Aluminum nitride powder ball milling pretreatment method and system based on particle size difference regulation

Abstract

The application discloses an aluminum nitride powder ball milling pretreatment method and system based on particle size difference regulation, relates to the technical field of aluminum nitride ceramic preparation, and achieves the original particle size distribution and particle size span characteristic value of aluminum nitride powder and yttrium oxide sintering aid powder, generates the target particle size span characteristic value of the two types of powder through a particle size span mismatch evaluation algorithm, determines the ball milling medium diameter, ball milling rotating speed and ball milling time length by adopting a ball milling parameter inverse calculation algorithm, corrects the remaining ball milling time length according to the deviation in the ball milling process, and obtains the to-be-molded mixed powder after reaching the standard. Through particle size span mismatch evaluation, ball milling parameter inverse calculation and process deviation correction, the particle size distribution of the aluminum nitride powder and the yttrium oxide sintering aid powder is regulated to a matching state, the micro-area difference of the mixed powder in the sintering process is reduced, and the grain size convergence degree after sintering is improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum nitride ceramic preparation technology, specifically to a ball milling pretreatment method and system for aluminum nitride powder based on particle size difference control. Background Technology

[0002] Aluminum nitride ceramics possess high thermal conductivity, good electrical insulation, and high-temperature resistance, making them widely used in electronic packaging, heat dissipation substrates for power devices, and the fabrication of high-performance ceramic structural components. In the fabrication process, aluminum nitride powder is typically mixed with yttrium oxide sintering aid powder in a specific ratio, followed by molding and sintering to obtain the target ceramic product. The particle size distribution, mixing uniformity, and particle size distribution before sintering of the powder raw materials affect the sintering activity distribution within the green body, thus impacting the uniformity of grain size and batch stability of the sintered product.

[0003] The limitations of the existing technology include at least the following problems: Under the process framework of directly mixing aluminum nitride powder and yttrium oxide sintering aid powder after they are supplied, there is a lack of targeted constraints on the particle size range of the two types of powders and the matching relationship between their particle size distributions. When there is a significant mismatch in the particle size range between aluminum nitride powder and yttrium oxide powder, the local packing density of the interface between particles of different sizes in the green body deviates from the accessibility of the sintering aid. The sintering aid is scarce in the neighborhood of coarse particles, while the sintering aid is excessively enriched in the agglomeration area of ​​fine particles. The sintering micro-regions coexisting in the same green body form differences in liquid phase generation, wetting time and densification shrinkage rate that are difficult to self-coordinate. The grain growth process is asynchronous between different sintering micro-regions, resulting in increased grain size dispersion and insufficient overall size convergence after sintering. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a ball milling pretreatment method and system for aluminum nitride powder based on particle size difference control. This solves the problem that the lack of effective control over the particle size range and matching relationship in the existing direct mixing process of aluminum nitride powder and yttrium oxide sintering aid leads to uneven sintering activity and insufficient grain size convergence inside the green body.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a ball milling pretreatment method for aluminum nitride powder based on particle size difference control, comprising the following steps: obtaining aluminum nitride powder and yttrium oxide sintering aid powder to be treated, sampling and performing particle size analysis respectively, and recording the original particle size distribution of aluminum nitride powder, the original particle size distribution of yttrium oxide sintering aid powder, the particle size span characterization value of aluminum nitride powder, and the particle size span characterization value of yttrium oxide sintering aid powder; through particle size difference control... The particle size mismatch assessment algorithm analyzes the original particle size distribution of aluminum nitride powder and yttrium oxide sintering aid powder, as well as the particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder, to generate target particle size span characterization values ​​for both powders. Based on these target particle size span characterization values, and the original particle sizes of the two types of powders... The distribution of aluminum nitride powder and yttrium oxide sintering aid powder was determined using a ball milling parameter back-calculation algorithm, including the diameter of the ball milling media, the ball milling speed, and the ball milling time. Based on the determined ball milling media diameter, speed, and time, the aluminum nitride powder and yttrium oxide sintering aid powder were subjected to ball milling refinement pretreatment. During the ball milling process, particle size distribution data were collected at preset detection intervals to calculate the intermediate particle size span characterization value. The remaining ball milling time was adjusted based on the deviation between the intermediate and target particle size span characterization values. When the intermediate particle size span characterization values ​​of the aluminum nitride powder and yttrium oxide sintering aid powder fell within the preset tolerance range of the corresponding target particle size span characterization value, the ball milling refinement pretreatment was stopped, and the pretreated aluminum nitride powder and yttrium oxide sintering aid powder were collected. The collected pretreated aluminum nitride powder and yttrium oxide sintering aid powder were mixed according to a preset ratio to obtain the mixed powder to be formed.

[0006] Further, the steps for determining the particle size span characterization value are as follows: Multiple samples are taken from both the aluminum nitride powder and the yttrium oxide sintering aid powder to be treated, resulting in two types of powder particle size detection samples; particle size is measured on both types of powder samples to obtain the original particle size distributions of the aluminum nitride powder and the yttrium oxide sintering aid powder; low-order and high-order particle size quantiles are extracted from the original particle size distributions of the aluminum nitride powder and the yttrium oxide sintering aid powder, respectively; based on the low-order and high-order particle size quantiles, the particle size span characterization values ​​for the aluminum nitride powder and the yttrium oxide sintering aid powder are calculated, respectively; the original particle size distributions of the two types of powder and their corresponding particle size span characterization values ​​are written into the particle size difference control dataset.

[0007] Furthermore, the specific steps of the particle size span mismatch evaluation algorithm are as follows: Read the original particle size distributions and corresponding particle size span characterization values ​​of the two types of powders in the particle size difference control dataset; perform particle size interval normalization processing on the original particle size distributions of the two types of powders to generate an alignment sequence of the particle size distributions of the two types of powders; calculate the particle size interval overlap based on the alignment sequence of the particle size distributions of the two types of powders, and calculate the particle size span deviation based on the particle size span characterization values ​​of the two types of powders; generate a particle size span mismatch value based on the particle size interval overlap and the particle size span deviation; generate the target particle size span characterization value for aluminum nitride powder and the target particle size span characterization value for yttrium oxide sintering aid powder based on the particle size span mismatch value.

[0008] Furthermore, the specific steps of the ball milling parameter back-calculation algorithm are as follows: Read the target particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder, as well as the original particle size distributions of the two types of powders; calculate the particle size span compression of aluminum nitride powder and yttrium oxide sintering aid powder respectively based on the original particle size distributions and corresponding target particle size span characterization values; match candidate ball milling media diameters, candidate ball milling speeds, and candidate ball milling times respectively based on the particle size span compression of aluminum nitride powder and yttrium oxide sintering aid powder; screen the candidate ball milling media diameters, candidate ball milling speeds, and candidate ball milling times based on ball milling energy constraints, eliminating parameter groups with over-milling risks; output the corresponding ball milling media diameters, ball milling speeds, and ball milling times for aluminum nitride powder and yttrium oxide sintering aid powder, respectively.

[0009] Further, the specific steps of the ball milling refinement pretreatment are as follows: Configure the first ball milling container according to the diameter of the ball milling media, the ball milling speed, and the ball milling time corresponding to the aluminum nitride powder; configure the second ball milling container according to the diameter of the ball milling media, the ball milling speed, and the ball milling time corresponding to the yttrium oxide sintering aid powder; add the aluminum nitride powder to be treated to the first ball milling container and start the first ball milling refinement pretreatment; add the yttrium oxide sintering aid powder to the second ball milling container and start the second ball milling refinement pretreatment; collect the process particle size distribution of the aluminum nitride powder and the yttrium oxide sintering aid powder at preset detection intervals.

[0010] Further, the specific steps for correcting the remaining ball milling time are as follows: Read the process particle size distribution of aluminum nitride powder and the process particle size distribution of yttrium oxide sintering aid powder; calculate the intermediate particle size span characterization value of aluminum nitride powder based on the process particle size distribution of aluminum nitride powder, and calculate the intermediate particle size span characterization value of yttrium oxide sintering aid powder based on the process particle size distribution of yttrium oxide sintering aid powder; calculate the first deviation between the intermediate particle size span characterization value of aluminum nitride powder and the target particle size span characterization value of aluminum nitride powder, and calculate the second deviation between the intermediate particle size span characterization value of yttrium oxide sintering aid powder and the target particle size span characterization value of yttrium oxide sintering aid powder; calculate the first deviation change rate and the second deviation change rate respectively based on the first deviation and the second deviation within the continuous detection interval; correct the remaining ball milling time corresponding to aluminum nitride powder and the remaining ball milling time corresponding to yttrium oxide sintering aid powder respectively based on the first deviation, the first deviation change rate, the second deviation, and the second deviation change rate.

[0011] Further, the specific steps for correcting abnormalities in the ball milling process are as follows: Read the intermediate particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder within multiple consecutive detection intervals; calculate the particle size span change rate of aluminum nitride powder and the particle size span change rate of yttrium oxide sintering aid powder between adjacent detection intervals; when the particle size span change rate is lower than a preset change threshold and the intermediate particle size span characterization value does not fall within the preset tolerance range of the target particle size span characterization value, generate an under-milling mark; when the intermediate particle size span characterization value is lower than the preset tolerance lower limit of the target particle size span characterization value, generate an over-milling mark; adjust the ball milling speed and remaining ball milling time of the corresponding powder based on at least one of the under-milling mark and the over-milling mark.

[0012] Further, the specific steps for determining the stop of ball milling pretreatment are as follows: Read the intermediate particle size span characterization value of aluminum nitride powder, the intermediate particle size span characterization value of yttrium oxide sintering aid powder, and the corresponding target particle size span characterization value; calculate the first tolerance offset of the intermediate particle size span characterization value of aluminum nitride powder relative to the target particle size span characterization value of aluminum nitride powder; calculate the second tolerance offset of the intermediate particle size span characterization value of yttrium oxide sintering aid powder relative to the target particle size span characterization value of yttrium oxide sintering aid powder; when both the first and second tolerance offsets are within a preset tolerance range, generate a stop ball milling command; collect the pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder according to the stop ball milling command.

[0013] Further, the preparation steps of the mixed powder to be formed are as follows: Pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder are obtained; the pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder are dried and sieved respectively; the particle size of the sieved pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder is re-measured to obtain the re-measured particle size distribution; when the particle size span characterization value corresponding to the re-measured particle size distribution falls within the preset tolerance range of the target particle size span characterization value, the two types of pretreated powder are weighed according to the preset ratio; the two types of pretreated powder are added to a mixing container, and the mixing operation is performed according to the preset mixing speed and preset mixing time to obtain the mixed powder to be formed.

[0014] A ball milling pretreatment system for aluminum nitride powder based on particle size difference control includes: a particle size detection module for performing particle size detection on the aluminum nitride powder and yttrium oxide sintering aid powder to be treated, and recording the original particle size distribution and particle size span characterization values; a mismatch evaluation module for generating target particle size span characterization values ​​for aluminum nitride powder and yttrium oxide sintering aid powder through a particle size span mismatch evaluation algorithm; and a ball milling parameter back calculation module for determining the diameter of the ball milling media, the ball milling speed, and the ball milling time through a ball milling parameter back calculation algorithm; and a ball milling media diameter, ball milling speed, and ball milling time. The grinding control module controls the ball mill to perform ball milling refinement pretreatment on the aluminum nitride powder and yttrium oxide sintering aid powder respectively, and corrects the remaining ball milling time based on the intermediate particle size span characterization value; the anomaly correction module generates at least one of under-grinding and over-grinding marks based on the intermediate particle size span characterization value within multiple consecutive detection intervals, and corrects the ball milling speed and the remaining ball milling time; the powder mixing module mixes the pretreated aluminum nitride powder and the pretreated yttrium oxide sintering aid powder according to a preset ratio to obtain the mixed powder to be shaped.

[0015] The present invention has the following beneficial effects: (1) The ball milling pretreatment method for aluminum nitride powder based on particle size difference control processes the original particle size distribution of aluminum nitride powder, the original particle size distribution of yttrium oxide sintering aid powder and the corresponding particle size span characterization value through a particle size span mismatch evaluation algorithm. It calculates the overlap of the particle size intervals and the deviation of the particle size span between the two types of powders, and generates the target particle size span characterization value of aluminum nitride powder and the target particle size span characterization value of yttrium oxide sintering aid powder. This changes the control object before ball milling from the refinement of a single powder to the matching of the particle size distribution of two types of powders, reducing the sintering micro-region differences caused by insufficient sintering aid in the neighborhood of coarse particles and enrichment of sintering aid in the agglomeration area of ​​fine particles.

[0016] (2) The ball milling pretreatment method for aluminum nitride powder based on particle size difference control calculates the particle size span compression of aluminum nitride powder and the particle size span compression of yttrium oxide sintering aid powder respectively through the ball milling parameter back calculation algorithm. Based on the compression, candidate ball milling media diameter, candidate ball milling speed and candidate ball milling time are matched. Then, the parameter group with the risk of over-grinding is eliminated by ball milling energy constraint. The ball milling conditions are determined according to the original particle size distribution of aluminum nitride powder and yttrium oxide sintering aid powder, reducing the problem of under-grinding of one type of powder and over-grinding of another type of powder caused by the same set of ball milling parameters.

[0017] (3) The ball milling pretreatment method for aluminum nitride powder based on particle size difference control collects process particle size distribution data at preset detection intervals during ball milling, calculates the intermediate particle size span characterization value, and corrects the remaining ball milling time based on the deviation between the intermediate particle size span characterization value and the target particle size span characterization value, so that the ball milling end point is adjusted according to the change of powder particle size, reducing the coarse particle tail end residue and the continued accumulation of excessively fine particles caused by fixed-time ball milling, and corrects the ball milling speed and remaining ball milling time through at least one of under-milling mark and over-milling mark.

[0018] (4) The aluminum nitride powder ball milling pretreatment system based on particle size difference control records the original particle size distribution and particle size span characterization value of the two types of powder through the particle size detection module, the mismatch evaluation module generates the target particle size span characterization value, the ball milling parameter back calculation module determines the diameter of the ball milling medium, the ball milling speed and the ball milling time, the ball milling control module and the abnormal correction module correct the ball milling process according to the intermediate particle size span characterization value, and the powder mixing module mixes the two types of pretreated powders according to the preset ratio, so that detection, calculation, ball milling, correction and mixing are executed according to the same particle size difference control chain.

[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0020] Figure 1 This is a flowchart of a ball milling pretreatment method for aluminum nitride powder based on particle size difference control according to the present invention.

[0021] Figure 2 This is a flowchart illustrating the steps for determining the particle size span characterization value in a ball milling pretreatment method for aluminum nitride powder based on particle size difference control, as described in this invention.

[0022] Figure 3 This is a block diagram of an aluminum nitride powder ball mill pretreatment system based on particle size difference control according to the present invention. Detailed Implementation

[0023] Please see Figure 1This invention provides a technical solution: a ball milling pretreatment method for aluminum nitride powder based on particle size difference control, comprising the following steps: obtaining aluminum nitride powder and yttrium oxide sintering aid powder to be treated, sampling and performing particle size detection respectively, and recording the original particle size distribution of aluminum nitride powder, the original particle size distribution of yttrium oxide sintering aid powder, the particle size span characterization value of aluminum nitride powder, and the particle size span characterization value of yttrium oxide sintering aid powder; analyzing the original particle size distribution of aluminum nitride powder, the original particle size distribution of yttrium oxide sintering aid powder, the particle size span characterization value of aluminum nitride powder, and the particle size span characterization value of yttrium oxide sintering aid powder through a particle size span mismatch evaluation algorithm, and generating target particle size span characterization values ​​for aluminum nitride powder and yttrium oxide sintering aid powder; based on the target particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder, and the original particle size distribution of the two types of powder, and taking... The diameter of the ball milling media, the ball milling speed, and the ball milling time for aluminum nitride powder and yttrium oxide sintering aid powder were determined using a ball milling parameter back-calculation algorithm. According to the determined ball milling media diameter, ball milling speed, and ball milling time, the aluminum nitride powder and yttrium oxide sintering aid powder to be treated were subjected to ball milling refinement pretreatment. During the ball milling process, particle size distribution data were collected at preset detection intervals to calculate the intermediate particle size span characterization value. The remaining ball milling time was adjusted based on the deviation between the intermediate particle size span characterization value and the target particle size span characterization value. When the intermediate particle size span characterization value of the aluminum nitride powder and yttrium oxide sintering aid powder fell within the preset tolerance range of the corresponding target particle size span characterization value, the ball milling refinement pretreatment was stopped, and the pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder were collected. The collected pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder were mixed according to a preset ratio to obtain the mixed powder to be formed.

[0024] Specifically, such as Figure 2 As shown, the steps for determining the particle size span characterization value are as follows: Multiple samples were taken from both the aluminum nitride powder and the yttrium oxide sintering aid powder to be treated, resulting in two types of powder particle size analysis samples, as follows: At different locations in the upper, middle and lower layers of the powder raw material stack, 5 to 8 sampling points were selected for micro-sampling. The weight of each sampling was kept consistent. The total number of samples for a single type of powder was not less than 10, and aluminum nitride powder particle size test samples and yttrium oxide sintering aid powder particle size test samples were obtained. In one implementation, the sampling amount for a single sample is set to 2g, and 10 samples are taken for a single type of powder.

[0025] Particle size distributions of the two types of powder samples were measured to obtain the original particle size distributions of aluminum nitride powder and yttrium oxide sintering aid powder, as follows: Two types of powder samples were placed in a dry laser particle size analyzer. Uniform parameters for detection refractive index, dispersion pressure and detection time were set. Particle size was detected one by one. Data on the proportion of particles in the full particle size range of each sample were collected. All sample detection data were summarized. After removing abnormal deviation data points, mean fitting was performed.

[0026] The low-order and high-order particle size quantiles were extracted from the original particle size distributions of aluminum nitride powder and yttrium oxide sintering aid powder, respectively. Specifically: Based on the fitted original particle size distribution curve, the particle size values ​​corresponding to the cumulative distribution percentages of 10% and 99% are calculated, where D 10 D 99 The lower and higher particle size quantiles represent the particle size distribution of the powder, i.e., the particle sizes corresponding to the cumulative distribution ratios of 10% and 99%, respectively. These are used as the lower and higher particle size quantiles to extract the respective lower and higher particle size quantiles for aluminum nitride powder and yttrium oxide sintering aid powder.

[0027] Based on the low and high particle size quantiles, the particle size span characterization values ​​for aluminum nitride powder and yttrium oxide sintering aid powder were calculated, respectively. Specifically: The difference between the higher and lower particle size quantiles is used as the characteristic value of particle size span, and the calculation formula is as follows: S=D 99 -D 10 ; Where S is the particle size span characterization value, and D 99 D represents the high particle size quantile. 10 These are the lower particle size quantile values; By substituting the quantile values ​​of the two types of powders into the formula, the particle size span characterization values ​​of each can be calculated.

[0028] The original particle size distributions and corresponding particle size span characterization values ​​of the two types of powders are written into the particle size difference control dataset, specifically as follows: A powder particle size control database was established, which archived and stored the original particle size distribution curve data, particle size interval proportion data and particle size span characterization values ​​of the two types of powders. At the same time, the powder type, sampling time and test batch information were labeled to form a particle size difference control dataset.

[0029] In this implementation scheme, the original particle size difference between aluminum nitride powder and yttrium oxide sintering aid powder is transformed into a particle size span characterization value by multi-point sampling, particle size detection, and high and low particle size quantile value calculation. This facilitates the subsequent judgment of the particle size distribution of the two types of powders using the same evaluation caliber.

[0030] Specifically, the steps of the particle size mismatch evaluation algorithm are as follows: The original particle size distributions and corresponding particle size span characterization values ​​of two types of powders in the particle size difference control dataset are read, specifically as follows: The algorithm's computational unit retrieves the original particle size distribution of aluminum nitride powder, the original particle size distribution of yttrium oxide sintering aid powder, and the corresponding initial particle size span characterization values ​​from the particle size difference control dataset. After removing incomplete and abnormal data, the data is imported.

[0031] The original particle size distributions of the two types of powders were normalized to generate aligned sequences of particle size distributions for the two types of powders, as follows: The full particle size distribution data of the two types of powders are mapped to a preset standard particle size range, and the discrete particle size distribution data are transformed into a numerical sequence with equal intervals and the same dimension. In one embodiment, the preset standard particle size range is 0 to 100 μm.

[0032] The overlap of particle size intervals is calculated based on the alignment sequence of the particle size distributions of the two types of powders, and the deviation of particle size span is calculated based on the characteristic values ​​of the particle size span of the two types of powders. Specifically: Based on the particle size distribution sequence after dimension alignment, the area of ​​the overlapping region of the two types of powder in the same particle size range is statistically analyzed, and the proportion of the overlapping area to the total particle size range area is taken as the particle size range overlap. Simultaneously, the absolute difference between the particle size span characterization values ​​of the two types of powders is calculated, and the ratio of this absolute difference to the original particle size span characterization value of aluminum nitride powder is used as the particle size span deviation to quantify the degree of particle size span mismatch between the two types of powders.

[0033] The particle size span mismatch value is calculated based on the overlap of particle size intervals, the deviation of particle size span, and the powder material correction coefficient. The calculation relationship is as follows: ; Where M is the particle size span mismatch value, O is the overlap of the particle size ranges of the two types of powder, ΔS is the particle size span deviation, and λ is the powder material correction coefficient; for aluminum nitride powder and yttrium oxide sintering aid powder, the material correction coefficient λ is preset according to the hardness and refining response of the two types of powder. In one implementation, λ is set to 0.92 to quantify the degree of mismatch in particle size span between the two types of powders.

[0034] Based on the particle size mismatch value, the target particle size span characterization values ​​for aluminum nitride powder and yttrium oxide sintering aid powder are generated: The system presets multiple mismatch values ​​corresponding to control thresholds. Based on the calculated particle size span mismatch value, it matches the corresponding control level. The larger the mismatch value, the greater the compression of the target particle size span; the smaller the mismatch value, the smaller the compression of the target particle size span. In one implementation, when the mismatch value is greater than 0.5, the compression ratio of the target particle size span between the two types of powders is set to 25% to 30%. When the mismatch value is between 0.2 and 0.5, the compression ratio should be set to 10% to 20%. When the mismatch value is less than 0.2, the target particle size span characterization value is generated based on the original particle size span characterization value, and finally the target particle size span characterization values ​​of the two types of powders are obtained.

[0035] In this implementation scheme, a particle size span mismatch value is generated by combining the particle size interval overlap and the particle size span deviation, so that the degree of particle size distribution mismatch between the two types of powders can be quantified, avoiding the need to judge whether the powder is suitable for direct mixing based solely on a single average particle size.

[0036] Specifically, the steps of the ball mill parameter inverse calculation algorithm are as follows: The target particle size span characterization values ​​of aluminum nitride powder, yttrium oxide sintering aid powder, and the original particle size distributions of the two types of powders were read, specifically as follows: The parameter inverse calculation module retrieves the target particle size span characterization values ​​of the two types of powders output by the mismatch evaluation algorithm, and simultaneously reads the original particle size distribution data stored in the dataset to calculate the range of difference between the original particle size span characterization value and the target particle size span characterization value.

[0037] Based on the original particle size distribution and corresponding target particle size span characterization values ​​of the two types of powders, the particle size span compression of aluminum nitride powder and yttrium oxide sintering aid powder were calculated respectively, as follows: The particle size span compression is calculated based on the original particle size span characterization value, the target particle size span characterization value, and the maximum initial particle size span threshold. The calculation relationship is as follows: ; Where, ΔS c S is the particle size span compression, S0 is the original particle size span characterization value of the powder, S t S represents the characterization value of the target particle size range of the powder. max This is the maximum allowable initial particle size span threshold for this type of powder raw material, used to adaptively calculate the required refinement and compression range for ball milling based on the initial particle size span.

[0038] Based on the compression of the particle size range of aluminum nitride powder and the compression of the particle size range of yttrium oxide sintering aid powder, candidate ball milling media diameters, candidate ball milling speeds, and candidate ball milling durations are matched respectively, as follows: Establish a corresponding matching relationship between particle size range compression amount and ball milling process parameters, with different compression amount ranges corresponding to different combinations of process parameters; In one implementation, the parameter matching correspondence is shown in Table 1. The interval division can actually be adjusted within the range of Φ5 to Φ20 according to the original particle size of the powder.

[0039] Based on the compression amount of the two types of powders, multiple sets of candidate process parameter combinations are obtained.

[0040] Based on the energy constraint of ball milling, candidate ball milling media diameter, candidate ball milling speed, and candidate ball milling duration are screened to eliminate parameter groups with the risk of over-milling. Specifically: The ball milling energy threshold is set according to the tolerance characteristics of the powder material. Both aluminum nitride powder and yttrium oxide sintering aid powder have a critical ball milling energy upper limit. When the total ball milling energy corresponding to the parameter combination exceeds the upper limit, the parameter combination is marked as the over-milling risk parameter group and removed from the candidate parameter group. The total ball milling input energy of each group of candidate parameters is calculated one by one, and the candidate parameter groups that do not exceed the ball milling energy threshold are retained.

[0041] The output values ​​for the ball milling media diameter, ball milling speed, and ball milling time for aluminum nitride powder and yttrium oxide sintering aid powder are as follows: Select the target parameter group from the candidate parameter group that has never exceeded the ball milling energy threshold, determine the ball milling media diameter, ball milling speed and ball milling time corresponding to aluminum nitride powder and yttrium oxide sintering aid powder respectively, and output them to the ball milling equipment execution end.

[0042] In this implementation scheme, the diameter of the ball milling media, the ball milling speed and the ball milling time are calculated by back-calculating the particle size span compression amount, so that the ball milling parameters correspond to the original particle size state and the target particle size span of the powder, thereby reducing the under-milling or over-milling caused by applying the same ball milling parameters to different powders.

[0043] Specifically, the specific steps of the ball milling pretreatment are as follows: The first ball mill container is configured according to the diameter of the ball milling media, the ball milling speed, and the ball milling time corresponding to the aluminum nitride powder, specifically as follows: The first planetary ball mill jar is selected as the first ball milling container. The residual powder and impurities on the inner wall of the jar are cleaned. According to the diameter of the ball milling media obtained by back calculation, the corresponding specification of ball milling media is added. The media filling rate is controlled at 45% to 55% of the jar volume. The equipment operating speed and maximum ball milling time are preset in advance to complete the ball milling parameter configuration of the first ball milling container.

[0044] The second ball mill container is configured according to the diameter of the ball milling media, the ball milling speed, and the ball milling time corresponding to the yttrium oxide sintering aid powder. Specifically: A second planetary ball mill jar with the same specifications as the first ball mill container was selected as the second ball mill container. The jar was cleaned independently. The ball milling media was added according to the diameter of the ball milling media, the ball milling speed and the ball milling time corresponding to the yttrium oxide sintering aid powder and the equipment parameters were set.

[0045] The aluminum nitride powder to be processed is added to the first ball mill container and the first ball milling fine pretreatment is started: According to the ratio of tank volume to powder filling, the aluminum nitride powder to be treated is added to the first ball mill container at a uniform speed. The powder filling amount does not exceed 30% of the effective volume of the tank. After sealing the tank, the ball mill equipment is started, and the aluminum nitride powder is ball milled and refined according to the preset speed. No yttrium oxide sintering aid powder is added during the ball milling process.

[0046] Add the yttrium oxide sintering aid powder to the second ball mill container and start the second ball milling fine pretreatment: The yttrium oxide sintering aid powder to be treated is added at a uniform rate into the prepared second ball mill container, maintaining the same powder filling ratio as the aluminum nitride powder. After sealing the container, the second ball mill is started, so that the first and second ball mills can perform ball milling according to their respective process parameters. No aluminum nitride powder is added during the ball milling process.

[0047] The particle size distribution of aluminum nitride powder and yttrium oxide sintering aid powder were collected at preset detection intervals, specifically as follows: A fixed time interval is preset as the detection interval; In one embodiment, the detection interval is set to 8 to 12 minutes. Each time a detection node is reached, the equipment automatically stops operating and extracts a small amount of powder sample from each of the two ball mill containers. The sample weight is controlled between 0.5 and 1 g. The particle size distribution of the sample is quickly detected by an online particle size analyzer, and the process particle size distribution data of the two types of powder are collected.

[0048] In this embodiment, by placing aluminum nitride powder and yttrium oxide sintering aid powder in separate ball milling containers for processing, the two types of powders are refined according to their respective ball milling parameters, reducing the uneven distribution of sintering aid caused by premature mixing of the two types of powders before the particle size range is controlled.

[0049] Specifically, the steps for correcting the remaining ball milling time are as follows: The particle size distributions of aluminum nitride powder and yttrium oxide sintering aid powder were read during the process, specifically as follows: The data acquisition unit reads the particle size distribution data of the two types of powder collected at each detection interval, including the proportion of particles in each particle size range, the maximum particle size, the minimum particle size, and other information, and transmits it synchronously to the computing unit to complete the process data import and caching.

[0050] The intermediate particle size span characterization value of aluminum nitride powder is calculated based on the process particle size distribution of aluminum nitride powder, and the intermediate particle size span characterization value of yttrium oxide sintering aid powder is calculated based on the process particle size distribution of yttrium oxide sintering aid powder. Specifically: D is extracted from the process particle size distribution of the current detection interval. 10 D 99 The particle size quantile value is substituted into the formula to calculate the intermediate particle size span characterization value of the current ball milling stage.

[0051] Calculate the first deviation between the characterized value of the intermediate particle size range of aluminum nitride powder and the characterized value of the target particle size range of aluminum nitride powder, and calculate the second deviation between the characterized value of the intermediate particle size range of yttrium oxide sintering aid powder and the characterized value of the target particle size range of yttrium oxide sintering aid powder: Based on the target particle size span characterization value, the corresponding deviation is obtained by subtracting the target particle size span characterization value from the intermediate particle size span characterization value. A positive deviation indicates that the current powder span does not meet the standard; A deviation within the preset deviation range indicates that the target range has been achieved. A negative deviation indicates an over-wearing trend.

[0052] Calculate the rate of change of the first deviation and the rate of change of the second deviation based on the first deviation and the second deviation within the continuous detection interval, respectively: A historical deviation attenuation coefficient is introduced to smooth the deviation changes within continuous detection intervals, and the deviation change rate is calculated using the following formula: ; Among them, V e E represents the rate of change of deviation. n E represents the current detection interval deviation. n-1 Δt is the deviation of the previous detection interval, α is the detection interval duration, α is the historical attenuation coefficient with a value of 0.15, and n is the number of consecutive detections, used to calculate the particle size range refinement trend.

[0053] Based on the first deviation, the first deviation change rate, the second deviation, and the second deviation change rate, the remaining ball milling time corresponding to aluminum nitride powder and the remaining ball milling time corresponding to yttrium oxide sintering aid powder are corrected respectively, as follows: The corrected remaining ball milling time is calculated based on the deviation change rate, deviation amount, standard refining rate, and maximum permissible deviation amount. The calculation relationship is as follows: ; Among them, T r The remaining ball milling time after correction, T0 is the initial remaining time, and V is the corrected remaining ball milling time. e V is the rate of change of deviation. set The preset standard refinement rate is given by E, where E is the deviation. max This is the maximum permissible deviation, used to calculate the remaining ball milling time after correction; In the formula, E represents the absolute value of the deviation between the intermediate particle size span characterization value and the target particle size span characterization value; when the calculated corrected remaining ball milling time is less than zero, the corrected remaining ball milling time is set to zero. When the corrected remaining ball milling time exceeds the preset maximum remaining time, the corrected remaining ball milling time will be set to the preset maximum remaining time.

[0054] In this implementation scheme, the remaining ball milling time is corrected by the deviation between the intermediate particle size span characterization value and the target particle size span characterization value, so that the ball milling termination time can be adjusted according to the actual powder refinement process, reducing the coarse particle residue or excessively fine particle accumulation caused by fixed-duration ball milling.

[0055] Specifically, the steps for correcting abnormalities in the ball milling process are as follows: The intermediate particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder were read within multiple consecutive detection intervals, specifically as follows: The intermediate particle size span data of 3 to 5 adjacent detection nodes are continuously retrieved to form a continuous time series of particle size span variation data.

[0056] The rates of change in particle size span of aluminum nitride powder and yttrium oxide sintering aid powder between adjacent detection intervals were calculated separately, as follows: The rate of change of particle size span is calculated based on the intermediate particle size span characterization value of adjacent detection nodes, the original particle size span characterization value, and the detection interval. The calculation relationship is as follows: ; Where, ΔS rate S represents the rate of change of particle size span. k S represents the current intermediate particle size span. k-1 S0 is the particle size span characterization value of the previous node, S0 is the original particle size span characterization value, and Δt is the detection interval time, which is used to determine the state of powder refinement rate.

[0057] When the rate of change of particle size span is lower than a preset rate of change threshold, and the intermediate particle size span characterization value does not fall within the preset tolerance range of the target particle size span characterization value, an under-wear mark is generated: A preset threshold for the rate of change of particle size span is set. When the rate of change of particle size span in multiple consecutive detection intervals is lower than this threshold, and the current span of the powder does not fall within the target tolerance range, an under-grinding mark is generated.

[0058] When the intermediate particle size span characterization value is lower than the preset tolerance lower limit of the target particle size span characterization value, an over-wear mark is generated. Specifically, the preset tolerance lower limit value of the target particle size span is used to generate an over-wear mark when the real-time intermediate particle size span characterization value is less than this lower limit value.

[0059] The ball milling speed and remaining ball milling time of the corresponding powder are adjusted according to at least one of the under-milling and over-milling indicators, specifically as follows: When the under-wear flag is triggered, the corresponding ball mill speed is increased and the corresponding remaining ball milling time is extended; When the over-grinding flag is triggered, the corresponding ball mill speed is reduced and the corresponding remaining ball milling time is shortened; If both under-grinding and over-grinding markers exist within the same testing cycle, first reduce the ball mill speed, and then adjust the remaining ball milling time based on the intermediate particle size span characterization value of the next testing interval.

[0060] In this implementation scheme, under-grinding and over-grinding marks are generated by continuously detecting the rate of change of particle size span within the interval, and the ball mill speed and remaining ball milling time are adjusted according to the mark type, so that the refining stagnation and over-refining in the ball milling process can be identified and processed before receiving the material.

[0061] Specifically, the steps for determining when to stop the ball milling pretreatment are as follows: The characterization values ​​of the intermediate particle size range of aluminum nitride powder, the intermediate particle size range of yttrium oxide sintering aid powder, and the corresponding target particle size range were read, specifically as follows: The shutdown judgment node retrieves the intermediate particle size span data of the two types of powders and the corresponding target particle size span characterization value to complete the data benchmarking preparation.

[0062] The first tolerance offset of the intermediate particle size span characterization value of aluminum nitride powder relative to the target particle size span characterization value of aluminum nitride powder is calculated as follows: The first tolerance offset is calculated based on the characterization values ​​of the intermediate particle size range and the target particle size range of aluminum nitride powder. The calculation relationship is as follows: ; in, S is the first tolerance offset. m1 S represents the characteristic value of the intermediate particle size range of aluminum nitride powder. t1 This represents the characteristic value of the target particle size span of aluminum nitride powder.

[0063] Calculate the second tolerance offset of the intermediate particle size span characterization value of yttrium oxide sintering aid powder relative to the target particle size span characterization value of yttrium oxide sintering aid powder: The second tolerance offset is calculated using the same method as the first tolerance offset, and the calculation formula is as follows: ; in, S is the second tolerance offset. m2 S represents the characteristic value of the intermediate particle size range of yttrium oxide sintering aid powder. t2 The value represents the target particle size span of yttrium oxide sintering aid powder.

[0064] When both the first tolerance offset and the second tolerance offset are within the preset tolerance range, a stop ball mill command is generated: Preset tolerance percentage; In one implementation, the tolerance percentage is 3%; When both the first tolerance offset and the second tolerance offset do not exceed this percentage, a stop ball mill command and a discharge command are generated.

[0065] According to the ball milling stop command, pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder are collected, specifically as follows: After receiving the shutdown command, the ball mill equipment stops running. After standing for 3 to 5 minutes, open the discharge ports of the two ball mill tanks respectively, collect the pretreated aluminum nitride powder and the pretreated yttrium oxide sintering aid powder separately, classify and store them separately.

[0066] In this implementation scheme, a stop ball milling command is generated only after the first tolerance offset and the second tolerance offset simultaneously meet the preset tolerance range. This ensures that both aluminum nitride powder and yttrium oxide sintering aid powder reach the corresponding target particle size range before entering the collection stage, reducing the situation where powder on one side meets the standard while powder on the other side does not.

[0067] Specifically, the preparation steps for the mixed powder to be shaped are as follows: The specific steps for obtaining pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder are as follows: The two types of pretreated powders that have been ball-milled and sorted were retrieved, and the agglomeration state and residual media state of the pretreated aluminum nitride powder and the pretreated yttrium oxide sintering aid powder were checked.

[0068] The pretreated aluminum nitride powder and the pretreated yttrium oxide sintering aid powder were dried and sieved, respectively, as follows: The two types of powders were placed in a vacuum drying oven and dried at a constant temperature of 60-80℃ for 2-3 hours to remove the moisture adsorbed on the surface of the powders. After drying, the two types of powders are sieved using a 200-300 mesh standard sieve to remove coarse particles and impurities generated during ball milling.

[0069] The particle size distribution of the pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder after sieving was re-measured, and the re-measured particle size distribution is as follows: After the powder has been dried and sieved, a laser particle size analyzer is used again to perform full particle size detection, and the particle size distribution data of the two types of powder are collected again to obtain the re-measured particle size distribution.

[0070] When the particle size distribution corresponding to the retested particle size distribution falls within the preset tolerance range of the target particle size distribution, two types of pretreated powder are weighed according to the preset ratio, specifically: According to the mass ratio of aluminum nitride powder to yttrium oxide sintering aid powder of 92:8 to 95:5, the corresponding weights of the two types of powders were weighed separately using an electronic scale, and the weighing error was controlled within ±0.5%.

[0071] The two types of pretreated powders, after being weighed, are added to a mixing container, and the mixing operation is performed according to the preset mixing speed and preset mixing time to obtain the mixed powder to be shaped, specifically as follows: The two types of powders are weighed and added simultaneously to a high-speed mixing container. The mixing speed is set to 800-1200 r / min and the mixing time is 15-25 min. The mixture is stirred in a closed container and the mixing operation is performed according to the preset speed and time. After the mixing is completed, the material is discharged to obtain the mixed powder to be shaped.

[0072] In this implementation plan, by drying, sieving, re-measuring the particle size of the pretreated aluminum nitride powder and the pretreated yttrium oxide sintering aid powder, and mixing them in proportion, the mixed powder before entering the molding process can simultaneously meet the particle size range requirements and proportion requirements, thereby reducing the risk of asynchronous local liquid phase generation and grain growth in the subsequent sintering stage.

[0073] Please see Figure 3 This invention provides a technical solution: an aluminum nitride powder ball milling pretreatment system based on particle size difference control, comprising: a particle size detection module for performing particle size detection on the aluminum nitride powder and yttrium oxide sintering aid powder to be treated, and recording the original particle size distribution and particle size span characterization value; a mismatch evaluation module for generating target particle size span characterization values ​​for aluminum nitride powder and yttrium oxide sintering aid powder through a particle size span mismatch evaluation algorithm; and a ball milling parameter back calculation module for determining the diameter of the ball milling media and the ball milling rotation speed through a ball milling parameter back calculation algorithm. The system includes a ball milling speed and milling time module; a ball milling control module, which controls the ball milling equipment to perform ball milling refinement pretreatment on the aluminum nitride powder and yttrium oxide sintering aid powder respectively, and corrects the remaining ball milling time based on the intermediate particle size span characterization value; an anomaly correction module, which generates at least one of under-milling and over-milling marks based on the intermediate particle size span characterization value within multiple consecutive detection intervals, and corrects the ball milling speed and remaining ball milling time; and a powder mixing module, which mixes the pretreated aluminum nitride powder and the pretreated yttrium oxide sintering aid powder according to a preset ratio to obtain the mixed powder to be shaped.

[0074] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0075] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A ball milling pretreatment method for aluminum nitride powder based on particle size difference control, characterized in that, Includes the following steps: Aluminum nitride powder and yttrium oxide sintering aid powder to be processed were obtained, and samples were taken and particle size was measured. The original particle size distribution of aluminum nitride powder, the original particle size distribution of yttrium oxide sintering aid powder, the particle size span characterization value of aluminum nitride powder, and the particle size span characterization value of yttrium oxide sintering aid powder were recorded. The original particle size distribution of aluminum nitride powder, the original particle size distribution of yttrium oxide sintering aid powder, the particle size span characterization value of aluminum nitride powder, and the particle size span characterization value of yttrium oxide sintering aid powder are analyzed by particle size span mismatch evaluation algorithm, and the target particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder are generated. Based on the target particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder, as well as the original particle size distribution of the two types of powder, the ball milling media diameter, ball milling speed and ball milling time of aluminum nitride powder and yttrium oxide sintering aid powder are determined by the ball milling parameter back calculation algorithm. According to the determined ball milling media diameter, ball milling speed and ball milling time, the aluminum nitride powder and yttrium oxide sintering aid powder to be treated were respectively subjected to ball milling refinement pretreatment. During the ball milling process, the process particle size distribution data were collected at preset detection intervals, the intermediate particle size span characterization value was calculated, and the remaining ball milling time was corrected according to the deviation between the intermediate particle size span characterization value and the target particle size span characterization value. When the intermediate particle size span characterization value of aluminum nitride powder and yttrium oxide sintering aid powder falls within the preset tolerance range of the corresponding target particle size span characterization value, the ball milling refinement pretreatment is stopped, and the pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder are collected. The collected pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder are mixed according to a preset ratio to obtain the mixed powder to be shaped.

2. The method for ball milling pretreatment of aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The steps for determining the particle size span characterization value are as follows: Multiple samples were taken from the aluminum nitride powder and the yttrium oxide sintering aid powder to be treated to obtain two types of powder particle size test samples; Particle size distributions of the two types of powder samples were measured to obtain the original particle size distributions of aluminum nitride powder and yttrium oxide sintering aid powder. Low and high particle size quantiles were extracted from the original particle size distributions of aluminum nitride powder and yttrium oxide sintering aid powder, respectively. Based on the low and high particle size quantiles, the particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder were calculated respectively. The original particle size distributions and corresponding particle size span characterization values ​​of the two types of powders were written into the particle size difference control dataset.

3. The ball milling pretreatment method for aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The specific steps of the particle size mismatch evaluation algorithm are as follows: Read the original particle size distribution and corresponding particle size span characterization values ​​of two types of powders in the particle size difference control dataset; The original particle size distributions of the two types of powders were normalized to generate aligned sequences of particle size distributions for the two types of powders. The overlap of particle size intervals is calculated based on the alignment sequence of particle size distribution of the two types of powders, and the deviation of particle size span is calculated based on the particle size span characterization value of the two types of powders. The particle size span mismatch value is generated based on the overlap of particle size intervals and the deviation of particle size span. The target particle size span characterization values ​​for aluminum nitride powder and yttrium oxide sintering aid powder are generated based on the particle size span mismatch value.

4. The ball milling pretreatment method for aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The specific steps of the ball mill parameter inverse calculation algorithm are as follows: Read the target particle size span characterization values ​​of aluminum nitride powder, the target particle size span characterization values ​​of yttrium oxide sintering aid powder, and the original particle size distributions of the two types of powders; Based on the original particle size distribution of the two types of powders and the corresponding target particle size span characterization values, the particle size span compression of aluminum nitride powder and the particle size span compression of yttrium oxide sintering aid powder were calculated respectively. Based on the compression of the particle size range of aluminum nitride powder and the compression of the particle size range of yttrium oxide sintering aid powder, candidate ball milling media diameter, candidate ball milling speed and candidate ball milling time are matched respectively; Based on the ball milling energy constraint, candidate ball milling media diameter, candidate ball milling speed and candidate ball milling time are screened to eliminate parameter groups with the risk of over-milling; Output the corresponding ball milling media diameter, ball milling speed, and ball milling time for aluminum nitride powder and yttrium oxide sintering aid powder, respectively.

5. The method for ball milling pretreatment of aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The specific steps of ball milling pretreatment are as follows: The first ball mill container is configured according to the diameter of the ball milling media, the ball milling speed and the ball milling time corresponding to the aluminum nitride powder; The second ball mill container is configured according to the diameter of the ball milling media, the ball milling speed and the ball milling time corresponding to the yttrium oxide sintering aid powder; The aluminum nitride powder to be processed is added to the first ball mill container and the first ball milling fine pretreatment is started. Add the yttrium oxide sintering aid powder to the second ball mill container and start the second ball milling fine pretreatment; The particle size distribution of aluminum nitride powder and yttrium oxide sintering aid powder were collected at preset detection intervals.

6. The method for ball milling pretreatment of aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The specific steps for correcting the remaining ball milling time are as follows: Read the particle size distribution of aluminum nitride powder and yttrium oxide sintering aid powder during the process; The intermediate particle size span characterization value of aluminum nitride powder is calculated based on the process particle size distribution of aluminum nitride powder, and the intermediate particle size span characterization value of yttrium oxide sintering aid powder is calculated based on the process particle size distribution of yttrium oxide sintering aid powder. Calculate the first deviation between the intermediate particle size span characterization value of aluminum nitride powder and the target particle size span characterization value of aluminum nitride powder, and calculate the second deviation between the intermediate particle size span characterization value of yttrium oxide sintering aid powder and the target particle size span characterization value of yttrium oxide sintering aid powder. Calculate the first deviation rate and the second deviation rate based on the first deviation and the second deviation within the continuous detection interval, respectively. Based on the first deviation, the first deviation change rate, the second deviation, and the second deviation change rate, the remaining ball milling time corresponding to aluminum nitride powder and the remaining ball milling time corresponding to yttrium oxide sintering aid powder are corrected respectively.

7. The method for ball milling pretreatment of aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The specific steps for correcting abnormalities in the ball milling process are as follows: Read the intermediate particle size span characterization values ​​of aluminum nitride powder and yttrium oxide sintering aid powder within multiple consecutive detection intervals; Calculate the rate of change of aluminum nitride powder particle size span and the rate of change of yttrium oxide sintering aid powder particle size span between adjacent detection intervals, respectively. When the rate of change of particle size span is lower than the preset change threshold, and the intermediate particle size span characterization value does not fall within the preset tolerance range of the target particle size span characterization value, an under-wear mark is generated. When the intermediate particle size span characterization value is lower than the preset tolerance lower limit of the target particle size span characterization value, an over-grinding mark is generated; The ball milling speed and remaining ball milling time of the corresponding powder are adjusted according to at least one of the under-milling and over-milling indicators.

8. The ball milling pretreatment method for aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The specific steps for determining when to stop ball milling pretreatment are as follows: Read the characterization values ​​of the intermediate particle size span of aluminum nitride powder, the characterization values ​​of the intermediate particle size span of yttrium oxide sintering aid powder, and the corresponding target particle size span characterization values; Calculate the first tolerance offset of the intermediate particle size span characterization value of aluminum nitride powder relative to the target particle size span characterization value of aluminum nitride powder; Calculate the second tolerance offset of the intermediate particle size span characterization value of yttrium oxide sintering aid powder relative to the target particle size span characterization value of yttrium oxide sintering aid powder; When both the first tolerance offset and the second tolerance offset are within the preset tolerance range, a stop ball milling command is generated; Collect pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder according to the ball milling stop command.

9. The method for ball milling pretreatment of aluminum nitride powder based on particle size difference control according to claim 1, characterized in that, The preparation steps for the mixed powder to be shaped are as follows: Obtain pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder; The pretreated aluminum nitride powder and the pretreated yttrium oxide sintering aid powder were dried and sieved respectively. The particle size distribution of the pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder after sieving was re-measured. When the particle size distribution corresponding to the retested particle size span characterization value falls within the preset tolerance range of the target particle size span characterization value, the two types of pretreated powders are weighed according to the preset ratio. The two types of pretreated powders are weighed and added to a mixing container. The mixing operation is performed according to the preset mixing speed and preset mixing time to obtain the mixed powder to be formed.

10. A ball milling pretreatment system for aluminum nitride powder based on particle size difference control, employing the ball milling pretreatment method for aluminum nitride powder based on particle size difference control as described in any one of claims 1 to 9, characterized in that, include: The particle size detection module is used to perform particle size detection on the aluminum nitride powder and yttrium oxide sintering aid powder to be processed, and record the original particle size distribution and particle size span characterization values; The mismatch assessment module is used to generate target particle size span characterization values ​​for aluminum nitride powder and yttrium oxide sintering aid powder through a particle size span mismatch assessment algorithm. The ball milling parameter back calculation module is used to determine the diameter of the ball milling media, the ball milling speed, and the ball milling time through the ball milling parameter back calculation algorithm. The ball milling control module is used to control the ball milling equipment to perform ball milling fine pretreatment on the aluminum nitride powder and yttrium oxide sintering aid powder to be processed, and to adjust the remaining ball milling time according to the intermediate particle size span characterization value; An anomaly correction module is used to generate at least one of under-grinding and over-grinding markers based on the intermediate particle size span characterization values ​​within multiple consecutive detection intervals, and to correct the ball milling speed and remaining ball milling time. The powder mixing module is used to mix pretreated aluminum nitride powder and pretreated yttrium oxide sintering aid powder according to a preset ratio to obtain the mixed powder to be shaped.

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