13 results about "Post oxidation" patented technology

The invention relates to the technical field of quenching processes, in particular to a casting multi-stage quenching process which comprises the following steps: putting a casting into a vacuum furnace, heating and preserving heat, then opening a furnace door, and continuously preserving heat in an air environment at the same temperature to obtain a pretreated casting; the pretreated casting is immersed in a quenching medium, ultrasonic treatment is applied during the period, the pretreated casting is taken out after being cooled and then air-cooled to the room temperature, and a quenched casting is obtained; the quenched casting is subjected to shot blasting treatment, then heated and subjected to heat preservation, and after the quenched casting is cooled to the room temperature, a surface layer low-carbon casting is obtained; and then nitriding treatment and post-oxidation treatment are carried out in sequence. According to the method, the medium-carbon casting is firstly heated in the vacuum furnace at a high temperature, then the medium-carbon casting is subjected to short-time high-temperature oxidation and decarburization in the air environment to reduce the carbon content of the surface layer of the casting, and nitrogen diffusion is prevented from being inhibited due to excessive carbon, so that the thickness of a nitriding layer is increased, the problem that the nitriding layer is thin and brittle is avoided, and the hardness, wear resistance and impact resistance of the finished casting are improved.

The application discloses a sintered neodymium-iron-boron composite coating with high bonding force and high hydrogen resistance and a preparation method thereof. The method comprises the following steps: (a) substrate pretreatment, wherein surface oxides are removed by energy gradient plasma sputtering cleaning; (b) sputtering an Al layer under an Ar atmosphere and oxidizing under O2 plasma assistance, thereby generating an intermetallic compound anchoring layer of FeAl3 / NdAl2 with a thickness of 1.0-1.5 nm in situ; (c) sequentially depositing 6 layers of Al2O3 layers to form an alternating stack with a total thickness of 20-30 nm, wherein the first, third and fifth layers are prepared by directly sputtering an Al2O3 ceramic target, and the second, fourth and sixth layers are prepared by first sputtering an Al layer and then completely converting by O2 oxidation; (d) low-temperature annealing to fully form Al-O-Fe bonds at the interface; and (e) cooling to room temperature. The application adopts a multi-dimensional in-situ closed-loop monitoring system to realize accurate process control, and is suitable for surface protection of sintered neodymium-iron-boron permanent magnets in hydrogen energy equipment.

This invention discloses a boron diffusion process, comprising the following steps: S1: placing a small boat containing a silicon wafer into a furnace tube; S2: evacuating the furnace tube; S3: leak detection; S4: introducing nitrogen and oxygen for pre-oxidation; S5: introducing nitrogen, oxygen, and a diffusion boron source for diffusion; S6: introducing nitrogen for heating diffusion; S7: introducing nitrogen, oxygen, and a diffusion boron source under constant temperature conditions; S8: introducing nitrogen and oxygen, heating for aerobic propulsion; S9: introducing oxygen, continuing heating for post-oxidation; S10: introducing mixed oxidation with large and small oxygen molecules; S11: introducing nitrogen and large oxygen molecules and cooling; S12: breaking the vacuum to atmospheric pressure; S13: removing the boat. This invention has advantages such as simple principle, low process temperature, and low BRL layer thickness, significantly shortening process time and increasing production capacity.

The invention discloses a worm gear slewing bearing for maritime affair hoisting equipment and a manufacturing method of the worm gear slewing bearing. The manufacturing method comprises the steps that raw material pretreatment is conducted, wherein thermal refining is conducted on a base material; mechanical rough machining is conducted, specifically, turning and milling rough machining are conducted on the base material, so that an inner ring structure and an outer ring structure are machined; carrying out gas nitrocarburizing treatment and post-oxidation treatment on the outer ring; the gas nitrocarburizing treatment comprises the steps that the outer ring is subjected to first heat treatment under inert mixed gas, so that a diffusion layer and a white bright layer are generated on the surface of the outer ring; the post-oxidation treatment comprises the steps that mixed gas composed of water vapor and nitrogen is introduced, and after second heat treatment, a Fe3O4 oxidation layer is generated on the surface of the white bright layer; and the inner ring and the outer ring are subjected to quenching treatment. The slewing bearing solves the problems that an existing slewing bearing for maritime lifting equipment cannot meet the strict use requirement of a maritime environment due to the fact that it is difficult to ensure that the depth of a hardening layer stably reaches the standard, control quenching deformation and improve product transmission precision.

The invention belongs to the technical field of porous sieve-shaped filter manufacturing, and particularly discloses a porous sieve-shaped filter surface layer composite strengthening heat treatment method. High-quality nitriding steel 38CrMoAl serves as a raw material, machining is conducted after thermal refining, the size of a workpiece is stabilized through high-temperature stress relief annealing treatment, plasma glow nitriding treatment is conducted after machining is conducted, the uniform deep nitriding effect of a porous sieve-shaped filter is achieved through an auxiliary tool, then post-oxidation treatment is conducted, a compact Fe3O4 film is formed on the surface of the workpiece, and the high-quality nitriding steel 38CrMoAl is obtained. Contact between a corrosive medium and matrix metal is effectively isolated, and the rust-proof and corrosion-resistant capacity of a workpiece is improved. For workpieces such as a porous sieve-shaped filter requiring high wear resistance and good anti-rust performance, the combination of ion nitriding and post-oxidation treatment can realize gentle hardness gradient decreasing amplitude and surface corrosion resistance and rust prevention. The nitriding layer provides high hardness and wear resistance, the surface oxidation film endows an anti-rust function, and the nitriding layer and the surface oxidation film cooperate to achieve the composite strengthening effect of high hardness and corrosion resistance of the surface layer.

The application provides a method for improving the white spot defect of a crystalline silicon wafer in a post-oxidation process, which comprises the following steps: (1) wafer loading; (2) first ozone purification; (3) temperature rising; (4) first vacuum pumping; (5) second ozone purification; (6) post-oxidation; (7) second vacuum pumping; (8) pressure recovery; (9) temperature falling; and (10) wafer unloading. The method utilizes ozone with strong oxidizing property to purify the air in a furnace tube, improves the cleanliness of the environment atmosphere in the post-oxidation process, reduces the proportion of pollutants in the furnace tube, and further effectively reduces the proportion of the white spot defect of the crystalline silicon wafer. The method is simple in operation, low in requirement for equipment, low in processing cost, and has a large-scale application prospect.

The invention discloses a high-wear-resistance and corrosion-resistance alloy steel chain and a preparation method thereof. The base material of the alloy steel chain comprises C, Si, Al, Mn, Cr, Mo, Ni, Cu, B, N, V and / or Nb, Ca and / or RE and Fe. The matrix material meets the following conditions: the total mass of Si and Al accounts for 0.85-1.25%, and the ratio of Al to Si is 0.6-1.2; the atomic ratio of N / B is 1.5-3.0; when V is contained, if Nb is not contained, the mass ratio of V to C is 0.35-0.65, and if Nb is contained at the same time, the mass ratio of V to (C-0. 129 * Nb) is 0.35-0.65. The preparation method comprises the steps of smelting, forming and welding, austenitizing, quenching and isothermal transformation, high-temperature tempering, plasma nitriding, post-oxidation and sealing treatment. The alloy steel chain realizes the cooperation of high strength and toughness and high wear resistance and corrosion resistance, and is suitable for harsh working conditions such as mines and ports.

The application provides a Nb micro-alloyed oriented silicon steel decarburization annealing oxidation layer structure regulation method, and relates to the technical field of oriented silicon steel decarburization annealing. The Nb micro-alloyed oriented silicon steel decarburization annealing oxidation layer structure regulation method comprises the following steps: S1, selecting oriented silicon steel with a Si element mass fraction of 3.0% as a base material, adding Nb element to the base material for micro-alloying treatment, and preparing Nb micro-alloyed oriented silicon steel; S3, placing the Nb micro-alloyed oriented silicon steel prepared in S1 in the decarburization annealing atmosphere prepared in S2 for decarburization annealing treatment, and precisely regulating the thickness of the oxidation layer and the content ratio of spherical oxides to strip-shaped oxides in the oxidation layer after decarburization annealing of the oriented silicon steel by regulating the Nb element addition amount, the decarburization annealing temperature and the holding time. The regulation law of Nb and process parameters on the oxidation layer is clear, the oxidation layer structure is precisely controllable, and the process standardization is supported.

The invention relates to a preparation method of a riveted post-oxidation contact. The preparation method comprises the steps of burdening, smelting, extruding, wiredrawing, annealing, upsetting, internal oxidation and cleaning. The prepared riveted post-oxidation contact is excellent in impact current resistance and small in splashing, and the technological process is shorter than that of a pre-oxidation wire upsetting contact; the yield of the whole process is much higher than that of a contact formed by upsetting a front oxidized wire and a rear oxidized sheet, and the process loss is small; in addition, the post-oxidation contact can be commonly used with a riveting line of a pre-oxidation wire upset contact, automatic riveting can be achieved, and efficiency is greatly improved.

This invention discloses the preparation and application of a highly stable underwater superoleophobic silicon carbide ceramic membrane. The preparation involves first placing an unoxidized silicon carbide ceramic membrane in a muffle furnace and sintering it at 500–900°C for 25–45 minutes to obtain a post-oxidized silicon carbide ceramic membrane. Then, the post-oxidized silicon carbide ceramic membrane is placed in a plasma cleaner and subjected to plasma modification at a vacuum of 300–800 mT for 5–120 minutes. Experiments have shown that the method of this invention produces a silicon carbide ceramic membrane that not only possesses excellent underwater superoleophobic properties but also retains these properties for a long time with high stability, showing great promise for application in oil-water separation. Furthermore, the preparation method of this invention is simple, uses mild conditions, is low-cost, and easily scalable.

The invention discloses a high-hardness nitrided steel material and a preparation method thereof, and belongs to the technical field of nitrided steel materials. According to the high-hardness nitrided steel material, 38CrMoAl steel serves as a raw material, and quenching and tempering, cutting, polishing, cleaning and drying pretreatment are sequentially conducted; then the pretreated 38CrMoAl steel is subjected to ion carburization through a rare earth permeation accelerant, then multiple times of post-oxidation are conducted, and one time of hydrogen sputtering is further conducted between every two adjacent times of post-oxidation; wherein the rare earth catalytic permeation agent adopts lanthanum-cerium alloy, and the lanthanum-cerium alloy comprises the following main chemical components: 32.4 wt% of lanthanum, 67.43 wt% of cerium, 0.15 wt% of praseodymium, less than 0.03 wt% of neodymium, 0.53 wt% of iron, less than 0.01 wt% of silicon and less than 0.01 wt% of phosphorus; the nitriding gas source adopts mixed gas of nitrogen and argon in a volume ratio of (3-4): (1-2). The prepared high-hardness nitrided steel material is better in hardness and wear resistance and lower in brittleness.

The application provides a diffusion process for improving high sheet resistance uniformity of a solar cell, comprising the following steps: pressure extraction; pre-oxidation; first deposition of large and small nitrogen and oxygen, pressure reduction by 10 mbar, and constant temperature; second deposition of large and small nitrogen and oxygen, temperature increase by 10 DEG C, and constant pressure; first pushing, stop of air supply, pressure increase by 10 mbar, and temperature increase by 70 DEG C; second pushing, oxygen supply, constant pressure and temperature; third pushing, stop of air supply, constant pressure and temperature; fourth pushing, temperature decrease by 70 DEG C, and constant pressure; third deposition of large and small nitrogen and oxygen, pressure reduction by 10 mbar, and constant temperature; fifth pushing, stop of air supply, pressure increase by 10 mbar, and constant temperature; phosphorus supplement, large and small nitrogen and oxygen supply, constant pressure and temperature; post-oxidation; and pressure return. The scheme realizes high sheet resistance of large-size cell pieces and improves the uniformity of high sheet resistance by optimizing the diffusion process, and achieves the optimization of cell efficiency distribution and the improvement of cell efficiency.

This invention relates to the field of workpiece surface treatment technology, and discloses a gas QPQ post-oxidation blackening agent, its preparation method, and its application. By weight, the gas QPQ post-oxidation blackening agent comprises the following components: 15-30 parts rare earth compounds, 10-15 parts citric acid and / or citrate, 5-15 parts ammonium molybdate, 3-8 parts ammonium chloride, 15-25 parts vitamin C, 10-30 parts formamide, 5-10 parts manganese dioxide, 5-10 parts phosphoric acid, 15-30 parts calcium nitrate, 30-40 parts ethanol, and 5000 parts water. In this invention, the components work together synergistically to ensure that the treated metal products fully meet their requirements for corrosion resistance and color.