43results about How to "Avoid severe oxidation" patented technology

The present invention relates to a flexible stress sensor. The flexible stress sensor comprises two sensing assemblies; each sensing assembly includes a flexible fiber wire and a nanostructured film coating the flexible fiber wire; the flexible fiber wire is made of a conductive material or the surface of the flexible fiber wire is provided with a conductive layer; the nanostructured film is made of a conductive material or a semiconductor material; the two sensing assemblies are cross-stacked; and the nanostructured films of the two sensing assemblies contact with each other at the intersection of the two sensing assemblies. The present invention also relates to a preparation method of the flexible stress sensor. The flexible stress sensor of the invention has the advantages of small size, high resolution, high sensitivity and simple preparation, is suitable for being applied to miniaturized and integrated equipment and can be used for making wearable equipment for detecting human health.

The invention discloses a brazing method of a tungsten-copper alloy and a chromium-zirconium-copper alloy, and relates to the field of welding. The method aims to shorten the brazing time for the tungsten-copper alloy and the chromium-zirconium-copper alloy, avoid the use of a solder resist, reduce the brazing cost and improve the brazing efficiency. According to the method, the tungsten-copper alloy and the chromium-zirconium-copper alloy are connected by adopting an ultrasonic wave-assisted brazing method, ultrasonic waves are used in the brazing process through a titanium alloy intermediatelayer, and the spreading and wetting of melted brazing filler metal on a brazing surface are promoted by utilizing the acoustic cavitation effect; when the tungsten-copper alloy and the chromium-zirconium-copper alloy are combined and brazed, one of a base metals is moved to promote the discharge of bubbles, and then the ultrasonic wave-assisted brazing process is completed in a short period of time under the low brazing pressure; and in addition, the method can perform brazing in an atmospheric environment, the technical requirements for brazing operators are low, and the brazing efficiencyis high. The invention is applied to the field of brazing.

The invention discloses a positive temperature coefficient (PTC) thermal resistance alloy wire and a preparation method thereof. The alloy wire comprises the chemical ingredients by weight percent of 45-82.0% of nickel, 0.1-0.6% of silicon, 0.22-0.35% of manganese, 0.02-0.04% of yttrium, 0.04-0.06% of misch metal, 0.05% or less of carbon, 0.01% or less of sulphur, 0.001% or less of phosphorus and the balance of iron. The mean resistance temperature coefficient at 0-150 DEG C is 2500*10(-6) per DEG C to 5000*10(-6) per DEG C by changing the matching content of the components; the PTC thermal resistance alloy wire of which the resistance temperature coefficient which is urgently needed at present and higher than 3000*10(-6) per DEG C is included; the highest mean resistance temperature coefficient can be 5000*10(-6) per DEG C, and the requirements of more sensitive temperature control of novel electrical equipment can be met.

An iron-copper bonded material and a preparation method thereof, belonging to the field of material technology, are formed by combining two metals, one metal is an iron alloy, and the other metal is a copper alloy; the joint of the two metals is in the form of atomic bonding; the preparation The method is: (1) process the iron alloy into an iron drum; (2) prepare the copper alloy raw material and carbonaceous material; (3) put the copper alloy raw material and carbonaceous material into the iron drum, and weld the iron cover on the iron drum , placed in a heating furnace, heated to form a melt; (4) centrifuged in a centrifuge until it is completely solidified into a copper alloy; placed in casting sand and cooled to room temperature; (5) cut along the vertical direction of the axis to obtain a double Metal disc; (6) Rolled into ring-shaped bimetallic sheet. The iron-copper bonding material in the present invention can be applied in bridging welding of dissimilar metals, high-temperature automatic protection of nuclear power plants, automatic control devices in unmanned environments, microgravity electric rotor connectors, and the like.

A brazing method for tungsten-copper alloy and chromium-zirconium-copper alloy, which relates to the field of welding. The purpose of the invention is to shorten the welding time of tungsten-copper alloy and chromium-zirconium-copper alloy, avoid the use of solder resist, reduce welding cost, and improve welding efficiency . The invention adopts the method of ultrasonic-assisted brazing to connect tungsten-copper and chromium-zirconium-copper alloy, and uses the ultrasonic wave in the welding process through the titanium alloy intermediate layer to promote the spreading and wetting of the melted solder on the welding surface by using the acoustic cavitation effect . When tungsten-copper alloy and chromium-zirconium-copper alloy are welded together, one of the base metals is moved to promote the discharge of air bubbles, and then the ultrasonic-assisted brazing process is completed in a short period of time under a lower welding pressure. In addition, the present invention can Welding in the atmospheric environment has low technical requirements for welding operators and high welding efficiency. The invention is applied in the field of welding.

The invention belongs to the technical field of metal welding, and particularly relates to a copper and steel bimetal bridging welding method. The method includes firstly adding copper material and charcoal into a steel drum, then placing the steel drum in a heating furnace to form flux inside, placing the steel drum with the flux into a centrifuge, turning on the centrifuge to rotate in the speed of 400 to 800 rpm, allowing the flux to cool till solidifying as copper alloy, allowing the middle of the copper alloy to form a sump, obtaining a bimetal drum, then placing the bimetal drum into casting sand to cool till room temperature, obtaining a bimetal combined drum, rolling, extruding, tensioning, forging and cutting the bimetal combined drum, obtaining a steel and copper welding bridge, welding steel to be welded to the steel side of the welding bridge, welding copper to be welded to the copper side of the welding bridge, and finishing steel and copper welding. According to the technical scheme, the atomically-bound copper and steel bimetal serves as a bridge, copper and copper, steel and steel can be welded easily, and copper and steel bimetal welding can be realized.

The invention discloses a continuous swaging device and method for manufacturing molybdenum rods or molybdenum alloy rods. The transmission mechanism is installed in a box capable of heat insulation and noise reduction. The product molybdenum rod or molybdenum alloy rod is sent out from the outlet of the box body; the top of the box body is equipped with an exhaust mechanism, and the transmission mechanism adopts a three-stage continuous swaging process, and the ventilation mechanism above the fourth transmission mechanism A spray cooler capable of cooling the molybdenum rod or molybdenum alloy rod on the fourth conveying mechanism is installed on the mechanism. The continuous swaging device of the present invention is used to manufacture molybdenum rods or molybdenum alloy rods, which realizes the automation and continuity of the production process, improves the environmental conditions of the production site, and solves the problems of oxidation and loss of products. The processing size precision is high, and the yield rate is significantly improved.

The invention provides a ceramic ball with an in-built alpha+beta titanium alloy skeleton. The ceramic ball is composed of an alpha+beta titanium alloy prepared skeleton with an integrated structure, and a ceramic ball body wrapped outside of the skeleton, and is manufactured in manners of integrated lamination and high-temperature sintering, wherein the total volume of the alpha+beta titanium alloy skeleton accounts for 3 to 5% of the volume of the ceramic ball; the size of the alpha+beta titanium alloy skeleton in the longest direction is smaller than 70% of the external diameter of the ceramic ball; and the ceramic ball body is prepared from an alumina based ceramic material. The invention also discloses a preparation method for the ceramic ball. The preparation method comprises procedures like batching, ball milling, spray granulation, aging in a stock bin, profiling processing, high-temperature sintering, powder-cleaning and polishing, and finished-product drying; and specifically, a great amount of improvements in the procedures of profiling processing and high-temperature sintering are performed. The ceramic ball with the in-built alpha+beta titanium alloy skeleton has better integrality and is insusceptible to breaking; meanwhile, the preparation method enables industrial production of the ceramic ball with the in-built alpha+beta titanium alloy skeleton to be possible through the improvements in the procedures of profiling processing and high-temperature sintering.

The invention discloses a method for improving brazing strength. According to the technical scheme, the method includes the steps of (1) preparation of ceramic particles for adhering metal nanopowder of used brazing filler metal: selecting appropriate ceramic particles according to actual brazing conditions, and preparing the ceramic particles for adhering the metal nanopowder in the used brazing filler metal; (2) brazed surface treatment: performing degreasing and surface oxide removal on a brazed surface, then enabling impact and friction to be generated between the brazed surface and the ceramic particles adhering the metal nanopowder by a shot blasting or vibration method, enabling the brazed surface to have different roughness heights, and coating a metal layer on the brazed surface; and (3) brazing: combining inert gas shielding and heat preservation processes to complete brazing. By the aid of the spot blasting or vibration method, brazed surface quality and brazing filler metal flowability are improved, evenness, diffusion depth and concentration of the brazing filler metal in the whole brazing area are improved, and further brazing connection strength is improved.