1870 results about "Grain boundary" patented technology

The invention discloses a zinc coating shedding performance detection method and system, particularly relates to the technical field of metal surface treatment quality detection, and is used for solving the problems of high misjudgment rate and insufficient detection precision caused by coating surface pseudo defect interference in the existing method. The method comprises the following steps: synchronously acquiring a multispectral reflection image and three-dimensional morphology data of the surface of a zinc coating through an industrial vision imaging device, extracting grain boundary distribution information based on multispectral data, and identifying radial pseudo defects in combination with a curvature manifold geodesic line energy gradient direction of the three-dimensional morphology; and further performing micro-crack topology analysis and grain boundary spatial correlation verification on the candidate region, eliminating texture interference and grain boundary overlapping regions, and finally outputting a high-confidence fall-off defect detection result, so that the identification capability of real defects under a complex galvanized surface is remarkably improved, and the method is suitable for automatic detection requirements of a high-speed continuous production line.

The invention discloses a rock crack evolution numerical simulation method based on data analysis, and relates to the technical field of rock mechanics engineering numerical simulation, and the method comprises the following steps: S1, obtaining microstructure data of a target rock, including a CT scanning image, an SEM image and mineral energy spectrum data; and S2, constructing a spatial distribution dynamic mechanical parameter field based on the microstructure data. According to the rock crack evolution numerical simulation method based on data analysis, a dynamic mechanical parameter field driven by a microstructure is constructed, so that the inherent defect that rock is simplified into a homogeneous material in a traditional method is overcome; microscopic characteristics such as mineral hardness gradient, grain boundary strength distribution and pore morphology are effectively quantified into an elastic modulus field, a tensile strength field and a fracture energy field which are spatially distributed, so that the numerical prediction of crack initiation and expansion truly reflects the inherent heterogeneity of the rock for the first time.

The invention discloses a production method of a high-performance sintered neodymium-iron-boron magnet. The production method comprises the steps of rapid quenching flaking, hydrogen decrepitation mixing, magnetic field forming, multi-stage treatment and composite coating. A nanocrystalline sheet is prepared through a rapid quenching technology, and uniform distribution of a grain boundary phase and rare earth elements is achieved through hydrogen decrepitation and material mixing; forming in a strong magnetic field and applying high pressure to improve the orientation degree; through high-temperature sintering, medium-temperature annealing and low-temperature aging treatment, magnet densification, grain boundary phase reconstruction and a magnetic domain structure are optimized; and finally, the corrosion resistance is improved by adopting a composite coating. The high-performance sintered neodymium-iron-boron magnet produced by the method comprises a main phase alloy, a grain boundary phase additive and a rare earth supplementary phase. Through low-oxygen nanocrystal preparation, grain boundary coordinated regulation and green process integration, compatibility of high performance, low cost and environmental protection is realized, and sustainable development of the rare earth permanent magnet material is promoted.

The invention relates to the technical field of high-performance structural ceramic materials and corrosion resistance optimization thereof, in particular to a preparation method of high-performance silicon nitride ceramic, which realizes performance improvement through dynamic optimization of a composite sintering aid, closed-loop regulation and control of air pressure sintering and multi-process data linkage. In the raw material pretreatment stage, a laser particle size analyzer is adopted for monitoring particle size distribution in real time, surface modification parameters are adjusted in a linkage mode, and a uniform monomolecular coating layer is formed; the proportion of rare earth oxide and aluminum oxide in the composite sintering aid is dynamically adjusted according to the fluctuation of the mixing torque, and agglomeration and segregation of the aid are inhibited. And in the air pressure sintering stage, the argon pressure and the heating rate are dynamically adjusted based on the slope of a shrinkage curve, and directional arrangement of beta-phase grains is promoted by combining low-temperature nitrogen protection and high-temperature argon densification. And multi-dimensional process control synergistically optimizes grain boundary components, structure and density, so that the corrosion resistance and the service life of the silicon nitride ceramic in a sulfur-containing environment are remarkably improved and the service life of the silicon nitride ceramic in the sulfur-containing environment is remarkably prolonged.

A method to achieve a yield ratio of 0.60 or more in a component from non-heat-treated steel having bainitic microstructure. The component includes a predetermined chemical composition, in mass %, in amounts such that a value of F1 obtained by Formula (1) is 0.65% or more, with the balance as Fe and inevitable impurity. Bainitic microstructure area fraction is 85% or more and Retained austenite area fraction is 5% or less. Crystal grains of the bainitic microstructure have an average diameter of 10 μm or more and 25 μm or less, an average aspect ratio of 0.5 or more, and an average ratio of crystal grain boundary length to crystal grain circumference of 60 or less.F⁢1=C+Si / 24+Mn / 6+Ni / 40+Cr / 5+Mo / 4+V / 14(1)

The invention discloses an yttrium-rich neodymium-iron-boron magnet and a preparation method thereof, and belongs to the technical field of rare earth permanent magnet material preparation. The preparation method comprises the following steps: mixing yttrium-rich neodymium-iron-boron matrix alloy powder with grain boundary doped alloy powder containing Gd and / or Ho, and carrying out compression molding and sintering tempering treatment to obtain a first yttrium-rich neodymium-iron-boron magnet. According to the invention, the grain boundary doped alloy powder containing Gd and / or Ho is added into the yttrium-rich neodymium iron boron matrix alloy powder and then is sintered, so that a continuous and uniform non-magnetic thin-wall grain boundary phase structure is formed in the grain boundary, and the coercive force of the magnet is enhanced. Dy and / or Tb heavy rare earth element grain boundary diffusion is carried out based on the first yttrium-rich neodymium-iron-boron magnet after grain boundary modification, a second yttrium-rich neodymium-iron-boron magnet is obtained, the diffusion depth of Dy and / or Tb in the magnet can be increased, the utilization rate can be increased, the cost can be reduced, the coercivity of the magnet can be improved, and the adverse effect of Dy and / or Tb on residual magnetism can be reduced.

The invention provides a perovskite thin film passivation modifier, a perovskite thin film and a preparation method thereof, and a perovskite solar cell. The passivation modifier comprises passivation molecules providing passivation groups; the passivation groups and uncoordinated lead ions or other defect sites in the perovskite thin film form coordinate bonds; the passivation group is amino. Amino groups in the passivation modifier have relatively strong coordination capability and can form coordination bonds with uncoordinated lead ions or other defect sites in the perovskite material, so that grain boundary and surface defects are passivated, and in addition, the three-dimensional structure of the passivation modifier is beneficial to preventing moisture and oxygen from invading the perovskite thin film; and the stability of the perovskite thin film is further improved.

The invention relates to the technical field of glass, in particular to microcrystalline glass and a preparation method thereof, reinforced microcrystalline glass and a preparation method thereof, and a glass product. The invention provides microcrystalline glass which comprises the following components in percentage by mass based on the total mass of 100%: 58.21-70.63% of SiO2; the content of Al2O3 is 6.46 to 7.83 percent; zrO2: 3.23% to 3.92%; 1.86%-2.3% of P2O5 (P2O5); 0.4 to 0.5 percent of B2O3; 1.9 to 14.4% of a rare earth metal oxide; an alkali metal oxide: 10.86 to 12.99%; wherein the rare earth metal oxide is prepared from Y2O3 and La2O3; the alkali metal oxide comprises Na2O and Li2O. According to the microcrystalline glass disclosed by the invention, the link of a glass network is enhanced by utilizing the rare earth metal oxide and Al2O3 together to form a high-density network structure, uniform nucleation is induced through the nucleating agent, fine grains are generated, grain boundary defects are reduced according to a multi-step nucleation-crystallization system, and the mechanical property is remarkably improved.

The invention belongs to the technical field of silicon nitride ceramic substrates, and particularly relates to a high-thermal-conductivity and high-breaking-strength silicon nitride substrate and a sintering method and application thereof. In order to simultaneously improve the thermal conductivity and the breaking strength of the existing silicon nitride ceramic substrate and ensure the stability and the consistency of the performance during the production of the silicon nitride substrate, the method comprises the following steps: coating the surface of a silicon nitride ceramic biscuit subjected to tape casting with isolation powder, carrying out nitrogen or air atmosphere glue removal treatment, and then sintering; in the sintering process, the cooling process is optimized, a multi-temperature heat preservation platform is arranged above the liquid phase conversion temperature, grain growth and grain boundary composition of the silicon nitride ceramic are regulated and controlled, grain size distribution of the silicon nitride ceramic is made to be more uniform, the grain boundary structure is made to be more optimized, and the heat conductivity coefficient and breaking strength of the substrate are remarkably improved. Meanwhile, the uniformity of a temperature field in the sintering furnace can be greatly improved through the sintering method, it is ensured that the product can reach the consistent performance standard in different areas, and the stability and reliability of the product are improved.

The invention discloses a method for automatically evaluating the average grain size of a metal material by using a cross-point method, and relates to the field of metal material metallographic image analysis, and the method comprises the following steps: selecting an identification model according to a tested material; inputting the optical microscope image pic into a system with an identification model; extracting scale information of the input image pic by using mask extraction and Hough straight line detection: firstly extracting a scale region by using a mask, then extracting a scale length by using a Hough straight line detection algorithm, and finally extracting a scale value by using a KNN classifier; and identifying the grain boundary pixels of the input image by using the selected identification model: classifying each pixel of the input optical microscope image pic by using UNet, judging whether the pixel is the grain boundary pixel, finally performing optimization, performing intercept method rating according to the optimized grain boundary image, counting the number of intersections per unit length, and calculating the grain size G. According to the method, the precision and consistency of grain size evaluation are remarkably improved.

The invention relates to a detection method and application of a bainite steel structure and / or grain boundary for nuclear power equipment, and relates to the technical field of new material detection. According to the detection method, the problem that the structure and the grain boundary of bainite steel for nuclear power equipment are difficult to display can be solved, a major breakthrough of a grain size detection technology is achieved, the clear and complete grain boundary can be accurately presented, and scientific evaluation of the grain size through a comparison method, a cut point method, an area method and the like according to standard requirements is further supported. When the detection method is used for evaluating the grain size, the results are highly consistent, the repeatability is good, and the problems of subjective experience dependence and measurement errors caused by blurred grain boundary display in a traditional nitric acid and alcohol corrosion method are effectively avoided.

The invention relates to the technical field of ITO coating materials, and provides a low-sheet-resistance and high-light-transmittance ITO coating film and a preparation method thereof.The preparation method comprises the steps that S1, an yttrium-doped zirconium oxide substrate is prepared; s2, performing surface activation on the yttrium-doped zirconium oxide substrate; s3, performing magnetron sputtering in a radio frequency magnetron sputtering chamber, and forming a layer of ITO film on the surface of the yttrium-doped zirconia substrate; and S4, annealing treatment and gradient cooling treatment are carried out. The epitaxial growth of the ITO coating film is optimized through the prepared yttrium-doped zirconia substrate, and the magnetron sputtering, annealing and gradient cooling processes are combined, so that the microstructure of the film is optimized, the carrier mobility and the uniformity and stability of the film are improved, the grain boundary defect and carrier scattering loss in the ITO coating film are reduced, and the performance of the film is improved. The low sheet resistance and high light transmittance of the ITO coating film are synergistically improved, and the obtained ITO coating film has important application value in the fields of high-performance optoelectronic devices, transparent conductive films and the like.

The invention discloses a grain boundary diffusion method of a sintered neodymium-iron-boron magnet. The grain boundary diffusion method comprises the following steps: providing a magnet to be diffused; coating the surface of the magnet to be diffused with coating slurry containing heavy rare earth metal powder, and performing grain boundary diffusion after vacuum heat preservation and dehydrogenation; the vacuum heat preservation dehydrogenation process comprises the steps that under the vacuum condition, the temperature is increased to 220-250 DEG C from the normal temperature after 1-1.5 h, heat preservation is conducted for 2-3 h, then the temperature is increased to 520-560 DEG C after 1-2 h, and heat preservation is conducted for 1-2 h; the grain boundary diffusion process comprises the following steps: heating to 650-750 DEG C after 1-1.5 hours, and preserving heat for 24-30 hours for permeation; and finally, the temperature is increased to 970-1000 DEG C after 1-1.5 h, and heat preservation is conducted for 2-3 h. According to the grain boundary diffusion method, the coercive force of the center part of the sintered neodymium-iron-boron magnet with the high permeation thickness can be remarkably improved, and the intrinsic coercive force gradient difference of the surface layer and the center part of the magnet is reduced.

The invention discloses a preparation method of thermal shock resistant magnesium aluminate spinel transparent ceramic, and belongs to the technical field of ceramic materials. The preparation method comprises the following steps: (1) synthesizing crystalline MgAl2O4 nano powder by adopting an additive-free hydrothermal method; (2) depolymerizing the powder, performing water-based gel casting to prepare a green body, and performing staged debonding treatment on the green body; (3) carrying out two-step vacuum presintering on the green body; (4) carrying out hot isostatic pressing densification treatment in a subgrain growth temperature region of 1380-1420 DEG C; and (5) carrying out annealing treatment on the densified ceramic. High-purity crystalline powder is synthesized through an additive-free hydrothermal method, grain boundary impurities are eliminated, and the intermediate infrared transmittance is remarkably improved; by combining the synergistic effect of optimized two-step pre-sintering and hot isostatic pressing in a sub-grain region, precise refinement of the grain size is realized; and finally, the bending strength, the fracture toughness and the critical thermal shock temperature difference of the material are greatly improved under the strengthening mechanism of ultrafine grains and defect-free grain boundaries.

The invention relates to an austenite structure display and grain size rating method, and belongs to the technical field of hot continuous rolling finishing mill production methods. According to the technical scheme, the method comprises the steps that an eroded sample is manufactured, and an austenite structure display graph is obtained; carrying out deep learning network training and grain boundary processing to obtain a boundary skeleton diagram; and grading the grain size by adopting a straight line intercept point method. The method has the beneficial effects that the Inconel 625 austenite structure with a uniform erosion surface and a clear and complete austenite grain boundary can be obtained, grain size rating is carried out on the austenite structure image through a deep learning algorithm, and compared with manual rating, the efficiency and accuracy of grain size rating are greatly improved.

The invention discloses a preparation method of a carbon-coated single-crystal sodium ferric pyrophosphate positive electrode material, which is specifically implemented according to the following steps: step 1, dissolving sodium salt, ferric salt and phosphate in deionized water in proportion, then adding a carbon source into the solution, and uniformly stirring to obtain a mixed solution; step 2, fully drying the mixed solution obtained in the step 1 to obtain precursor powder; and 3, carrying out heat treatment on the precursor powder in a protective atmosphere, and cooling to obtain the carbon-coated single-crystal sodium ferric pyrophosphate positive electrode material. The invention also discloses a coating prepared by the method, a single-crystal structure is combined with uniform carbon coating, grain boundary defects are eliminated, conductivity is improved, high specific capacity and long cycle life are realized, single-crystal growth and carbon layer in-situ coating are synchronously realized by a synthesis process, and structural integrity and efficient conductive network construction can be ensured.

The invention belongs to the technical field of neodymium iron boron rare earth permanent magnets, and relates to a cerium-containing neodymium iron boron magnet with high coercivity and high stability and a preparation method thereof. According to the preparation method, the cerium-containing copper auxiliary alloy and the neodymium iron boron magnetic powder are ingeniously combined, the whole preparation process is optimized, and remarkable technical progress and economic benefits are achieved. Firstly, in the aspect of magnetic performance, Ce in a specific proportion is added into the cerium-containing copper auxiliary alloy, the cerium-containing copper auxiliary alloy is used, the coercive force of a magnet is effectively improved, high residual magnetism is kept to a certain degree, and introduction of Cu is beneficial to refining of grains and improvement of a grain boundary phase structure; therefore, the reverse magnetization resistance in the magnet is enhanced, and the magnet can maintain stable performance in a wider temperature range.

The invention discloses a sintered neodymium-iron-boron magnet and a preparation method and application thereof. The magnet comprises main phase crystal particles with RE2Fe14B structures and a grain boundary phase. The grain boundary phase comprises a two-particle grain boundary phase between two main phase crystal particles and a grain boundary triple-phase point composed of more than three main phase crystal particle gaps; the ratio of the number of the main phase crystal particles to the number of grain boundary triphase points is smaller than or equal to 3. According to the sintered neodymium-iron-boron magnet, through proper component design, reasonable control over the (Cu + Ga) / X ratio and control over the thickness of an alloy sheet and the ratio relation between the average width of columnar crystals in the alloy sheet and the granularity of magnetic powder, concentrated distribution of grain boundary three-phase points can be effectively restrained, the grain boundary phase proportion can be increased, grain boundary phase distribution can be optimized, and the performance of the sintered neodymium-iron-boron magnet can be improved. Therefore, both high magnetic performance and high impact toughness are achieved. The sum of the magnetic energy product and the coercive force of the sintered neodymium-iron-boron magnet is larger than or equal to 75, the impact toughness of the sintered neodymium-iron-boron magnet is larger than or equal to 20 kJ / m < 2 >, and the sintered neodymium-iron-boron magnet can be applied to new energy automobile motors, energy-saving

The invention provides a modified sulfide solid electrolyte and a preparation method and application thereof.The modified sulfide solid electrolyte comprises lithium thioborate crystals, composite grain boundaries are contained between the lithium thioborate crystals, and lithium iodide is contained in the composite grain boundaries. The structures of crystal lattices and composite crystal boundaries in the modified sulfide solid electrolyte are stable, so that the lithium ion migration capability of the modified sulfide solid electrolyte can be improved, and the ionic conductivity of the modified sulfide solid electrolyte is obviously improved.

The invention relates to the technical field of intelligent manufacturing, in particular to a process control optimization method and system based on a metal composite material, and the method comprises the following steps: extracting a crystal grain deviation section based on a path crossing section, judging shear response delay, recognizing a rhythm difference region, dividing a shear strain trend mutation section, and building a boundary layer partition map; and sorting shear stress responses, constructing a slippage thermal orientation chain, and adjusting a loading sequence to obtain a path section structure table. According to the method, the change trend of the included angle between the grain arrangement and the path is analyzed, the grain section deviating from the main direction of the path is extracted, the time difference between the shear response moment and the loading rhythm is combined, the response differentiation area is identified, and the deformation direction turning section is divided according to the trend divergence of the shear strain direction between layers; and constructing a response sequence by utilizing the consistency of grain boundary slippage and heat flow direction, comparing a path loading sequence with a response offset relationship, matching a path direction with a structure rhythm, and enhancing the coherence of a loading action and a grain slippage trend.

The invention relates to a copper foil and a preparation method and application thereof, the copper foil comprises an electrolytic copper foil layer and secondary long copper layers located on the surfaces of the two sides of the electrolytic copper foil layer, the maximum Feret diameter average value of crystal grains of the secondary long copper layers is 2.5-3 microns, and the maximum Feret diameter average value of crystal grains of the electrolytic copper foil layer is 1-2 microns. The maximum Feret diameter average value of grains of the secondary growing copper layer on the surface of the copper foil is 2.3-3 microns, the maximum Feret diameter average value of grains of the internal electrolytic copper foil layer is 1-2 microns, a structure with the grain size of the surface layer being large and the grain size of the inner layer being small is formed, and when the copper foil is used for transmitting a high-speed high-frequency electric signal, due to the skin effect of current, the high-speed high-frequency electric signal can be transmitted. More electric signals are transmitted along the surface layer of the copper foil, the grain size of the surface layer is large, the grain boundary is correspondingly reduced, and the obstruction to current is reduced, so that the loss of the electric signals is reduced, and the transmission integrity of the electric signals is improved.

The invention discloses a heat treatment method for optimizing a gear steel structure and refining grains, and belongs to the technical field of heat treatment process control. The method is particularly suitable for a production scene of cold forging gear parts such as three pin shafts; according to the method, a pre-normalizing or annealing heat treatment process with specific parameters is added after cold forging forming and before carburizing, so that an AlN precipitated phase in the steel forms segregation again at a grain boundary, the grain boundary is effectively pinned, and austenite grain growth is inhibited, and therefore the phenomenon of mixed crystals is avoided, the structure is refined, and the fatigue performance is improved. Experiments prove that after normalizing pretreatment at the temperature of 900 DEG C or above or annealing pretreatment at the temperature of 720 DEG C is adopted, the original cold forging mixed crystal area with the grain size of 0-4 grade can be increased to 7 grade or above, grains are uniform and compact, and the structure property is remarkably improved. The process parameters are clear, the flow is controllable, and the method is suitable for optimization and application of the batch gear steel heat treatment process.

The invention relates to the technical field of substrate material surface plating, in particular to a method for electrochemical plating of a perovskite thin film through an ionic electrolyte, and the method comprises the following steps: S1, preparing the ionic electrolyte containing a double-complexing agent system and a two-dimensional nano filler; s2, the ion electrolyte and the substrate are placed in a rotating magnetic field for a pulse electrodeposition process, and ultrasonic waves are applied to the bottom of the rotating magnetic field; s3, adopting an asymmetric third-order pulse waveform in the pulse electrodeposition process; s4, in the pulse electrodeposition process, synchronizing terahertz time-domain spectroscopy and confocal Raman imaging to monitor grain boundary defects of the deposition layer; and S5, entering an annealing stage after the process is ended, and introducing pyrrolidone steam to form a C-N bond passivation layer. According to the method, the ion electrolyte containing the specific double complexing agent system and the two-dimensional nano filler is accurately prepared, so that the uniformity and efficiency of the plating process are improved, and the stability of the ion electrolyte is ensured.

The invention relates to the technical field of nickel-based superalloy grain segmentation and extraction, in particular to a nickel-based superalloy grain segmentation and extraction method based on a VGG and U-Net fusion model. The method comprises the following steps: preparing an Inconel 740H high-temperature alloy sample; carrying out an in-situ tensile experiment according to the manufactured sample, and observing the microstructure by using a scanning electron microscope in the experiment process; acquiring image data according to different stages of the experiment; performing data enhancement on the acquired image according to the brightness contrast; marking according to the characteristics of the crystal grains to be segmented; obtaining a reference image data set according to the annotation file; performing normalization processing according to the reference image data set to obtain a data set; designing a feature extraction module according to the VGG network model; designing a feature fusion module according to the U-Net network model; carrying out fusion according to the two designed modules to obtain a V-Unet fusion model; designing a loss function according to gray information and structural information of the grain boundary area of the reference image grain relative to other areas, and obtaining a loss function weight of the grain boundary area of the reference image grain; calculating according to the weight of the loss function to obtain model feedback; training according to the V-Unet fusion model to obtain a model; carrying out grain segmentation extraction on an Inconel 740H high-temperature alloy scanning electron microscope image according to the model; performing morphological post-processing according to a segmentation extraction result to obtain a grain image result; and performing statistics and data analysis according to a grain image result. The method can be used for segmenting, extracting and counting the same type of grains at different positions of the nickel-based superalloy and refining the grains to improve the mechanical property of the superalloy, and has great significance.

The invention discloses a method for measuring the original austenite grain size of medium carbon steel. The method comprises the following steps: heating a medium carbon steel sample to a temperature above an original austenitizing temperature, and keeping the temperature for a period of time to precipitate carbides from an original austenite grain boundary; cutting and embedding the heat-treated medium carbon steel sample to prepare a medium carbon steel metallographic sample; carrying out grinding and fine polishing treatment on the medium carbon steel metallographic sample, and carrying out ultrasonic cleaning on the medium carbon steel metallographic sample in alcohol; immersing and corroding for a certain time by using nitric acid alcohol, then cleaning the surface of the medium carbon steel metallographic sample by using alcohol, and drying until an austenite grain boundary is clearly displayed; completing microscopic image rating; and calculating the austenite grain grade by adopting an intercept point method. According to the method, the original austenite grain boundary can be clearly displayed, and the effective size of the original austenite grain size of the medium carbon steel can be rapidly and accurately obtained.

A method for preparing a high-coercivity and high-thickness NdFeB magnet belongs to the technical field of rare earth permanent magnet material preparation and solves the technical problem of preparing high-thickness and high-coercivity NdFeB magnets. The method comprises the following steps: first, sequentially subjecting the NdFeB magnets to rapid solidification strip spinning, hydrogen crushing, airflow milling, magnetic field orientation molding, cold isostatic pressing, and vacuum low-temperature sintering to obtain a thin low-temperature sintered green body; second, subjecting the low-temperature sintered green body to a grain boundary thermal diffusion treatment after preparing a heavy rare earth element layer on the surface of the low-temperature sintered green body; third, subjecting the low-temperature sintered green body after the diffusion heat treatment to mechanical coarse crushing, hydrogen crushing, powder mixing, airflow milling, magnetic field orientation molding, and cold isostatic pressing to obtain a thick, high-thickness compact; finally, subjecting the high-thickness compact to vacuum low-temperature heat treatment, vacuum high-temperature sintering, and two heat treatments to obtain a high-coercivity and high-thickness NdFeB magnet. The method has a simple preparation process, significantly improves the coercivity of bulk NdFeB sintered magnets, and enables the magnets to have a high magnetic energy product.

A composite cathode active material and a cathode and a lithium battery including the composite cathode active material. The composite cathode active material has a core including a plurality of primary particles including a nickel-containing first lithium transition metal oxide having a layered crystal structure; a grain boundary disposed between adjacent primary particles of the plurality of primary particles; and a shell on the core, the shell including a second lithium transition metal oxide having a spinel crystal structure, wherein the grain boundary includes a first composition having a spinel crystal structure.

The invention relates to the technical field of processing control, and discloses an intelligent control method and system for diamond compact laser processing equipment. The method comprises the following steps: scanning a diamond compact by adopting a spectral reflection sensor and an acoustic emission signal device to obtain a four-dimensional characteristic tensor; inputting the tensor into a two-channel convolutional network to identify the grain boundary type; a PDC-Lambda algorithm is executed to construct a crystal boundary-power response mapping matrix; and establishing a three-level power regulation and control framework based on the mapping matrix to realize accurate processing control. According to the invention, accurate classification and positioning of different grain boundary types are realized. The problem that a traditional method lacks a grain boundary-power mapping mechanism is solved, and the corresponding relation between grain boundary characteristics and optimal machining parameters is established. The problem of insufficient power regulation and control precision is solved, fine parameter control from macroscopic to microscopic is realized through a three-stage regulation and control architecture, and thermal damage and microcrack formation of a grain boundary region are effectively prevented.

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 provides a nickel-based rare earth composite powder material for high-speed laser cladding and a preparation method of a nickel-based rare earth composite coating, and relates to the technical field of laser cladding and metal surface modification. The nickel-based rare earth composite coating takes Inconel 625 nickel-based alloy as a matrix phase material; a trace amount of rare earth oxide Y2O3 is introduced into a powder system to serve as a second phase enhancing component, and the material is prepared and formed at a time under the condition of a high-speed laser cladding process; in the high-speed laser cladding process, due to high scanning speed, low heat input per unit length and high cooling rate, metal liquid in a molten pool has the characteristic of rapid solidification; the rare earth oxide Y2O3 can stably exist in a molten pool, the particle surface of the rare earth oxide Y2O3 provides a large number of heterogeneous nucleation cores for the alloy solidification process, meanwhile, grain growth is restrained through the grain boundary pinning effect, and therefore the solidification structure form of the nickel-based cladding coating is remarkably improved.