may be integrated with chemical reaction of a boron compound to produce borohydride compounds. A metal salt and a borate are charged to the cathode of an electrolytic cell wherein the borate reacts with the hydride, to produce the borohydride compound.

The silicon tetrachloride hydrogenating process of producing trichloro-hydrosilicon includes: mixing powdered nickel catalyst and silicon powder in the mass ratio of 1-10 and activating the mixture in hydrogen atmosphere and at the temperature of continuously change from 20 deg.C to 420 deg.c; and making mixed gas of hydrogen and SiCl4 in the molar ratio of 1-10 pass through the activated catalyst and silicon powder layer for hydrogenating SiCl4 continuously at 400-500 deg.c temperature and 1.2-1.5 MPa pressure. The equipment, system and operation of the present invention has high once SiCl4 converting rate and low power consumption and may be used in large-scale production.

A capacitor fabricating method for a semiconductor device where a dielectric film is thermally treated under hydrogen atmosphere to improve interface characteristics between the dielectric film and an electrode. In the method, a lower electrode is formed on a semiconductor substrate. A dielectric film is formed on the lower electrode. The dielectric film is thermally treated under hydrogen atmosphere. An upper electrode is formed on the dielectric film, thereby completing formation of the capacitor. The thermal treatment under the hydrogen atmosphere is performed at a temperature of 300 to 600 DEG C. using H2 gas or H2 plasma for 5 to 60 minutes. Thus, the density of an interface trap between the electrode and the dielectric film of the capacitor is reduced.

There is provided a high-purity ruthenium sputtering target with a low impurity content, in particular producing extremely few particles, which is suitable for applications such as the formation of semiconductor thin films. The high-purity ruthenium sputtering target is manufactured by feeding crude ruthenium powder into a sodium hydroxide solution; blowing an ozone-containing gas while or after blowing chlorine gas into the solution to form ruthenium tetroxide; absorbing the ruthenium tetroxide in a hydrochloric acid solution or a mixed solution of hydrochloric acid and ammonium chloride, and evaporating the solution to dryness; sintering the resultant ruthenium salt in a hydrogen atmosphere to form high-purity ruthenium powder; and hot-pressing the ruthenium powder into a sputtering target.

The invention relates to a silicon carbide ceramic support body and a preparation method thereof. The raw material powder of the support body is mixed powder consisting of silicon carbide powder 1 and silicon carbide powder 2, wherein the silicon carbide powder 1 has a median particle diameter D50 of 25-45mu m, the silicon carbide powder 2 has a median particle diameter D50 of less than 5mu m, the ratio of the D50 of the silicon carbide powder 1 to the D50 of the silicon carbide powder 2 is not less than 6, and the consumption of the silicon carbide powder 2 is 0.5-13 percent of the weight of the used silicon carbide powder 1. The raw material powder is mixed with a solvent, an adhering agent, a plasticizer and a pore-forming agent to form pug, the pug is subjected to stamping to form a raw blank, the raw blank is dewatered and degreased to form a calcined product, and the calcined product is sintered in argon or hydrogen atmosphere or vacuum to form the support body of a recrystallized silicon carbide ceramic membrane. The support body of the recrystallized silicon carbide ceramic membrane has filtering flux and strength which are higher than those of the traditional commercial support body of an aluminum oxide ceramic membrane.

The present invention relates to one kind of superfine cobalt powder and its production process. The production process includes the following steps: setting cobalt carbonate or cobalt oxalate powder, grinding dispersant and hard alloy balls in certain weight proportion into high energy ball mill pot; vacuumizing the ball mill pot and introducing protective argon; sealing the ball mill pot, and ball milling at controlled rotation speed to obtain superfine cobalt carbonate or cobalt oxalate powder; and reducing the superfine cobalt carbonate or cobalt oxalate powder in hydrogen atmosphere to obtain superfine cobalt powder in oxygen content not more than 0.5 % and granularity smaller than 0.6 micron. The superfine cobalt powder is applied in producing high quality hard alloy, and has simple production process and low cost.

The invention relates to a method for preparing dihydric alcohol from lignocellulosic biomass, which has main steps of: 1, adding alkali liquor, acid liquor or water for pretreatment after lignocellulosic biomass crushing; 2, carrying out enzymolysis and concentrating liquid glucose filtered through enzymolysis after decoloration and ion exchange impurity removal; 3, adding catalysts with hydrogenation hydrogenolysis activity for carrying out hydrogenation hydrogenolysis reaction on the concentrated liquid glucose under the conditions of the pH being 8 to 14, the temperature being 130 to 250 DEG C and hydrogen atmosphere, separating the catalysts, and producing various dibasic alcohol with the carbon number being 2 to 6 after product rectification. The method utilizes the lignocellulosic biomass pretreatment-zymolyting glucose liquid as raw materials, and monosaccharide, soluble polysaccharides and sugar degradation products can respectively react, so both the efficiency and the process controllability can be greatly improved, and products can be independently used through separation and can be directly used for producing unsaturated polyester resin, polyurethane, fuel additives, surface active agents, emulsifying agents, motor vehicle antifreeze fluid and the like without depth separation.

Provided is a silicon carbide epitaxial wafer, the entire surface of which is free of step bunching. Also provided is a method for manufacturing said silicon carbide epitaxial wafer. The provided method for manufacturing a silicon carbide semiconductor device includes: a step wherein a 4H—SiC single-crystal substrate having an off-axis angle of 5° or less is polished until the lattice disorder layer on the surface of the substrate is 3 nm or less; a step wherein, in a hydrogen atmosphere, the polished substrate is brought to a temperature between 1400° C. and 1600° C. and the surface of the substrate is cleaned; a step wherein silicon carbide is epitaxially grown on the surface of the cleaned substrate as the amounts of SiH₄ gas and C₃H₈ gas considered necessary for epitaxially growing silicon carbide are supplied simultaneously at a carbon-to-silicon concentration ratio between 0.7 and 1.2 to 1; and a step wherein the supply of SiH₄ gas and the supply of C₃H₈ gas are cut off simultaneously, the substrate temperature is maintained until the SiH₄ gas and the C₃H₈ gas are evacuated, and then the temperature is decreased.

Process for manufacturing a foil of ferritic stainless steel having a high aluminum content, which can be used in particular for a catalyst support in a motor-vehicle exhaust, wherein a ferritic stainless steel sheet of the following composition: 0.005%<carbon<0.060% 10%<chromium<23% 0.1%<aluminum<3% 0.003%<nitrogen<0.030% 0.1%<manganese<2% 0.1%<silicon<2% rare-earth elements in a proportion of between 0.03% and 0.15%, is subjected to: plating between two sheets of aluminum in order to obtain a laminate, rolling the laminate to a thickness of 0.03-0.25 mm to form a foil, static diffusion annealing the foil in a hydrogen atmosphere, and finish rolling greater than 20%.

A process for the conversion of lignin to chemical precursors is presented. The process comprises treating the lignin to form less acidic compounds. The process includes reacting lignin with a hydrogenation catalyst under a hydrogen atmosphere to convert acidic oxygenate compounds to less acidic oxygenates or hydrocarbons. The oxygenate compounds are reacted in a dehydrogenation and deoxygenation process to remove the oxygen and to convert the cyclic hydrocarbons back to aromatic compounds.

The invention relates to a manufacturing method for non-oriented electric steel. The method comprises the following steps of: smelting according to a clean steel process and continuously casting into billets; heating the continuous casting billets; performing hot rolling; reeling; naturally cooling to room temperature; normalizing; performing acid washing conventionally; performing cold rolling for the first time; performing intermediate annealing in the total hydrogen atmosphere or the mixed atmosphere of hydrogen and nitrogen; performing cold rolling for the second time; performing final annealing; and cooling conventionally, coating and finishing for later use. The finished product silicon steel with coarse grains and good texture can be obtained by adopting lower process heat treatment temperature; brittleness of the steel is reduced and cold rolling performance of a steel plate is improved by adopting lower normalizing temperature and intermediate annealing temperature; the problems of surface oxidation of the steel plate, nodulation of a furnace bottom roller and the like can be effectively solved by adopting lower finished product annealing temperature; and the high-grade non-oriented silicon steel with lower iron loss can be produced stably.

Epitaxially coated silicon wafers, are produced by epitaxially coating a multiplicity of wafers polished at least on their front sides, successively and individually in an epitaxy reactor, by placing a silicon wafer on a susceptor, pretreating under a hydrogen atmosphere followed by addition of an etching medium to the hydrogen atmosphere, coating epitaxially on the polished front side and removing the water from the epitaxy reactor. The susceptor is then heated, in each case, to a temperature of at least 1000° C. under a hydrogen atmosphere, and furthermore an etching treatment of the susceptor and a momentary coating of the susceptor with silicon are effected after a specific number of epitaxial coatings. Silicon wafers characterized by a parameter R30-1 mm of −10 nm to +10 nm, determined at a distance of 1 mm from the edge of the silicon wafer are produced.

There is disclosed a method of sintering cemented carbide bodies including heating said bodies to the sintering temperature in a suitable atmosphere and cooling. If said cooling at least to below 1200° C. is performed in a hydrogen atmosphere of pressure 0.4-0.9 bar cemented carbide bodies with no surface layer of binder phase are obtained. This is an advantage when said bodies are to be coated with wear resistant layers by the use of CVD-, MTCVD- or PVD-technique.

The invention discloses a process for coproducing piperazine and N-alkyl piperazine, which comprises the following steps of: dissolving N-beta-hydroxyethyl ethylenediamine in carbinol with carbon atom number of 1-7, and in hydrogen atmosphere, reacting under the catalysis of a catalyst to obtain a mixture of piperazine and N-alkyl piperazine. The process has the advantages that: the piperazine is produced and a corresponding N-alkyl substituted piperazine compound is coproduced; the conversion rate of the N-beta-hydroxyethyl ethylenediamine is over 99 percent; the process is easy and convenient to operate; and synthesized products have high yield.

The invention relates to a method for forming bonded iron-based powder by a high velocity compaction technology, and belongs to the technical field of powder metallurgy. Coarse and fine water-atomized iron powder with different particle sizes are matched, and the mass ratio of the coarse powder to the fine powder is 2:1 to 4:1. In accordance with the particle size matching requirement and the iron-based alloy composition ratio, Ni, Cu, C and iron-phosphorus alloy powder are added into the water-atomized iron powder and then are uniformly pre-mixed with the water-atomized iron powder in a planetary ball mill. 0.3 to 0.8wt. % of plasticizer is added into the pre-mixed powder and then is mixed with the pre-mixed powder for 2 to 5 hours to obtain the bonded powder. The bonded powder is heatedto 600 to 950 DEG C by using a multi-stage heating process to be subjected to plasticizing treatment to obtain plasticized iron-based powder. The plasticized iron-based powder is pressed by a high-speed forming press to obtain a high-density compac. The compact is sintered at a temperature of 1100 to 1250 DEG C in a hydrogen atmosphere for 2 to 5 hours to obtain a high-density powder metallurgy iron-based material. The method integrates the advantages of powder modification treatment, die wall lubrication and high-speed pressing, and is more suitable for preparing the high-density powder metallurgy iron-based material.

The invention provides a nanometer carbonized tungsten compound powder, which includes carbonized tungsten, vanadium carbide or/and chrome carbide, and a metallic element without binding phase exists in the compound powder. The preparation method of the nanometer carbonized tungsten compound powder is characterized in that the powdery ammonium tungstate, the carbonaceous reducing agent and the inhibitor are adopted as raw materials, the raw materials are dissolved in deionized water or distilled water and evenly stirred so as to obtain a solution, then the solution is heated and dried, the precursor powder is obtained finally, the precursor powder is put into a high-temperature reaction furnace, under the vacuum, argon or hydrogen atmosphere protection condition and the condition of 1,000 to 1,200 DEG C and 30 to 60 min, the carbonized tungsten compound powder with the average particle diameter less than 100 nm and even particle size distribution is obtained through carbonization. The method has the characteristics of low reaction temperature, short reaction time, low manufacturing cost, simple process and the like, which is suitable for the industrial production and used for the ultrafine hard alloy nanometer carbonized tungsten compound powder.

A nano-class RE-W particle contains RE oxide powder (CeO2, La2O3, or Y2O3) (0.5-30 wt%) and W (70-99.5 wt%), and is prepared through dissolving the ammonium metatungstate powder and RE oxide powder in water respectively, mixing, clarifying, dispersing it in liquid nitrogen by nitrogen sprayer for pre-freezing, vacuum freeze drying, and secondary reducing in hydrogen atmosphere. Its advantage is molecule-class mixing uniformly.

The invention provides a device and a method for continuously synthesizing amine-terminated polyether by utilizing a fixed bed. The device for continuously synthesizing amine-terminated polyether by utilizing the fixed bed comprises a fixed bed reactor, a preheater, two gas-liquid separators, a compressor, a circulating compressor, a raw material pump, a liquid ammonia pump and two buffer tanks, hydrogen is preheated by virtue of the preheater and is fed into the fixed bed reactor with raw material and liquid ammonia; the amine-terminated polyether is synthesized in a hydrogen atmosphere of the fixed bed; the fixed bed reactor is at the temperature of 150-300 DEG C and the pressure of 1-20MPa, ammonia alcohol ratio is 1-15, and unreacted hydrogen and ammonia are recycled. The device and method for continuously synthesizing amine-terminated polyether by utilizing the fixed bed overcome the defects of tedious operation, unstable product quality, low synthesis efficiency and the like of the existing technology as a batch-type operation is adopted, a continuous reaction technological design is adopted, a technology is simple, performance is stable, yield is high, excessive ammonia and hydrogen are recycled, pollution to the environment is reduced, production cost is reduced, and energy is saved; conversion rate of hydroxyl-terminated polyether or derivative thereof and selectivity of the amine-terminated polyether product are obviously improved, so that production cost of the amine-terminated polyether product is obviously reduced.

The invention relates to a carbon nanotube-metal composite enhanced copper-based composite material and a preparation method thereof, and belongs to the field of preparation of composite materials. The preparation method comprises the following steps: preparing colloidal sol by using soluble salts containing metallic elements and copper ions and carbon nanotube as raw materials, carrying out spray granulation by using the colloidal sol through a spray dryer so as to obtain nanoscale mixed powder, calcining the mixed powder in an oxygen-free atmosphere so as to obtain black powder, reducing the black powder in a hydrogen atmosphere so as to obtain carbon nanotube-metallic element composite enhanced copper-based powder, carrying out isostatic press moulding on the mixed powder, and then sintering in the hydrogen atmosphere so as to obtain the carbon nanotube-metallic element composite enhanced copper-based composite material, wherein the content of a metallic element X in the composite material is 0.1-2wt%, and the content of the carbon nanotube in the composite material is 0.1-2wt%. The preparation method has the advantages that corresponding carbides can be formed, the problem of reinforcement agglomeration caused by poor interface bonding between reinforcement and a copper matrix is solved, and the copper-based composite material with excellent combination properties can be obtained.