Preparation method of chromium carbide powder

Abstract

The invention provides a preparation method of chromium carbide powder. The preparation method comprises the steps of raw material selection and pretreatment; analyzing the particle size of the powder; observing the morphology of the powder; a step of carrying out thermogravimetric analysis; carrying out carbonization reaction kinetic analysis; a step of carrying out carbonization reaction condition optimization; carrying out X-ray diffraction analysis on a reaction product; carrying out statistical analysis on particle size distribution; carrying out product morphology and structure characterization; according to the method, uniform mixing and granularity control of the raw materials are ensured, and the problem of incomplete reaction caused by non-uniform mixing in a traditional method is avoided. The carbonization reaction conditions are optimized, and the reaction efficiency and the product purity are improved. The phase, the structure and the performance of the product are comprehensively represented, and the high quality and the high performance of the chromium carbide powder are ensured. The particle size distribution is analyzed through a statistical method, a scientific basis is provided for process optimization, and the problem of uneven particle size distribution in a traditional method is solved.

Description

Technical Field

[0001] The present invention specifically relates to a method for preparing chromium carbide powder. Background Art

[0002] Chromium carbide is an inorganic metal ceramic material with good wear resistance, corrosion resistance, oxidation resistance, high melting point (1870 °C), and high bonding strength at high temperatures (1000 - 1100 °C). Due to its special high-temperature properties, it is widely used as a thermal spraying material for metal surface protection processes, a welding electrode or flux-cored wire for surfacing, and a hard alloy additive.

[0003] Existing methods for preparing chromium carbide powder have problems such as uneven mixing of raw materials, low reaction efficiency and product purity during the production process, poor quality assurance of chromium carbide powder, and uneven particle size distribution. Therefore, a method for preparing chromium carbide powder is proposed to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing chromium carbide powder in view of the deficiencies of the prior art, which can well solve the above problems.

[0005] To meet the above requirements, the technical solution adopted by the present invention is: providing a method for preparing chromium carbide powder, which includes the following steps:

[0006] S1: Steps of raw material selection and pretreatment; select chromium metal powder with a purity of greater than or equal to 99.9% and a carbon source with a purity of greater than or equal to 99.5%. The particle size of the chromium powder is controlled within the range of 1 - 10 μm, and the particle size of the carbon source should be controlled within the range of 5 - 20 μm. Weigh the chromium powder and the carbon source accurately according to the stoichiometric ratio of 1:1. Put the weighed powder into a planetary ball mill of a high-energy ball mill. The ball milling medium is a cemented carbide ball with a diameter of 5 mm, the ball-to-powder ratio is 15:1, the rotation speed is 400 rpm, and the ball milling time is 36 hours. During the ball milling process, stop the machine for 10 minutes every 6 hours to cool the equipment. After the ball milling is completed, screen the mixed powder through a sieve with a mesh aperture of 50 μm to remove large particles and aggregates;

[0007] S2: Steps of performing powder particle size analysis; use a laser particle size analyzer to analyze the particle size of the mixed powder after ball milling. Disperse the powder sample in deionized water, add 0.1% of a dispersant, and perform ultrasonic treatment for 15 minutes to ensure uniform dispersion of the particles. Inject the sample into the particle size analyzer, measure the particle size distribution, record the D10, D50, and D90 values, measure each sample three times, and take the average value as the final result. Analyze the particle size distribution curve and calculate the specific surface area and particle size distribution width;

[0008] S3: Steps for powder morphology observation; Observe the morphology of the mixed powder using a field emission scanning electron microscope. Fix the powder sample on a conductive tape, perform gold spraying treatment, and then place it in the FE-SEM sample chamber. Under the condition of an acceleration voltage of 20 kV, observe the microscopic morphology of the powder, take high-magnification photos, analyze the elemental distribution of the powder using an energy spectrometer, record the elemental content and distribution uniformity of chromium and carbon, and observe at least 5 different regions for each sample to ensure the representativeness of the data;

[0009] S4: Steps for performing thermogravimetric analysis; Perform thermogravimetric analysis on the mixed powder using a thermogravimetric analyzer. Place the powder sample in the TGA sample pan, heat it from room temperature to 1500 °C at a heating rate of 5 °C / min under an argon atmosphere, record the mass change of the sample, analyze the change in the reaction rate using the differential thermogravimetric curve, measure each sample twice, take the average value as the final result, fit the TGA curve, and determine the starting temperature, peak temperature, and ending temperature of the reaction;

[0010] S5: Steps for performing carbonization reaction kinetics analysis; Based on the TGA data, use the improved Kissinger-Akahira-Sunose method to calculate the activation energy of the carbonization reaction. The KAS equation is:

[0011]

[0012] Where:

[0013] α is the reaction conversion rate, f(α) is the reaction mechanism function, T0 is the initial temperature, T is the current temperature. By numerically integrating the above equation, the activation energy E a and the pre-exponential factor A can be calculated;

[0014] S6: Steps for optimizing the carbonization reaction conditions; According to the results of the kinetic analysis, optimize the carbonization reaction conditions. Place the mixed powder in a high-temperature furnace, perform the carbonization reaction under an argon atmosphere, the reaction temperature is 1100 °C, the holding time is 3 hours, the heating rate is 5 °C / min, use a PID controller to precisely control the furnace temperature to ensure that the temperature fluctuation is less than ±2 °C. After the reaction is completed, naturally cool the sample to room temperature, take it out and screen it through a sieve with a mesh aperture of 50 μm to remove large particles and aggregates;

[0015] S7: Steps for performing X-ray diffraction analysis of the reaction product; Perform phase analysis on the product after the carbonization reaction using an X-ray diffractometer. Press the powder sample into a tablet and place it on the XRD sample stage. Perform scanning under Cu Kα radiation with λ being 1.5406 Å, the scanning range is from 10° to 90°, the step size is 0.01°, measure each sample twice, take the average value as the final result, analyze the diffraction pattern, and determine the phase composition and crystal structure of the product;

[0016] S8: Steps for performing particle size distribution statistical analysis; using statistical methods to analyze the particle size distribution of chromium carbide powder, the particle size distribution follows a Weibull distribution, and its probability density function is:

[0017]

[0018] where x is the particle size vector, μ is the mean vector, Σ is the covariance matrix, and n is the number of dimensions; fitting the particle size distribution data by maximum likelihood estimation, calculating the mean vector μ and the covariance matrix Σ, and evaluating the particle size uniformity of chromium carbide powder;

[0019] S9: Steps for performing product morphology and structure characterization; using a high-resolution transmission electron microscope to observe the microstructure and crystal structure of chromium carbide powder, dispersing the powder sample in ethanol, dropping it on a copper grid after ultrasonic treatment, and putting it into the HR-TEM sample chamber after drying. Under the condition of an accelerating voltage of 300 kV, observing the microstructure of the sample and taking high-resolution lattice images, and using selected area electron diffraction to analyze the crystal structure to determine the lattice constant and interplanar spacing.

[0020] Preferably, it further includes step S10: Steps for performing product performance testing; specifically including testing the hardness, wear resistance, and oxidation resistance of chromium carbide powder.

[0021] Preferably, the hardness is measured by the following method: using a Vickers hardness tester to measure the hardness, with a load of 1 kg and a holding time of 15 seconds, measuring 10 points for each sample, and taking the average value as the final result.

[0022] Preferably, the wear resistance test is carried out by the following method: using a ball-on-disk wear tester to test the wear resistance, with a load of 10 N, a rotation speed of 100 rpm, and a time of 30 minutes.

[0023] Preferably, the oxidation resistance test is carried out by the following method: using a thermogravimetric analyzer to test the oxidation resistance, heating from room temperature to 800 °C at a heating rate of 10 °C / min in an air atmosphere, recording the mass change of the sample, measuring each sample twice, and taking the average value as the final result.

[0024] The advantages of this method for preparing chromium carbide powder are as follows:

[0025] (1) By high-energy ball milling and particle size analysis, this method ensures the uniform mixing and particle size control of raw materials, avoiding the problem of incomplete reaction caused by uneven mixing in traditional methods.

[0026] (2) By thermogravimetric analysis and kinetic calculations, the carbonization reaction conditions are optimized, improving the reaction efficiency and product purity.

[0027] (3) The phase, structure, and properties of the product were comprehensively characterized by XRD, HR-TEM, and performance tests, ensuring the high quality and high performance of the chromium carbide powder.

[0028] (4) The particle size distribution was analyzed by statistical methods, providing a scientific basis for process optimization and solving the problem of uneven particle size distribution in traditional methods. Description of the Drawings

[0029] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The same reference numerals are used to represent the same or similar parts in these drawings. The schematic embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0030] Figure 1 The schematic flow diagram of the method for preparing chromium carbide powder according to an embodiment of the present application is schematically shown. Detailed Embodiments

[0031] To make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] In the following description, references to "an embodiment", "embodiment", "an example", "example", etc. indicate that the embodiment or example so described may include a specific feature, structure, characteristic, property, element, or limitation, but not every embodiment or example necessarily includes the specific feature, structure, characteristic, property, element, or limitation. Additionally, repeated use of the phrase "according to an embodiment of the present application" does not necessarily refer to the same embodiment.

[0033] For simplicity, certain technical features known to those skilled in the art are omitted in the following description.

[0034] According to an embodiment of the present application, a method for preparing chromium carbide powder is provided, as Figure 1 shown, including the following steps:

[0035] S1: Steps of raw material selection and pretreatment; Select chromium metal powder with high purity (≥99.9%) and carbon source with high purity (≥99.5%). The particle size of chromium powder should be controlled within the range of 1 - 10 μm, and the particle size of carbon source should be controlled within the range of 5 - 20 μm. Weigh the chromium powder and carbon source accurately according to the stoichiometric ratio (Cr:C = 1:1), and use an electronic balance (accuracy 0.0001 g) to ensure the accurate ratio. Put the weighed powders into a high-energy ball mill (such as a planetary ball mill), with the ball milling medium being cemented carbide balls (diameter 5 mm), the ball-to-powder ratio being 15:1, the rotation speed being 400 rpm, and the ball milling time being 36 hours. During the ball milling process, stop the machine for 10 minutes every 6 hours to cool the equipment and prevent overheating. After ball milling, screen the mixed powder (sieve mesh aperture is 50 μm) to remove large particles and agglomerates.

[0036] Mechanical alloying makes the chromium powder and carbon source uniformly mixed at the microscale through high-energy ball milling, increasing the reaction contact area. During the ball milling process, the powder particles are subjected to strong impact, shear, and compression, resulting in grain refinement and an increase in defect density, thus improving the reaction activity. The longer the ball milling time, the better the mixing uniformity, but the equipment wear and energy consumption need to be balanced. The screening process can remove large particles and agglomerates to ensure the uniformity of the powder.

[0037] Raw material selection is the basis of the preparation process, and high purity and accurate ratio are the prerequisites for the success of subsequent steps. The mixed powder after ball milling provides a uniform sample for particle size analysis and morphology observation.

[0038] S2: Steps of powder particle size analysis; Use a laser particle size analyzer (such as Malvern Mastersizer3000) to analyze the particle size of the mixed powder after ball milling. Disperse the powder sample in deionized water, add 0.1% dispersant (such as sodium hexametaphosphate), and perform ultrasonic treatment for 15 minutes to ensure uniform dispersion of the particles. Inject the sample into the particle size analyzer, measure the particle size distribution, and record the D10, D50, and D90 values. Each sample is measured three times, and the average value is taken as the final result. Use software (such as the software supporting Mastersizer 3000) to analyze the particle size distribution curve and calculate the specific surface area and particle size distribution width.

[0039] Laser particle size analysis is based on the Mie scattering theory. By measuring the angular and intensity distributions of the scattered light, the particle size distribution is calculated. The particle size distribution data can be used to evaluate the ball milling effect and provide a reference for the subsequent carbonization reaction. The specific surface area and particle size distribution width are important parameters for evaluating the powder uniformity.

[0040] The particle size of the powder after ball milling directly affects the uniformity and efficiency of the subsequent reaction. The particle size analysis results provide the basic data of the particle size distribution for morphology observation.

[0041] S3: Steps for powder morphology observation; Use a field emission scanning electron microscope (FE-SEM, such as Hitachi SU-8010) to observe the morphology of the mixed powder. Fix the powder sample on a conductive tape, perform gold spraying treatment (thickness about 5 nm), and then place it in the FE-SEM sample chamber. Under the condition of an acceleration voltage of 20 kV, observe the microscopic morphology of the powder and take high-magnification photos (magnification from 500× to 50000×). Use an energy-dispersive spectrometer (EDS) to analyze the element distribution of the powder, and record the element content and distribution uniformity of chromium and carbon. Observe at least 5 different regions for each sample to ensure the representativeness of the data.

[0042] FE-SEM generates secondary electron and backscattered electron signals through the interaction between the electron beam and the sample surface, forming a high-resolution surface morphology image. EDS analyzes the element distribution and content by measuring characteristic X-rays. Morphology observation and element analysis can evaluate the ball milling effect and mixing uniformity.

[0043] The particle size analysis results provide a reference for the particle size distribution in morphology observation. The morphology observation results provide intuitive information about the powder microstructure for thermogravimetric analysis.

[0044] S4: Steps for performing thermogravimetric analysis; Use a thermogravimetric analyzer (such as Netzsch STA 449F3) to perform thermogravimetric analysis on the mixed powder. Place the powder sample in the TGA sample pan, heat it from room temperature to 1500 °C at a heating rate of 5 °C / min under an argon atmosphere, and record the mass change of the sample. Use the derivative thermogravimetry (DTG) curve to analyze the change in the reaction rate. Measure each sample twice and take the average as the final result. Use software (such as Proteus Analysis) to fit the TGA curve to determine the starting temperature, peak temperature, and ending temperature of the reaction.

[0045] TGA analyzes the thermal stability and reaction process by measuring the mass change of the sample during heating. The DTG curve provides information on the change in the reaction rate by differentiating the TGA curve. Fitting the TGA curve can determine the kinetic parameters of the reaction.

[0046] The morphology observation results provide a reference for the powder microstructure in thermogravimetric analysis. The TGA data provide an experimental basis for the kinetic analysis of the carbonization reaction.

[0047] S5: Steps for performing carbonization reaction kinetic analysis; Based on the TGA data, use the modified Kissinger-Akahira-Sunose (KAS) method to calculate the activation energy of the carbonization reaction. The KAS equation is:

[0048]

[0049] Where:

[0050] α is the reaction conversion rate, f(α) is the reaction mechanism function, T0 is the initial temperature, and T is the current temperature. Solving the above equation through numerical integration (such as Simpson integration method) can calculate the activation energy E more accurately. a and the pre-exponential factor A.

[0051] The kinetic equation in integral form describes the reaction process more precisely by considering the integral relationship between the reaction conversion rate and temperature change. The numerical integration method (such as Simpson integration method) improves the calculation accuracy by approximating the integral value in segments.

[0052] The TGA data provides an experimental basis for kinetic analysis. The results of kinetic analysis provide a theoretical basis for optimizing the carbonization reaction conditions.

[0053] The specific working method in this step is as follows:

[0054] 1. Data preparation:

[0055] Obtain the mass loss curves at different heating rates (5 °C / min, 10 °C / min, 15 °C / min) from the thermogravimetric analysis (TGA) experiment.

[0056] Extract the reaction start temperature (TiTi), peak temperature (TpTp), and end temperature (TfTf) of each curve.

[0057] 2. Kinetic model selection:

[0058] Select the Kissinger-Akahira-Sunose (KAS) method as the basic model for kinetic analysis. Introduce the modified Arrhenius equation, considering diffusion limitation and non-isothermal effects.

[0059] 3. Formula application and calculation:

[0060] Use the KAS equation to calculate the activation energy E a and the pre-exponential factor A:

[0061]

[0062] where β is the heating rate, T p is the peak temperature, and R is the gas constant.

[0063] Introduce the modified Arrhenius equation:

[0064]

[0065] where D(T) is the temperature-dependent diffusion coefficient, given by the Stokes-Einstein equation:

[0066]

[0067] where k B is the Boltzmann constant, η is the viscosity, and r is the particle radius.

[0068] 4. Numerical integration and fitting:

[0069] Numerically solve the kinetic equation in integral form using the Simpson integration method:

[0070]

[0071] where α is the reaction conversion rate and f(α) is the reaction mechanism function. Fit the experimental data using the least squares method to optimize the activation energy E a and the pre-exponential factor A. Compare the fitting results at different heating rates in this step to verify the accuracy of the model. Calculate the correlation coefficient R 2 to evaluate the goodness of fit.

[0072] S6: Steps for optimizing the carbonization reaction conditions; optimize the carbonization reaction conditions according to the kinetic analysis results. Put the mixed powder into a high-temperature furnace and carry out the carbonization reaction under an argon atmosphere. The reaction temperature is 1100 °C, the holding time is 3 hours, and the heating rate is 5 °C / min. Use a PID controller to precisely control the furnace temperature to ensure that the temperature fluctuation is less than ±2 °C. After the reaction, naturally cool the sample to room temperature, take it out and sieve it (the sieve mesh aperture is 50 μm) to remove large particles and agglomerates.

[0073] At high temperatures, chromium powder reacts with the carbon source through a solid-phase reaction to form chromium carbide (Cr3C2). Control the reaction rate and product purity by optimizing the reaction temperature and holding time. The argon atmosphere can prevent oxidation and ensure the smooth progress of the reaction.

[0074] The kinetic analysis results provide a theoretical basis for optimizing the reaction conditions. The product after the carbonization reaction provides samples for XRD analysis.

[0075] S7: Steps for X-ray diffraction analysis of the reaction product; use an X-ray diffractometer (such as Bruker D8Advance) to perform phase analysis on the product after the carbonization reaction. Press the powder sample into a tablet and place it on the XRD sample stage, and scan it under Cu Kα radiation in the range of 10° to 90° with a step size of 0.01°. Measure each sample twice and take the average as the final result. Analyze the diffraction pattern using software (such as Jade) to determine the phase composition and crystal structure of the product.

[0076] XRD analyzes the crystal structure and phase composition of a sample by measuring the change in diffraction angle. Fitting the diffraction pattern can determine the phase composition and purity of chromium carbide.

[0077] The product after the carbonization reaction provides a sample for XRD analysis. The XRD analysis results provide phase information for the statistical analysis of the product particle size distribution.

[0078] S8: Steps for performing statistical analysis of particle size distribution; Use statistical methods to analyze the particle size distribution of chromium carbide powder. The particle size distribution follows a Weibull distribution, and its probability density function is:

[0079]

[0080] where \(x\) is the particle size vector, \(\mu\) is the mean vector, \(\sum\) is the covariance matrix, and \(n\) is the number of dimensions. Fit the particle size distribution data by maximum likelihood estimation (MLE), calculate the mean vector \(\mu\) and the covariance matrix \(\sum\), and evaluate the particle size uniformity of chromium carbide powder.

[0081] The multivariate normal distribution model more accurately describes the particle size distribution by considering the correlation between particle sizes. Maximum likelihood estimation fits the particle size distribution data by maximizing the likelihood function, improving the fitting accuracy.

[0082] The XRD analysis results provide phase information for the statistical analysis of particle size distribution. The statistical results of particle size distribution provide particle size data for the characterization of the product morphology and structure.

[0083] The specific working method in this step is as follows:

[0084] 1. Data preparation:

[0085] Measure the particle size distribution of chromium carbide powder using a laser particle size analyzer to obtain particle size data (D10, D50, D90). Convert the particle size data into a particle size vector \(x=(x_1,x_2,\cdots,x_n)\), where \(x_i\) is the \(i\)-th particle size value.

[0086] 2. Distribution model selection:

[0087] Select the Weibull distribution as the basic model to describe the unimodal characteristics of the particle size distribution. Introduce the mixture Gaussian model to describe the multimodal characteristics of the particle size distribution.

[0088] 3. Formula application and calculation:

[0089] Use the probability density function of the Weibull distribution to fit the particle size data:

[0090]

[0091] Among them, k is the shape parameter and λ is the scale parameter.

[0092] Use the Gaussian mixture model to fit the particle size data:

[0093]

[0094] Among them, m is the number of Gaussian distributions, w i is the weight of the i-th Gaussian distribution, μ i is the mean vector, ∑ i is the covariance matrix.

[0095] 4. Parameter estimation and fitting:

[0096] Use the maximum likelihood estimation (MLE) to fit the Weibull distribution parameters k and λ. Use the expectation maximization (EM) algorithm to fit the Gaussian mixture model parameters w i , μ i and ∑ i .

[0097] 5. Result verification:

[0098] Compare the fitting results of the Weibull distribution and the Gaussian mixture model, and select the optimal model. Calculate the goodness-of-fit indicators (AIC, BIC) to evaluate the model performance.

[0099] In this step, the Weibull distribution describes the unimodal characteristics of the particle size distribution and evaluates the particle size uniformity by fitting the particle size data.

[0100] The Gaussian mixture model describes the multimodal characteristics of the particle size distribution and improves the model accuracy by fitting the particle size data.

[0101] The maximum likelihood estimation (MLE) fits the Weibull distribution parameters by maximizing the likelihood function.

[0102] The expectation maximization (EM) algorithm fits the Gaussian mixture model parameters through iterative optimization.

[0103] S9: Steps for product morphology and structure characterization; Use a high-resolution transmission electron microscope (HR-TEM, such as JEOL JEM-2100F) to observe the microscopic morphology and crystal structure of chromium carbide powder. Disperse the powder sample in ethanol, ultrasonically treat it, drop it on a copper grid, and place it in the HR-TEM sample chamber after drying. Observe the microscopic morphology of the sample and take high-resolution lattice images under the condition of an acceleration voltage of 300 kV. Use selected area electron diffraction (SAED) to analyze the crystal structure and determine the lattice constant and interplanar spacing.

[0104] HR-TEM forms high-resolution images and diffraction patterns by penetrating the sample with an electron beam. SAED determines the lattice constant and interplanar spacing of the crystal by analyzing the diffraction spots.

[0105] The statistical results of particle size distribution provide particle size data for morphology and structure characterization. The results of morphology and structure characterization provide microstructural information for the product performance test.

[0106] S10: Steps for product performance testing; test the hardness, wear resistance and oxidation resistance of chromium carbide powder. Measure the hardness using a Vickers hardness tester with a load of 1 kg and a holding time of 15 seconds. Measure 10 points for each sample and take the average as the final result. Test the wear resistance using a ball-on-disk wear tester with a load of 10 N, a rotation speed of 100 rpm and a time of 30 minutes. Test the oxidation resistance using a thermogravimetric analyzer, heat from room temperature to 800 °C at a heating rate of 10 °C / min in an air atmosphere, and record the mass change of the sample. Measure each sample twice and take the average as the final result.

[0107] The hardness test calculates the hardness value by measuring the length of the indentation diagonal. The wear resistance test evaluates the wear resistance of the material by measuring the wear amount. The oxidation resistance test evaluates the stability of the material in a high-temperature oxidation environment by measuring the mass change.

[0108] The results of morphology and structure characterization provide microstructural information for performance testing. The results of performance testing provide performance data for the application of the final product.

[0109] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the claims described.

Claims

1. A method for preparing chromium carbide powder, characterized in that: The steps include: S1: raw material selection and pretreatment step; select chromium metal powder with a purity greater than or equal to 99.9% and a carbon source with a purity greater than or equal to 99.5%, the particle size of the chromium powder is controlled within the range of 1-10μm, and the particle size of the carbon source should be controlled within the range of 5-20μm, accurately weigh the chromium powder and the carbon source according to the stoichiometric ratio of 1:1, put the weighed powder into a high-energy ball mill planetary ball mill, the ball milling medium is a cemented carbide ball with a diameter of 5mm, the ball-to-material ratio is 15:1, the rotation speed is 400rpm, and the ball milling time is 36 hours. During the ball milling process, stop the machine for 10 minutes every 6 hours to cool the equipment. After the ball milling is completed, the mixed powder is sieved with a sieve aperture of 50μm to remove large particles and agglomerates; S2: Steps for performing powder particle size analysis; using a laser particle size analyzer to perform particle size analysis on the mixed powder after ball milling, dispersing the powder sample in deionized water, adding 0.1% dispersant, and ultrasonically treating for 15 minutes to ensure uniform dispersion of the particles, injecting the sample into the particle size analyzer, measuring the particle size distribution, and recording the D10, D50 and D90 values. Each sample is measured three times, and the average value is taken as the final result. The particle size distribution curve is analyzed, and the specific surface area and particle size distribution width are calculated; S3: Steps for observing the powder morphology: Use a field emission scanning electron microscope to observe the morphology of the mixed powder, fix the powder sample on a conductive tape, and place it in the FE-SEM sample chamber after gold spraying. Under the condition of an accelerating voltage of 20 kV, observe the microscopic morphology of the powder and take high-magnification photos. Use an energy spectrometer to analyze the element distribution of the powder, record the element content and distribution uniformity of chromium and carbon, and observe at least 5 different areas for each sample to ensure the representativeness of the data; S4: Steps of performing thermogravimetric analysis; using a thermogravimetric analyzer to perform thermogravimetric analysis on the mixed powder, placing the powder sample in a TGA sample pan, heating from room temperature to 1500°C at a heating rate of 5°C / min under an argon atmosphere, recording the mass change of the sample, using a differential thermogravimetric curve to analyze the change in reaction rate, measuring each sample twice, taking the average value as the final result, fitting the TGA curve, and determining the starting temperature, peak temperature, and end temperature of the reaction; S5: Steps for carbonization reaction kinetic analysis; Based on TGA data, the activation energy of the carbonization reaction is calculated using the modified Kissinger-Akahira-Sunose method, and the KAS equation is: in: α is the reaction conversion rate, f(α) is the reaction mechanism function, T0 is the initial temperature, and T is the current temperature. By numerically integrating the above equation, the activation energy E can be calculated. a and pre-exponential factor A; S6: a step of optimizing the carbonization reaction conditions; according to the kinetic analysis results, the carbonization reaction conditions are optimized, the mixed powder is placed in a high-temperature furnace, and the carbonization reaction is carried out in an argon atmosphere, the reaction temperature is 1100°C, the holding time is 3 hours, the heating rate is 5°C / min, and the furnace temperature is accurately controlled by a PID controller to ensure that the temperature fluctuation is less than ±2°C. After the reaction is completed, the sample is naturally cooled to room temperature, taken out and sieved, and the mesh size is 50μm to remove large particles and agglomerates; S7: a step of performing X-ray diffraction analysis of the reaction product; using an X-ray diffractometer to perform phase analysis on the product after the carbonization reaction, pressing the powder sample into a tablet and placing it on an XRD sample stage, scanning under Cu Kα radiation with a λ of 1.5406 angstroms, a scanning range of 10° to 90°, a step length of 0.01°, measuring each sample twice, taking the average value as the final result, analyzing the diffraction spectrum, and determining the phase composition and crystal structure of the product; S8: Step of performing statistical analysis on particle size distribution; using statistical methods to analyze the particle size distribution of chromium carbide powder, the particle size distribution obeys Weibull distribution, and its probability density function is: Wherein, x is the particle size vector, μ is the mean vector, ∑ is the covariance matrix, and n is the number of dimensions; the particle size distribution data is fitted by maximum likelihood estimation, the mean vector μ and the covariance matrix ∑ are calculated, and the particle size uniformity of chromium carbide powder is evaluated; S9: Steps for characterizing the morphology and structure of the product; using a high-resolution transmission electron microscope to observe the microscopic morphology and crystal structure of the chromium carbide powder, dispersing the powder sample in ethanol, dripping it on a copper mesh after ultrasonic treatment, and placing it in the HR-TEM sample chamber after drying. Under the condition of an acceleration voltage of 300 kV, observe the microscopic morphology of the sample, take a high-resolution lattice image, use selected area electron diffraction to analyze the crystal structure, and determine the lattice constant and crystal plane spacing.

2. The method for preparing chromium carbide powder according to claim 1, characterized in that: The method further comprises step S10: a step of conducting a product performance test; specifically, the method comprises conducting a hardness, abrasion resistance and oxidation resistance test on the chromium carbide powder.

3. The method for preparing chromium carbide powder according to claim 2, characterized in that: The hardness was measured using the following method: a Vickers hardness tester was used to measure the hardness, with a load of 1 kg and a load holding time of 15 seconds. Ten points were measured for each sample, and the average value was taken as the final result.

4. The method for preparing chromium carbide powder according to claim 2, characterized in that: The wear resistance test adopts the following method: the wear resistance is tested using a ball-on-disc wear tester with a load of 10N, a rotation speed of 100rpm, and a time of 30 minutes.

5. The method for preparing chromium carbide powder according to claim 2, characterized in that: The oxidation resistance test adopts the following method: the oxidation resistance is tested using a thermogravimetric analyzer, heating from room temperature to 800°C at a heating rate of 10°C / min in an air atmosphere, recording the mass change of the sample, measuring each sample twice, and taking the average value as the final result.

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