302results about How to "Reduce defects" patented technology

The invention belongs to the field of thin films, and particularly discloses an atomic layer deposition method and a thin film prepared through the atomic layer deposition method. According to the deposition method, the reaction cavity, the two input pipeline systems, the outlet valve and the vacuum pump in the atomic layer deposition system are used for controlling precursor pulse deposition and inert gas purging conditions in the atomic deposition process, and the film deposition state is improved; the efficiency of purging and removing substances and impurity residues such as a precursor and a reaction product thereof is improved, the problem that the quality of a deposited film is affected by the impurity residues in a reaction system or on the surface of a sample in the film deposition process is avoided, the uniformity and compactness of film deposition and the coverage rate and conformal rate of a film on the surface of a base material hole are improved, the defects of the film are reduced, and the yield is improved. And the method can be applied to a substrate with a high aspect ratio structure to deposit the film, so that the purpose of manufacturing a large-size complicated special-shaped structure device is achieved.

The invention belongs to the technical field of ceramic materials, and particularly discloses whisker toughened zirconium oxide-aluminum oxide composite ceramic and an additive manufacturing method thereof, the composite ceramic comprises the following components by mass: 94 parts of zirconium oxide toughened aluminum oxide ceramic and 5 parts of silicon carbide whisker; the zirconium oxide toughened aluminum oxide ceramic is prepared from the following components in parts by mass: 76 parts of aluminum oxide and 24 parts of zirconium oxide, and 3mol% of yttrium oxide is added into the zirconium oxide. According to the whisker toughened zirconium oxide-aluminum oxide composite ceramic and the additive manufacturing method thereof, the preparation method has unique design of components and process, and the preparation of a high-density and high-performance ceramic-based composite material part based on a fused deposition modeling technology is successfully realized. Further, the prepared silicon carbide whisker toughened zirconium oxide-aluminum oxide-based composite ceramic has relatively high density and excellent obdurability.

According to the pole piece thickness control method, a dynamic regulation and control mechanism is constructed by detecting the thickness of a pole piece in real time and calculating the thickness deviation in real time, once the thickness deviation is larger than a preset threshold value, a system can give out an instruction in real time, a rolling mechanism is driven to adjust a roll gap, and it is ensured that the rolling thickness of the follow-up pole piece is stable and consistent; the requirements on the thickness consistency and stability of the pole piece are met, so that the product defects are reduced, and the product qualification rate is improved; reworking and scrapping are reduced, the production cost is reduced, meanwhile, the downtime is shortened, and the production efficiency is improved.

The invention discloses a rare earth aluminum alloy cable material and a preparation method and application thereof, and relates to the technical field of aluminum alloy material preparation. The rare earth aluminum alloy cable material is prepared from the following raw material components in percentage by mass: 0.3 to 0.6 percent of Ce, 0.3 to 0.6 percent of Sc, 0.05 to 0.15 percent of Y, 0.10 to 0.20 percent of Fe, 0.05 to 0.15 percent of Si and the balance of Al. The preparation process comprises the steps of melting, refining, casting, homogenizing treatment, hot rolling, drawing and aging treatment. The rare earth elements Ce, Sc and Y are added, a specific heat treatment process and a processing process are combined, and the three rare earth elements Ce, Sc and Y have a synergistic effect, so that the performance and the electric conductivity of the cable material are balanced, and the cable material has good electric conductivity and elongation on the premise of ensuring certain tensile strength, and can meet the requirements of the cable industry.

A box type guide rail of a hydraulic climbing device of a tower building machine comprises two side plates, a middle plate is arranged between the two side plates, and the middle plate and the side plates are connected in an inserted mode and then fixed in a welding mode to form the box type guide rail. The box-type guide rail aims to solve the technical problem of a box-type guide rail in a hydraulic climbing device of a tower building machine, a traditional box-type guide rail is difficult to weld and form and poor in consistency, an innovative structure that the middle plate and the side plates are welded after being connected in an inserted mode is adopted, the middle plate and the side plates are cut through laser, and matched plugs and insertion holes are designed; wherein a chamfer is arranged at the outer side end of the plug, so that the welding difficulty is successfully reduced, the consistency of each box type rail finished product is ensured, the production quality and efficiency of the box type guide rail are effectively improved, and reliable guarantee is provided for stable operation of a tower building machine.

The utility model relates to a kind of A-shaped frame anti-crack casting model for mine car in sand casting technology field, include A-shaped frame body, the A-shaped frame body includes two head portion integrated connection's inclined strut leg, the first muscle plate is connected between the inner corresponding face head end of two inclined strut legs, the head portion integrated connection's two side surfaces of two inclined strut legs are respectively provided with first riser piece and second muscle plate, the long strip tie between the inner corresponding face tail end of two inclined strut legs is connected, the long strip tie middle part is provided with the gate piece in the same direction with first riser piece, the tail end of two inclined strut legs is equipped with the second riser piece in the same direction with first riser piece;The casting model can avoid casting defects.

This invention relates to a boron-doped multi-element polyanionic sodium-ion battery cathode material and its preparation method, comprising the following steps: [The method involves] mixing Na₄Fe₂O₃ with... 3‑X B X (PO4) 2‑Y (SiO4) Y The stoichiometric ratio of P2O7 is determined by adding ferrous source, boric acid, sodium source, phosphorus source, and silicon source to water, followed by the addition of carbon source and mixing thoroughly to obtain a mixed slurry; wherein 0.2≤X≤0.5, 0<Y≤1; the mixed slurry is then ground to obtain a sand-milled slurry; the sand-milled slurry is dried to obtain precursor powder; under a protective atmosphere, the precursor powder is sintered at 450~550℃ to obtain boron-doped multi-element polyanion sodium-ion battery cathode material. The introduction of boron and silicon elements in this invention helps reduce raw material costs, improve the electrochemical performance of the material, especially enhancing the structural stability, rate performance, and cycle life of the cathode material, and also lowers the sintering temperature, meeting the requirements for cost reduction and efficiency improvement.

This invention provides a heat treatment apparatus that reduces defects caused by bubbles during film formation on a substrate. The heat treatment apparatus includes: a mounting section on which the substrate, before the film formed on it is cured, is placed; and a heating section that heats the substrate placed on the mounting section at a temperature lower than the boiling point of the solvent contained in the film.

This invention discloses a silicon nitride grinding device, relating to the technical field of silicon nitride grinding devices. The device includes a support frame and a collection box. A conical cylinder is fixedly mounted on the upper surface of the support frame, and the collection box is disposed on the lower surface of the support frame. A feed trough is fixedly mounted on the upper surface of the conical cylinder, and a water storage tank is fixedly mounted on the circumferential surface of the conical cylinder. A water spray head is provided on the inner wall of the conical cylinder. A rotating shaft is rotatably mounted on the upper surface of the inner wall of the conical cylinder, and a grinding head is fixedly mounted on the lower surface of the rotating shaft. A grinding disc is fixedly mounted on the inner wall of the conical cylinder. A material unblocking device is also provided inside the conical cylinder. When the feed trough is blocked, it affects the grinding efficiency, potentially causing a decrease in output or production stoppage. Blockage causes material to accumulate in the feed trough, increasing the pressure and stress on the material. If this blockage persists for a long time, it may damage the feed trough.

The utility model relates to a kind of LED epitaxial structures, comprising: substrate;N type layer;Active layer is located on N type;P type layer, located on active layer;Wherein, the P type layer includes P type window layer, P type window layer includes several first laminated structure, each first laminated structure includes the GaInP layer, first GaP layer and second GaP layer of sequentially laminated, the P type doping concentration of second GaP layer in each first laminated structure is greater than the P type doping concentration of first GaP layer.The GaInP layer of the utility model has higher band gap, plays the role of optical window layer, can reduce light absorption loss;GaP has lower band gap, first GaP layer and second GaP layer play the role of buffer layer / transition layer, so the combination of GaInP layer, first GaP layer and second GaP layer realizes the balance of band matching and carrier transport efficiency, conducive to the efficient extension of current.

This invention relates to the field of die-casting mold technology and discloses a die-casting mold for aluminum alloy forming, comprising a moving mold and a fixed mold, and further comprising: a pre-vacuuming mechanism, fixedly installed inside the fixed mold, the pre-vacuuming mechanism including a sealing element and a pre-vacuuming channel communicating with the sealing element, and a slot corresponding to the sealing element on the moving mold; a vacuuming mechanism, including a fixed mold vacuuming component fixed on the fixed mold and a moving mold vacuuming component fixed on the moving mold; and a feeding assembly, fixedly installed on the side of the fixed mold away from the moving mold. This die-casting mold for aluminum alloy forming, by setting the pre-vacuuming mechanism and the vacuuming mechanism, initiates pre-vacuuming during the mold closing process, utilizing the dynamic stage of the gradually decreasing cavity volume to expel most of the gas in advance; a second vacuuming is performed after mold closing to further extract residual gas. The synergistic effect of the two vacuuming processes effectively reduces the initial gas content in the cavity.

The invention relates to a high-entropy ceramic capacitor, a ceramic dielectric material for the high-entropy ceramic capacitor and a preparation method, the raw material composition of the ceramic dielectric material comprises NaNbO3, (Na0. 2Bi0. 2Ba0. 2Mg0. 2Zn0. 2) TiO3, H3BO3, CaZrO3 and the like, by controlling the raw material ratio and preparation process parameters of sodium niobate and adopting a multi-step grinding synthesis method, NaNbO3-based high-entropy ceramic is designed, so that the insulation resistance of the high-entropy ceramic capacitor is effectively improved; on the other hand, chemical modification treatment is carried out by introducing (Na0. 2Bi0. 2Ba0. 2Mg0. 2Zn0. 2) TiO3, H3BO3, CaZrO3 and the like, so that the structural stability of an antiferroelectric phase is enhanced, the compactness of the material is improved, and finally, the energy storage performance of the material is optimized and improved.

The present application relates to a kind of drug bottle body defect detection equipment and detection method, and it is related to the technical field of medical instrument detection;Including detection platform, medicine bottle conveying part and angle adjusting component;Medicine bottle conveying part includes two clamping conveyors, and clamping conveyor is equipped with clamping block at equal intervals;Angle adjusting component includes two telescopic skeletons, and limit rotating shaft is rotatably arranged at the corner of two telescopic skeletons, and limit rotating shaft on telescopic skeleton is equipped with angle adjusting belt;The present application can solve the following problems existing in the prior art:First, the prior art mainly shoots the image of the whole bottle body, and a large number of pixel points and mosaic will appear in the image when the image is enlarged and detected, which will affect the accuracy of bottle body defect detection, so that some small scratches on the bottle body cannot be effectively identified;Second, the prior art has certain singleness, and it can only detect defects for single size of drug bottle body.

The invention discloses a semiconductor device and a method of manufacturing the same. The semiconductor device includes a substrate; a channel layer positioned on the substrate, extending in a first direction perpendicular to a top surface of the substrate, and including an inverted trapezoidal profile; and a word line including a word line dielectric layer consistently and laterally surrounding the channel layer, and a word line conductive layer laterally and partially surrounding the word line dielectric layer, extending along a second direction parallel to a top surface of the substrate, and including an inverted trapezoidal profile.

This invention discloses an epitaxial wafer for a deep ultraviolet (UV) light-emitting diode (LED) and its fabrication method, relating to the field of semiconductor optoelectronic devices. The UV LED epitaxial wafer includes a substrate and a buffer layer, an N-type AlGaN layer, an active layer, an electron blocking layer, and a P-type AlGaN layer sequentially grown on the substrate. The active layer has a periodic structure, with each period comprising a sequentially stacked quantum well layer and a quantum barrier layer, and the number of periods in the active layer is ≥2. The quantum barrier layer comprises a sequentially stacked AlInGaN layer and a P-AlInGaN layer. Implementing this invention can effectively improve the luminous efficiency of deep ultraviolet LEDs.

This invention relates to transition layer materials and welding processes for welding dissimilar steel and aluminum materials, belonging to the field of welding technology. The transition layer material for welding dissimilar steel and aluminum materials of this invention comprises a copper layer, a copper alloy layer, and a zinc alloy layer arranged sequentially; the copper layer is adjacent to the steel base material, and the zinc alloy layer is adjacent to the aluminum base material; the copper content in the copper alloy layer is 62.0%-64.0%; the zinc content in the zinc alloy layer is 89.0%-91.0%; the mass ratio of the copper layer, copper alloy layer, and zinc alloy layer is (0.9-1.1):(2.3-2.7):(1.8-2.2). By sequentially setting the copper layer, copper alloy layer, and zinc alloy layer between the steel base material and the aluminum base material, a gradual transition from the steel base material to the aluminum base material is achieved, effectively avoiding the formation of brittle Fe-Al intermetallic compounds during direct welding, and enhancing the mechanical properties and durability of the welded joint.

This invention discloses a method for preparing silicon carbide fibers with an in-situ boron nitride coating. The method involves melt spinning a metal-doped polycarbosilane precursor to obtain doped polycarbosilane precursor fibers. These precursor fibers are then subjected to a non-melting treatment in an oxidizing atmosphere to obtain non-melting fibers. The non-melting fibers are then subjected to inorganic pyrolysis to obtain inorganic fibers. These inorganic fibers are then densified and sintered to obtain boron-containing SiC fibers. Finally, the boron-containing SiC fibers are subjected to high-temperature treatment in a nitrogen atmosphere to obtain silicon carbide fibers with an in-situ boron nitride coating. This invention provides a simple preparation method, resulting in an in-situ self-grown BN coating with high crystallinity, good stability, and excellent uniformity. The coating is tightly bonded to the SiC fibers, is low-cost, and can be mass-produced. Furthermore, it significantly improves the fiber's temperature resistance and high-temperature creep resistance, allowing the fiber to serve for extended periods at higher temperatures.

The application belongs to the technical field of polymer materials, and particularly relates to a nylon powder and a preparation method and application thereof. The nylon powder comprises high-viscosity nylon resin, low-viscosity nylon resin and an additive, wherein the relative viscosity of the high-viscosity nylon resin is 1.75-1.85, the relative viscosity of the low-viscosity nylon resin is 1.55-1.65, the mass ratio of the high-viscosity nylon resin to the low-viscosity nylon resin is 10:1-3, and the additive comprises an antioxidant. The high-viscosity nylon resin and the low-viscosity nylon resin with specific viscosities are compounded and used in proportion, the high-viscosity nylon resin serves as a skeleton of a hydrogen storage bottle inner container and provides mechanical property support, and the low-viscosity nylon resin provides fluidity and ensures few defects in bottle forming. The use of the nylon powder of the application improves the mechanical property of the hydrogen storage bottle inner container and the integrity of the inner container structure, and a stable and defect-free type IV nylon hydrogen storage bottle inner container is prepared.

The application provides a manufacturing method of glass direct copper clad circuit, relates to the technical field of microelectronic circuit manufacturing, and comprises the following steps: S01, copper foil surface planarization: the copper foil is adhered to a UV photosensitive adhesive film, and the surface of the adhered copper foil is ground; after the surface of the copper foil is ground to reach a target roughness, the copper foil is cleaned and dried; S02, laminated static pressure: a glass substrate, the UV photosensitive adhesive film with the adhered copper foil and a carrier plate are sequentially laminated and fixed, vacuum is drawn and sealed, static pressure is applied to the formed sealed body, and a structure to be welded is obtained; and S03, laser selective welding: an ultrashort pulse laser and a short pulse are combined, and multiple compound scans are performed by using an energy gradient, so that the problem that an interface gap cannot be effectively reduced and the interface is easy to be ablated when a laser is used for welding to manufacture a glass copper clad circuit is solved, and the interface fusion capacity between the copper foil and the glass is improved.

This utility model provides a stainless steel flange device, including a support base and a side bracket. A servo motor is installed in the middle of the upper end of the support base. The shaft end of the servo motor is connected and fixed to the flange table through a flange and bolts. Multiple support rods are installed longitudinally on the lower edge of the flange table. Multiple lower mold seats and multiple signal transmitters are fixed on the upper edge of the flange table. A side bracket is welded to the lower left side of the support base. This design solves the problem that the original thin-walled stainless steel flange device is difficult to adapt to the material characteristics of stainless steel and is prone to defects due to "deformation concentration and stress loss" in a single punching of the convex ring. This utility model adopts a semi-automatic drive structure, which can facilitate the two-stage punching and flanged of stainless steel pipes of different sizes. The "conical pre-punching + flat final punching" achieves controllable stress, improved accuracy and reduced defects through step-by-step dispersion of deformation. It is especially suitable for high-precision and multi-specification stainless steel flange scenarios.

The utility model discloses chain paint dipping equipment, and particularly relates to the technical field of chain production, the chain paint dipping equipment comprises a shell, a paint dipping tank is fixedly connected in the shell, a paint dipping assembly and heating mechanisms are installed in the shell, and the paint dipping assembly is installed between the heating mechanisms; the paint dipping assembly comprises a hydraulic cylinder, the output end of the hydraulic cylinder is fixedly connected with a fixing disc, the top end of the fixing disc is fixedly connected with a variable frequency motor, the output end of the variable frequency motor is fixedly connected with a first gear, the first gear is rotationally connected with the interior of the fixing disc, one side of the first gear is meshed with a first fluted disc, and the first fluted disc is rotationally connected with the interior of the fixing disc. By arranging the paint dipping assembly and the heating mechanism, paint liquid flowing can be accelerated, bubbles can be promoted to escape rapidly, paint film defects caused by bubble residues are reduced, the adhesive force of a paint film is improved, meanwhile, a chain can be heated before paint dipping, and the adhesive force of the paint liquid on the surface of the chain can be improved.

The application provides an anode foil and a preparation method thereof. The preparation method comprises the following steps: providing an unformed foil, wherein the unformed foil comprises an aluminum foil base material and an aluminum powder sintering layer arranged on the surface of the aluminum foil base material; and sequentially performing the following processes on the unformed foil: water boiling, first-stage chemical conversion, second-stage chemical conversion, third-stage chemical conversion, power feeding treatment, fourth-stage chemical conversion, fifth-stage chemical conversion, first-stage heat treatment, first chemical conversion repair, first phosphoric acid treatment, second chemical conversion repair, second-stage heat treatment, third chemical conversion repair and second phosphoric acid treatment. The solutes of the electrolyte of the first-stage chemical conversion, the second-stage chemical conversion and the third-stage chemical conversion comprise citric acid, triammonium citrate, adipic acid, ammonium adipate, salicylic acid, hypophosphite, boric acid and ammonium salt, and the solvent is water. The solutes of the electrolyte of the fourth-stage chemical conversion and the fifth-stage chemical conversion comprise citric acid, triammonium citrate, sebacic acid, ammonium sebacate, salicylic acid, sodium hypophosphite, boric acid and ammonium salt, and the solvent is water. An anode foil prepared by the preparation method has a high specific capacity and a small hydration leakage current.

The application discloses a method for preparing submicron and micron alkylated graphene oxide by using coal, and comprises the following steps: 1, graphitizing coal powder to rearrange carbon atoms and grow submicron crystal regions; 2, oxidizing and peeling the graphitized coal under the action of sulfuric acid, phosphoric acid and potassium permanganate; 3, adding hydrogen peroxide to react with potassium permanganate and high-valence manganese salt in the solution until the solution turns yellow; 4, screening the solution to remove unreacted black impurities; 5, centrifuging the solution to reserve the precipitate, and then washing and centrifuging the precipitate with dilute hydrochloric acid and ethanol; 6, dispersing the precipitate with diethyl ether, and then obtaining graphene oxide powder through suction filtration. The prepared graphene oxide has an average size of 800 nm, an average layer number of 1-2 layers, and a yield of 107%. The method has simple steps, low cost and high yield, and is easy to realize industrial production, and has a very broad prospect in the present situation of urgently realizing high-value utilization of coal.

The invention belongs to the field of coordination polymers, and discloses an antiferromagnetic tetranuclear cobalt coordination polymer constructed by mixed polydentate ligands and a preparation method and application thereof. The chemical formula of the polymer is (C9H9O6) 2 (C26H18N4) 2 (OH) 2Co4. (H2O) 7, C9H9O6 is 1, 3, 5-cyclohexane tricarboxylic acid, C26H18N4 is 1, 2, 4, 5-tetrapyridyl benzene, the polymer is a monoclinic system and a P21 / c space group, the cell parameters are alpha = 90 degrees, beta = 96.166 (8) degrees and gamma = 90 degrees, and the polymer has few defects, high crystallinity and good stability and can be applied to the fields of adsorption separation, hydrogen storage, energy storage, molecular magnets, catalysis, sensing or molecular recognition and the like.

This utility model relates to the field of nanocrystal processing technology and discloses a resin impregnation device for nanocrystals. The device includes an impregnation tank with a sealing cap. An immersion chamber is located inside the tank, containing a stirring assembly and a circulation assembly. The stirring assembly includes multiple stirring paddles. A fixed frame is located at the bottom of the immersion chamber, and a rotating shaft is rotatably connected to the fixed frame. The stirring paddles are arranged in a circular array on the rotating shaft. A rotating shaft is rotatably connected to the sealing cap, and a motor is mounted on the sealing cap. One end of the rotating shaft is connected to the output end of the motor. A slot is formed at the top of the rotating shaft, and a locking element that mates with the slot is located at the bottom of the rotating shaft. The circulation assembly includes a circulation pump fixed to the outside of the impregnation tank. Liquid pipes one and two are connected to the circulation pump, respectively connecting to the bottom and top of the impregnation tank. The stirring and circulation assemblies overcome penetration resistance and more thoroughly remove air bubbles, improving the uniformity and quality of impregnation.

The application provides a 3D printing method for preparing a low-cost TA15 part based on a bimodal particle size distribution near-spherical powder and a high-performance low-cost TA15 part. The 3D printing method uses a bimodal particle size distribution near-spherical TA15 alloy powder with good uniformity as a raw material, improves the near-spherical powder bed density through bimodal grading of coarse powder and fine powder, and then prepares a low-cost high-performance TA15 part through an optimized selective laser melting (SLM) process parameter window suitable for bimodal distribution powder, thereby providing a more cost-effective preparation method for TA15 titanium alloy parts in aerospace.

This invention belongs to the field of composite material technology, specifically disclosing a high-dielectric-constant, low-dielectric-loss polyphenylene sulfide composite material, its preparation method, and its applications. The composite material comprises the following components in parts by weight: 100 parts of polyphenylene sulfide matrix, 10-60 parts of high-dielectric-constant nanofiller, 0.5-8 parts of metal nanoparticles, and 0.5-5 parts of surface modifier. This invention utilizes the aforementioned high-dielectric-constant, low-dielectric-loss polyphenylene sulfide composite material, its preparation method, and its applications. The composite material exhibits a high dielectric constant and achieves low dielectric loss. It also enhances its mechanical strength and toughness, enabling the composite material to maintain its electronic properties while possessing excellent physical properties.

A kind of copper clad steel grounding wire is used to straightening device, it is related to copper clad steel grounding wire straightening technical field, including mounting plate and the support frame for supporting mounting plate, a group of straightening rollers for extruding grounding wire is rotationally arranged on mounting plate, and once straightening area is formed between two straightening rollers, which can be passed through by grounding wire, first sliding plate capable of sliding along the direction perpendicular to the movement direction of grounding wire is arranged on mounting plate, and another straightening roller is rotationally connected with first sliding plate;Multiple auxiliary rollers are arranged on the side of straightening roller away from the entry of grounding wire, and multiple auxiliary rollers are respectively located at the two sides of grounding wire, so that secondary straightening area is formed between the two sides of auxiliary roller of grounding wire, which can be passed through by grounding wire, multiple second sliding plates capable of sliding along the direction perpendicular to the movement direction of grounding wire are arranged on mounting plate, and second sliding plate is located at the same side with first sliding plate, corresponding second sliding plate is rotationally connected with the side auxiliary roller, and the interval between straightening rollers can be adjusted to adapt to grounding wire of different diameters.

The application discloses a chuck assembly and a semiconductor device, relates to the technical field of semiconductor devices, and comprises a chuck and one or more shaft cylinders, wherein the last shaft cylinder of the plurality of shaft cylinders or one shaft cylinder is connected with the chuck, the inside of each shaft cylinder is provided with a central hole, the central hole is provided with a balance mass and an elastic damping piece, and the elastic damping piece is sleeved with the balance mass to form a balance mass-spring-damping system. The chuck assembly is sleeved with the balance mass through the elastic damping piece to form the balance mass-spring-damping system, the balance mass-spring-damping system generates reverse vibration matched with the vibration of the chuck, micro-vibration generated between the disc surface of the chuck and the contact surface of the substrate is inhibited, generation of friction particles is reduced, stability and cleanliness of a core area of a process environment are improved, process quality of a deposited film is improved, and the needs of high-end processes for extremely low defect rate and ultra-high uniformity of the deposited film are met.

The invention belongs to the technical field of fluorescent ceramic preparation, and relates to an enhanced near-infrared luminescence MgAl2O4: Cr < 3 + > fluorescent ceramic and a preparation method thereof, and the preparation method comprises the following steps: dissolving Mg (NO3) 2.6 H2O, Al (NO3) 3.9 H2O and Cr (NO3) 3.9 H2O in deionized water, then adding urea, stirring and dissolving; transferring the mixed solution into a reaction kettle for hydrothermal reaction to obtain MgAl2O4: Cr < 3 + > powder; adding a sintering aid CaF2 into the MgAl2O4: Cr < 3 + > powder, and carrying out ball milling and mixing; the ball-milled powder is poured into a mold to be compacted and then put into an SPS sintering furnace to be sintered; the sintered ceramic is subjected to annealing treatment; the surface of the annealed ceramic is sequentially subjected to coarse grinding and polishing operation, and the MgAl2O4: Cr < 3 + > fluorescent ceramic is obtained. According to the method, the luminescent property of Cr < 3 + > is remarkably promoted, and meanwhile, the high density and excellent mechanical property of the ceramic are guaranteed.