646 results about "Low melting point" patented technology

A process or method for manufacturing a fire-retardant treated wood composite board or panel, such as oriented-strand board, with a low melting point fire retardant (FR) material, such as boric acid, while the press is operating at typical press temperatures above the FR material melting point. An intervening overlay is applied to the top surface of the mat on the forming line, after the use or application of any FR material within or on the mat, prior to entry into the press. The intervening overlay covers the top surface so as to prevent the melting fire retardant material from contacting the press platen(s). After pressing, the intervening overlay may be removed from the top surface by sanding, buffing, or other methods. The intervening overlay also may be sized so as to extend over one or more edges of the underlying panel, for ease of removal post-process.

The invention discloses a porous ceramic filter for liquid magnesium alloy purification and a preparation method thereof, and the porous ceramic filter comprises the following raw materials in percentage by mass: 70-85wt% of ceramic particles, 8-15wt% of multi-element oxide system microcrystalline glass brazing filler metal and the balance of a binder, al2O3-B2O3-SiO2-MgO-CaO multi-element oxide system microcrystalline glass brazing filler metal is adopted, under the condition of air atmosphere high-temperature calcination, a compact reaction layer containing a low-melting-point glass phase, an aluminum oxide phase, a magnesium aluminate spinel phase, a calcium aluminosilicate phase, a borate phase and a silicate phase is generated on the surfaces of ceramic particles of a porous ceramic filter through a chemical reaction; the magnesium alloy filter has high strength and good high-temperature stability, and the problems that the filter loses efficacy and magnesium alloy melt is polluted due to the fact that the filter is eroded by magnesium alloy liquid are effectively solved.

The invention relates to the technical field of part manufacturing, in particular to a hollow non-straight section composite part which is characterized in that a low-melting-point alloy is used for manufacturing a core mold to serve as a forming inner mold, fiber prepreg is laid on the surface of the core mold and subjected to curing treatment to form a shell structure, finally, the inner mold is removed in a melting mode, and the hollow non-straight section composite part is obtained. According to the hollow non-straight composite material part manufacturing method, the characteristic that materials can be controllably removed is utilized, the mold design is greatly simplified, the manufacturing cost is reduced, and meanwhile the forming freedom degree of a complex geometric structure is improved.

The invention provides a fault indication device of a lightning arrester and the lightning arrester. The fault indication device comprises a target resistor, a low-melting-point alloy, a counterweight and a shell, the target resistor, the low-melting-point alloy and the counter weight are all located in the shell; the first end of the target resistor is connected with a shell of the lightning arrester, the second end of the target resistor is grounded, the upper end of the low-melting-point alloy is in fixed contact with the target resistor, and the lower end of the low-melting-point alloy is connected with the balance weight; the shell comprises a visual subarea at the bottom; the target resistor generates different heat according to the magnitude of the leakage current of the lightning arrester, and when the temperature of the target resistor is higher than the melting point temperature of the low-melting-point alloy, the low-melting-point alloy is melted, and the counterweight falls into the visual partition. According to the device, by triggering melting of the low-melting-point alloy, advanced visual early warning can be provided before the lightning arrester breaks down, and the problem that fault indication of the lightning arrester is not timely is solved.

The invention provides a thermal response self-ceramization fireproof coating and a preparation method thereof. The thermal response self-ceramization fireproof coating is prepared from the following raw materials in parts by mass: 3 to 10 parts of acrylic monomer, 3 to 10 parts of organic sulfonate, 1 to 4 parts of silane coupling agent, 0.5 to 3 parts of silicate ester, 4 to 6 parts of ceramic precursor, 3 to 6 parts of fluxing agent and 0.05 to 0.4 part of initiator. The fluxing agent comprises a component A and a component B, the component A is one of boric oxide, zinc borate or low-melting-point glass powder, and the component B is one of phosphorus pentoxide and ammonium polyphosphate. The silane coupling agent can be copolymerized with an acrylic monomer to construct a C-C main chain, the C-C main chain and silicate ester are subjected to hydrolytic condensation to form a Si-O-Si three-dimensional network, a chemical cross-linked skeleton is formed, and the chemical cross-linked skeleton can generate silicon dioxide at high temperature to participate in a ceramization reaction; the ceramic precursor and silicate ester can form a strong physical cross-linking effect, so that the fireproof coating with a chemical and physical double-cross-linked network can be formed, and the fireproof coating has excellent mechanical property and machinability at normal temperature.

An oxyide dispersion-strengthened (ODS) alloy is disclosed that is compatible with melt-based additive manufacturing processes, such as laser powder bed fusion (L-PBF) while achieving material properties, such as resistance to frictional ignition, comparable to or better than wrought ODS alloys. This is accomplished, in part, by adjusting the composition of the ODS alloy and / or adjusting the operating parameters of the additive manufacturing process to reduce or, in some instances, mitigate dispersoid coarsening and slag formation. For example, a nickel (Ni)-based ODS alloy may include less than 0.3 wt % aluminum (Al) to reduce the formation of low melting point oxides that are prone to coarsening and slag formation. In another example, various processing parameters associated with a selective laser melting process, such as beam power, beam spot size, and scan speed, may be chosen to reduce a melt time associated with the additive manufacturing process.

The invention belongs to the technical field of brazing materials, and particularly relates to micro-nano particle reinforced nickel-based ultralow-melting-point wear-resistant brazing filler metal and a preparation method and application thereof. The invention provides micro-nano particle reinforced nickel-based ultralow-melting-point wear-resistant brazing filler metal. The micro-nano particle reinforced nickel-based ultralow-melting-point wear-resistant brazing filler metal comprises 94-99 parts of ultralow-melting-point nickel-based brazing filler metal and 1-6 parts of micro-nano particles. The ultralow-melting-point nickel-based brazing filler metal contains B, Si, In, Sn and Cu elements at the same time, and the melting temperature of the brazing filler metal can be cooperatively reduced; and meanwhile, the micro-nano particles are added, so that the strengthening and abrasion increasing effects on the nickel-based brazing filler metal can be effectively guaranteed, and meanwhile the flowability of the brazing filler metal is not affected. Therefore, through component design of the nickel-based brazing filler metal and synergistic cooperation of the micro-nano particles, the melting point of the brazing filler metal can be remarkably reduced, the brazing filler metal can be endowed with excellent hardness and wear resistance, and the technical bottlenecks that traditional nickel-based brazing filler metal is high in melting temperature and poor in wear resistance and brazed diamond is subjected to thermal damage are solved; and the method has a wide application prospect in brazing of diamond tools.

The invention discloses a method for preparing an ultrahigh-temperature ceramic coating by an ultrahigh-temperature metal gas source based on a molten salt medium, which comprises the following steps of: mixing low-melting-point salt A, metal fluoride and metal M to obtain a mixture C, putting the mixture C into a first crucible, mixing low-melting-point salt B and metal M to obtain a mixture D, putting the mixture D into a second crucible, putting a carbon base material into a deposition furnace, and performing vacuum drying to obtain the ultrahigh-temperature ceramic coating. Heating the first crucible to melt the mixture C to obtain a melt E, and heating the second crucible to melt the mixture D to obtain a melt F; carrier gas is guided into the first crucible, the carrier gas flow passes through the melt E to form gas flow containing a metal gas source, the gas flow containing the metal gas source is guided into the second crucible, and the gas flow containing the metal gas source is filtered by the melt F in the second crucible to form a pure metal reaction gas source, and finally, a pure metal reaction gas source is introduced into the deposition furnace for deposition of the carbon base material, and the ultra-high-temperature ceramic coating is obtained. The method is easy to operate and low in cost.

The invention discloses an aluminum-based composite material and a preparation method thereof. The preparation method comprises the following steps: firstly, mixing powder of an intermediate alloy, a simple substance metal and a reinforcement with a binder, and carrying out cold pressing to form a green body; degreasing and sintering the green body to obtain a sintered part; and heating the sintered part, performing closed die forging, performing heat treatment and fine trimming to obtain a finished product, and if the performance does not meet the requirements, performing hot extrusion on the sintered part, and performing heat treatment and fine trimming to obtain the finished product. Oxide is removed through ball milling, the surface of the Al-Mg powder is activated, and passivation is protected through a binder; a reinforced phase SiC is designed to be blended with a binder, and then the mixture is mixed with other powder to form a specific microstructure; low-melting-point Sn is introduced to limit the sintering temperature, element diffusion is promoted through a liquid phase, and generation of a harmful intermediate phase is avoided; a sintered part with the density being 80-95% is adopted, a low-strain soft area is formed around a reinforced phase in cooperation with a specific microstructure, deformation coordination is improved, meanwhile, the peak aging time of the aluminum alloy is prolonged through SiC, the electric conduction and heat conduction performance is improved, and the comprehensive performance of the composite material is comprehensively improved.

The invention belongs to the technical field of thermal power heating surface treatment, and provides a gradient functional composite coating applied to a boiler heating surface and a preparation method of the gradient functional composite coating in order to solve the technical problems that an existing protective coating of the boiler heating surface is prone to abrasion and oxidation and high in cost. Collaborative design is formed, and gradient matching of mechanical properties and environmental failure resistance is achieved. The low-melting-point glass powder is combined with the rare earth catalytic effect, low-temperature ceramization is achieved, and thermal damage to a matrix is avoided. After the metal ceramic transition layer is sprayed, high-frequency induction remelting treatment is carried out, meanwhile, laser cladding is carried out on the surface of the ceramic surface layer, a nanocrystalline-amorphous composite structure is formed, and the bonding strength of the coating is improved.

The invention provides a low-melting-point PET short fiber, and relates to the technical field of fiber production. The low-melting-point PET short fiber comprises a high-strength low-melting-point PET short fiber, the short fiber is of a skin-core composite structure, a skin layer of the skin-core composite structure is modified low-melting-point polyester and is prepared by melt copolymerization of PET, 10-30% of rigid comonomers and 5-15% of flexible chain segments, the melting point is 110-160 DEG C, and the glass-transition temperature (Tg) is larger than or equal to 60 DEG C. The gradient interface enhancement technology is adopted, the PET-g-PE grafting layer is introduced between the skin layer and the core layer, the grafting rate reaches 5-8% through melt blending, a transition layer of 1-3 microns is formed, the peel strength is improved to 1.5 N / cm or above, and the problem of interface stripping of traditional composite fibers is solved.

The invention discloses a method for improving performance of rare earth permanent magnet sintered neodymium iron boron grain boundary diffusion, and belongs to the technical field of rare earth permanent magnet materials. The method comprises the steps that a low-melting-point metal layer and a diffusion layer containing heavy rare earth elements are sequentially formed on the surface of a clean sintered neodymium-iron-boron magnet, and then vacuum diffusion heat treatment and tempering treatment are conducted. Wherein the low-melting-point metal layer comprises at least one of copper, aluminum, gallium and tin or an alloy of the copper, the aluminum, the gallium and the tin; the heavy rare earth element comprises at least one of dysprosium, terbium, holmium and gadolinium. The low-melting-point metal layer is preferentially diffused and wets the grain boundary in the heat treatment process, heavy rare earth elements are promoted to be deeply and uniformly diffused towards the interior of the magnet along the grain boundary, so that a heavy rare earth-rich shell layer is formed outside main phase grains of the magnet, and the intrinsic coercive force is improved; meanwhile, the low-melting-point metal forms a strengthening phase at the grain boundary, the brittleness of the magnet after diffusion is improved, the surface corrosion phenomenon is restrained, and collaborative optimization of the comprehensive performance of the magnet is achieved.

The invention discloses a high-Al and Ti difficult-to-deform high-temperature alloy hot working method, which avoids the melting risk of low-melting-point intermetallic compounds through high-temperature diffusion on one hand, and can realize effective and uniform diffusion of chemical elements on the other hand; on the other hand, through gradual heating number cooling forging, a high-temperature small-deformation forging process is carried out in an as-cast structure interval, and a low-temperature large-deformation process is adopted after the as-cast structure is crushed, so that an ideal uniform and fine recrystallized grain structure is finally realized, and the problems of high possibility of cracking, non-uniform forging structure, coarse grains and the like in a high-temperature alloy forging process are solved; and the high-quality requirement for use of downstream aero-engine components is met.

The present invention relates to a bismuth alloy composition and a design method thereof. The alloy composition according to the present invention is an alloy composition comprising bismuth and a second element. The second element selected on the basis of an atomic radius difference between constituent atoms and mixing enthalpy is alloyed in an appropriate content according to a principle of improving liquid stability to provide an alloy composition satisfying a low melting point and a high degree of supercooling and exhibiting excellent flowability, which can be used as a liquid metal ion source.

The present application belongs to the technical field of ceramic alloy flywheel, and particularly relates to a liquid-liquid composite ceramic inlaid high-wear-resistance flywheel and a preparation method thereof, which is suitable for high-strength impact environment such as mines and metallurgy. The flywheel realizes metallurgical bonding of ceramic-metal by step-by-step pouring and temperature control solidification of basalt melt and high-density W-Ni-Fe alloy melt in a specific mold structure. The ceramic core is composed of multiple inorganic oxides and low-melting-point glass powder, and has excellent interface compatibility and structural stability. During the preparation process, the initial setting state of basalt and the alloy flow path are accurately controlled to improve the interface bonding strength and overall density. The finally obtained flywheel has high hardness, high toughness and excellent wear resistance, and significantly prolongs the service life.

The invention provides a high-thermal-conductivity and high-adhesion thermal interface material and a preparation method thereof, and belongs to the technical field of thermal interface materials. The thermal interface material is prepared by in-situ cross-linking reaction of the following components: a polymer matrix comprising a polymer containing active functional groups and a cross-linking agent; the heat-conducting filler accounts for more than 90wt% of the total weight of the thermal interface material; the low-melting-point organic medium accounts for 0.1-5wt.% of the total weight of the thermal interface material, and the melting point of the low-melting-point organic medium is lower than the crosslinking curing temperature of the polymer matrix; wherein the heat-conducting filler forms a continuous three-dimensional heat-conducting path in a cross-linked polymer network, and the low-melting-point organic medium is uniformly dispersed in the network. Under the ultrahigh filler content, high bulk phase thermal conductivity and high initial viscosity are realized at the same time, and the contradiction between high thermal conductivity and high interface contact resistance is solved. The high viscosity at room temperature is beneficial to operation and storage, and is softened due to melting of an organic medium at the working temperature of a device, so that the interface wettability is dynamically enhanced, and the contact thermal resistance is minimized.

A thermoforming method for a high-strength steel part. A hot stamping die comprises an upper die (1) and a lower die (2); the lower die is located in a water tank (3); the water tank is used for containing hot water above 60°C; during use, the lower die is partially or completely immersed in hot water; the lower die is provided with at least two sheet supports; each sheet support comprises a fixed rod (7) vertically fixed on the bottom surface of the water tank; the upper end of the fixed rod is rotatably connected to a cross beam (8) by means of a rotating shaft (9); one ends of the cross beams of the sheet supports cooperate with each other to support sheets, and the other ends of the cross beams are rotatably connected to the upper ends of pull rods (10); the lower ends of the pull rods are connected to the fixed rods by means of springs (11); and in an initial state, the height of the cross beams is greater than the liquid level of hot water. Further provided is a low-melting-point coating part with a low micro-crack depth. The low-melting-point coating part comprises a substrate and a low-melting-point coating located on the surface of the substrate; the low-melting-point coating part is formed by hot stamping; micro-cracks are generated in the substrate and the low-melting-point coating in the forming process; and most of the micro-cracks extending from the low-melting-point coating to the substrate are located at concave fillet tangent points of the low-melting-point coating part, and a small part of the micro-cracks extending from the low-melting-point coating to the substrate are located at positions other than the concave fillet tangent points of the low-melting-point coating part. Further provided are a thermoforming method for the low-melting-point coating part, a hot bath edge cutting device for the high-strength steel part, and a method for using the hot bath edge cutting device. According to the thermoforming method, in the direct forming process, the micro-crack expansion process of the low-melting-point coating and the substrate is effectively inhibited, the service life of the low-melting-point coating part is ensured, and excellent corrosion resistance is shown.

The invention discloses a packaging material as well as a preparation method and application thereof. The packaging material comprises the following components in parts by mass: 40-85 parts of matrix resin, 5-30 parts of phase change PCM particles, 3-20 parts of self-repairing microcapsules, 1-8 parts of an interface compatilizer and 10-20 parts of a heat-conducting network reinforcing material, the melting point of the phase change PCM particles is not more than 80 DEG C; a core layer of the self-repairing microcapsule comprises dicyclopentadiene and a ruthenium catalyst, and a shell layer of the self-repairing microcapsule comprises polyurea or polyurethane; the PCBA packaging material with the intelligent response function is formed by combining the low-melting-point phase-change PCM particles with the self-repairing microcapsule system, when the PCBA temperature is too high, the low-melting-point phase-change PCM particles are molten, junction temperature suddenly rising is restrained through melting heat absorption, meanwhile, the adjacent microcapsules are triggered to be broken through volume expansion, DCPD monomers are released and subjected to in-situ polymerization under the action of a catalyst, and the PCBA packaging material with the intelligent response function is obtained. Microcracks generated by thermal stress are rapidly repaired, and the heat dissipation stability and the electrical insulation reliability of the material in long-term thermal circulation are remarkably improved.

The invention relates to the technical field of chemical fibers, in particular to a low-melting-point polyester FDY (fully drawn yarn) preparation process which comprises the following steps: preparing raw materials, selecting polyester chips and a low-molecular-weight polyester copolymer, mixing the polyester chips and the low-molecular-weight polyester copolymer according to a ratio, melting and blending the polyester chips and the low-molecular-weight polyester copolymer with the additive amount of 5-8wt% and the intrinsic viscosity of 0.65-0.70 dL / g, and performing extrusion molding to obtain the low-melting-point polyester FDY. And putting the mixed raw materials into a screw extruder, and carrying out melt blending and spinning treatment at 250-260 DEG C. According to the low-melting-point polyester FDY and the preparation method thereof disclosed by the invention, a component regulation end is arranged, so that a synergistic effect mechanism of a polyester matrix and a low-melting-point copolymer is accurately matched in a preparation process of the low-melting-point polyester FDY, and the uniformity of melt components is ensured; meanwhile, the copolymerization structure design directivity acts on molecular chain regularity regulation and control, thermal stability fluctuation in the spinning process is inhibited in real time, it is guaranteed that the continuous forming capacity of fibers is maintained under the high-speed spinning condition, and the stability of a production line is improved.

The invention provides a method for connecting a titanium-aluminum material and a nickel-based superalloy and a brazing filler metal composition, and relates to the technical field of material welding, and the brazing filler metal composition for connecting the titanium-aluminum material and the nickel-based superalloy comprises a high-entropy alloy middle layer and a Cu middle layer. The Cu intermediate layer is introduced between the high-entropy alloy intermediate layer and the base metal nickel-based superalloy, the low melting point of the Cu intermediate layer is utilized, the Cu intermediate layer is melted into a liquid phase in the welding process, a high-temperature liquid phase environment is formed, element diffusion of the high-entropy alloy intermediate layer and the nickel-based superalloy is facilitated, element exchange between the high-entropy alloy intermediate layer and the nickel-based superalloy is promoted, and the welding quality is improved. And the welding temperature is reduced by 30-100 DEG C, the welding temperature is reduced to 1100-1160 DEG C, the welding temperature is lower than the Ni-based high-temperature alloy solution treatment temperature, Ni-based high-temperature alloy grain growth is avoided, the high-temperature creep property of the Ni-based high-temperature alloy grain growth is kept, the joint structure is optimized, and the welding quality is improved.

The invention belongs to the technical field of preparation of soft magnetic composite materials, and particularly relates to an insulation coating method and application of a soft magnetic powder material. The insulating coating method comprises the following steps: (1) uniformly mixing low-melting-point metal or alloy powder with silica sol, a silane coupling agent and a thermocuring resin glue solution to obtain coating slurry; and (2) uniformly mixing soft magnetic powder with the coating slurry obtained in the step (1), firstly performing hot-pressing curing molding at the temperature of 60-100 DEG C under a vacuum condition, and then performing hot-pressing sintering treatment at the temperature higher than the melting point temperature of low-melting-point metal or alloy powder and under an oxygen-containing atmosphere condition to obtain the insulated and coated soft magnetic powder material. According to the insulating coating method, the advantages of an organic material insulating coating method and an inorganic material insulating coating method are combined, the defects of the organic material insulating coating method and the inorganic material insulating coating method are overcome, and the stability and the insulating coating effect of the insulating coating layer are remarkably improved.

The present invention provides a low-boron R-Fe-B permanent magnet material and a preparation method thereof, and belongs to the technical field of rare earth permanent magnet materials. The present invention crushes and dehydrogenates R-Fe-B-M alloy and grain boundary phase R-Ga-M alloy in sequence respectively, obtains coarse material and mixes with antioxidant, lubricant and dispersant, and then carries out press forming, cold isostatic pressing, vacuum degassing, vacuum low-temperature sintering and aging treatment. In the present invention, the content of R in the R-Fe-B-M alloy is 29wt%~36wt%, and the content of B element is 0.8wt%~0.96wt%, which belongs to an alloy with excessive rare earth elements and low B element content, which is conducive to producing more rare earth-rich grain boundary phases, and the R-Ga-M alloy has a low melting point, which is conducive to liquid phase sintering. In combination with vacuum degassing first, a pressure-assisted diffusion air pressure three-stage heating delay sintering process is used to obtain a low-boron R-Fe-B permanent magnet material.

The application discloses a flexible strain sensor with high linearity and low hysteresis, a preparation method and application thereof, and belongs to the technical field of sensors. The composite sensitive material prepared by using an electric spray gun has high linearity and low hysteresis performance. The physical contact between silver nanowires and two-dimensional MXene nanosheets makes the sensor have high sensitivity in a tensile state. Meanwhile, the liquid metal particles as a structural framework have inherent room-temperature low-melting-point characteristics, so that the liquid metal particles are in a liquid state at room temperature, and the gap between the MXene nanosheets and the silver nanowires is reduced. The coordination bond formed between the MXene nanosheets and the liquid metal enhances the interface interaction between the MXene nanosheets and the liquid metal, and reduces energy dissipation. The uniform composite sensing network layer obtained based on a spray mixing technology has a uniform distance between the sensitive materials in the composite sensitive layer with the gradual increase of external stress; and the existence of the buckling structure strengthens the interaction between the sensitive materials. Therefore, the resistance has a linear relationship with the change of the stretching amount, that is, high linearity; and the flexible strain sensor has high sensitivity.

The invention discloses a silver-gold-palladium-chromium-indium-yttrium alloy and a preparation method and application thereof, and belongs to the technical field of precise materials for semiconductor detection. The alloy comprises the following components in percentage by mass: 15%-20% of Au, 15%-18% of Pd, 8%-12% of Cr, 0.1%-0.3% of In, 0.2%-0.4% of Y and the balance of Ag. According to the preparation method, alloy component design is optimized, and an optimized preparation method is combined, so that a nano-to-micron Pd-Cr dispersed phase and Y element grain boundary segregation composite strengthened structure is formed through a multi-element synergistic strengthening mechanism, and the problems of In low-melting-point volatilization, columnar crystal length-diameter ratio control, high processing wire breakage rate and the like are solved; the alloy material with excellent comprehensive performance such as hardness, resistivity and machinability is obtained, meanwhile, the preparation cost of the alloy material is reduced, and the alloy material has better adaptability to a test probe subsequently matched with a process chip below 5nm.

The invention discloses a high-strength and high-plasticity low-melting-point aluminum alloy brazing material and a preparation method and application thereof, and relates to the technical field of solder manufacturing. The low-melting-point aluminum alloy welding flux is prepared from the following components in percentage by weight: 10 to 14 percent of Si, 4 to 20 percent of Cu, 0.04 to 0.25 percent of Eu, 0.78 to 0.82 percent of Fe, 0.13 to 0.17 percent of Mn, 0.08 to 0.12 percent of Mg, 0.18 to 0.22 percent of Zn and the balance of aluminum and inevitable impurities. The Al-Si-Cu ternary alloy is constructed to form a low-melting-point eutectic phase, the melting point of the material is effectively reduced, meanwhile, Eu atoms are doped, the aluminum matrix is subjected to the pressure stress effect, the interplanar spacing is reduced, the grain size of the matrix aluminum phase is reduced, the elemental Si phase is refined, the eutectic Al-Si phase content is increased, and precipitation of the brittle Al2Cu phase is restrained; therefore, the aluminum alloy solder has high tensile strength and elongation after fracture under the condition that the melting point is low.

The invention discloses a water-based organic silicon high-temperature-resistant insulating coating and a preparation method thereof, and belongs to the technical field of insulating coatings. The water-based high-temperature-resistant organic silicon resin is used as a film forming matter, water is used as a solvent, and the low-melting-point fluxing filler with different molten state temperature intervals, the multi-scale insulating filler and the reinforcing filler are added, so that the high temperature resistance and the insulativity of the water-based high-temperature-resistant insulating coating are improved; meanwhile, nanoscale flaky or spherical aluminum oxide is distributed in micron-sized particles such as silica powder and talcum powder, the functional filler in a system and SiO2 ash formed after organic silicon resin is subjected to high temperature are bonded together by the low-melting-point fluxing filler in a molten state, a continuous, complete and compact protective layer is formed on the surface of a base material, and the coating is prevented from cracking. The thickness of the coating prepared by the method is 120 + / -10 microns, the adhesive force is 1-2 grades, the pencil hardness is 2H-3H, and the impact resistance is 40kg. Cm-50kg. Cm.

The invention relates to the field of polymer composite materials, discloses a polyester-based composite calendering film material and a preparation method thereof, and particularly discloses a nano composite calendering film material based on a polyester / polyolefin blending system. The material is mainly composed of 60-80% of low-melting-point PET / HDPE, 10-25% of light nano calcium carbonate, 1-5% of calcium stearate, 5% of needle-like wollastonite, 3-8% of nano TiO2, 2-5% of PE-g-MAH and 2-5% of GMA-polyester, and a plasticizer, a heat stabilizer, a softening agent and an antioxidant are not needed. The tensile strength of the obtained film is larger than or equal to 45 MPa in the longitudinal direction, larger than or equal to 38 MPa in the transverse direction (ASTM D882), the right-angle tearing strength is larger than or equal to 120 kN / m (GB / T16578.2), and the film passes FDA 21 CFR 177.1520 food contact safety certification. The material adopts non-toxic, harmless and recyclable infant-grade green and environment-friendly raw materials, has the characteristics of high strength, high toughness, good processability, no toxicity, environment friendliness and the like, and has a wide application prospect.

The invention relates to the technical field of hot stamping forming of parts, in particular to a low-melting-point coating part with the low microcrack depth and a hot stamping forming technology thereof.The part comprises a base body and a low-melting-point coating located on the surface of the base body, the part is formed through hot stamping, and in the forming process, the base body and the coating or the coating generate microcracks; most of the microcracks are located at the indent fillet tangency point of the part. According to the method, under the direct forming technology, the micro-crack growth process of a part coating and a steel plate base body is effectively restrained, the micro-crack depth is controlled within 10 microns, the service life of a part is guaranteed, and meanwhile the part shows excellent corrosion resistance.

A braze tape includes a first portion, a second portion, and a central portion located between and adjacent to the first portion and the second portion. The first portion includes a low melting temperature alloy material, the second portion includes a high melting temperature alloy material, and the central portion includes a mixture of the low melting temperature alloy material and the high melting temperature alloy material. The central portion may gradually change between the low melting temperature alloy material and the high melting temperature alloy material. A related method is also disclosed.

The invention discloses a grain refinement process of a sintered neodymium-iron-boron magnet and the neodymium-iron-boron magnet, and belongs to the technical field of rare earth permanent magnet materials.The grain refinement process comprises the following steps that under the inert atmosphere protection condition, hyperbranched polycarbosilane is diluted with a solvent and then sprayed to the surface of low-melting-point rare earth alloy powder, and after the solvent is dried, the low-melting-point rare earth alloy powder is obtained; ndFeB alloy magnetic powder and low-melting-point rare earth alloy powder are fully and uniformly mixed and then subjected to orientation forming in a magnetic field, a blank is prepared through an isostatic pressing forming or compression molding forming process and enters a sintering furnace, heat preservation is conducted for 2-5 h at the temperature of 550-600 DEG C, and then presintering, high-temperature sintering and tempering heat treatment are conducted. The coercive force of the sintered neodymium-iron-boron magnet is improved through the technology, the coupling effect can be demagnetized to the maximum extent by combining the double-alloy technology and polycarbosilane, and meanwhile the comprehensive magnetic performance of the sintered neodymium-iron-boron permanent magnet can be improved.