48 results about "Quaternary alloy" patented technology

The present invention discloses a copper-iron-chromium-nickel quaternary alloy planar sputtering target and a preparation method thereof. The preparation method comprises at least a vacuum induction melting and casting step: copper, iron, chromium, and nickel raw materials are placed in a vacuum induction melting furnace according to a preset mass ratio to form a shaped target material, wherein the shaped target material has a relative density of not less than 99%. Since the shaped target material is melted in the vacuum induction melting furnace, the copper, iron, chromium, and nickel raw materials disclosed in the present invention can be fully fused in the vacuum induction melting furnace. Moreover, since the copper-iron alloy has good electrical and thermal conductivity, high mechanical strength, and wear resistance, the addition of chromium can further improve the corrosion resistance and mechanical properties of the alloy. The addition of nickel can fully cooperate with chromium to transform the metallographic structure from a single-phase ferrite to a two-phase structure of austenite and ferrite, thereby effectively improving the corrosion resistance and mechanical properties of the alloy target material.

The invention relates to a high-hardness and high-strength palladium-silver-copper-nickel quaternary alloy rod for a probe and a preparation method thereof, and the palladium-silver-copper-nickel quaternary alloy rod comprises the following elements in percentage by mass: 30-38% of Pd, 40-46% of Cu, 10-20% of Ag and 8-15% of Ni. The sum of the mass of Ag and Ni is 18-30%, and the sum of the mass of Pd and Ni is 41-50%; the hardness of the palladium-silver-copper-nickel quaternary alloy bar subjected to heat treatment is larger than 300 HV, and the strength is larger than 1000 MPa. According to the invention, nickel with low cost is used as an important strengthening element and cooperates with silver and copper to realize strengthening in an alloy matrix with low palladium content, and an efficient quality-improving forming process is matched, so that the balance of high hardness and high strength of the alloy is realized on the premise of controllable cost, and the harsh demand of a test probe can be met.

The present invention relates to the technical field of anti-corrosion treatment for the surface of steel, and specifically, to an anti-corrosion treatment process for the surface of bridge steel. It includes: S1. Pretreating the substrate by using plasma activation and sandblasting processes; S2. Spraying a Zn-Al-based quaternary alloy onto the surface of the substrate through a spraying and deposition process to form an inner coating for sacrificial anode protection; processing inverted conical micropores on the surface of the inner coating by using femtosecond laser; S3. Electrostatically spraying a fluorocarbon resin composite coating, spraying it twice. After two sprays, the micropores are filled and a dense barrier layer is formed. Through the characteristic micropore process of the inner coating and the secondary spraying process of the outer coating, the present invention forms micropore interlocking to enhance mechanical bonding. At the same time, the sacrificial anode of the inner coating continuously provides cathodic protection, and the self-healing function of the outer coating repairs damages in real time; the graphene oxide and fluorocarbon resin of the outer coating form a dense anti-permeation layer. Secondly, the micropore-filled gradient-cured resin reduces the interfacial residual stress and effectively inhibits the crack propagation caused by dynamic loads.

A preparation method of a tin-silver-copper-aluminum quaternary alloy and its application in the negative electrode of a secondary battery belong to the technical field of secondary batteries. The present invention aims to solve the problems of limited materials, high cost, complex preparation process, and unsatisfactory electrochemical performance of alloy negative electrodes in existing secondary batteries. Method: 1. Using tin, silver, copper, and aluminum targets as raw materials, setting the argon gas flow rate; 2. Setting the magnetron sputtering power parameters of the tin target, silver target, copper target, and aluminum target respectively; 3. Setting the magnetron sputtering time and substrate speed, turning on the magnetron sputtering power supply, starting sputtering on the current collector, and ending sputtering to obtain a tin-silver-copper-aluminum quaternary alloy. A tin-silver-copper-aluminum quaternary alloy is used as the negative electrode active material of a secondary battery. The preparation process of the present invention is relatively simple, so the cost is greatly reduced. The present invention solves the shortcomings of limited lithium resource reserves and high cost of existing lithium-ion batteries. In addition, the present invention is simpler, safer, more reliable, and has higher energy density than existing sodium-ion batteries.

The invention discloses a platinum alloy electrode material and a preparation method thereof, and belongs to the technical field of rare and noble metal high-temperature alloys. Metal of high-melting-point Pt (1772 DEG C), Ni (1450 DEG C), V (1902 DEG C) and Ru (2334 DEG C) serves as alloy elements, the vacuum induction melting and suction casting rapid solidification technology is adopted for preparing PtNiVRu quaternary alloy block-shaped and cylindrical cast ingots, and the cast ingots have the advantages of being uniform in structure, free of segregation, shrinkage cavities and looseness and the like; products in the shapes of sheets and wires are finally obtained through proper heat treatment and cold machining processes. The finally obtained platinum alloy electrode material is high in density, high in hardness, low in resistivity and good in fusion welding resistance and arc ablation resistance.

The invention relates to a 1200MPa-grade low-cost nickel-based alloy for a second-generation high-temperature superconducting baseband and a preparation method of the 1200MPa-grade low-cost nickel-based alloy, and belongs to the technical field of materials. The nickel-based alloy comprises the following chemical components in percentage by weight: 15.0 to 17.0 percent of Cr, 10.0 to 30.0 percent of W, 2.0 to 10.0 percent of Fe, Clt and the balance of Ni. 0.005%, Plt; 0.005%, Slt; 0.002%, Olt; 0.002%, Nlt; 0.002%, and the balance being nickel. The Ni-Cr-W-Fe quaternary alloy component design thought is innovatively put forward, the contents of the W element and the Fe element are optimally designed, the follow-up optimized homogenization treatment, the forging process, the hot rolling process, the solution treatment and the cold machining process are matched, and after the nickel-based alloy is annealed for 5 min at the temperature of 900 DEG C, the nickel-based alloy with the yield strength of 1050 MPa or above and the tensile strength of 300 MPa or above can be obtained. The nickel-based alloy with the tensile strength of 1200 MPa or above and the ductility of 25% or above meets the requirement that the tensile strength of a second-generation high-temperature superconducting high-performance metal-based strip reaches 1200 MPa or above.

This invention discloses a biodegradable zinc alloy wire for microtia correction surgery and its preparation method, belonging to the field of biomedical materials. The biodegradable zinc alloy wire for microtia correction surgery is characterized in that it is a Zn-Cu-Mn-Fe zinc alloy, with the alloy element composition by mass percentage as follows: 0 < Cu ≤ 3 wt.%, 0 < Mn ≤ 1 wt.%, 0 < Fe ≤ 1 wt.%, and the remainder being Zn. This alloy wire is prepared through processes including melting, casting, reverse extrusion, cold drawing combined with hot drawing, and heat treatment. The Zn-Cu-Mn-Fe quaternary alloy wire obtained by this invention has a tensile strength of 100–150 MPa, a yield strength of 80–120 MPa, and an elongation greater than 58%. It possesses the excellent plasticity, suitable tensile strength, and yield strength required for suture materials in microtia correction surgery. It can maintain the required mechanical properties in the early stages of implantation and gradually degrades completely under the influence of implant tissue fluid in the later stages.

This invention relates to a high-hardness, high-strength palladium-silver-copper-nickel quaternary alloy rod for probes and its preparation method. The elemental composition of the palladium-silver-copper-nickel quaternary alloy rod, by mass percentage, is: Pd 30-38%, Cu 40-46%, Ag 10-20%, Ni 8-15%; the sum of the mass of Ag and Ni is 18-30%, and the sum of the mass of Pd and Ni is 41-50%. The heat-treated palladium-silver-copper-nickel quaternary alloy rod has a hardness greater than 300 HV and a strength greater than 1000 MPa. The invention utilizes relatively low-cost nickel as a key strengthening element, synergistically strengthening it with silver and copper in an alloy matrix with a low palladium content. Combined with an efficient and high-quality forming process, a balance between high hardness and high strength is achieved in the alloy while maintaining controllable costs, meeting the stringent requirements of testing probes.

This disclosure relates to a semiconductor device and a method for manufacturing the same. The semiconductor device includes: an interlayer insulating film disposed on a substrate and having a recessed portion of the substrate exposed; a bottom electrode contact embedded in at least a portion of the recessed portion; a magnetic tunnel junction (MTJ) layer disposed on the interlayer insulating film and the bottom electrode contact; and a offset cancellation layer with a magnetization direction parallel to the antiparallel side of a fixed layer, wherein the offset cancellation layer may include a Co alloy, Fe alloy, Ni alloy, or Mn alloy comprising at least one selected from the group consisting of Al, Ga, B, Ir, Zr, Hf, and rare earth metals, or a ternary or quaternary Co alloy, Fe alloy, or Ni alloy comprising one selected from the group consisting of Pt or Pd and at least one selected from the group consisting of Cr, Al, Tb, Si, and B.

The invention provides a CdZnSeS quantum dot as well as a preparation method and application thereof, and belongs to the technical field of synthesis of nano materials. By optimizing the synthesis process, the long-standing technical problem that'narrow half-peak width (high color purity) 'and'high quantum yield (high luminous efficiency)' are difficult to achieve at the same time in the synthesis of quaternary alloy quantum dots such as CdZnSeS and the like is successfully solved. Meanwhile, the high luminous efficiency (the quantum yield is larger than or equal to 90%) close to the theoretical limit and the extremely high color purity (the red half-peak width lt, 30 nm and green lt, 25 nm) are achieved, the long-standing performance balancing problem in the field is successfully solved, and the obtained quantum dot product is particularly suitable for high-end photoelectric devices with the extreme requirements for color and efficiency.

The invention discloses a degradable zinc alloy wire for small ear malformation correction and a preparation method of the degradable zinc alloy wire, and belongs to the field of biomedical materials. A degradable zinc alloy wire material for microtympanic malformation correction is characterized in that the degradable zinc alloy wire material is Zn-Cu-Mn-Fe zinc alloy, and the alloy elements of the degradable zinc alloy wire material comprise, by mass, 0 < Cu < = 3 wt.%, 0 < Mn < = 1 wt.%, 0 < Fe < = 1 wt.%, and the balance Zn. The alloy wire is prepared through the working procedures of smelting, casting, backward extrusion, cold drawing combined with hot drawing, heat treatment and the like. According to the Zn-Cu-Mn-Fe quaternary alloy wire obtained through the method, the tensile strength ranges from 100 MPa to 150 MPa, the yield strength ranges from 80 MPa to 120 MPa, the ductility is larger than 58%, the excellent plasticity, the appropriate tensile strength and the appropriate yield strength needed by a wire for microauricular malformation correction suture are achieved, the needed mechanical property can be maintained in the early stage of implantation into a body, and the service life of the wire is prolonged. And in the later stage, complete degradation can be gradually realized under the action of implant tissue fluid.

The invention relates to the technical field of liquid metal heat pipe liquid filling, and discloses a graphitization furnace waste heat utilization-based liquid metal heat pipe liquid filling control system which comprises a lithium-sodium-potassium-gallium quaternary alloy storage tank, a molecular sieve, a high-purity tank, a filling conversion tank, a high-pressure argon tank, a two-stage vacuum pump set and a high-temperature-resistant heat pipe, the lithium-sodium-potassium-gallium quaternary alloy storage tank is connected with the molecular sieve through a pipeline, and a valve I and a valve II are sequentially mounted on the pipeline connected with the molecular sieve; a pipeline is arranged between the valve I and the valve II and is connected with the high-purity tank; a valve III is mounted on the pipeline; the lithium-sodium-potassium-gallium quaternary alloy serves as a working medium, argon serves as shielding gas, purification is conducted through the molecular sieve, metering is conducted through the ultrasonic electromagnetic flowmeter, vacuumizing is conducted through the two-stage vacuum pump set, the device can adapt to the ultra-high-temperature environment of the graphitization furnace, the filling safety of the high-temperature-resistant heat pipe is improved, the service life of the heat pipe is prolonged, and the process requirements of the high vacuum degree and the like are met.

A precious metal alloy mainly including a quaternary alloy of Pt, Au, Ni, and Pd includes 7.5% by atom or more and 72.5% by atom or less of Pt, 5.5% by atom or more and 62.5% by atom or less of Au, 3% by atom or more and 62.5% by atom or less of Ni, and 0.15% by atom or more and 38% by atom or less of Pd. When respective concentrations (% by atom) of Pt, Au, Ni, and Pd represent CPt, CAu, CNi, CPd, the value of the following first compositional parameter z1 is 0.5 or more and 2.88 or less and also the concentration CPd of Pd satisfies CPd≤z2 with respect to the following second compositional parameter z2. A present inventive precious metal alloy is a high-hardness precious metal alloy to which a strengthening mechanism by spinodal decomposition and / or ordering is applied.z⁢1=(CPt×CAu×CNi) / 10000[Expression⁢ 1]z⁢2=a×(CAu)3+b×(CAu)2+c×CAu+d[Expression⁢ 2]coefficients a, b, c, and d are the following numerical values.a=0.00077, b=−0.102,c=3.607, d=1.722

The present disclosure provides a Ti-Sn-Al-Nb quaternary alloy and a preparation method thereof. The Ti-Sn-Al-Nb quaternary alloy of the present disclosure is an intermetallic compound material with Ti-Sn-Al ordered phase and Ti-Al-Nb ordered phase as the matrix; wherein the chemical composition of the alloy comprises, in atomic percentage, Al: 5-30 at%, Sn: 5-30 at%, Nb: 1-15 at%, Hf: 0.01-0.5 at%, and the balance: Ti and inevitable impurity elements. The alloy after heat treatment has excellent high-temperature strength, good room-temperature plasticity and excellent oxidation resistance, and is suitable for aerospace high-temperature components.

The invention relates to the technical field of alloys, and discloses a high-strength and high-toughness tin-based quaternary alloy and a preparation method thereof.The high-strength and high-toughness tin-based quaternary alloy comprises, by weight, 1%-5% of copper, 0.1%-0.5% of hafnium, 0.05%-0.15% of yttrium and the balance tin and inevitable impurities; the preparation method of the high-toughness tin-based quaternary alloy comprises the following steps that raw materials are weighed according to the weight percentage and smelted in a vacuum induction furnace, and M1 is obtained; the M1 is cooled to enter a semi-solid state area, ultrasonic vibration and low-frequency electromagnetic stirring are applied at the same time, and M2 is obtained; the M2 is rapidly solidified in a high-frequency alternating magnetic field through a melt-spinning method, and M3 is obtained; performing hot isostatic pressing treatment on the M3 to obtain M4; carrying out solid solution heat treatment on the M4 to obtain M5; keeping the temperature of M5 at 150-170 DEG C for 1-3 hours to obtain M6; the temperature of M6 is kept at 115-125 DEG C for 6-10 h, and M7 is obtained; and the M7 is subjected to heat preservation for 12-24 h at the temperature of 90-100 DEG C, and the high-toughness tin-based quaternary alloy is obtained. The tin-based quaternary alloy disclosed by the invention has very good obdurability.

The invention relates to a method for controlling the form of non-metallic inclusions in tire cord steel, which comprises the following steps: 1) controlling the components of molten steel: preparing a Fe-Si-Mg-Al quaternary alloy and adding the Fe-Si-Mg-Al quaternary alloy in the form of a cored wire; (2) controlling a refining slag system; and the refining slag system comprises the following components: w (CaO) / w (SiO2) = 0.8-1.2, w (MgO) = 6-9%, and w (Al2O3) is less than 10.0%. According to the tire cord steel quality control requirement, the powerful non-metallic inclusion control function of magnesium metal and the converter-refining-continuous casting production technology are combined, the tire cord steel non-metallic inclusions are controlled from the two aspects of tire cord steel molten steel component control and refining slag component control, and the tire cord steel quality is effectively improved.

A vertical thin-film (VTF) light emitting diode (LED) having embedded contacts is described. The vertical thin-film (VTF) light emitting diode (LED) having embedded contacts has structure where the metal layer constitutes both bondpad(s) and associated electric contact to the semiconductor. The metal layer is embedded and, hence, no longer blocking light from the light emitting surface. The vertical thin-film (VTF) light emitting diode (LED) having embedded contacts comprises a plurality of group III-V semiconductor material layers, including binary, ternary, and quaternary alloys of gallium (Ga), aluminum (Al), indium (In), and phosphorus (P) and a multiple quantum well layer on a substrate. At least one ne of the plurality of group III-V semiconductor material layers comprise an aluminum indium phosphide (AlInP) layer or a low confinement layer (LCL) comprising aluminum indium gallium phosphide (AlInGaP)

The application provides a method for calculating stress of nitride dendrites under forced convection in a steel liquid solidification process, and relates to the technical field of metal solidification. The composition of the steel grade and the involved thermodynamic and kinetic parameters and complex F-H boundary conditions are collected. The free boundary condition is added to the right side along the x direction velocity, and the stress growth model of Fe-C-M-N quaternary alloy steel in the flow field is established by coupling D2Q9 and cellular automaton model. Finally, the visual processing module is used to analyze the shape, size and flow field distribution of the nitride dendrites during solidification. The application optimizes the solidification technology, predicts the stress analysis of the nitride dendrites under forced convection, and provides theoretical guidance for improving the quality of the casting blank.

Disclosed herein are aluminum nitride (AlN) piezoelectric materials, piezoelectric devices and related methods of fabricating said devices. The piezoelectric materials comprise a doping element that enhances the piezoelectric properties of the material and a stiffening element, which enhances the mechanical properties of the piezoelectric material. The incorporation of an enhancing and stiffening element to binary alloys of AlN, results in a quaternary AlN alloy, which reduces current trade-offs between the piezoelectric tensor component (e33), and stiffness of the material (C33).

The application relates to a PtRhRuCu quaternary alloy nanoscale enzyme and a preparation method and application thereof, relates to the field of catalytic materials and analytical chemistry, and the quaternary alloy nanoscale enzyme is a nanoparticle composed of Pt, Rh, Ru and Cu and having an isolated island-shaped structure. The preparation method of the PtRhRuCu quaternary alloy nanoscale enzyme comprises the following steps: S1, mixing K2PtCl4 solution, K3RhCl6 solution, RuCl3 solution and CuCl2 solution to obtain a mixed solution I; S2, adding polyvinylpyrrolidone powder to the mixed solution I while stirring, heating to 150-220 DEG C, and constant-temperature reaction for 6-8 hours to obtain a mixed solution II; and S3, cooling the mixed solution II to room temperature, centrifuging, washing, separating out solid precipitates, and freeze-drying to obtain the PtRhRuCu quaternary alloy nanoscale enzyme. The application introduces the transition group metal element Cu into the three noble metals Pt, Rh and Ru, causes a multi-element effect, significantly improves the peroxidase-like activity, inhibits the oxidase-like activity, and achieves the effect of "directional regulation" of catalytic activity.

Disclosed herein are piezoelectric aluminum nitride (AlN) materials, piezoelectric devices, and associated methods for manufacturing these devices. The piezoelectric materials comprise a doping element that enhances the piezoelectric properties of the material and a stiffening element that improves the mechanical properties of the piezoelectric material. The incorporation of a reinforcing and stiffening element into binary AlN alloys results in a quaternary AlN alloy that overcomes the current trade-offs between the piezoelectric tensor component (e) and the piezoelectric tensor component (e). 33 ) and the stiffness of the material (C 33 ) reduced.

This invention discloses a method for real-time control of epitaxial layer growth stress. During epitaxial growth, the change in the curvature of the epitaxial film is closely related to the thickness and stress of the epitaxial film. Several 200nm quaternary InGaAsP alloys with different stresses are grown on an InP substrate, and the film stress monitoring software curvature is retrieved during the growth process. This method for real-time control of epitaxial layer growth stress summarizes the relationship between the stress of the InGaAsP quaternary alloy epitaxial layer and the rate of change of the epitaxial film curvature, and refines it into a formula; at the same time, it summarizes the relationship between epitaxial stress and epitaxial process parameters, and refines it into a formula. By applying these two formulas, on the one hand, the epitaxial growth process parameters for a given stress can be quickly located, and on the other hand, the stress can be monitored during the epitaxial growth of the quaternary alloy, and the stress can be adjusted in situ, reducing the number of growth cycles and improving growth efficiency.

The invention discloses a PtPdCuFe alloy nano enzyme material, and belongs to the technical field of nano materials and analytical chemistry. According to the technical key points, four metal atoms of platinum, palladium, copper and iron are uniformly distributed on the nanoscale to form an alloy structure, and the unique quaternary composition and atomic-scale mixing generate a synergistic effect, so that the catalyst has excellent oxidase-like and peroxidase-like activities at the same time. The invention also discloses a colorimetric sensor containing the material, and a method for detecting in a buffer system through catalytic oxidation and coupling with nitrite by using the oxidase-like activity of the material. According to the method, the peroxidase-like activity of the material is utilized, and TMB oxidation is inhibited through thiophanate-methyl in the presence of hydrogen peroxide for detection. The invention further discloses a method for synthesizing the quaternary alloy material through a one-step hydrothermal method. The method is mainly used for high-sensitivity and high-selectivity rapid colorimetric analysis of nitrite pollutants and thiophanate-methyl pesticide residues in food and environmental samples.

Apparatuses for rapid-cycle high-temperature heating and cooling are disclosed. The apparatuses can be used for elementary, binary, tertiary, and quaternary alloys of wide and ultra-wide band gap compound semiconductors. The apparatuses can be used for wafer annealing, and can include an induction coil, and at least one gas nozzle. A susceptor holds a workpiece with a first face of the workpiece exposed and a second face of the workpiece in thermal contact with a first surface of the susceptor. The first gas nozzle is arranged to disperse cooling gas to the susceptor and workpiece assembly. Each heating operation uses inductive coupling to the susceptor to heat the workpiece from 800° C-1100° C to 1400° C-2500° C in about one second (for one example). Each cooling operation uses cooling gas dispersion to cool the workpiece from 1400° C-2500° C to 800° C-1100° C in about one second (for another cooling example).

The application discloses a copper-based core / multilayer shell structure quantum dot based on gradient active zinc source and a preparation method thereof, and relates to the technical field of quantum dot materials. The application adopts a CuInZnS quaternary alloy core-three-layer ZnS shell structure design, cooperates with zinc source types and solvent coordination system to synergistically control a gradient active zinc source, performs quantum dot step-by-step growth through gradually reducing the activity of the zinc source from inside to outside, realizes fast and uniform nucleation, releases interface stress from inside to outside of the ZnS shell layer in stages, passivates defects and avoids stress concentration to introduce new defects. The prepared copper-based core / multilayer shell structure quantum dot has a significantly improved fluorescence quantum yield; the stability of the quantum dot film in luminescence properties is obviously increased under the condition of a general indoor environment below 200 DEG C high temperature. Compared with a regulation mode of changing the zinc source type alone, the regulation precision is higher, the step-by-step growth requirement of the multilayer shell can be accurately matched, the preparation process is an oil phase conventional process, the operation is simple, the repeatability is good, and the application is suitable for industrialized scale production.

The invention relates to the technical field of metal materials, and particularly discloses a temperature-controlled step-by-step smelting preparation method of a hydrogen-purified vanadium-platinum alloy, and the hydrogen-purified vanadium-platinum alloy is prepared from the following raw materials in parts by weight: 88-92 parts of a vanadium raw material; 8-12 parts of a platinum raw material; 0.03 to 0.06 part of a primary gas phase activator; and 0.15 to 0.25 part of a secondary composite trapping agent. The first-stage gas-phase activating agent is prepared from nano carbon black and lanthanum hexaboride, and the weight ratio of the nano carbon black to the lanthanum hexaboride is (50: 1)-(60: 1). The secondary composite trapping agent is prefabricated quaternary alloy powder and comprises zirconium, yttrium, boron and silicon, and the weight ratio of the zirconium to the yttrium to the boron to the silicon is 40: 40: 5: 15. According to the method, the first-stage gas phase activator and the second-stage composite trapping agent are adopted for synergistic purification, interstitial impurities can be effectively removed, generation of a brittle hard phase is inhibited, the high-plasticity vanadium-platinum alloy is obtained, and the problems that a traditional material is large in brittleness and difficult to carry out cold rolling machining due to oxygen and nitrogen pollution are solved.

The invention discloses a FeNi series magnetically soft alloy with high-frequency magnetic performance and low loss. The alloy is a ternary alloy system or a quaternary alloy system. When the FeNi series soft magnetic alloy is a ternary alloy system, the FeNi series soft magnetic alloy is composed of, by mass, 49-51% of Fe, 0.3-1.5% of X and the balance Ni, and X is selected from one of Cu, Nb, Zr and Y; when the FeNi series soft magnetic alloy is a quaternary alloy system, the FeNi series soft magnetic alloy is composed of, by mass, 49%-51% of Fe, 0.3%-1.5% of M, 0.1%-1.2% of N and the balance Ni, M is selected from one of Cu, Nb, Zr and Y, and N is selected from Ti or Cr. Through trace alloying, the grain size of a FeNi alloy system is refined, and the resistivity is improved, so that the loss of the FeNi soft magnetic alloy in a high-frequency magnetic field environment is reduced.

The invention provides a preparation method of quantum dots. The preparation method comprises the following steps: S1, preparing a first mixture containing fatty acid silver, optional fatty amine and a non-coordination solvent; s2, mixing the first mixture with a first sulfur precursor, and carrying out heating reaction in a container at a first reaction temperature for a first time to generate silver sulfide nanoparticles; s3, continuously adding an indium precursor and a second sulfur precursor into the container at a second reaction temperature, and reacting for a second time; s4, continuously adding a gallium precursor and a third sulfur precursor into the container at a third reaction temperature, and reacting for a third time, wherein the third reaction temperature is higher than the second reaction temperature; and S5, the third reaction temperature is increased to the fourth reaction temperature for alloying, the AgInGaS quaternary alloy quantum dots are obtained, and the first time is smaller than or equal to 60 seconds. According to the preparation method, a uniform quaternary alloy can be formed, so that high quantum yield and narrow fluorescence half-peak width are realized.

A permanent magnet usable for an ultra-high vacuum atmosphere is made of a magnetic alloy coated with a non-evaporable getter (NEG) layer made of a binary, ternary or quaternary NEG alloy containing elements selected among Ti, Zr, V, Hf, Nb, Fe, Al and Cu which comprises at least Zr from 20 to 85 at % and V from 8 to 63 at %, with respect to the sum of the alloy elements in the NEG alloy.