108 results about "Oxygen impurity" patented technology

A method and apparatus for producing a purified liquid argon product in which liquid argon having oxygen impurities is produced in a cryogenic air separation plant by separating argon from oxygen within an argon column. An impure liquid argon stream, composed of part of the liquid argon, is purified in an adsorbent bed by adsorbing the oxygen impurities in an adsorbent to produce a purified liquid argon stream that constitutes the purified liquid argon product. During adsorption, the adsorbent bed is maintained at a reduced temperature with a coolant to prevent vaporization of the liquid argon. The bed is then regenerated by draining residual liquid argon from the adsorbent bed, introducing the residual liquid argon back into the air separation plant and then desorbing the oxygen impurities with a regeneration gas. After regeneration, the adsorbent bed is refilled with purified liquid argon prior to being brought back on-line.

The invention provides a preparation method of high-purity and low-loss chalcogenide glass, belonging to a preparation method of the chalcogenide glass. The preparation method comprises the following steps of: removing hydrocarbon impurity in the glass by taking ultra-dry gallium chloride as a purifying agent, and distilling and purifying the glass in combination with the conventional deoxidant, aluminum, magnesium or zirconium metal; placing glass mixture into a quartz ampoule to be sealed in by means of vacuum supply, founding the glass mixture in a vacuum ampoule, dynamically distilling the glass, and remelting the mixture after distilling; and effectively removing the hydrocarbon impurity in the glass by taking the ultra-dry gallium chloride as the purifying agent, so that the Mie scattering imperfection is hardly formed in the finally-obtained high-purity chalcogenide glass, and the low-loss homogeneous glass can be obtained. According to the high-purity chalcogenide glass synthesized by the preparation method provided by the invention, the minimum loss under the infrared transmission waveband is less than 0.3dB/m, and the corresponding loss of the absorption peak of the residual impurity is less than 8dB/m, so that the preparation method can be used in the field of an infrared glass optical element and an infrared optical fiber. The ultra-dry gallium chloride purifying agent can be easily obtained, and is lower in price; the carbon, hydrogen and oxygen impurities can be removed from the chalcogenide glass at high efficiency; the prepared chalcogenide glass is better in uniformity and less in light scattering.

The invention belongs to the technical field of ceramic material preparation and relates to a method for preparing silicon nitride ceramics with high thermal conductivity by adding fluoride. In the present invention, α-Si3N4 is used as a raw material, and a mixture of silicon magnesium nitride and rare earth fluoride is used as a sintering aid, and the additive amount is 1 to 15 wt%. First, use nano-TiC to pretreat the surface of Si3N4 powder, put the treated raw materials, additives, binders, crystal seeds, defoamers, and solvents into a ball mill and mix them evenly, and then add a dispersant for secondary Secondary ball milling, the mixed slurry after ball milling is dried, granulated, shaped, sintered, and heat treated to prepare silicon nitride ceramics with high thermal conductivity. The present invention prevents the oxygen in the auxiliary agent from entering into the crystal lattice of silicon nitride ceramics by adding rare earth metal fluoride, reduces the adverse effect of lattice oxygen impurity content on the thermal conductivity of ceramics, and the prepared silicon nitride ceramics has relatively high High thermal conductivity has great application potential in the field of electronic packaging materials.

The invention provides a titanium-aluminium alloy material and the preparation technology thereof. The titanium-aluminium alloy material is characterized by comprising the following components in percent by weight: 7 to 7.5 percent of Al, 0.1 to 0.25 percent of Cr, 0.5 to 0.8 percent of Mn, 1.2 to 1.4 percent of Nb, 0.15 to 0.3 percent of Mo, 5 to 6 percent of W, 0.75 to 0.9 percent of Bi, 0.05 to 0.08 percent of Dy, 0.05 to 0.15 percent of Gd, 0.3 to 0.45 percent of Er, 3 to 4 percent of Ce, 2 to 2.5 percent of Zr, 3 to 3.5 percent of Sn, and the balance of Ti; the titanium-aluminium alloy material is free from nitrogen-oxygen impurities, has the advantages of good corrosion resistance, high intensity, good low-temperature performance, small heat conduction elasticity and the like, is suitable for manufacturing components of air compressors for airplane motors, and structural parts of rockets, guided missiles and high speed crafts next.

The invention discloses a method for growing large-size fluoride crystals through a top seed crystal kyropoulos method. The method comprises the following steps: weighing and mixing fluoride crystals and deoxidant powder, and pressing a mixture to form a block; drying the pressed block; putting the block into a crucible, sequentially installing thermal field components and installing seed crystals; vacuumizing, and heating to smelt the material until observing that the block is molten; descending the seed crystals to contact with a melting liquid level so as to slightly melt the seed crystals, pulling seed crystal rods and growing the block on the seed crystals in a condensation manner; after finishing crystal seeding, entering a shouldering period at power reduction, maintaining the crystals rotating and keeping the crystal pulling speed in the period, gradually increasing the diameters of the crystals in an upward pulling process, and entering an isometrical growth period until the crystal growth is finished; and cooling and annealing after the crystal weight reaches the feed weight. The method is low in growth cost and short in growth period; the method is suitable for large-size fluoride crystals, and the fluoride crystals grow in a vacuum condition without oxygen impurities; and the growth process is visible and controllable, so that the crystal quality is improved.

The application discloses high-purity silicon carbide powder and a preparation method therefor and belongs to the field of preparation of semiconductor materials. The preparation method for the high-purity silicon carbide powder comprises the following steps: providing beta silicon carbide powder and/or alpha silicon carbide powder as an initial silicon carbide powder material; recrystallizing theinitial silicon carbide powder material, so as to prepare a silicon carbide polycrystalline block; and subjecting the silicon carbide polycrystalline block to decarburization purification, thereby preparing the high-purity silicon carbide powder, wherein a temperature of recrystallization is not low 2,500 DEG C. According to the high-purity silicon carbide powder and the preparation method therefor, the purity of the prepared high-purity silicon carbide powder is improved by a recrystallization method, impurity removal by a hydrometallurgy or pickling step is not required, and the high-puritysilicon carbide powder is light in pollution, low in toxicity and high in operability; by a decarburization purification step of introducing oxygen gas to pure silicon carbide powder at a temperatureof 600 DEG C to 799 DEG C, the decarburization effect of the carbonized polycrystalline block is good, the prepared high-purity silicon carbide powder is low in degree of oxidation, and the influenceon an oxygen impurity is low when the high-purity silicon carbide powder is applied to growth of silicon carbide monocrystals; and by the preparation method, the high-purity silicon carbide powder with purity not lower than 99.9999% can be prepared, and the particle size of the high-purity silicon carbide powder is controllable.

The invention relates to a red light semiconductor laser structure with an aluminum-free waveguide layer, which sequentially comprises a substrate, a lower limit layer, a lower waveguide layer, a quantum well layer, an upper waveguide layer, an upper limit layer and an ohmic contact layer from the bottom up, wherein the lower waveguide layer, the quantum well layer and the upper waveguide layer are made of a gallium indium phosphide material. The waveguide layer adopts the aluminum-free gallium indium phosphide material, so that there is no aluminum in an active region, and requirements for the growth environment, especially for the concentration of oxygen impurities, are no longer so harsh. Meanwhile, the oxidation resistance is increased because there is no aluminum in the active regionwhen cavity surface cleavage is performed, so that cavity surface defects are effectively reduced. The design not only reduces oxygen impurity defects inside the material, but also reduces the formation of cavity surface defects, thereby being capable of reducing the light absorption, and improving the anti-burning ability of the cavity surface and the life of a semiconductor laser.

The invention discloses a method and a device for highly purifying gas. The method comprises the steps that: alkali metal in a closed container is heated to produce alkali metal atom steam, then gas required to be purified is fed into the container, and alkali metal surface, the alkali metal atom steam and water, oxygen and oxygen impurities contained in the gas required to be purified are subjected to reaction and purification; the gas required to be purified flows out of the container after reaction and purification. The device has excellent property of highly gas purifying, particularly has pertinency, and eliminates the hidden danger that alkali metal in a laser pre-polarization system of a magnetic resonance contrast medium is oxidized. The method can be applied to the manufacture of similar operating systems or devices containing alkali metal, such as highly purifying working gas of atomic steam bubbles in an atomic frequency standard, an atomic filter, an atomic magnetometer and other systems.

The invention belongs to the field of polysilicon purification, and concretely relates to a method for removing oxygen impurities in polysilicon through electron beam continuous melting, and an apparatus thereof. A traditional oxygen removal mode is broken, and electron beam melting is adopted to remove oxygen in order to solve the removal problem of impurity oxygen in the polysilicon. An overturning mechanism and a loading crucible are arranged to guarantee the semi-continuous production of electron beam melting oxygen removal and high output per furnace. The method and the apparatus have the following advantages: 1, electron beam bombardment melting is carried out for 5-15min to make the oxygen content lower than 0.0571ppmw and solar battery's requirements on the oxygen content of polysilicon cast ingots met; 2, the photoelectric conversion efficiency of battery slices is above 0.1% higher than that of polysilicon obtained without an oxygen removal technology; and 3, continuous production is realized, and the production efficiency increases by above 35%.

The invention relates to a method for growing a high-crystal quality high-resistance GaN epitaxial layer, which reduces the concentration of oxygen impurities in GaN and reduces background electron concentration which needs to be compensated via pre-depositing low-temperature AlN on a sapphire substrate and carrying out annealing treatment (AlN pretreatment for short), so the high-resistance GaN epitaxial layer can be obtained only by introducing less edge dislocation into the GaN epitaxial layer for compensation. The resistivity of the high-resistance GaN epitaxial layer prepared by the method is greatly larger than 107 ohm. cm at room temperature, the surface roughness (RMS) of 3 mu m x 3 mu m area reaches 0.2-0.3 nm, and the surface is smooth; the full width at half maximum of X-ray diffraction ohm scanning (102) swing curve can be controlled to about 600 arc sec, and the dislocation density is 40-50% lower than that in conventional edge dislocation compensation high-resistance GaN; and the high-resistance GaN growth technology has excellent repeatability, and meets industrial application requirements. The method is simple, and does not cause any pollution on the MOCVD system.

A spectroscopy system for spectro-chemical analysis of a sample includes a plasma torch (50) for generating a microwave induced plasma (90) as a spectroscopic source. The plasma forming gas is nitrogen which can contain an oxygen impurity. Thus the system includes a nitrogen generator (70) which is preferably supplied with compressed atmospheric air from a compressor (75) for oxygen to be removed from the air by adsorption. The invention allows the use of an on-site nitrogen gas generator and thus gives cost savings because the need to obtain supplies of bottled high purity gas is eliminated.

The invention provides a modified molecular sieve for olefin purification and a method for removing oxygen impurities from olefins by the modified molecular sieve. The modified molecular sieve is modified with an organometallic compound. The method comprises the following steps: olefin flow containing water, ether, aldehyde, ketone, alcohol and other oxygen impurities passes through an organometallic compound modified molecular sieve bed layer, and high-purity olefin flow is obtained. The molecular sieve bed layer can be regenerated by purging with inert gas at a high temperature after the molecular sieve bed layer is saturated. Olefins, especially isobutene, purified with the method meets the standard of high purity and can be applied to polymerization-stage reaction and organic synthesisreaction.

The invention discloses a silicon material cleaning method, belongs to the technical field of semiconductor silicon materials, and solves the problems that cleanness of a traditional silicon materialcleaning method is not high, the purity of a cleaned silicon material is not high, and the performance of a product using a silicon material as a raw material is seriously affected. The method mainlyincludes grinding, acid washing, alkali washing, cleaning, wet oxygen impurity removal, washing and drying and other operational processes. The invention has high cleanliness and high purity of the cleaned silicon material, and the high-purity silicon material greatly improves the performance of the product using the silicon material as a raw material. The silicon obtaining rate is high, the silicon material running away in the cleaning process can be recycled, the effects of low carbon, energy saving and environment protection are achieved, considerable economic and social benefits can be created for enterprises, and thus the silicon material cleaning method is of great significance in the technical field of semiconductor silicon material.

The invention relates to the technical field of ceramic material preparation, provides high-thermal-conductivity silicon nitride ceramic and a preparation method thereof, and solves the problem of lowthermal conductivity of silicon nitride ceramic in the prior art. The silicon nitride ceramic comprises the following components in parts by weight: 60-90 parts of silicon nitride, 8-12 parts of silicon carbide, 3-5 parts of rare earth chloride, 0.2-1 part of ytterbium fluoride, 0.5-2 parts of zirconium nitride and 5-10 parts of dispersing agent. According to the preparation method, the rare earth chloride is added, so that the sintering activity of the silicon nitride powder is improved under the condition of not additionally introducing oxygen, and densification of the silicon nitride ceramic is realized; the ytterbium fluoride can promote diffusion of Si and N and react with oxygen impurities in silicon nitride crystal lattices, so that the content of dissolved oxygen in the silicon nitride crystal lattices is effectively reduced, and the heat conductivity of silicon nitride is improved; zirconium ions in the zirconium nitride have strong affinity to oxygen and can absorb part of oxygen impurities in crystal lattices. Rare earth chloride, ytterbium fluoride and zirconium nitride are matched with one another, the size of silicon nitride grains can be increased, and oxygen impurities can be discharged.

The invention belongs to the field of infrared optical glass preparation, specifically relates to an infrared glass preparation method and a water removing device thereof and aims at solving the defect that impurities of hydrogen and oxygen in the infrared glass cannot be removed effectively in the prior art. The water removing device comprises an inert gas inlet pipe, a chlorine inlet pipe, a heating furnace, a raw material pipe and a gas outlet pipe, wherein the inert gas inlet pipe, the chlorine inlet pipe and the gas outlet pipe are each communicated with the raw material pipe, and the heating furnace is arranged outside the raw material pipe. Chlorine is utilized to remove water of infrared glass, the chlorine can effectively remove absorption peaks generated at 2.9 and 4.3 micrometer positions by O-H and H-S bonds, and practical foundation of the infrared glass is established. The technological principle is that a strong oxidant, namely of the chlorine, is mainly utilized to snatch the hydrogen impurity in the glass, hydrogen chloride gas is generated to be exhausted out glass melting liquid, and the hydrogen impurity is eliminated.

The invention discloses a method for growing a cerium fluoride crystal by a non-vacuum descent process. The method comprises the following steps: a) uniformly mixing cerium fluoride powder and polytetrafluoroethylene powder at a mass ratio of 100:(1-5); b) performing vacuum drying of the mixed powder obtained in the step a); and c) putting the dried mixed powder obtained in the step b) into a crucible, and performing crystal growth at a descent rate of 0.5-1.5mm/h in a non-vacuum condition. According to the method disclosed by the invention, the oxygen impurity can be effectively cleared by adding certain amount of polytetrafluoroethylene powder, thus the growth of CeF3 crystal using the Bridgman method in a non-vacuum condition is realized, the growth technology of CeF3 crystal is greatly simplified, and large-scale production of CeF3 crystal is facilitated; and compared with the prior art, the method has remarkable progress and practical value.

The invention provides a crucible for a polycrystalline silicon ingot with a coating structure. The crucible comprises a crucible body and the coating structure arranged on the inner surface or the inner and outer surfaces of the crucible body, wherein the crucible body comprises a base and side walls which upward extend from the base; an accommodation space is defined by the base and the side walls; the coating structure comprises impurity absorbing layers and silicon nitride layers; the impurity absorbing layers and the silicon nitride layers are sequentially and alternatively arranged to form an (AB)n arrangement form from the crucible body to the coating structure along the thickness direction; A represents the impurity absorbing layers, B represents the silicon nitride layers, and n is an integer which is greater than or equal to 1; and the A is a polycrystalline silicon powder coating of which the surface is provided with a SiO2 oxide layer, or a mixed coating of a material of which the melting point is greater than or approximates to that of crystalline silicon and surface-unoxidized polycrystalline silicon powder and/or polycrystalline silicon powder of which the surface is provided with the SiO2 oxide layer. The coating structure in the crucible can stop metal impurities and oxygen impurities in the crucible from diffusing into the crucible during ingot casting. The invention also provides a production method of the crucible and application of the crucible in the ingot casting.

The invention relates to the field of fine chemical engineering, in particular to a purification method of electronic-grade octafluorocyclopentene. The method comprises the steps of rectification purification, low-temperature adsorption purification, pressurized adsorption purification and the like. According to the method, the final product octafluorocyclopentene is obtained from raw material cyclopentene which is easy to obtain by using a gas phase process. A low-temperature rectification technology is adopted, and combined with a low-temperature adsorption technology and a pressurized adsorption technology to purify the octafluorocyclopentene; modified coconut shell charcoal is used as a mesoporous low-temperature adsorbent; further separation purification is performed through membraneseparation, so that the volume concentration of a water impurity in the octafluorocyclopentene product is less than or equal to 5 ppm; the volume concentration of an oxygen impurity is less than or equal to 3.5 ppm, and the volume concentration of nitrogen which is difficult to separate in the traditional process is less than or equal to 1 ppm. The purity of the product is effectively improved, the purity of the octafluorocyclopentene product is 99.999% or above, and the requirements of semiconductor and microelectronic industries on electronic special gas are met.

The invention provides a preparation method of high-purity hexagonal boron nitride powder, which is low in cost, easy to implement and good in effect. The preparation method has good control effect onmetallic element impurities and non-metallic element impurities, especially an oxygen impurity element and a carbon impurity element which are in a large quantity. The prepared boron nitride powder has a low oxygen content and carbon content, has very low contents of the metallic element impurities and other non-metallic element impurities, is good in hot press performance, can be used to preparepure hexagonal boron nitride ceramic products or parts for high-temperature electric insulation in a non-oxidizing atmosphere, and can be also mixed with high-stability resin such as polytetrafluoroethylene to prepare high-voltage insulation plastic products or parts in a hot press or extrusion way.

The invention relates to a preparation process of monocrystalline silicon for a solar cell panel. The preparation process comprises the steps: charging, fusion, necking-down growth, shouldering growth, isometric growth and tail growth. According to the preparation process, monocrystalline silicon raw materials are heated at a low temperature so as to release internal stress before being sent into a crystal growth furnace, so that the dislocation generated during the crystal growth is reduced, and the crystallization quality is improved; in a fusion process, the crystal growth furnace is heated to 800-900 DEG C and is vacuumized, and argon is introduced into the crystal growth furnace, so that on the one hand, the internal stress of the monocrystalline silicon raw materials is further released, on the other hand, bubbles and oxygen impurity in the monocrystalline silicon raw materials are removed through heating and are discharged out of the crystal growth furnace together with argon, and the purity of the monocrystalline silicon raw materials is guaranteed; and monocrystalline silicon prepared by virtue of the preparation process has few internal defects, is high in crystallization quality, has relatively high photoelectric conversion efficiency when being used as the solar cell panel and simultaneously is long in service life.