Ceramic composite powder forming process for ultra-high-speed laser cladding

Abstract

A ceramic composite powder forming process for ultra-high-speed laser cladding, by PVD coating cobalt on the surface of ceramic powder, a new type of composite powder is prepared to improve the performance of ceramic powder in ultra-high-speed laser cladding. First, by PVD coating cobalt, the wettability of ceramic powder and metal matrix can be improved. Cobalt, as a metal, has good affinity with the metal matrix. In the process of ultra-high-speed laser cladding, the cobalt coating layer can play a bridge role between the ceramic powder and the matrix, promote the metallurgical bonding between the two, and reduce the generation of defects such as coating crack and peeling. Secondly, the cobalt coating layer can protect the ceramic powder from the direct action of high-energy laser to a certain extent, reduce the decomposition and burning loss of ceramic powder in the cladding process, ensure the effective content of ceramic phase in the coating, and improve the hardness, wear resistance and other properties of the coating.

Description

Technical Field

[0001] This invention relates to the field of material surface modification technology, specifically to a ceramic composite powder forming process for ultra-high-speed laser cladding. Background Technology

[0002] Ultra-high-speed laser cladding technology, as a novel surface treatment technology, boasts high cladding efficiency and rapid cooling rates, enabling excellent metallurgical bonding between the coating and substrate under low heat input. This significantly promotes microstructure refinement and uniform composition distribution, making it a promising field for preparing high-performance coatings for industrial parts. Commonly used powder materials in ultra-high-speed laser cladding include various pure metal powders, alloy powders, and ceramic powders. For ceramic powders… Ceramic powder is widely used due to its advantages such as high hardness, high wear resistance, good high temperature resistance, and chemical stability. However, simple... There are some problems with ceramic powder in the ultra-high-speed laser cladding process. On the one hand, Ceramic powder has poor wettability with metal substrates, making it difficult to achieve good bonding during cladding. This can easily lead to defects such as cracks and peeling in the coating, affecting its quality and service life. On the other hand, under the high-energy laser action of ultra-high-speed laser cladding, The ceramic powder may undergo partial decomposition or burn-off, thereby reducing the effective content of the ceramic phase in the coating and weakening the coating performance.

[0003] Current Status of PVD Technology: Physical vapor deposition (PVD) is a common method for preparing thin films or coatings on material surfaces. PVD technology also has some applications in the surface treatment of ceramic powders. However, currently, the use of PVD technology for... There are some technical challenges in coating ceramic powder. For example, in the PVD process, due to... Due to the surface properties and irregular shape of ceramic powder, it is difficult to achieve the desired effect of cobalt in ceramic powder. Uniform coating of ceramic powder surface leads to unstable properties of the coated composite powder. Furthermore, traditional PVD equipment and process parameters are unsuitable for... The process optimization for coating cobalt onto ceramic powder surfaces is not yet perfect, resulting in insufficient film adhesion. During subsequent ultra-high-speed laser cladding, the coating layer is prone to detachment, failing to fulfill its intended function. Furthermore, the PVD process itself suffers from low process stability; fluctuations in deposition parameters such as gas pressure and temperature can lead to batch-to-batch performance differences, affecting the quality consistency of the composite powder.

[0004] Limitations of existing powders: Currently available powder materials for ultra-high-speed laser cladding are either simple... Ceramic powder, there are problems such as poor bonding with the matrix, easy decomposition and burning loss; or is prepared by other conventional methods The ceramic-based composite powder cannot fully meet the requirements of the powder material for the super-high-speed laser cladding in performance, such as the inability to effectively control the quality and performance of the coating during the cladding process, and the difficulty in obtaining a coating with good comprehensive performance such as good bonding strength, high hardness, high wear resistance and corrosion resistance. In actual industrial applications, due to the performance limitations of these powder materials, the application of super-high-speed laser cladding technology in some key parts manufacturing and repair fields with high requirements for coating performance is limited, and the demand for high-performance coating on the surface of parts in high-end equipment manufacturing industry cannot be met. SUMMARY

[0005] Therefore, the present application provides a ceramic composite powder forming process for super-high-speed laser cladding.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] A ceramic composite powder forming process for super-high-speed laser cladding, comprising the following steps:

[0008] Step 1: raw material preparation, selecting ceramic powder with a purity of not less than 99% as raw material, and preparing cobalt target material with a purity of more than 99.9% as cobalt source in the PVD coating process; The ceramic powder is used as raw material, and the cobalt target material with a purity of more than 99.9% is prepared as the cobalt source in the PVD coating process;

[0009] Step 2: PVD equipment preparation, using a plasma enhanced physical vapor deposition device, installing a powder dispersing device and a gas flow guiding system in the vacuum chamber of the device;

[0010] Step 3: vacuumizing, after the ceramic powder is put into the vacuum chamber of the PVD device, the vacuum pump is started, and the air pressure in the chamber is pumped to below 5.0x10⁻ 4 Pa; Step 4: preheating, under vacuum, the ceramic powder is preheated to a temperature of 350~450℃ and kept for 45~90min;

[0011] Step 5: argon ion bombardment cleaning and surface activation, working gas is introduced, plasma is generated by the radio frequency power supply of glow discharge, the working gas is ionized to form a plasma atmosphere, and the atoms on the surface of the ceramic powder are further activated under the action of the plasma;

[0012] Step 6: cobalt deposition, the sputtering device of the cobalt target material is started, the cobalt atoms on the surface of the cobalt target material are sputtered out, and the cobalt atoms are uniformly deposited on the surface of the ceramic powder under the driving of the plasma;

[0013] Step 6: cobalt deposition, the sputtering device of the cobalt target material is started, the cobalt atoms on the surface of the cobalt target material are sputtered out, and the cobalt atoms are uniformly deposited on the surface of the ceramic powder under the driving of the plasma; ​​Ceramic powder surface;

[0014] Step 7: Cooling and Removal. After deposition, turn off the sputtering device and plasma source, stop the supply of working gas, and allow the temperature inside the vacuum chamber to cool naturally to room temperature. Then, slowly introduce air to release the vacuum and remove the coated material. Composite powder with cobalt coated on the surface of ceramic powder;

[0015] Step 8: Quality Inspection and Control: Conduct comprehensive quality inspections on the prepared composite powder, including using a scanning electron microscope to observe the surface morphology and uniformity of the coating layer, using an energy dispersive spectroscopy (EDS) analyzer to detect the cobalt content and distribution in the coating layer, and using an X-ray diffractometer to analyze the phase structure of the composite powder. Based on the test results, adjust the PVD process parameters in a timely manner to ensure that the quality of each batch of composite powder is stable and its performance meets the requirements.

[0016] Preferably, in step one The particle size distribution of the ceramic powder is 15~45µm.

[0017] Preferably, the working gas in step five is high-purity argon, with a purity ≥ 99.999%.

[0018] Preferably, in step five, the radio frequency power supply of the glow discharge is used to... The surface is subjected to plasma bombardment treatment to achieve atomic-level cleanliness. .

[0019] Preferably, the power of the glow discharge is 50W~200W, the working pressure during the glow discharge is 0.5~10Pa, and the radio frequency power supply of the glow discharge is... The surface bombardment time is 5 min to 30 min.

[0020] Preferably, the After the surface is subjected to plasma bombardment treatment, the The surface forms dangling bonds, lattice defects, and step structures for cobalt atom deposition.

[0021] Preferably, the After the surface is subjected to plasma bombardment treatment, the film formation mode is either layered growth or island-layer hybrid growth.

[0022] Preferably, in step six, the sputtering method of the sputtering device is DC magnetron sputtering, the sputtering power is 3~6kW, and the working gas pressure during the sputtering process is 0.3~0.9Pa.

[0023] The beneficial effects of this invention are: through the... A novel composite powder was prepared by PVD-coating cobalt onto the surface of ceramic powder to improve... The performance of ceramic powder in ultra-high-speed laser cladding. First, by PVD coating cobalt, the wettability of ceramic powder and metal matrix can be improved Cobalt, as a metal, has good affinity with the metal matrix. During the ultra-high-speed laser cladding process, the cobalt coating layer can act as a bridge between the ceramic powder and the matrix, promoting metallurgical bonding between the two and reducing defects such as coating cracks and peeling. Secondly, the cobalt coating layer can protect the ceramic powder to some extent from the direct action of high-energy laser, reducing the decomposition and burning loss of ceramic powder during the cladding process, ensuring the effective content of ceramic phase in the coating, and thus improving the hardness, wear resistance and other properties of the coating. The composite powder after coating has significant advantages in ultra-high-speed laser cladding. Due to the presence of the cobalt coating layer, the bonding force between the cladding layer and the matrix is greatly improved, effectively reducing the cracking and peeling phenomenon of the coating during use due to external force, prolonging the service life of the coating. At the same time, the protective effect of the cobalt coating layer on the ceramic powder effectively controls the decomposition and burning loss of ceramic phase during the cladding process, and the distribution of ceramic phase in the coating is more uniform and the content is more stable, thereby improving the overall hardness and wear resistance of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] The Fig. 1 original powder scanning electron microscope photos;

[0026] The Fig. 2 powder scanning electron microscope photos after PVD coating;

[0027] The Fig. 3 powder cross-section scanning electron microscope photos after PVD coating. DETAILED DESCRIPTION

[0028] ​​​The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The present invention will now be further described with reference to the accompanying drawings.

[0030] This invention provides the following technical solution:

[0031] As attached Figs. 1-3 As shown, this invention discloses a ceramic composite powder forming process for ultra-high-speed laser cladding, comprising the following steps:

[0032] Step 1: Raw material preparation, selecting materials with a purity of not less than 99%. Ceramic powder is used as the raw material, and a cobalt target with a purity of 99.9% or higher is prepared as the cobalt source in the PVD coating process; specifically, in this step, a cobalt target with a purity of not less than 99% is selected. Ceramic powder is used to ensure the stability of the final composite powder performance and to avoid the introduction of impurities due to insufficient raw material purity, which would affect the quality of the cladding layer. Cobalt sputtering material with a purity of 99.9% or higher is used as the cobalt source because high-purity cobalt sputtering material can provide purer cobalt elements during the PVD coating process, ensuring the accuracy of the coating layer composition and thus improving the overall performance of the composite powder.

[0033] Step Two: PVD Equipment Preparation. A plasma-enhanced physical vapor deposition (PVD) system is used. A powder dispersion device and a gas flow system are installed within the vacuum chamber of the equipment. Specifically, in this step, the powder dispersion device and gas flow system can adopt mature designs from existing technologies (e.g., ultrasonic vibration generation systems and mechanical oscillation systems for microparticle samples; see ZL 200510014639.6; ZL 200520026799.8). The powder dispersion device ensures uniform dispersion of ceramic powder within the vacuum chamber, preventing agglomeration and guaranteeing coating uniformity. The gas flow system precisely controls the flow direction and velocity of the gas within the chamber, creating a stable gaseous environment for the PVD coating process, which is beneficial for the uniform deposition of cobalt on the ceramic powder surface.

[0034] Step 3: Vacuum extraction, After the ceramic powder is placed into the vacuum chamber of the PVD equipment, the vacuum pump is started to evacuate the air pressure inside the chamber to 5.0 x 10⁻⁻⁻⁶. 4 Below Pa; specifically, in this step, the air pressure in the chamber is evacuated to 5.0 x 10⁻ 4The pressure is below 100 Pa to create a highly clean and low-pressure environment. In this environment, the interference of residual gas molecules within the chamber on the PVD coating process can be minimized, preventing unnecessary chemical reactions between impurity gases and cobalt or ceramic powder, thus ensuring the quality and purity of the coating layer. Simultaneously, the low-pressure environment helps improve the stability and activity of the plasma, allowing cobalt to be deposited more efficiently on the surface of the ceramic powder.

[0035] Step 4: Preheating, under vacuum conditions, for The ceramic powder is preheated to 350℃~450℃ and held for 45~90 minutes. Specifically, in this step, the purpose of preheating is to obtain an atomically clean and highly active deposition surface without altering the powder's inherent properties. The desorption of water molecules and organic pollutants adsorbed on the surface requires sufficient energy; therefore, when the preheating temperature is below 350°C, The desorption rate of surface-adsorbed water molecules, especially physically adsorbed water and some chemically adsorbed water, is very slow, making it impossible to complete purification within a reasonable time. This results in severely insufficient adhesion of the subsequent cobalt coating layer. Furthermore, when the preheating temperature exceeds 450℃... Ceramic powder will exhibit sintering, although The melting point is extremely high (~2072°C), but at the micron level, when the temperature reaches its sintering activation temperature (typically 1 / 2 to 2 / 3 of the material's melting point, but nano / micron powders become active at even lower temperatures), atomic diffusion begins at the contact points between particles, causing the particles to agglomerate and form larger aggregates. Once sintering occurs, the fluidization properties of the powder decrease drastically, making uniform coating impossible. Therefore, 450°C is suitable for particles of 15-45µm. A relatively safe upper limit is set for the powder.

[0036] If the preheating time is too short (less than 45 minutes), insufficient heat transfer and desorption processes will occur. Powder is a poor conductor of heat, and a certain amount of time is required for the entire powder bed to reach the set uniform temperature. Simultaneously, the desorption of water molecules is also a time-consuming kinetic process. If the time is too short, only the surface powder is heated, while the internal powder temperature remains insufficient, significantly reducing the purification effect. Once the powder reaches desorption equilibrium during preheating, extending the heating time (i.e., exceeding 90 minutes) does not significantly improve the purification effect. Instead, it reduces production efficiency, increases energy consumption, and slightly increases the risk of powder sintering. Therefore, from an economic and process stability perspective, it is not advisable to extend the heating time indefinitely. In summary, a temperature of 350-450°C and a time of 45-90 minutes represent the optimal balance between thoroughly purifying the powder surface and preventing powder sintering / reducing production costs, ensuring an ideal starting surface for the PVD process.

[0037] Step 5: Argon ion bombardment cleaning and surface activation. A working gas is introduced, and plasma is generated by a glow discharge radio frequency power supply. This ionizes the working gas to form a plasma atmosphere, further activating the surface under the influence of the plasma. The atoms on the surface of the ceramic powder; specifically, in this step, argon is usually chosen as the working gas because it is an inert gas with stable chemical properties and will not react with... The ceramic powder undergoes a chemical reaction, ensuring the purity of the cleaning and activation processes. After the glow discharge radio frequency power supply generates plasma, the plasma atmosphere formed by the ionization of the working gas contains a large number of high-energy particles, such as argon ions. These argon ions are accelerated under the influence of the electric field, bombarding the surrounding environment at extremely high speeds. On the surface of ceramic powder, during bombardment, argon ions knock away residual impurities, contaminants, and unstable atomic layers adsorbed on the ceramic powder surface, achieving deep cleaning and bringing the ceramic powder surface to an atomic level of cleanliness. Simultaneously, the bombardment by high-energy argon ions breaks some chemical bonds on the ceramic powder surface atoms, activating surface atoms and increasing their activity. This creates more favorable conditions for subsequent cobalt deposition, improving the bonding ability between cobalt and the ceramic powder surface, thereby enhancing the quality and adhesion of the coating layer.

[0038] Step Six: Cobalt Deposition. The sputtering device for the cobalt target is activated, causing cobalt atoms on the target surface to be sputtered out. Driven by the plasma, the cobalt atoms are uniformly deposited on the target. The ceramic powder surface; specifically, in this step, after starting the sputtering device for the cobalt target, by precisely controlling sputtering parameters such as sputtering power and working gas pressure, it is ensured that cobalt atoms on the surface of the cobalt target can be sputtered at a suitable rate. Driven by plasma, these sputtered cobalt atoms acquire certain energy and directionality, thus enabling them to be uniformly deposited on the surface after argon ion bombardment cleaning and surface activation. On the surface of ceramic powder. During the deposition process, cobalt atoms interact with activated atoms on the surface of ceramic powder to form stable chemical bonds, further enhancing the bonding force between cobalt and the ceramic powder surface, laying the foundation for the formation of a high-quality coating layer.

[0039] Step seven: cooling and taking out, after the deposition is completed, the sputtering device and the plasma source are closed, the working gas is stopped, the temperature in the vacuum chamber is naturally cooled to room temperature, then the air is slowly put in to release the vacuum state, and the coated ceramic powder surface coated with cobalt composite powder; specifically, in this step, after the deposition is completed, the sputtering device and the plasma source are closed and the working gas is stopped, which is a necessary operation step, which can avoid unnecessary energy consumption and possible safety problems such as overheating of the equipment caused by continuous operation of the equipment. Let the temperature in the vacuum chamber naturally cool to room temperature, because if you use rapid cooling, the sudden change in temperature may cause stress inside the coated composite powder, affecting the performance and structural stability of the powder. Slowly put in air to release the vacuum state, in order to prevent the rapid influx of external air causing a sharp change in pressure in the chamber, such a sudden change in pressure may impact the coating layer, causing cracks, peeling and other defects in the coating layer. Finally, the coated ceramic powder surface coated with cobalt composite powder, these composite powders have good performance after a series of rigorous process steps, and can provide high-quality raw materials for subsequent ultra-high-speed laser cladding and other applications.

[0040] Step eight: quality detection and control: the prepared composite powder is comprehensively detected, including using a scanning electron microscope to observe the surface morphology of the composite powder and the uniformity of the coating layer, using an energy spectrum analyzer to detect the content and distribution of cobalt in the coating layer, and using an X-ray diffractometer to analyze the phase structure of the composite powder, etc. According to the test results, adjust the PVD process parameters in time to ensure the quality of each batch of composite powder is stable and the performance meets the requirements. Specifically, in this step, the surface morphology of the composite powder and the uniformity of the coating layer are observed by scanning electron microscope, which can directly see the cobalt coating layer on The coverage of the ceramic powder surface, whether there is agglomeration, uneven deposition and other problems. If the coating is found to be uneven, it can be analyzed whether the powder dispersion device is working abnormally in the PVD process, or the sputtering parameter setting is unreasonable, etc. to cause, and then adjust the corresponding link. The content and distribution of cobalt in the coating layer can be accurately known by using a spectrometer to detect the content and distribution of cobalt in the coating layer. If the content of cobalt is low or unevenly distributed, it may be that the sputtering efficiency of the cobalt target is not high, or the gas flow system does not uniformly guide the cobalt atoms to the surface of the ceramic powder, so as to optimize the equipment or parameters. The phase structure of the composite powder can be analyzed by X-ray diffractometer to determine whether new phases are generated during preparation or whether the original phase has changed. If abnormal phases appear, it may be that the process parameters such as preheating temperature and cobalt deposition time are not properly controlled, affecting the phase structure of the powder, and the process parameters can be corrected accordingly. According to these test results, the PVD process parameters are adjusted in time, such as adjusting the operating parameters of the powder dispersion device, optimizing the design of the gas flow system, changing the sputtering power and working gas pressure, adjusting the preheating temperature and time, etc. to ensure the quality of each batch of composite powder is stable and the performance meets the requirements, providing reliable and high-quality ceramic composite powder materials for ultra-high-speed laser cladding.

[0041] Further, the step one includes The particle size distribution of the ceramic powder is 15-45 µm. Specifically, in this embodiment, powders with a particle size less than 10 µm have extremely high specific surface area and surface energy, and are extremely prone to agglomeration. In the PVD vacuum chamber, this agglomeration phenomenon will cause the powder to be unable to be effectively dispersed and fluidized, and the surface of a large number of particles cannot be exposed to cobalt atom vapor, thereby causing the coating layer to be extremely uneven in thickness, and even some particles are not coated at all. By setting the lower limit of 15 µm, the agglomeration effect caused by van der Waals force can be significantly reduced, and the good dispersibility of the powder in the subsequently designed powder dispersion system can be ensured; and ceramic powder with a particle size greater than 50 µm may not be completely melted in a very short heating time due to its high melting point and low thermal conductivity. Unmelted particles will exist in the form of "inclusions" in the cladding layer, mechanically combined with the metal melt, becoming the source of cracks, and severely weakening the compactness and bonding strength of the coating. By controlling the upper limit of the particle size to 45 µm, it is ensured that under typical ultra-high-speed cladding parameters, most particles can be fully melted or at least reach the melting-reaction state; therefore, by precisely controlling the particle size of the powder in the narrow distribution range of 15-45 µm, the contradiction between the uniformity of PVD coating and the adaptability of ultra-high-speed laser cladding is solved at the source, laying a foundation for the preparation of high-quality composite powder and the final coating.

[0042] ​Specifically, the following parameters are used to strictly define the particle size distribution:

[0043] (1) Volume median particle size (D50): 25µm±5µm;

[0044] (2) 10% cumulative distribution particle size (D10): not less than 15µm;

[0045] (3) 90% cumulative distribution particle size (D90): not greater than 45µm;

[0046] (4) Particle size distribution width (Span): (D90-D10) / D50≤1.0, preferably≤0.8;

[0047] (5) Powder morphology: Near-spherical or sub-spherical powder is preferred to improve powder flowability and rolling probability during PVD coating process.

[0048] Furthermore, the working gas in step five is high-purity argon, with a purity ≥ 99.999%. Specifically, in this embodiment, high-purity argon with a purity of 99.999% or higher is selected because, during the argon ion bombardment cleaning and surface activation process, extremely high-purity argon gas can minimize the introduction of impurity gases into the plasma atmosphere. The presence of impurity gases may introduce new contaminants during bombardment cleaning, interfering with the process. Deep cleaning of the ceramic powder surface cannot achieve the ideal atomic-level cleanliness. Meanwhile, high-purity argon gas ensures plasma stability, guaranteeing that the number and energy of high-energy particles (such as argon ions) are within a suitable range. This allows for stable and efficient bombardment cleaning and activation of the ceramic powder surface, creating favorable conditions for the subsequent uniform deposition of cobalt.

[0049] Furthermore, in step five, the radio frequency power supply of the glow discharge is used to... The surface is subjected to plasma bombardment treatment to achieve atomic-level cleanliness. Specifically, in this embodiment, the plasma generated by the radio frequency power supply of the glow discharge has high energy characteristics. When these high-energy particles bombard... When applied to a surface, it not only removes adsorbed impurities and contaminants but also activates surface atoms. This activation effect allows... The surface atoms are in a more active state, providing favorable conditions for subsequent cobalt deposition. By precisely controlling the power and bombardment time of the glow discharge radio frequency power supply, it can be ensured that... The surface achieves atomic-level cleanliness while avoiding surface damage caused by excessive bombardment. The use of high-purity argon further ensures the purity of the process, preventing other gaseous components from affecting the surface. Surface contamination.

[0050] Furthermore, the power of the glow discharge is 50W~200W, the working pressure during the glow discharge is 0.5~10Pa, and the radio frequency power supply for the glow discharge is... The surface bombardment time is 5 to 30 minutes. Specifically, in this embodiment, the glow discharge power is 50 W to 200 W. This power range ensures stable glow discharge of the plasma, generates ions with sufficient energy for surface bombardment, and effectively controls damage to the powder matrix. The working gas pressure during the glow discharge is 0.5 Pa to 10 Pa. The working gas pressure is crucial for maintaining stable glow discharge and controlling ion behavior. This pressure needs to ensure sufficient gas molecule density to form plasma while also ensuring that the ions have sufficient mean free path to gain energy. The radio frequency power supply for the glow discharge... The surface bombardment time ranges from 5 to 30 minutes. The selection of bombardment time requires a balance between ensuring treatment effectiveness (thorough cleaning and sufficient activation) and avoiding material damage (oversplashing or particle agglomeration). For chemically stable surfaces... Ceramic powder requires sufficient time to process.

[0051] Furthermore, the aforementioned After the surface is subjected to plasma bombardment treatment, the The surface forms dangling bonds, lattice defects, and step structures for cobalt atom deposition. Specifically, in this embodiment, after plasma bombardment treatment by a glow discharge radio frequency power supply, Significant microstructural changes occurred on the surface. The originally smooth surface is now covered with dangling bonds, lattice defects, and step structures. These unique surface features provide ideal sites for cobalt atom deposition. The presence of dangling bonds means that surface atoms have unsaturated chemical bonds, which are eager to combine with other atoms to achieve a stable state. Therefore, cobalt atoms are easily captured by these dangling bonds and form stable chemical bonds. Lattice defects, on the other hand, break... The periodic structure of the surface provides more embedding sites for cobalt atoms, contributing to the formation of a uniform and dense coating layer. The stepped structure, on the other hand, increases the surface roughness, further enhancing the ability of cobalt atoms to... Surface adhesion and deposition efficiency. These microstructural changes work together to improve the adhesion and deposition efficiency of surfaces treated with plasma bombardment. The surface becomes an ideal substrate for cobalt atom deposition, laying a solid foundation for the subsequent preparation of high-quality ceramic composite powders.

[0052] Furthermore, the aforementioned After surface plasma bombardment treatment, the film formation mode is either layered growth or island-layer hybrid growth. Specifically, in this embodiment, after plasma bombardment treatment... The surface underwent significant changes in its microstructure, providing ideal nucleation sites for cobalt atom deposition. When cobalt atoms begin to deposit, if the surface energy is low and cobalt... The wettability between them is good, and the film formation mode tends to be layered growth, that is, cobalt atoms cover the film layer by layer. On the surface, a continuous and uniform coating layer is formed. This growth mode helps to obtain a coating layer with high smoothness and strong adhesion, improving the overall performance of the composite powder. However, in the actual deposition process, due to... Local energy differences or fluctuations in cobalt atom deposition rates may exist on the surface, potentially leading to a hybrid island-layer growth pattern. In this case, cobalt atoms initially form island-like structures at higher surface energies. As deposition continues, these island-like structures gradually expand and connect, eventually forming a coating layer covering the entire surface. While this hybrid growth pattern may result in some surface roughness in the coating layer, it adapts to a wider range of deposition conditions, ensuring relatively stable composite powder quality under different process parameters. Therefore, in actual production, deposition parameters need to be flexibly adjusted according to specific process requirements and raw material characteristics to optimize the film formation pattern and prepare high-performance ceramic composite powders.

[0053] Furthermore, in step six, the sputtering method of the sputtering device is DC magnetron sputtering, with a sputtering power of 3-6 kW and a working gas pressure of 0.3-0.9 Pa during the sputtering process. Specifically, in this embodiment, the sputtering power is set within the range of 3 kW to 6 kW to ensure that cobalt atoms can be effectively sputtered while avoiding excessive power leading to excessive equipment wear and instability in the sputtering process. The working gas pressure is controlled at 0.3 to 0.9 Pa because under this pressure condition, the plasma state is relatively ideal, allowing cobalt atoms to be better deposited under the drive of the plasma. On the surface of ceramic powder. If the working gas pressure is too low, the plasma density will be insufficient, reducing the deposition efficiency of cobalt atoms; if the working gas pressure is too high, it may affect the movement trajectory of cobalt atoms, leading to uneven deposition. By setting these parameters, it can be ensured that cobalt atoms are deposited on the surface of ceramic powder at an appropriate rate and state, guaranteeing the formation of a high-quality coating layer.

[0054] Example 1

[0055] A ceramic composite powder forming process for ultra-high-speed laser cladding includes the following steps:

[0056] Step 1: Raw material preparation, selecting materials with a purity of not less than 99%. Ceramic powder is used as raw material, and a cobalt target with a purity of over 99.9% is prepared as the cobalt source in the PVD coating process;

[0057] Step 2: PVD equipment preparation. A plasma-enhanced physical vapor deposition (PVD) system is used, and a powder dispersion device and a gas flow system are installed in the vacuum chamber of the equipment.

[0058] Step 3: Vacuum extraction, After the ceramic powder is placed into the vacuum chamber of the PVD equipment, the vacuum pump is started to evacuate the air pressure inside the chamber to 5.0 x 10⁻⁻⁻⁶. 4 Below Pa;

[0059] Step 4: Preheating, under vacuum conditions, for The ceramic powder was preheated at 350℃ for 90 minutes. Water molecules and organic pollutants adsorbed on the surface of ceramic powder can be fully desorbed, resulting in an atomically clean and highly active surface to be deposited. At the same time, the powder sintering phenomenon is avoided, ensuring the fluidization performance of the powder and laying a good foundation for the uniform deposition of cobalt.

[0060] Step 5: Argon ion bombardment cleaning and surface activation. A working gas is introduced, and plasma is generated by a glow discharge radio frequency power supply. This ionizes the working gas to form a plasma atmosphere, further activating the surface under the influence of the plasma. The atoms on the surface of the ceramic powder; the power of the glow discharge is 50W, the working gas pressure during the glow discharge process is 0.5Pa, and the bombardment time of the surface by the radio frequency power supply of the glow discharge is 5min. Under these conditions, the plasma glow discharge is stable, and the ion energy is moderate, which can effectively remove... Impurities and contaminants on the surface of ceramic powder can be removed without causing excessive damage to the powder matrix. At the same time, the lower working gas pressure ensures that the ions have sufficient mean free path to gain energy, thereby improving the efficiency of bombardment cleaning and activation.

[0061] Step Six: Cobalt Deposition. The sputtering device for the cobalt target is activated, causing cobalt atoms on the target surface to be sputtered out. Driven by the plasma, the cobalt atoms are uniformly deposited on the target. Under sputtering power of 3kW and working pressure of 0.3Pa on a ceramic powder surface, cobalt atoms on the cobalt target surface can be sputtered at a relatively stable and suitable rate. The lower sputtering power avoids excessive energy input that could cause excessive equipment wear and tear, reducing potential problems such as overheating and component damage caused by excessive power, thus ensuring the long-term stable operation of the sputtering device. Simultaneously, the 0.3Pa working pressure ensures that the plasma is in a relatively ideal state, with particles possessing suitable energy and density. In this plasma environment, the sputtered cobalt atoms acquire appropriate energy and directionality, allowing them to be sputtered relatively uniformly towards... The cobalt atoms deposited on the surface of the ceramic powder move smoothly and are successfully deposited on the surface of the ceramic powder after plasma bombardment cleaning and surface activation. Under these conditions, the deposited cobalt atoms and the activated atoms on the ceramic powder surface can fully interact to form relatively stable and uniform chemical bonds, thereby forming a high-quality coating layer with good adhesion, laying a good foundation for the subsequent preparation of high-performance ceramic composite powders.

[0062] Step 7: Cooling and Removal. After deposition, turn off the sputtering device and plasma source, stop the supply of working gas, and allow the temperature inside the vacuum chamber to cool naturally to room temperature. Then, slowly introduce air to release the vacuum and remove the coated material. Composite powder with cobalt coated on the surface of ceramic powder;

[0063] Step 8: Quality Inspection and Control: Conduct comprehensive quality inspections on the prepared composite powder, including using a scanning electron microscope to observe the surface morphology and uniformity of the coating layer, using an energy dispersive spectroscopy (EDS) analyzer to detect the cobalt content and distribution in the coating layer, and using an X-ray diffractometer to analyze the phase structure of the composite powder. Based on the test results, adjust the PVD process parameters in a timely manner to ensure that the quality of each batch of composite powder is stable and its performance meets the requirements.

[0064] Example 2

[0065] A ceramic composite powder forming process for ultra-high-speed laser cladding differs from Example 1 in that: (1) the preheating temperature in step four is 450℃ and the preheating holding time is 45min. Under these conditions, the powder surface can be purified while effectively preventing powder sintering, and the production efficiency is improved to a certain extent, while reducing energy consumption; (2) the power of the glow discharge in step five is 100W, the working gas pressure during the glow discharge process is 5Pa, and the radio frequency power supply of the glow discharge is... The surface was bombarded for 15 minutes. Under these conditions, the plasma glow discharge was more stable, the ion energy was higher, and the cleaning and activation were more thorough. Ceramic powder surface. At the same time, the appropriate working pressure and bombardment time balance the relationship between the treatment effect and material damage, ensuring high-quality treatment of the powder surface; (3) When the sputtering power in step six is ​​6kW and the working pressure is 0.9Pa, under this sputtering power and working pressure conditions, the cobalt atoms on the surface of the cobalt target material obtain higher energy and can be sputtered at a faster rate. Although the higher sputtering power increases the energy consumption of the equipment, it also improves the sputtering efficiency, so that more cobalt atoms participate in the deposition process in the same time. At the same time, the working pressure of 0.9Pa makes the plasma more active, and the particle energy and density are relatively high. This environment causes the sputtered cobalt atoms to rush towards the surface with higher kinetic energy. The ceramic powder surface is purified, which effectively removes adsorbed water molecules and impurities and avoids powder sintering, so that the powder surface presents a suitable active state, laying a good foundation for subsequent uniform deposition of cobalt atoms.

[0066] Example Three

[0067] A ceramic composite powder forming process for ultra-high-speed laser cladding differs from Example One in that: (1) the preheating temperature in Step Four is 400°C, and the preheating holding time is 65 min. Under these conditions, The ceramic powder surface is effectively purified, which effectively removes adsorbed water molecules and impurities and avoids powder sintering, so that the powder surface presents a suitable active state, laying a good foundation for subsequent uniform deposition of cobalt atoms. (2) The power of the glow discharge in Step Five is 200 W, the working gas pressure during the glow discharge process is 10 Pa, and the bombardment time of the radio frequency power source of the glow discharge on the ceramic powder surface is 30 min. Under these conditions, the plasma glow discharge reaches a high level, and the ion energy is sufficient to deeply clean and fully activate the ceramic powder surface. Although the working gas pressure and bombardment time are relatively high, for chemically stable ceramic powder, it can still ensure the treatment effect while avoiding excessive damage. (3) The sputtering power in Step Six is 4 kW, and the working gas pressure is 0.6 Pa. Under these sputtering power and working gas pressure conditions, cobalt atoms on the cobalt target surface are sputtered at a moderate rate. A sputtering power of 4 kW will not cause insufficient sputtering efficiency due to low energy, nor will it cause excessive equipment wear and unstable sputtering process due to high energy. A working gas pressure of 0.6 Pa allows the plasma to be in a relatively moderate state, with moderate particle energy and density in the plasma. In such a plasma environment, sputtered cobalt atoms can obtain suitable energy and directionality, and they can move relatively uniformly toward the ceramic powder surface and effectively deposit on the ceramic powder surface that has been cleaned and activated by plasma bombardment. At this time, cobalt atoms and activated atoms on the ceramic powder surface can fully interact to form stable and uniform chemical bonds, thereby forming a coating layer with good quality and moderate adhesion. The ceramic composite powder prepared under these conditions has a cobalt coating layer with good overall performance, which can meet the needs of most conventional application scenarios.

[0068] ​​The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A ceramic composite powder forming process for ultra-high speed laser cladding, characterized in that: Comprising the following steps: Step 1: raw material preparation, select the purity of not less than 99% ceramic powder as raw material, and prepare cobalt target material with purity of 99.9% or above as cobalt source in PVD coating process; Step two: PVD equipment preparation, using a plasma enhanced physical vapor deposition equipment, installing a powder dispersion device and a gas flow guide system in the vacuum chamber of the equipment; Step three: vacuum, put the ceramic powder into the vacuum chamber of the PVD equipment, start the vacuum pump, and vacuum the chamber to 5.0x10⁻ After the ceramic powder is put into the vacuum chamber of the PVD equipment, the vacuum pump is started, and the air pressure in the chamber is vacuumed to 5.0x10⁻ 4 Pa below; Step four: preheating, in a vacuum state, preheating the ceramic powder to a temperature of 350-450°C and maintaining for 45-90 min; Step four: preheating, in a vacuum state, preheating the ceramic powder to a temperature of 350-450°C and maintaining for 45-90 min; Step five: argon ion bombardment cleaning and surface activation, working gas is introduced, and plasma is generated by the radio frequency power of glow discharge to ionize the working gas to form a plasma atmosphere, which further activates atoms on the surface of the ceramic powder; Step six: cobalt deposition, start the sputtering device of cobalt target material, so that cobalt atoms on the surface of the cobalt target material are sputtered out, under the driving of plasma, the cobalt atoms are uniformly deposited on the surface of the ceramic powder ceramic powder Step seven: cooling and taking out, after the deposition is completed, the sputtering device and the plasma source are closed, the working gas is stopped, the temperature in the vacuum chamber is naturally cooled to room temperature, then the air is slowly put in to release the vacuum state, and the coated Ceramic powder coated with cobalt composite powder; Step eight: quality detection and control: the prepared composite powder is comprehensively detected, including observing the surface morphology of the composite powder and the uniformity of the coating layer by using a scanning electron microscope, detecting the content and distribution of cobalt in the coating layer by using an energy spectrum analyzer, analyzing the phase structure of the composite powder by using an X-ray diffractometer, according to the detection results, timely adjusting the PVD process parameters, and ensuring that the quality of each batch of composite powder is stable and the performance meets the requirements.

2. The ceramic composite powder forming process for ultra-high speed laser cladding according to claim 1, characterized in that: The step one in The ceramic powder has a particle size distribution of 15 to 45 µm.

3. The ceramic composite powder forming process for ultra-high speed laser cladding according to claim 1, characterized in that: The working gas in the step five is high-purity argon, and the purity of the high-purity argon is ≥99.999%. 4.The ceramic composite powder forming process for ultra-high-speed laser cladding according to claim 1, characterized in that: In the fifth step, the surface is subjected to plasma bombardment treatment by means of a radio frequency power supply for glow discharge to obtain an atomically clean surface . 5.The ceramic composite powder forming process for ultra-high-speed laser cladding according to claim 4, characterized in that: The power of the glow discharge is 50W~200W, the working pressure during the glow discharge is 0.5~10Pa, and the radio frequency power supply of the glow discharge is... The surface bombardment time is 5 min to 30 min. 6.The ceramic composite powder forming process for ultra-high-speed laser cladding according to claim 4, characterized in that: The The surface is subjected to a plasma bombardment treatment, which forms dangling bonds, lattice defects and step structures on the surface for the deposition of cobalt atoms. The surface is subjected to a plasma bombardment treatment, which forms dangling bonds, lattice defects and step structures on the surface for the deposition of cobalt atoms.

7. The ceramic composite powder forming process for ultra-high speed laser cladding according to claim 4, characterized in that: The After the surface is treated by plasma bombardment, the film formation mode is layer growth or island-layer mixed growth. 8.The ceramic composite powder forming process for ultra-high-speed laser cladding according to claim 1, wherein: The sputtering mode of the sputtering device in the step six is direct current magnetron sputtering, the sputtering power is 3-6 kW, and the working gas pressure in the sputtering process is 0.3-0.9 Pa.

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