Powder particle surface micro-shaping method and device

Abstract

The invention relates to a powder particle surface micro-shaping method and a powder particle surface micro-shaping device. The powder particle surface micro-shaping method comprises the following steps: grinding powder particles in a grinding system by adopting a grinding medium under a preset temperature condition; gas is conveyed into the grinding system; the gas can stir powder particles and drive the powder particles to be in contact with the grinding medium; and when the mass of the powder particles meets the preset mass requirement, the powder particles are driven out of the grinding system by the gas. The technical problem to be solved is how to provide the powder particle surface micro-shaping method, corners of powder particles in irregular shapes are trimmed, polished and rounded, the powder particles are processed into powder particles with uniform sizes and regular shapes, and the flowability of slurry prepared from powder is improved.

Description

Technical Field

[0001] The present invention belongs to the field of powder technology, and in particular relates to a powder particle surface micro-shaping method and a device thereof. Background Art

[0002] Currently, powders such as silicon carbide, silicon nitride, and aluminum oxide are widely used in electronics, optoelectronics, ceramics, coatings, catalysts, and other fields due to their low density, high temperature resistance, and high Mohs hardness. However, due to their high hardness and low density, these powders often suffer from irregular shapes (such as angular shapes) and easy agglomeration during production and preparation. This in turn affects the flowability of the slurry prepared with these powders, ultimately affecting product quality.

[0003] In order to improve the fluidity of the slurry prepared by the above-mentioned powder, the traditional method often uses a separate mechanical ball milling method and a separate high-temperature calcination method to perform surface micro-shaping on the powder particles. Among them, the separate mechanical ball milling method can effectively grind the powder into fine powder, and during the grinding process, some of the edges and corners on the surface of the powder particles are polished to make them spherical, so as to improve the fluidity of the prepared slurry. However, the separate mechanical ball milling method is difficult to accurately control the shape of the powder particles. The surface of the powder particles after grinding is rough, and it is difficult to accurately control the quality of the powder surface. Therefore, the use of only mechanical ball milling method to improve the fluidity of the slurry prepared by the powder by accurately controlling the surface quality of the powder is limited. And for micron-sized powder particles, the separate mechanical ball milling method requires at least 4 hours, which takes a long time and has a large mechanical force. It is not only easy to introduce ball-milling impurities, but also has low production efficiency. High-temperature calcination alone can be used to perform micro-reshaping on the surface of powder particles. However, due to the high calcination temperature, it is easy to cause powder particles to agglomerate, and the shape and surface quality of the resulting powder particles are also uncontrollable. In addition, too high a calcination temperature may have a negative impact on the chemical properties of the powder particles, ultimately affecting the quality of the product.

[0004] In summary, how to propose a powder particle surface micro-shaping method based on traditional methods, so that the surface shape of the powder particles treated by this method can be controlled, the surface quality of the powder particles can be improved, and the fluidity of the slurry prepared with the powder can be improved, is a technical difficulty to be overcome in this field. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method and device for micro-shaping the surface of powder particles. The technical problem to be solved is to sphericalize the powder particles, control the surface shape of the powder particles, improve the surface quality of the powder particles, and improve the fluidity of the slurry prepared with the powder; and the shaping efficiency is high.

[0006] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. According to the present invention, a method for micro-shaping the surface of powder particles is proposed, which includes the following steps:

[0007] The powder particles are ground in a grinding system using grinding media under preset temperature conditions; gas is delivered into the grinding system; the gas can stir the powder particles and drive them into contact with the grinding media; and the powder particles are driven out of the grinding system by the gas when the quality meets the preset quality requirements.

[0008] Preferably, in the aforementioned surface micro-shaping method, the gas drives the powder particles to flow from a low position to a high position in the grinding system.

[0009] Preferably, in the aforementioned surface micro-shaping method, the powder particles have a temperature resistance of ≥1000°C, a Mohs hardness of 8 to 10, and an elastic modulus of ≥300 GPa.

[0010] Preferably, in the aforementioned surface micro-shaping method, the powder particles are any one of aluminum oxide, aluminum nitride, silicon nitride, and silicon carbide.

[0011] Preferably, in the aforementioned surface micro-shaping method, the gas is appropriately selected from any one of air, nitrogen, argon and helium.

[0012] Preferably, in the aforementioned surface micro-shaping method, the ratio of the total mass of all grinding media to the total mass of all powder particles in the grinding system is 3 to 8:1.

[0013] Preferably, in the aforementioned surface micro-shaping method, the gas flows out from the rotating structure at a rotation speed of n1 to stir the powder particles; the grinding system drives the grinding media to rotate at a rotation speed of n2; the powder particle size D 50 ≤100μm, n1 is 500~2000rpm, n2 is 100~600rpm.

[0014] Preferably, in the aforementioned surface micro-shaping method, the gas is fed into the grinding system to meet the following conditions: the total mass of the powder particles in the grinding system is M, the flow rate of the gas input per cubic meter of the grinding system is S; under standard atmospheric pressure, 0.1 kg ≤ M < 3 kg, S is 0.5 to 1.2 m 3 / s; 3kg≤M<10kg, S is 1.5~3m 3 / s; when M≥10kg, S is 3.5~5m 3 / s.

[0015] Preferably, in the aforementioned surface micro-shaping method, small grinding balls with a diameter of 3 to 6 mm and large grinding balls with a diameter of 8 to 12 mm are mixed and ground; the mass ratio of the small grinding balls to the large grinding balls is 3 to 5:1.

[0016] Preferably, in the aforementioned surface micro-shaping method, the powder particles are aluminum oxide, the preset temperature is 300-500° C., the n1 is 800-1500 rpm; and the n2 is 300-500 rpm.

[0017] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0018] The present invention also provides a powder particle surface micro-shaping device, which comprises:

[0019] A mixing system, the mixing system comprising a mixing drum; the axis of the mixing drum forms an angle θ with the horizontal plane, and 0°C < θ ≤ 30°C; the mixing drum is further provided with a feed port and a discharge port;

[0020] An air intake system, the air intake system comprising an air intake channel; the air intake channel has a rotating structure inside;

[0021] A heating system is arranged around the periphery of the mixing barrel; and

[0022] A transmission system is connected to the mixing drum; the transmission system can drive the mixing drum to rotate.

[0023] Preferably, in the aforementioned micro-plastic surgery device, the temperature θ is 1 to 4°C.

[0024] Preferably, the aforementioned micro plastic surgery device is further provided with a control system; the control system is connected to the heating system, the air intake system and the transmission system;

[0025] During the operation of the micro-plastic surgery device, the control system can at least regulate the heating speed and heating time of the heating system; can regulate the ventilation flow and ventilation time of the intake system; and can regulate the rotation speed and rotation time of the transmission system.

[0026] By means of the above technical solution, the method and device for micro-shaping the surface of powder particles proposed by the present invention have at least the following advantages:

[0027] 1. The present invention provides a method for micro-shaping the surface of powder particles, which simultaneously heats and mechanically grinds the powder particles to achieve coupled thermal energy and mechanical energy, so as to better remove sharp corners and edges on the surface of the powder particles; and gas is transported in the grinding system and stirred by the gas, so that it has a dispersing effect on the powder particles, reducing or even avoiding the adhesion and agglomeration of the powder particles during the heating process, so that the powder particles are polished and trimmed by the grinding medium, and the gas evenly disperses the powder particles and the grinding medium, and drives the powder particles to collide, rub and shear with the grinding medium and the inner wall of the grinding system, further promoting the grinding and trimming of irregular sharp corners and edges on the surface of the powder particles by the grinding medium and the inner wall of the grinding system, which is beneficial to the sphericalization of the powder particles; the present invention The gas input into the grinding system also has a lubricating effect, forming a gas lubrication protective film between the powder particles and the grinding media, reducing the burrs on the grinding surface formed by the powder particles and the grinding media, reducing the roughness of the grinding surface, and facilitating the spheroidization of the powder particles; in addition, the input gas can also promptly remove the heat generated by the local grinding of the powder particles, so as to stabilize the temperature of the grinding system and avoid the influence of excessive temperature on the chemical properties of the powder particles; more importantly, the grinding surface formed by the powder particles after grinding with the grinding media is rough, and the gas can further finely grind the aforementioned grinding surface to make it smoother, which is conducive to forming powder particles with uniform and regular shapes and improving the surface quality of the powder particles, thereby helping to improve the fluidity of the slurry prepared with the powder.

[0028] Furthermore, in the process of powder particles being ground in the grinding system, many tiny powder particles will be generated on the surface of the powder particles, and the gas can blow off the tiny powder generated by the grinding of the powder particles in time, so that it can be separated from the grinding system in time; and, since the sharp corners and edges on the surface of the powder particles are removed to achieve sphericalization, the particle size and mass of the powder particles are correspondingly reduced. The present invention drives the powder particles by gas to achieve grading of the powder particles according to quality, and the powder particles that meet the quality requirements are driven out of the grinding system by the gas in time; the present invention will complete the shaping of the powder particles and separate them from the grinding system in time, which not only helps to avoid the problem of reaggregation of the shaped powder particles due to the inability to escape in time, so as to ensure the shaping effect, but also helps to improve efficiency. Therefore, the powder particle surface micro-shaping method provided by the present invention is adopted to achieve sphericalization of the powder particles, with uniform and regular shapes, improve the fluidity of the slurry prepared by the powder, and has high efficiency, simple process, and is convenient for production and use.

[0029] 2. The present invention also provides a device for micro-shaping the surface of powder particles. Through this device, powder particles are mechanically ground at a high temperature, and gas is introduced into the grinding system. The gas forms a rotating gas through a rotating structure. The rotating gas can stir the powder particles in the mixing barrel, so that the powder particles are fully mixed and contacted with the grinding medium, thereby driving the powder particles and the grinding medium and the inner wall of the mixing barrel to collide, rub, and shear, which helps to enhance the micro-shaping effect of the powder particle surface and accelerate the micro-shaping of the powder particle surface. In addition, the angle θ formed by the axis of the mixing barrel and the horizontal plane is 0°C < θ ≤ 30°C, which prevents the powder particles and the grinding medium from gathering at the lower position of the mixing barrel. After the gas is introduced into the mixing barrel, the powder particles are driven by the gas in the mixing barrel and can gradually flow from a low position to a high position. The smaller the mass of the powder particles, the higher their position in the mixing barrel, thereby achieving quality classification of the powder particles in the mixing barrel. Powder particles that meet the preset quality standards are driven out of the mixing barrel by the gas. Therefore, the powder particle surface micro-shaping device provided by the present invention can achieve rapid shaping of the powder particle surface with good shaping effect, simple process, low cost and practical application.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 .Schematic diagram of the powder particle surface micro-shaping device;

[0032] Figure 2 .Details of the device for micro-shaping the surface of powder particles. DETAILED DESCRIPTION

[0033] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following, in combination with the accompanying drawings and preferred embodiments, describes in detail the specific implementation method, structure, characteristics and effects of a powder particle surface micro-shaping method and device proposed by the present invention.

[0034] The term "powder particles" refers to small particles; preferably, the powder particles of the present invention are micron particles. The "powder" hereinafter refers to an aggregate composed of a large number of powder particles of the present invention.

[0035] The present invention provides a method for micro-shaping the surface of powder particles, which comprises the following steps:

[0036] The powder particles are ground using grinding media under preset temperature conditions in a grinding system; the grinding system is a mixed reaction system for grinding the powder particles. Under the preset temperature conditions, the powder particles do not undergo chemical changes, such as changes in the crystal structure of the powder particles and decomposition of substances.

[0037] Gas is delivered to the grinding system; the gas can stir the powder particles and drive them to contact with the grinding medium; in some embodiments, the gas introduced into the grinding system passes through a rotating structure to form a rotating gas, and the rotating gas can rotate and stir the powder particles, thereby driving the powder particles and the grinding medium and the inner wall of the grinding system to contact and rub, thereby increasing the contact area between the powder particles and the grinding medium and the inner wall of the grinding system per unit time, thereby driving the powder particles to collide, rub and shear with the grinding medium and the inner wall of the grinding system, promoting the grinding and trimming of irregular sharp corners and edges on the surface of the powder particles by the grinding medium, and accelerating the surface micro-shaping of the powder particles; the gas stirring the powder particles also helps to disperse the powder particles The performance is better, and the re-agglomeration of powder particles that have been shaped is avoided. In addition, since the grinding surface formed in the process of grinding the powder particles by the grinding medium is generally rough and the surface quality of the powder particles is poor, the use of the gas to stir the powder particles can, on the one hand, form a gas lubrication protection layer between the grinding medium and the powder particles in time, thereby improving the surface quality of the powder particles. Moreover, the high-speed rotation of the gas in the grinding system can further finely grind the powder particles, making the powder particles smaller in size and the grinding surface smoother, so as to make the powder particles more uniform and regular in shape, and the surface quality of the powder particles is better. The present invention effectively balances the grinding medium, temperature, and the effect of the rotating gas on the powder particles, so that the powder particles have a good shaping effect and high shaping efficiency.

[0038] Furthermore, when the quality of the powder particles meets the preset quality requirements, they are driven out of the grinding system by the gas. During the grinding process of the powder particles in the grinding system, many tiny powder particles will be generated on the surface of the powder particles. The gas can promptly blow off the tiny powder generated by the grinding on the surface of the powder particles, so that they can be promptly separated from the grinding system. In addition, since the edges and corners of the powder particles are continuously polished during the sphericalization process, the particle size and mass of the powder particles will gradually decrease. Therefore, the present invention conveys gas into the grinding system so that the powder particles are graded according to the quality of the powder particles under the drive of the gas. When the quality of the powder particles meets the preset quality requirements, they are driven out of the grinding system by the gas. Powder particles that do not meet the preset quality requirements will continue to be ground under heating conditions in the grinding system. Under these conditions, the powder particles that have completed surface shaping are collected in a timely manner, which not only helps to improve the grinding efficiency, but also helps to avoid the problem of re-agglomeration of the shaped powder particles due to failure to be removed in time, thereby ensuring the shaping effect.

[0039] By adopting the aforementioned technical solution of the present invention, the powder particles are effectively polished and trimmed by coupling the effects of thermal energy and mechanical energy on the powder particles, so that they are formed into spherical particles. The shape of the powder particles is uniform and regular, which improves the fluidity of the slurry prepared with the powder. The shaping effect is good, the shaping efficiency is high, the process is simple, and it is easy to produce and use.

[0040] Preferably, in the aforementioned technical solution, the gas drives the powder particles from a lower position to a higher position in the grinding system. Under the driving action of the gas, the kinetic energy exerted on the powder particles by the gas is partially converted into gravitational potential energy; the smaller the mass of the powder particle, the higher its position in the grinding system, thereby achieving mass-based classification of the powder particles. This method is simple and easy to operate.

[0041] Preferably, in the aforementioned technical solution, during the shaping process of the powder particles, the grinding system has a channel connected to the outside air, and the gas drives the powder particles in the grinding system out of the grinding system along this channel. This arrangement not only promotes good gas flow within the grinding system, but also helps to prevent excessive heat accumulation in the grinding system, thereby preventing the impact of heat accumulation on the calcination and micro-shaping of the powder.

[0042] Preferably, the aforementioned technical solution is particularly suitable for powder particles with a temperature resistance of ≥1000°C, a Mohs hardness of 8 to 10, and an elastic modulus of ≥300GPa. The reason is that such powder particles are widely used in the fields of electronics, optoelectronics, ceramics, coatings, catalysts, etc., but due to the high hardness and low density of the powder particles, there are generally irregular shapes (such as containing sharp edges, etc.), and problems such as easy agglomeration, which make the fluidity of the slurry prepared by the powder poor, affecting the quality of the above-mentioned field products prepared by such powders. However, the surface micro-shaping method of the powder particles provided by the present invention is used to perform surface micro-shaping on such powder particles, which not only has a good shaping effect, but also improves the shaping efficiency, shortens the mechanical grinding time, reduces or even avoids the introduction of grinding media into the powder finally obtained, thereby ensuring the purity of the powder, and does not introduce other substances during the shaping process, thereby being able to achieve high purity and powder particles with good fluidity of the prepared slurry, which is particularly important for the quality of products in the fields of electronics, optoelectronics, ceramics, coatings, catalysts, etc.

[0043] Preferably, in the aforementioned technical solution, the powder particles are any one of aluminum oxide, aluminum nitride, silicon nitride, and silicon carbide. This type of powder particles is often used as raw materials for preparing products in the fields of electronics, optoelectronics, ceramics, etc. due to its advantages of low density, high temperature resistance, and high Mohs hardness. In addition, this type of powder particles all have problems such as irregular shape (such as containing sharp edges, etc.), low density, and easy agglomeration. The surface micro-shaping method of the powder particles disclosed in the present invention is used to perform surface micro-shaping on this type of powder particles. Not only is the shaping effect good, but the shaping efficiency is also high. During the shaping process, the introduction of impurities into the powder particles is reduced or even avoided, thereby ensuring the purity of the powder particles, which is beneficial to the preparation of subsequent products and the improvement of quality.

[0044] Preferably, in the aforementioned technical solution, the purity of the powder particles is ≥99.5%; this is because the present invention is different from the prior art, and no other chemical reagents are added during the shaping process of the powder particles. Therefore, the product obtained by the powder particle surface micro-shaping method of the present invention has high purity and is easy to be applied to the surface micro-shaping of high-purity powder particles.

[0045] Preferably, in the above technical solution, the gas is selected from any one of air, nitrogen, argon and helium. The gas delivered by the grinding system can be determined according to the properties of the powder particles, and the delivered gas does not chemically react with the powder particles.

[0046] Preferably, in the aforementioned technical solution, the total mass ratio of all grinding media to the total mass of all powder particles in the grinding system is 3 to 8:1; the mass ratio of the total mass of the grinding media to the total mass of the powder particles is strictly limited, so that the particles in the powder particles are fully polished and trimmed by the grinding media, ensuring that the powder particles are better subjected to surface micro-shaping, ensuring the sphericalization of the shaped powder particles, and improving the fluidity of the prepared slurry; avoiding the problem that the powder particles are polished due to insufficient grinding media, and thus avoiding the problem that insufficient trimming affects the sphericalization of the powder particles, ensuring the fluidity effect of the slurry prepared by the powder; or avoiding the problem that too much grinding media increases the driving burden of the fluid medium, affects production efficiency, and wastes resources.

[0047] Preferably, in the above technical solution, the gas is accelerated by the rotating structure and flows out of the rotating structure at a rotation speed of n1 to form a rotating gas, which rotates along the inner wall of the grinding system to stir the powder particles in the grinding system; at the same time, the grinding media inside the grinding system can rotate freely, and the grinding system drives the grinding media to rotate at a rotation speed of n2. When the particle size D of the powder particles is 50When the particle size is ≤100μm, the powder particles are more likely to agglomerate at higher temperatures due to their small particle size, and mechanical grinding can reduce the agglomeration effect. However, when the mechanical grinding speed is too fast, it is not conducive to reducing the agglomeration effect of the powder particles. Moreover, when the grinding speed is too fast, the powder particles generate more heat due to friction, which will affect the chemical properties of the powder particles. The present invention strictly limits n1 to 500-2000rpm and n2 to 100-600rpm, so that the powder particles are mechanically ground during the heating process, which can better balance the temperature and the effect of grinding on the agglomeration of the powder particles, and reduce or even avoid the impact on the chemical properties of the powder particles.

[0048] Further preferably, in the above technical solution, the gas is delivered to the grinding system to meet the following conditions: the total mass of the powder particles in the grinding system is M, the flow rate of the gas input per cubic meter of the grinding system is S; under standard atmospheric pressure, 0.1 kg ≤ M < 3 kg, S is 0.5 to 1.2 m 3 / s; 3kg≤M<10kg, S is 1.5~3m 3 / s; when M≥10kg, S is 3.5~5m 3 / s. This condition is obtained based on a large number of experimental studies. Under this condition, the gas can better disperse the powder particles, and can better balance the protective effect of the gas lubrication protective layer formed between the powder particles and the grinding media on the grinding surface and the grinding effect of the grinding media on the powder particles, so that the powder particles can be fully ground by the grinding media, and the formed grinding surface has better smoothness. In addition, under this condition, the gas can better fully and finely grind the powder particles, so that the powder particles finally formed are not only more uniform and regular, but also have good surface quality and smaller particle size, which ultimately significantly improves the fluidity of the slurry prepared with the powder. If the gas input is too small, the gas will not disperse the powder particles sufficiently; and the lubrication and protection effect on the grinding surface is weak, and the fine grinding effect of the gas on the powder particles is weak, which is not conducive to the formation of powder particles with good surface quality. If the gas input is too much, the powder will gain a large kinetic energy and be driven to the discharge barrel by the gas before being fully ground by the grinding media; and the gas lubrication protective layer formed between the powder particles and the grinding media is too thick, which in turn hinders the grinding of the powder particles by the grinding media and is not conducive to the surface micro-shaping of the powder particles.

[0049] Further preferably, the aforementioned technical solution utilizes a mixed grinding process using small grinding balls with a diameter of 3 to 6 mm and large grinding balls with a diameter of 8 to 12 mm; the mass ratio of the small grinding balls to the large grinding balls is 3 to 5:1. The present invention utilizes a mixed grinding process using large and small grinding balls, with a defined mass ratio, so that accumulated or agglomerated particles are ground and dispersed by the large grinding balls. The small grinding balls provide better grinding and trimming for small-particle powders or small agglomerated powders, ultimately yielding uniformly spherical powder particles and improving the fluidity of the powder-based slurry.

[0050] Further preferably, in the aforementioned technical solution, when the powder particles are alumina, when their particle size is ≤100μm, the preset temperature is 300-500℃, the n1 is 800-1500rpm; and the n2 is 300-500rpm. Under this condition, the alumina powder particles can be better surface micro-shaped, the formed powder particles have good surface quality, uniform and regular shape, the fluidity of the slurry prepared with the powder is significantly improved, and the chemical stability of the alumina powder particles is good. Preferably, the powder particle size is ≤50μm; further preferably, the powder particle size is ≤40μm; further preferably, the powder particle size is ≤30μm. The present invention strictly limits the particle size range under this process condition, can better trim and polish the surface of the powder particles, and has a better shaping effect on the powder particles.

[0051] The present invention also provides a powder particle surface micro-shaping device, which comprises:

[0052] A mixing system comprising a mixing drum; an axis of the mixing drum forms an angle θ with a horizontal plane, wherein 0°C < θ ≤ 30°C; the value of θ is not limited to an integer and can be any value within the range. The strict restriction of the value of θ helps prevent powder particles and grinding media from accumulating at the lower end of the mixing drum.

[0053] The mixing barrel is also provided with a feed port and a discharge port. In some embodiments, the feed port is provided at the lower end of the mixing barrel, and the discharge port is provided at the higher end of the mixing barrel. In other embodiments, both the feed port and the discharge port are provided at the higher end of the mixing barrel. In some embodiments, the feed port is provided at a port at the lower end of the mixing barrel. In other embodiments, the feed port is provided at the upper side of the lower end of the mixing barrel. The present invention does not impose any specific restrictions on the location of the feed port and the discharge port, as long as the powder particles can be shaped starting from the lower end of the mixing barrel.

[0054] After gas is introduced into the mixing barrel, the powder particles are driven by the gas in the mixing barrel and gradually flow from a low position to a high position. The smaller the mass of the powder particles, the higher their position in the mixing barrel, thereby realizing the quality grading of the powder particles in the mixing barrel; for powder particles that meet the preset quality standards, they will be driven out of the mixing barrel by the gas.

[0055] An air intake system includes an air intake channel; the air intake channel has a rotating structure inside; gas is introduced into the grinding system, and the gas forms a rotating gas through the rotating structure. The rotating gas can stir the powder particles, so that the powder particles are fully mixed and contacted with the grinding media, and drive the powder particles and the mechanical grinding media and the inner wall of the mixing barrel to collide, rub, and shear, thereby achieving a better surface micro-shaping effect of the powder particles, accelerating the surface micro-shaping of the powder particles, and improving production efficiency. The present invention does not specifically limit the location of the air intake channel, as long as it can achieve gas blowing of the powder particles from the lower port to the higher port of the mixing barrel.

[0056] A heating system is arranged around the periphery of the mixing barrel; in some embodiments, the heating system includes a heating element and a temperature sensor; the heating element surrounding the periphery of the mixing barrel not only helps to heat the powder particles inside the mixing barrel, but also prevents the powder particles from directly contacting the heating element, causing local excessive temperature to affect the chemical properties of the powder particles.

[0057] A transmission system is connected to the mixing drum; the transmission system is capable of driving the mixing drum to rotate. In some embodiments, during the shaping of powder particles using the powder particle surface micro-shaping device of the present invention, grinding balls are freely distributed in the mixing drum. In other embodiments, the transmission system includes gears and a motor, and the motor drives the gears to rotate, driving the mixing drum and the grinding media to rotate at the same speed.

[0058] By using the powder particle surface micro-shaping device provided by the present invention, mechanical energy and thermal energy are coupled, and the powder particles are timely graded according to quality, and the shaped powder particles are promptly driven out of the mixing barrel. The shaping effect is good, the shaping efficiency is high, the process is simple, and it is suitable for production.

[0059] Preferably, in the aforementioned technical solution, the angle θ between the axis of the mixing barrel and the horizontal plane is 1 to 4°. Under this condition, not only is it better to avoid the powder particles and the grinding ball media inside the mixing barrel from gathering at the lower port of the mixing barrel, but in the process of the powder particles being driven by gas in the mixing barrel, the powder particles obtain vector and oblique upward forces, which drive the powder particles to collide, rub and shear with the mechanically ground media and the inner wall of the mixing barrel, promote the grinding and trimming of the irregular shapes on the surface of the powder particles, and accelerate the micro-shaping of the powder particle surface; and it can better balance the gravitational potential energy that the powder particles need to overcome during the shaping process in the device described in the present invention, so that the technical solution of the present invention not only has a good shaping effect, but also has a high shaping efficiency, reducing the waste of resources.

[0060] Preferably, the aforementioned technical solution is further provided with a control system; the control system is connected to the heating system, the air intake system, and the transmission system; during the operation of the micro-plastic surgery device, the control system is capable of regulating at least the heating rate and heating time of the heating system; the ventilation flow rate and ventilation time of the air intake system; and the rotation speed and rotation time of the transmission system. This allows the various process parameters of the device to be easily and flexibly controlled during operation.

[0061] In some embodiments of the aforementioned technical solution, during the process of surface micro-shaping of powder particles by the device, grinding media, such as grinding balls, are added to the mixing system; preferably, large-diameter grinding balls and small-diameter grinding balls are mixed and added for grinding, so that the accumulated or agglomerated particles are ground and dispersed by the large-diameter grinding balls; for small-particle powders or small-agglomerated powders, small-diameter grinding balls are better for grinding and trimming them; and finally, spherical powder particles with uniform shape are obtained, which helps to improve the fluidity of the slurry prepared with the powder.

[0062] Preferably, the aforementioned technical solution is further provided with a material receiving system; the material receiving system is composed of a screen and a material receiving barrel; the screen is provided at the end of the mixing barrel. Preferably, the aforementioned technical solution is provided with a screen on the discharge port. In some embodiments, during the operation of the surface micro-shaping device, after the feeding is completed, the feed port is in a closed state and the discharge port is in an open state. Such a setting, on the one hand, helps the gas to flow well in the mixing barrel, and on the other hand, the interior of the mixing barrel is connected to the outside world, which helps to avoid excessive heat accumulation in the mixing barrel, thereby avoiding the influence of the heat accumulation on the calcination and micro-shaping of the powder.

[0063] Preferably, in the aforementioned technical solution, the surface micro-shaping device is further provided with a cooling system to help promptly reduce the temperature of the device, avoid or even reduce the impact of heat energy generated during the shaping process on the chemical properties of the powder particles, and improve safety. In some embodiments, the surface micro-shaping device is provided with a fan above the mixing barrel to achieve rapid cooling.

[0064] Preferably, in the aforementioned technical solution, the surface micro-shaping device is further provided with an outer shell for protecting the various systems inside it.

[0065] The present invention also specifically provides a powder surface micro-shaping device:

[0066] Use Figure 1 、 2 The structure of the powder surface micro-shaping device is as follows:

[0067] The invention is composed of a control system 1, a heating system 2, a mixing system 3, a transmission system 4, a cooling system 5, a collecting system 6, and an air intake channel 7; wherein the control system 1 is composed of a control panel 1-1 and a controller 1-2; the heating system 2 is composed of a heating element 2-1 and a temperature sensor 2-2; the mixing system 3 is composed of a mixing barrel 3-1 and a grinding ball 3-2; the transmission system 4 is composed of a gear 4-1 and a motor 4-2; the cooling system 5; the collecting system is composed of a screen 6-1 and a collecting barrel 6-2; and the interior of the air intake channel 7 is a rotating structure.

[0068] The present invention further specifically provides a method for using a powder surface micro-shaping device, and the operating steps are as follows:

[0069] (1) Place high-purity grinding balls of the same material as the powder particles to be processed into the mixing barrel; start the control system, set the heating speed and heating time, the rotation speed and rotation time of the gears of the transmission system, and the ventilation flow rate and ventilation time of the air intake system;

[0070] (2) The micro-shaping device is preheated, and after it reaches the preheating temperature, the air intake system (partially not shown) starts to operate according to the set ventilation flow rate and ventilation time to allow gas to enter the mixing barrel; after the gas fills the mixing barrel, the transmission system starts to operate according to the set rotation speed and rotation time; and then the powder particles to be processed are added;

[0071] (3) During the micro-shaping process of the powder particles by the device, driven by the rotating gas, the powder particles after surface micro-shaping flow from the low potential of the mixing cylinder to the high potential, are filtered by the screen of the receiving system, and are collected by the receiving cylinder;

[0072] (4) Turn off the control system and end the operation of the micro-plastic surgery device.

[0073] The present invention will be further described below with reference to specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0074] Unless otherwise specified, the materials and reagents mentioned below are commercially available products familiar to those skilled in the art. Unless otherwise specified, the methods described are all well-known methods in the art. Unless otherwise defined, technical or scientific terms used shall have the same meanings as those commonly understood by those skilled in the art.

[0075] Example 1

[0076] This embodiment uses the surface micro-shaping device of the present invention to micro-shape high-purity powder particles. The specific operations are as follows:

[0077] Prepare

[0078] Weigh 100 g of high-purity alumina powder particles with a purity of 99.99%.

[0079] Powder surface micro-shaping

[0080] Use Figure 1 The surface micro-shaping device shown has a mixing cylinder with a length of 150 cm and a diameter of 90 cm; the angle θ between the axis of the mixing cylinder and the horizontal plane is 4°.

[0081] 400 g of high-purity alumina grinding balls with a diameter of 5 mm (hereinafter referred to as "φ5") and 100 g of high-purity alumina grinding balls with a diameter of 10 mm (hereinafter referred to as "φ10") were added to the mixing cylinder.

[0082] Turn on the control power supply in the control panel of the control system and set the process parameters: the preset temperature of the mixing barrel is 400℃, the transmission system drives the mixing barrel to rotate at a speed of 300rpm; air is delivered to the mixing barrel with a gas flow rate of 1.0m 3 / s; the gas is accelerated by a rotating structure with a rotation radius of 5 cm and an angular velocity of 2000 rpm. The gas's time in the rotating structure is adjusted so that it flows out of the rotating structure at a rotation speed of 1200 rpm and into the mixing barrel. The gas rotates along the inner wall of the mixing barrel, stirring the powder particles.

[0083] After the parameters are set, the device begins operation and preheats. Once the mixing drum reaches the preset temperature, air is delivered to the mixing drum, and the transmission system begins operating according to the set conditions. After 5 minutes, the weighed high-purity alumina powder particles are added to the mixing drum, and surface micro-shaping of the powder particles begins.

[0084] During the shaping process, the micro-shaped alumina powder is transported by gas to the end of the mixing drum. As it passes through the discharge port at the end of the mixing drum, it is filtered through a 500-mesh screen installed at the discharge port. The micro-shaped high-purity alumina powder is collected by the collection drum. The program ends when no more powder particles flow through the screen. The control panel power is turned off, the machine stops, and the remaining powder particles in the mixing drum are passed through a 500-mesh screen.

[0085] Index detection:

[0086] Count the time of surface micro-shaping of powder particles; detect the time of high-purity alumina powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of ceramic green body formed by powder molding and sintering; recovery rate; the method is as follows:

[0087] Surface micro-shaping time statistics: from the time the powder particles are added into the mixing barrel until no more powder particles flow out of the screen at the discharge port;

[0088] Particle size detection: using laser particle size analyzer HORIBA LA-960;

[0089] Flowability test: Pour the powder into a slurry and pour it through a 500-mesh sieve; observe the slurry passing through the 500-mesh sieve, record the time when the slurry no longer flows out of the sieve, and measure the percentage of slurry passing through the sieve;

[0090] Density testing of ceramic bodies formed by powder molding and sintering: The shaped powder is prepared into ceramic test blocks and sintered at 1560°C. The bulk density of the shaped powder sintered into ceramics is measured and the relative density is calculated. This is compared with the relative density of ceramics formed and sintered from unshaped powder to determine the effectiveness of the powder shaping process. Relative density = bulk density / theoretical density. The better the powder surface shaping effect, the higher the relative density of the sintered ceramic. This is because powder surface shaping can improve the dispersion and uniformity of the powder and reduce agglomeration, thereby allowing the ceramic to densify better during the sintering process and increase the relative density.

[0091] Recovery rate: Recovery rate (%) = mass of powder particles passing through the sieve after shaping / mass of powder particles before shaping × 100%.

[0092] Example 2

[0093] This embodiment is basically the same as the first embodiment, except that:

[0094] Prepare

[0095] Weigh 100 g of high-purity aluminum nitride powder particles with a purity of 99.95%.

[0096] Powder surface micro-shaping

[0097] Add 400g of φ5 and 100g of φ10 high-purity aluminum nitride grinding balls into the mixing barrel. The mixing barrel is preset to 500℃ and the rotating speed of the mixing barrel is 450rpm. Helium is delivered into the mixing barrel with a gas flow rate of 0.5m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 1000rpm.

[0098] Index detection:

[0099] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of ceramic green body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1. Wherein, the sintering temperature of the ceramic green body formed by molding and sintering the powder particles is 1700°C.

[0100] Example 3

[0101] This embodiment is basically the same as the first embodiment, except that:

[0102] Prepare

[0103] Weigh 100 g of high-purity silicon carbide powder particles with a purity of 99.95%.

[0104] Powder surface micro-shaping

[0105] Add 400g of φ5 and 100g of φ10 high-purity silicon carbide grinding balls into the mixing barrel. The mixing barrel is preset to a temperature of 400°C and a rotating speed of 500rpm. Nitrogen is supplied to the mixing barrel at a gas flow rate of 0.8m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 750rpm.

[0106] Index detection:

[0107] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of ceramic green body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1. Wherein, the sintering temperature of the ceramic green body formed by powder molding and sintering is 1800°C.

[0108] Example 4

[0109] This embodiment is basically the same as the first embodiment, except that:

[0110] The angle θ between the axis of the mixing cylinder and the horizontal plane is 30°.

[0111] Weigh 2.5 kg of high-purity alumina powder particles with a purity of 99.6%.

[0112] Powder surface micro-shaping

[0113] Add 16kgφ3 and 4kgφ8 high-purity alumina grinding balls into the mixing drum. The mixing drum is preset to a temperature of 300℃ and a rotating speed of 400rpm. Nitrogen is delivered to the mixing drum at a gas flow rate of 1.2m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 800rpm.

[0114] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0115] Example 5

[0116] This embodiment is basically the same as the first embodiment, except that:

[0117] The angle θ between the axis of the mixing cylinder and the horizontal plane is 15°.

[0118] Weigh 3 kg of high-purity alumina powder particles with a purity of 99.5%.

[0119] Powder surface micro-shaping

[0120] Add 18kgφ6 and 6kgφ12 high purity alumina grinding balls into the mixing drum. The mixing drum is preset to 400℃ and the rotating speed is 500rpm. Nitrogen is delivered into the mixing drum with a gas flow rate of 1.5m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 1200rpm.

[0121] Index detection

[0122] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0123] Example 6

[0124] This embodiment is basically the same as the first embodiment, except that:

[0125] The angle θ between the axis of the mixing cylinder and the horizontal plane is 4°.

[0126] Weigh 6 kg of high-purity alumina powder particles with a purity of 99.5%.

[0127] Powder surface micro-shaping

[0128] Add 36kgφ5 and 12kgφ10 high purity alumina grinding balls into the mixing drum. The mixing drum is set to a temperature of 400℃ and a rotating speed of 450rpm. Air is delivered into the mixing drum at a flow rate of 3m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 1000rpm.

[0129] Index detection

[0130] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0131] Example 7

[0132] This embodiment is basically the same as the first embodiment, except that:

[0133] The angle θ between the axis of the mixing drum and the horizontal plane is 1°;

[0134] Weigh 10 kg of high-purity alumina powder particles with a purity of 99.5%.

[0135] Powder surface micro-shaping

[0136] Add 40kgφ6 and 10kgφ12 high-purity alumina grinding balls into the mixing drum. The preset temperature of the mixing drum is 400℃, the rotation speed of the mixing drum is 500rpm, and air is transported into the mixing drum with a gas flow rate of 3.5m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 1000rpm.

[0137] Index detection

[0138] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0139] Example 8

[0140] This embodiment is basically the same as the first embodiment, except that:

[0141] The angle θ between the axis of the mixing drum and the horizontal plane is 3°;

[0142] Weigh 15 kg of high-purity alumina powder particles with a purity of 99.5%.

[0143] Powder surface micro-shaping

[0144] Add 72kgφ5 and 18kgφ10 high-purity alumina grinding balls into the mixing drum. The preset temperature of the mixing drum is 350℃, the rotation speed of the mixing drum is 450rpm, and air is transported into the mixing drum with a gas flow rate of 5m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 1500rpm.

[0145] Index detection

[0146] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0147] Example 9

[0148] This embodiment is basically the same as the first embodiment, except that:

[0149] Powder surface micro-shaping

[0150] The rotating speed of the mixing drum is 100 rpm; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing drum at a rotating speed of 500 rpm.

[0151] Index detection

[0152] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0153] Example 10

[0154] This embodiment is basically the same as the first embodiment, except that:

[0155] Powder surface micro-shaping

[0156] The mixing drum rotates at a speed of 600 rpm. After being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing drum at a rotation speed of 2000 rpm.

[0157] Index detection

[0158] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0159] Comparative Example 1

[0160] Prepare

[0161] Weigh 100 g of high-purity alumina powder particles with a purity of 99.99%.

[0162] Calcination and ball milling

[0163] High-purity alumina powder was placed in a covered alumina crucible and then calcined in a high-temperature sintering furnace (silicon-molybdenum rods) in an air atmosphere at 400°C for 1 hour. The calcined powder particles were ball-milled using a vertical planetary ball mill as a powder dispersion machine. 100g of the calcined powder particles was added to a 500mL ball milling jar. 400g of φ5 and 100g of φ10 high-purity alumina grinding balls were added to the jar. An appropriate amount of deionized water was added as a solvent. The ball milling speed was set to 400rpm and the milling time was 60 minutes.

[0164] The high-purity alumina powder after ball milling is dried, crushed, and passed through a 500-mesh sieve.

[0165] Index detection

[0166] Detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90); flowability test; density of ceramic green body formed by powder molding and sintering; detection recovery rate; method is the same as Example 1; statistics of powder particle shaping time; powder particle heating time and ball milling time.

[0167] Comparative Example 2

[0168] The process and method of this comparative example are basically the same as those of Example 1. 100g of high-purity alumina powder particles with a purity of 99.99% are weighed. The difference is:

[0169] The angle θ between the axis of the mixing drum and the horizontal plane is 0°C; the preset temperature of the mixing drum is 400°C; the rotation speed of the grinding medium is 100 rpm; the flow rate of the gas delivered to the mixing drum is 0.3m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 800rpm.

[0170] Index detection

[0171] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0172] Comparative Example 3

[0173] The process and method of this comparative example are basically the same as those of Example 1. 100g of high-purity alumina powder particles with a purity of 99.99% are weighed. The difference is:

[0174] The angle θ between the axis of the mixing drum and the horizontal plane is 45°; the preset temperature of the mixing drum is 800°C; the rotation speed of the mixing drum is 800 rpm; the flow rate of the gas delivered to the mixing drum is 1.5m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 2500rpm.

[0175] Index detection

[0176] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0177] Comparative Example 4

[0178] This comparative example is basically the same as Example 5 in terms of process and method. 3 kg of high-purity alumina powder particles with a purity of 99.5% are weighed. The difference is that:

[0179] The angle θ between the axis of the mixing drum and the horizontal plane is 15°; the preset temperature of the mixing drum is 500°C; the rotation speed of the mixing drum is 800 rpm; the flow rate of the gas delivered to the mixing drum is 4m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 1500rpm.

[0180] Index detection

[0181] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0182] Comparative Example 5

[0183] This comparative example is basically the same as Example 5, but weighs 3 kg of high-purity alumina powder particles with a purity of 99.5%. The difference is that:

[0184] The mixing drum is set to a temperature of 400°C. 18 kg of φ5 and 6 kg of φ10 high-purity alumina grinding balls are added to the mixing drum. The mixing drum rotates at a speed of 800 rpm. The flow rate of gas delivered to the mixing drum is 0.8 m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 2500rpm.

[0185] Index detection

[0186] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0187] Comparative Example 6

[0188] This comparative example is basically the same as Example 8, but weighs 15 kg of high-purity alumina powder particles with a purity of 99.5%. The difference is that:

[0189] Add 108kgφ5 and 27kgφ10 high-purity alumina grinding balls into the mixing barrel; the preset temperature of the mixing barrel is 500℃; the rotation speed of the mixing barrel is 500rpm; the flow rate of gas delivered to the mixing barrel is 6m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 900rpm.

[0190] Index detection

[0191] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0192] Comparative Example 7

[0193] This comparative example is basically the same as Example 8, but weighs 15 kg of high-purity alumina powder particles with a purity of 99.5%. The difference is that:

[0194] Add 24kgφ5 and 6kgφ10 high-purity alumina grinding balls into the mixing barrel; the preset temperature of the mixing barrel is 400℃, the rotation speed of the mixing barrel is 400rpm, and air is transported into the mixing barrel with a gas flow rate of 6m 3 / s; after being accelerated by the rotating structure, the gas flows out of the rotating structure into the mixing barrel at a rotation speed of 2500rpm.

[0195] Index detection

[0196] Count the powder particle shaping time; detect the powder particles before shaping (D 50 、D 90 ), particle size after shaping (D 50 、D 90 ); flowability test; density test of the ceramic body formed by powder molding and sintering; recovery rate; the method is the same as that of Example 1.

[0197] The powders of the above examples and comparative examples before and after shaping were tested for particle size, fluidity, and sintered body density, as shown in Table 1 below.

[0198] D 50 The median particle size of the powder, that is, in the particle size distribution of the powder, 50% of the particles have a particle size smaller than this value;

[0199] D 90 In the particle size distribution of powder particles, 90% of the particles have a particle size less than or equal to this value;

[0200] t1 is the time from the moment the slurry prepared before powder shaping begins to pass through the 500-mesh screen to the moment when no more slurry flows out of the screen;

[0201] t2 is the time from when the slurry prepared after powder shaping starts to pass through the 500-mesh screen to when no more slurry flows out of the screen.

[0202] Table 1. Test results of various indicators of the embodiments and comparative examples

[0203]

[0204]

[0205] In combination with the embodiments, comparative examples and Table 1, it can be seen that the high-purity alumina powder, high-purity aluminum nitride powder and high-purity silicon carbide powder are treated by the powder surface micro-shaping method provided by the present invention, and the particle size of the powder particles is significantly reduced, and the recovery rate is high; when the prepared slurry passes through a 500-mesh sieve, more than 90% of the slurry passes through the 500-mesh sieve within 4 minutes, and the relative density of the sintered bodies of the above three high-purity powders is above 93%. Compared with the powders that have not been treated by the powder surface micro-shaping method provided by the present invention, the slurry has good fluidity. The reason is that: the high-purity powder particle surface micro-shaping method provided by the present invention is adopted to realize the coupling effect of mechanical energy and thermal energy. Through the mutual coordination of grinding media, gas and temperature, the irregular shape of the powder particle surface is continuously polished and trimmed to form powder particles with uniform surface shape. The surface quality of the powder particles is good, and the fluidity of the slurry prepared by the powder is significantly improved; and in the shaping process, the effects of temperature, gas and grinding media on the activity of the powder particles are better balanced, so that the slurry prepared by the powder has better fluidity and the sintering density of the sintered body is improved.

[0206] Furthermore, it can be seen from Comparative Example 1 and Table 1 that when the slurry prepared by heating to form a sintered body and then grinding the obtained powder passes through a 500-mesh sieve, no slurry flows out of the sieve after 8 minutes, and only 68.03% of the slurry passes through the sieve, and the relative density of the sintered body is less than 80%; it can be seen that the slurry prepared by the powder after shaping has poor fluidity, and compared with before shaping, the density of the sintered body formed is not significantly improved.

[0207] Furthermore, although Comparative Examples 2-4 adopted the powder surface micro-shaping of the present invention, the powder particles D 90It is larger than that of the embodiment, which to a certain extent reflects that the powder particles have strong agglomeration; the powder particle recovery rate obtained is significantly lower than that of the embodiment. When the prepared slurry passes through a 500-mesh sieve, no slurry flows out of the sieve after 5-6 minutes, and the percentage of slurry passing through the sieve is less than 80%. It can be seen that the slurry prepared by the prepared powder has poor fluidity, the relative density of the formed sintered body is less than 90%, and the density of the sintered body is not significantly improved compared with before shaping. The reason is that: when the angle θ between the mixing barrel and the horizontal plane of Comparative Example 2 is 0°C, the powder particles have poor classification effect during the heating ball milling process in the mixing barrel, and the shaped powder particles cannot be separated from the mixing barrel in time, but re-agglomerate; and during the research process, the air flow rate per unit volume is reduced to prevent the powder particles from being directly blown out by the gas. However, due to the small amount of gas input, its dispersion effect on the powder particles is weak, and the powder particles are easy to agglomerate; the gas lubrication protective layer between the powder particles and the grinding medium is weak, the grinding surface formed on the surface of the powder particles is relatively rough, the surface quality of the powder particles is poor, and the shaping effect is not good. Compared with before shaping, the improvement of the fluidity of the slurry prepared with the powder is not significant; and the shaping time is prolonged and the efficiency is reduced. When the angle θ between the mixing barrel and the horizontal plane of Comparative Example 3 is 45°, the inclination angle of the mixing barrel is too large, and a large amount of powder gathers at the lower end of the mixing barrel, and uniform ball milling of the powder particles cannot be achieved, so the powder agglomerates strongly; and, during the research process, the gas input per unit volume was increased to promote the flow of powder particles inside the mixing barrel; in order to fully grind the powder particles, the temperature in the mixing barrel was increased, the rotation speed of the mixing barrel and the stirring speed of the gas on the powder particles were increased; however, the results showed that its shaping effect was not improved; this is because the above measures make the gas lubrication protection layer on the grinding surface of the powder particles and the grinding medium too thick, and the grinding effect of the grinding medium on the powder particles is weakened; the temperature is too high and the stirring speed is too fast, which is not conducive to grinding and dispersing the grinding medium to form irregular powder particles, but makes the agglomeration more serious, the shaped powder cannot be separated in time, and the shaping time is too long, which prolongs the heating time of the powder, and ultimately makes the density of the sintered body formed lower than that of the embodiment. Comparative Example 4 ventilation flow does not meet the requirements of the present invention of 3kg≤M<10kg, S is 1.5~3m 3 / s required range, the ventilation volume is large, on the one hand, the powder particles are blown out of the mixing barrel before they are fully shaped in the mixing barrel; on the other hand, the gas protection layer formed on the surface of the powder particles is thicker, and the grinding media does not grind the powder particles sufficiently, so the powder particle shaping effect is poor.

[0208] Furthermore, although Comparative Example 5 adopts the powder surface micro-shaping of the present invention, the powder particles D 90Compared with the embodiment, it is larger, which to a certain extent reflects that the powder particles have strong agglomeration; the powder particle recovery rate obtained is low. When the prepared slurry passes through a 500-mesh sieve, no slurry flows out of the sieve after 8 minutes, and the percentage of slurry passing through the sieve is less than 75%. It can be seen that the slurry prepared by the powder has poor fluidity; and the relative density of the sintered body is less than 90%, and the density of the formed sintered body is not significantly improved compared with that before shaping. The reasons are: on the one hand, the amount of gas introduced into the mixing barrel per unit volume and unit time is too small, the gas has a weak dispersing effect on the powder particles, and the powder particles are easy to agglomerate; and the gas lubrication protective layer between the powder particles and the grinding medium is weak, and the grinding surface formed on the surface of the powder particles is relatively rough. Even if the rotation speed of the mixing barrel and the rotation speed of the gas are increased under appropriate temperature conditions, the powder particles cannot be fully ground, the surface quality of the powder particles is poor, and the shaping effect is not good. Therefore, the fluidity of the slurry prepared by the powder and the density of the sintered body are not significantly improved.

[0209] Although Comparative Examples 6 and 7 adopted the powder surface micro-shaping of the present invention, the powder particles D 90 It is larger than that in the embodiment, which to a certain extent reflects that the powder particles have strong agglomeration; the recovery rate of the powder particles obtained is low, and when the prepared slurry passes through a 500-mesh sieve, no slurry flows out of the sieve after 8 minutes, and the percentage of slurry passing through the sieve is less than 70%. It can be seen that the slurry prepared by the powder has poor fluidity; the relative density of the sintered body is <90%, and the density of the sintered body is not significantly improved compared with that before shaping. The reasons are as follows: on the one hand, since the mass ratio of the ball milling medium to the powder particles to be ground is too large or too small, it is not conducive to sufficient grinding of the powder particles. Even if the rotation speed of the gas is changed and the gas flow rate is increased, the fluidity of the powder slurry formed is still not significantly improved compared with before shaping; on the other hand, when the gas rotation speed is too fast, the fine powder particles are more likely to agglomerate, which is not only not conducive to the micro-shaping of the powder particles, but also increases the burden of shaping; thirdly, when the gas input per unit time is too large, more powder particles are taken out of the mixing barrel before they are completely shaped. The powder particles are not completely shaped and their surface quality is poor, which is not conducive to improving the fluidity of the prepared slurry or improving the density of the sintered body formed.

[0210] The technical features in the claims and / or the specification of the present invention may be combined, and the manner of combination is not limited to the combination obtained by reference in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification are also within the scope of protection of the present invention.

[0211] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for micro-shaping the surface of powder particles, characterized in that: It includes the following steps: Grinding the powder particles using grinding media under preset temperature conditions in a grinding system; Gas is delivered into the grinding system; the gas can stir the powder particles and drive them to contact with the grinding medium; when the quality of the powder particles meets the preset quality requirements, they are driven out of the grinding system by the gas.

2. The micro plastic surgery method according to claim 1, characterized in that: The gas drives the powder particles to flow from the lower position to the higher position of the grinding system.

3. The micro plastic surgery method according to claim 1, characterized in that: The powder particles have a temperature resistance of ≥1000°C, a Mohs hardness of 8 to 10, and an elastic modulus of ≥300 GPa.

4. The micro plastic surgery method according to claim 3, characterized in that: The powder particles are any one of aluminum oxide, aluminum nitride, silicon nitride and silicon carbide.

5. The micro plastic surgery method according to claim 4, characterized in that: The gas is appropriately selected from any one of air, nitrogen, argon and helium.

6. The micro plastic surgery method according to claim 5, characterized in that: The ratio of the total mass of all grinding media to the total mass of all powder particles in the grinding system is 3 to 8:

1.

7. The micro plastic surgery method according to claim 6, characterized in that: The gas flows out of the rotating structure at a rotation speed of n1 to stir the powder particles; the grinding system drives the grinding media to rotate at a rotation speed of n2; the particle size of the powder particles is D 50 ≤100μm, n1 is 500~2000rpm, n2 is 100~600rpm.

8. The micro plastic surgery method according to claim 6 or 7, characterized in that: The gas is delivered to the grinding system to meet the following conditions: the total mass of the powder particles in the grinding system is M, and the flow rate of the gas input into the grinding system per cubic meter is S; Under standard atmospheric pressure, 0.1kg≤M<3kg, S is 0.5~1.2m 3 / s; 3kg≤M<10kg, S is 1.5~3m 3 / s; when M≥10kg, S is 3.5~5m 3 / s.

9. The micro plastic surgery method according to claim 8, characterized in that: Small grinding balls with a diameter of 3 to 6 mm and large grinding balls with a diameter of 8 to 12 mm are used for mixed grinding; the mass ratio of the small grinding balls to the large grinding balls is 3 to 5:

1.

10. The micro plastic surgery method according to claim 9, characterized in that: The powder particles are aluminum oxide, the preset temperature is 300-500° C., the n1 is 800-1500 rpm, and the n2 is 300-500 rpm.

11. A powder surface micro-shaping device, characterized in that: It includes: A mixing system, the mixing system comprising a mixing barrel; the axis of the mixing barrel forms an angle θ with the horizontal plane, and 0°C<θ≤30°C; the mixing barrel is also provided with a feed port and a discharge port; An air intake system, the air intake system comprising an air intake passage; the air intake passage has a rotating structure inside; A heating system is disposed around the outer periphery of the mixing barrel; and A transmission system is connected to the mixing barrel; the transmission system can drive the mixing barrel to rotate.

12. The micro plastic surgery device according to claim 11, characterized in that: The θ is 1 to 4°C.

13. The micro plastic surgery device according to claim 11 or 12, characterized in that: It is also provided with a control system; the control system is connected to the heating system, the air intake system and the transmission system; During the operation of the micro-plastic surgery device, the control system can at least regulate the heating speed and heating time of the heating system; can regulate the ventilation flow and ventilation time of the intake system; and can regulate the rotation speed and rotation time of the transmission system.

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