127results about How to "Small difference in coefficient of thermal expansion" patented technology

The high temperature alloy protecting technology includes the first forming binding layer in the same components as the substrate on the surface of the high temperature alloy substrate and the subsequent baking composite oxide coating on the surface. The composite oxide coating consists of basic enamel material and added Al2O3 or MgO in 10-40 wt% and Y2O3 in 1-5 wt%; and the basic enamel material consists of ZrO2 3-6 wt%, Al2O3 3-6 wt%, ZnO 8-12 wt%, CaO 3-6 wt%, B2O3 3-6 wt%, Na2O 3-6 wt%, K2O 5-8 wt%, TiO2 1-4 wt% and SiO2 for the rest. The present invention raises the high temperature oxidation resistance and heat corrosion resistance of the substrate and raise the stripping-off resistance of the coating and avoids the mutual diffusion between elements.

The invention discloses a welding connection method of oxide ceramic and metal, using brazing filler metal as an interlayer to connect ceramic and stainless steel metal in a vacuum high temperature environment. The method comprises the following steps: step S1: preparing the ceramic; step S2: making a brazing sample; step S3: performing high-temperature high-vacuum brazing on the sample. The invention relates to the field of connection between different materials, in particular to a connection method of the oxide ceramic and the stainless steel metal, integrating performance advantages of bothceramic and metal in application. Particularly a brazing connection method of aluminum oxide ceramic as well as composite ceramic thereof and the stainless steel metal is disclosed; the used interlayer adopts (Ag72-Cu28)96Ti4 brazing filler metal. The toughness, strength, wear resistance and the like can meet the application requirements in fields such as kitchenware, mobile phone cover plates, auto parts and aviation.

A protection coating for a hi-temp alloy is characterized in that, the coating is a compound coating of metal and enamel formed by spreading some metallic powder on an enamel substrate. Wherein, the metallic powder is MCrAlY powder of high thermal expansion rate coefficient and good resistance to hi-temp corrosion, M is one from Ni, Co, NiCo or any combination of them. Way for preparing the protection coating for hi-temp alloy is: first of all the metallic powder is fully mixed with the enamel powder, then the mixed powder is sprayed on the surface of a specimen, still then a metal-enamel compound coating spread on the enamel substrate is formed by high temperature sintering. The metal-enamel compound coating prepared by the invention is not only furnished with excellent resistance to hi-temp corrosion, but also highly improved thermal expansion rate coefficient because of the addition of plastic metallic powder, and greatly improved thermal vibration property.

The invention discloses a surfacing treatment method of a winding drum of a wire drawing machine. The surfacing treatment method comprises the following steps of: carrying out cylindrical turning a winding drum body subjected to destressed heat treatment, carrying out sand-spraying oil-removing and water-removing pretreatment on the surface, preheating the winding drum in an electric furnace to be 350-400 DEG C, carrying out automatic surfacing with submerged arcs, stopping the surfacing when a surfacing layer reaches 5-6mm, then carrying out slow-cooling treatment, heating the winding drum in the electric furnace to be 400 DEG C, insulating for 2 hours, cooling along with the furnace, and finally forming the winding drum by turning and grinding. The surfacing treatment method has the advantages that the hardness of the winding drum reaches HRC57-60, the wear resistance is good and the service life is long.

The invention relates to an alloy electrode for a skutterudite thermoelectric element and a preparation method thereof. The alloy electrode provided by the invention is an alloy electrode deposited at two end parts of the skutterudite thermoelectric element. The alloy electrode is made of a Ni-Mo alloy or a Ni-W alloy, wherein the molar percentage content of Mo in the Ni-Mo alloy is 10%-40%, the molar percentage content of W in the Ni-W alloy is 5%-40%. In the invention, the selected electrode material is a Ni(Mo) or Ni(W) alloy electrode prepared through an electroplating or chemical plating method. The alloy electrode is good in conductivity and excellent in weldability, the coefficient of thermal expansion of a Ni-containing electrode can be adjusted through substances with a small coefficient of thermal expansion such as Mo and W, and the difference between the electrode material and a skutterudite thermoelectric material in coefficient of thermal expansion is reduced.

The invention discloses a method for manufacturing a gallium nitride-based LED (Light Emitting Diode) with a vertical structure. The method comprises the following steps of: (1) extending an n-type semiconductor layer and a p-type semiconductor layer on a sapphire substrate in sequence to form an LED wafer, performing metal evaporation on the surface of the LED wafer and treating in a nitrogen atmosphere at the temperature between 200 DEG C and 400 DEG C for 1-10 minutes to form a p electrode, and partitioning the LED wafer into independent LED chips; (2) evaporating gold layers on the upper surface and the lower surface of a composite metal substrate respectively, wherein the composite metal substrate is made of a copper-molybdenum alloy or an aluminum-silicon alloy; (3) reversely welding the independent LED chips obtained in the step (1) onto the upper surface of the composite metal substrate respectively; (4) stripping substrates of the LED chips; and (5) manufacturing an n-type electrode on an n-type semiconductor material of each LED chip. In the method, a CuMo or AlSi composite metal substrate with high thermal conductivity is taken as a transfer substrate and has a small thermal expansion coefficient difference from a transferred LED chip, the thermal stress is small, and the bonding yield is increased.

The invention relates to a method for manufacturing a polycrystalline cubic boron nitride (PCBN) grinding wheel work layer with an abrasive particle dressing function, belonging to the manufacture field of superhard grinding material tools. The method comprises the following steps: abrading particles for Cu-Sn-Ti alloy powder and PCBN, fusing TiC particles, preparing a blank and sintering at hightemperature. The PCBN abrasive particle is formed by sintering CBN (cubic boron nitride) microcrystalline particles and AlN binder at high temperature and under high pressure. Once the CBN microcrystalline particles are blunt, the junction interface of CBN microcrystalline 5 and AlN binder is weakened along with the rise of the grinding force and the grinding temperature, so that the blunt CBN microcrystalline particles fall, and new CBN microcrystalline particles are quickly exposed to participate in the grinding process. The micro-breaking characteristics of the PCBN abrasive particles cause the superhard grinding material grinding wheel to still keep high sharp degree and avoid the phenomenon that grinding force and grinding temperature rapidly rise.

Stress regulated semiconductor devices and associated methods are provided. In one aspect, for example, a stress regulated semiconductor device can include a semiconductor layer, a stress regulating interface layer including a carbon layer formed on the semiconductor layer, and a heat spreader coupled to the carbon layer opposite the semiconductor layer. The stress regulating interface layer is operable to reduce the coefficient of thermal expansion difference between the semiconductor layer and the heat spreader to less than or equal to about 10 ppm/ DEG C.

The invention relates to a method for alleviating thermal stress of a porous silicon nitride ceramic and a transparent aluminum nitride ceramic in a connection process. By adopting the method, the porous silicon nitride ceramic is adopted as a transition layer to relieve the thermal stress of the porous silicon nitride ceramic and the transparent aluminum nitride ceramic in the connection process,the porosity of the porous silicon nitride ceramic is 30-70%, preferably 45-60%.

The invention belongs to the technical field of solid oxide electrolytic cells, and particularly relates to oxygen electrode slurry of a solid oxide electrolytic cell, a preparation method of the oxygen electrode slurry and the solid oxide electrolytic cell. The invention provides a preparation method of oxygen electrode slurry of the solid oxide electrolytic cell, which comprises the following steps: step 1, loading metal oxide nanoparticles in an oxygen electrode powder material to prepare oxygen electrode powder; and 2, mixing the oxygen electrode powder, a second pore-forming agent and a binder to prepare the oxygen electrode slurry of the solid oxide electrolytic cell. The invention provides oxygen electrode slurry of the solid oxide electrolytic cell, a preparation method of the oxygen electrode slurry and the solid oxide electrolytic cell, and can effectively overcome the technical defects that the initial internal resistance of the existing SOEC is large and the impedance of anoxygen electrode is increased quickly.

The invention discloses a laser additive manufacturing method of an iron nickel-manganese copper dissimilar material metal part. The method comprises the following steps that firstly, an iron-nickel alloy is deposited on a substrate by adopting a laser additive manufacturing method; secondly, mixed powder composed of iron-nickel alloy powder with the iron-nickel alloy powder mass content larger than 70% or smaller than 50% and manganese-copper alloy powder serves as a raw material, and an iron nickel-manganese copper transition area is formed through deposition with the laser additive manufacturing method; and thirdly, manganese-copper alloy is deposited on the iron nickel-manganese copper transition area through the laser additive manufacturing method, the substrate is removed, and the iron nickel-manganese copper dissimilar material metal part is obtained. According to the method, by adjusting the deposition direction and controlling the transition path of the mixed powder, the defects of cracking, undissolved particles and the like of the iron nickel-manganese copper gradient material are overcome, and the obtained iron nickel-manganese copper dissimilar material metal part is compact in structure and small in transition area size, has the damping performance and low expansion performance and is wide in application range.

The invention provides an inversed LED (Light Emitting Diode) chip structure which comprises a silicon alloy substrate, a metal middle layer, a P-type gallium nitride semiconductor layer, an active layer and a N-type gallium nitride semiconductor layer sequentially stacked from bottom to top. According to the inversed LED chip structure, a transfer substrate made of silicon alloy which is approximate to a growth substrate in thermal expansion coefficient is adopted as the substrate of the LED chip to reduce the staggered damage of lattices of an LED chip apparatus layer, therefore, the leakage current is reduced, and the performance of product is improved. The invention further provides a preparation method of the inversed LED chip structure.