An apparatus for sintering agglomerated powder and a sintering method of agglomerated powder

Abstract

The application provides an apparatus for agglomerated powder sintering and a sintering method of agglomerated powder, which comprises a sintering chamber and a gas feeding device; the sintering chamber is provided with a cavity, and a container for placing agglomerated powder is arranged in the cavity, the container can release the agglomerated powder in the container; a heating device is arranged in the cavity; a gas feeding port of the gas feeding device is communicated with the bottom of the sintering chamber, so that the gas fed by the gas feeding device can blow up the released agglomerated powder and keep the agglomerated powder dispersed. The apparatus for agglomerated powder sintering and the sintering method of agglomerated powder provided by the embodiment of the application can realize dynamic sintering of the agglomerated powder, the sintered powder can keep the original shape and size of the agglomerated powder, the sintering of the strength of the agglomerated powder is maximized, and the performance of the prepared agglomerated powder product is ensured.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology, specifically relating to an apparatus for sintering agglomerated powder and a sintering method for agglomerated powder. Background Technology

[0002] With the development of rail transit, 5G communication technology, and the continuous emergence of new materials, the requirements for workpiece machining precision in various fields are becoming increasingly stringent. Ultra-precision grinding and polishing technology has become a current research hotspot. Grinding tools with high grinding efficiency, low environmental pollution, and low surface roughness have become a new development trend. Ordinary diamond has serious drawbacks in precision machining due to its self-sharpening properties and limited depth of cut. However, spherical abrasive aggregates, utilizing their spherical multi-edge characteristics, can maintain high grinding force and avoid scratching materials during grinding and polishing, and have begun to be applied to the grinding of hard and brittle materials such as sapphire, silicon carbide, and gallium nitride. Compared to ordinary abrasives, after grinding, the abrasive on the surface of abrasive aggregates becomes passivated. Under certain pressure, the passivated abrasive will detach from the abrasive aggregate, while new abrasive continues to participate in the grinding process, thus reducing the need for dressing.

[0003] The preparation of agglomerated abrasives generally involves bonding fine, irregular raw abrasive particles together with ceramic or resin binders to obtain agglomerated powder. This agglomerated powder is then sintered to obtain agglomerated abrasives with a specific size, shape, and strength. Currently, the sintering of agglomerated powders mostly involves placing them statically in a container (e.g., a crucible) for sintering. However, the applicant has discovered that because the agglomerated powder is statically placed and aggregated in the container for sintering, it tends to agglomerate together during high-temperature sintering (the temperature that ensures the strength of the powder after sintering), making it difficult to maintain its original shape and size. While lowering the sintering temperature can reduce the agglomerated powder from agglomerating, it also reduces the strength of the sintered powder, affecting the performance of the final agglomerated abrasive product. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide an apparatus for sintering agglomerated powder, which can realize the dynamic sintering of agglomerated powder, so that the sintered powder can maintain the original shape and size of the agglomerated powder, and achieve the maximum sintering strength of the agglomerated powder, thereby ensuring the performance of the prepared agglomerated powder product.

[0005] Another objective of this invention is to provide a sintering method for agglomerated powder, which employs dynamic sintering to maintain the original shape and size of the agglomerated powder after sintering, thereby maximizing the strength of the agglomerated powder and ensuring the performance of the prepared agglomerated powder product.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first aspect of the present invention provides an apparatus for sintering agglomerated powder, comprising a sintering chamber and an air supply device;

[0008] The sintering chamber has a cavity, and the cavity is equipped with a container for placing agglomerated powder, which can release the agglomerated powder inside; the cavity is also equipped with a heating device.

[0009] The air outlet of the air supply device is connected to the bottom of the sintering chamber, so that the gas supplied by the air supply device can blow the released agglomerated powder upward and keep it dispersed.

[0010] In one embodiment of the present invention, the container is a container with an open top, and the container is connected to a rotating shaft that allows the open top of the container to rotate downwards;

[0011] Preferably, the rotating shaft passes through the side wall of the sintering chamber and its end is located outside the sintering chamber; the end of the rotating shaft is connected to an operating handle; or

[0012] The end of the rotating shaft is connected to a rotation drive device via a transmission mechanism.

[0013] In one embodiment of the present invention, the container is a container with an open bottom, and the open bottom of the container is provided with an openable baffle;

[0014] Preferably, the baffle is hinged to the bottom of the container, and a push-pull rod is provided between the bottom of the baffle and the side wall of the sintering chamber.

[0015] In one embodiment of the present invention, a collection section is provided at the bottom of the sintering chamber, and the air outlet of the air supply device is connected to the bottom end of the collection section;

[0016] Preferably, the inner diameter of the collecting part gradually decreases, and a screen is provided at the bottom end of the collecting part.

[0017] In one embodiment of the present invention, the air supply device is a cyclone generator, the cyclone generator includes a housing, the housing has an air chamber, the top of the housing is provided with an air outlet communicating with the air chamber; the side wall of the housing is provided with a plurality of air inlets communicating with the air chamber, and each air inlet is connected to an air source through a pipeline;

[0018] Preferably, the housing includes an upper housing and a lower housing, the upper housing being fixedly connected to the collecting part, and the lower housing being detachably connected to the upper housing.

[0019] In one embodiment of the present invention, the apparatus for sintering agglomerated powder further includes a vacuum device connected to the sintering chamber;

[0020] Preferably, the inner wall of the sintering chamber is provided with a temperature measuring device mounting section;

[0021] Preferably, the sintering chamber is provided with an exhaust valve that communicates with the cavity.

[0022] A second aspect of the present invention provides a method for sintering agglomerated powder, utilizing the aforementioned equipment for sintering agglomerated powder, the sintering method comprising the following steps:

[0023] A. The agglomerated powder is placed in the container and heated by the heating device to pre-sinter and degumme the agglomerated powder in the container;

[0024] B. Gas flowing upwards is introduced into the cavity of the sintering chamber through the air supply device, and then the agglomerated powder in the container is released, so that the agglomerated powder is blown up by the upward-flowing gas and kept dispersed.

[0025] C. Continue to increase the temperature and maintain the heat for the predetermined time;

[0026] D. Stop heating, the air supply device stops supplying air, and collect the powder product after it has cooled to room temperature.

[0027] In one embodiment of the present invention, in step A, the heating rate during pre-sintering is 4-8℃ / min, and the temperature is held for 60-180min at 100-120℃, 300-330℃, and 500-700℃ respectively.

[0028] Preferably, in step A, before pre-sintering, the cavity of the sintering chamber is evacuated by a vacuum pumping device, and a protective atmosphere, such as nitrogen, argon, or hydrogen, is introduced into the cavity of the sintering chamber by the air supply device.

[0029] In one embodiment of the present invention, in step B, the gas delivered by the air supply device is sintering gas;

[0030] Preferably, the sintering gas is one or more of compressed air, nitrogen, argon, hydrogen, methane, and ammonia;

[0031] Preferably, the flow rate of the gas delivered by the air supply device is 40-100 sccm.

[0032] In one embodiment of the present invention, in step C, the temperature is raised to 650-920°C and held for 180-400 minutes.

[0033] Compared with the prior art, the advantages and beneficial effects of the embodiments of the present invention are as follows:

[0034] The apparatus and method for sintering agglomerated powder provided in this invention release the agglomerated powder from the container and blown up by an upward airflow during sintering. This results in high dispersion of the agglomerated powder during sintering, rapid and uniform heat transfer, and prevents the agglomerated powder from sintering together. After sintering, the agglomerated powder retains its original shape (e.g., spherical multi-edged) and size (e.g., particle size). Furthermore, the apparatus and method for sintering agglomerated powder provided in this invention allow for high-temperature sintering without lowering the sintering temperature, thus maximizing the strength of the agglomerated powder during sintering. Attached Figure Description

[0035] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0036] Figure 1 A perspective view of an apparatus for sintering agglomerated powders provided in an embodiment of the present invention;

[0037] Figure 2 A top view of an apparatus for sintering agglomerated powders provided in an embodiment of the present invention;

[0038] Figure 3 This is a longitudinal sectional schematic diagram of the equipment for sintering agglomerated powder provided in an embodiment of the present invention;

[0039] Figure 4 A longitudinal sectional schematic diagram of an apparatus for sintering agglomerated powders provided in other embodiments of the present invention;

[0040] Figure 5 Photographs of the spherical powders prepared in Examples 1-3 of this invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1-Sintering chamber, 11-Cavity, 12-Support leg, 13-Exhaust valve, 14-Temperature measuring device mounting part, 2-Air supply device, 21-Shell, 211-Upper shell, 212-Lower shell, 22-Pipeline, 3-Container, 31-Rotating shaft, 32-Baffle, 33-Push-pull rod, 4-Heating device, 5-Collection part, 51-First collection part, 52-Second collection part. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. Indeed, those skilled in the art will recognize that modifications and variations can be made to the invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the invention encompass such modifications and variations falling within the scope of the appended claims and their equivalents.

[0044] In the description of this invention, the terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. The terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected," "linked," and "set up" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a direct connection or an indirect connection through intermediate components; a wired connection, a radio connection, or a wireless communication signal connection. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0045] like Figure 1 , Figure 2 As shown, an embodiment of the present invention provides an apparatus for sintering agglomerated powder, including a sintering chamber 1 and an air supply device 2.

[0046] like Figure 3 As shown, the sintering chamber 1 has a cavity 11, and a container 3 for holding agglomerated powder is provided inside the cavity 11. The container 3 can release the agglomerated powder inside. A heating device 4 is also provided inside the cavity 11 for heating the entire cavity 11. In this embodiment of the invention, the container 3 is located in the middle of the cavity 11, and the heating device 4 is a resistance wire located on the inner wall of the sintering chamber 1. Furthermore, a support leg 12 extends downward from the bottom edge of the sintering chamber 1 to support the sintering chamber 1. In order to discharge the gas inside the sintering chamber 1, the sintering chamber 1 is provided with an exhaust valve 13 communicating with its cavity 11, for example, located on the side wall of the sintering chamber 1.

[0047] In order to release the agglomerated powder inside the container 3, in this embodiment of the invention, the container 3 is a container with an open top, and the container 3 is connected to a rotating shaft 31 that allows the top opening of the container 3 to rotate downward, so as to pour the agglomerated powder out from the top opening of the container 3.

[0048] The rotating shaft 31 can be fixedly connected to the side or bottom of the container 3. Furthermore, to operate the rotating shaft 31, it passes through the side wall of the sintering chamber 1 and its end is located outside the sintering chamber 1. The operator can operate the outer end of the rotating shaft 31 to rotate it, thereby causing the top opening of the container 3 to rotate downwards. For ease of operation, an operating handle (not shown in the figure), such as a circular handle, is connected to the end of the rotating shaft 31. To save labor and improve efficiency, the end of the rotating shaft 31 can also be connected to a rotation drive device (not shown in the figure, such as a drive wheel set) via a transmission mechanism (not shown in the figure, such as a drive wheel set). By controlling the rotation drive device, the speed at which the top opening of the container 3 rotates downwards can be more precisely adjusted, thereby regulating the speed and flow rate of the agglomerated powder being poured outwards.

[0049] like Figure 4 As shown, in other embodiments of the present invention, the container 3 can also be a container with an open bottom, and the bottom opening of the container 3 is provided with an openable baffle 32. After the baffle 32 is opened, the agglomerated powder inside the container 3 can also be released downwards.

[0050] In this embodiment, the baffle 32 is hinged to the bottom of the container 3, and a push-pull rod 33 is provided between the bottom of the baffle 32 and the side wall of the sintering chamber 1. The opening and closing of the baffle 32 can be controlled by extending and retracting the push-pull rod 33. The end of the push-pull rod 33 can be located outside the sintering chamber 1 for easy manual operation, or it can be a high-temperature resistant electric or pneumatic push-pull rod located inside the sintering chamber 1.

[0051] like Figure 3 As shown, the air outlet of the air supply device 2 is connected to the bottom of the sintering chamber 1, so that the gas supplied by the air supply device 2 can blow the agglomerated powder released in the container 3 upward and keep it dispersed. In this embodiment, the air outlet of the air supply device 2 is directly connected to the bottom of the sintering chamber 1; in other embodiments, the air outlet of the air supply device 2 can also be connected to the bottom of the sintering chamber 1 through a pipe. When the temperature inside the cavity 11 of the sintering chamber 1 reaches the predetermined sintering temperature, the air supply device 2 starts to supply air, forming an upward airflow inside the sintering chamber 1; the agglomerated powder in the container 3 begins to be slowly released downward and blown up by the upward airflow to keep it dispersed, i.e., dynamic sintering is performed. After sintering is completed, after the sintering chamber 1 cools to room temperature, the sintered agglomerated powder product is collected, and the container 3 is restored to its initial state.

[0052] The apparatus for sintering agglomerated powder provided in this embodiment of the invention allows the agglomerated powder to be released from container 3 and blown up by an upward airflow during sintering. This results in high dispersion of the agglomerated powder during sintering, rapid and uniform heat transfer, and prevents the agglomerated powder from sintering together. After sintering, the agglomerated powder retains its original shape (e.g., spherical multi-edged) and size (e.g., particle size). Furthermore, since there is no need to lower the sintering temperature as in the prior art (to prevent the agglomerated powder from sintering together), the agglomerated powder in this embodiment of the invention can be sintered at high temperatures. Higher temperatures result in greater powder strength after sintering, thus maximizing the strength of the agglomerated powder during sintering.

[0053] In this embodiment of the invention, to facilitate the collection of agglomerated powder products after sintering, the bottom of the sintering chamber 1 is provided with a collection section 5 that gradually decreases in size radially downwards. The top of the collection section 5 is connected to the cavity 11 of the sintering chamber 1 via a flared guide plate, and the bottom end of the collection section 5 is connected to the air outlet of the air supply device 2. Preferably, the bottom end of the collection section 5 is provided with a screen to prevent agglomerated powder from falling into the air supply device 2. In this embodiment, the collection section 5 is gyroscope-shaped, including a cylindrical first collection section 51 and a conical second collection section 52.

[0054] In this embodiment of the invention, the air supply device 2 is a cyclone generator, specifically, as follows: Figure 1 , Figure 3 As shown, the cyclone generator includes a housing 21, which contains a gas chamber. An air outlet communicating with the gas chamber is located at the top of the housing 21. Several air inlets are located on the side wall of the housing 21, communicating with the gas chamber. Each air inlet is connected to a gas source (not shown) via a pipe 22. Depending on the environment required for sintering the agglomerated powder, the gas source is a sintering gas, which can be one or a mixture of compressed air, nitrogen, argon, hydrogen, methane, and ammonia. To maintain a stable temperature within the sintering chamber 1, a preheating device, such as an electric heater, is installed inside the gas chamber or on the pipes connecting the air inlets to the gas source. This preheats the gas from the gas source to minimize temperature fluctuations within the cavity 11 of the sintering chamber 1 caused by airflow, thus ensuring the sintering temperature.

[0055] Specifically, for ease of installation, such as Figure 3 As shown, the housing 21 includes an upper housing 211 and a lower housing 212. The upper housing 211 is fixedly connected to the bottom end of the collecting part 5, and the lower housing 212 is detachably connected to the upper housing 211, for example, by bolts.

[0056] To accommodate sintering requiring a protective atmosphere, the apparatus for sintering agglomerated powders provided in this embodiment of the invention further includes a vacuum pumping device (not shown in the figure), which is connected to the sintering chamber 1. First, the sintering chamber 1 is evacuated to a specific vacuum level, and then a protective gas is introduced through the air supply device 2.

[0057] In order to monitor the temperature inside sintering chamber 1 in real time, such as Figure 1 , Figure 3 As shown, the inner wall of the sintering chamber 1 is provided with a temperature measuring device mounting part 14, which can be used to install temperature measuring devices, such as thermometers and thermocouples.

[0058] The present invention also provides a sintering method for agglomerated powder, utilizing the aforementioned equipment for sintering agglomerated powder, the sintering method comprising the following steps:

[0059] A. The agglomerated powder is placed in the container 3, and heated by the heating device 4 to pre-sinter and degumme the agglomerated powder in the container 3; in this embodiment of the invention, the degumming and pre-sintering processes are carried out simultaneously;

[0060] B. Gas flowing upwards is introduced into the cavity 11 of the sintering chamber 1 through the air supply device 2, and then the agglomerated powder in the container 3 is released downwards (when using...). Figure 3 When the rotating container is shown, it is slowly released at an angular velocity of 0.2 to 0.5 r / min, so that the agglomerated powder is blown up by the upward flow of gas and kept dispersed;

[0061] C. Continue to increase the temperature and maintain the heat for the predetermined time;

[0062] D. Stop heating, the air supply device 2 stops supplying air, and collect the powder product after it has cooled to room temperature.

[0063] In one embodiment of the present invention, in step A, the heating rate during pre-sintering is 4–8 °C / min (e.g., 4 °C / min, 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min), and the temperature is increased to 100–120 °C (e.g., 100 °C, 105 °C, 110 °C, 120 °C) or 300–330 °C (e.g., 300 °C, 305 °C, 310 °C, 315 °C, 320 °C, 325 °C, 330 °C). Hold at 500-700℃ (e.g., 500℃, 505℃, 510℃, 515℃, 520℃, 525℃, 530℃, 535℃, 540℃, 545℃, 550℃, 600℃, 650℃, 700℃) for 60-180 minutes (e.g., 60 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 150 min, 180 min).

[0064] In this embodiment of the invention, in step B, the gas delivered by the air supply device 2 is one or more of compressed air, nitrogen, argon, hydrogen, methane, and ammonia. Preferably, the flow rate of the gas delivered by the air supply device 2 is 40-100 sccm (e.g., 40 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm).

[0065] When sintering needs to be performed under a protective atmosphere, in step A, before pre-sintering, the cavity 11 of the sintering chamber 1 is evacuated by a vacuum pump, and a protective atmosphere is introduced into the cavity 11 of the sintering chamber 1 by the air supply device 2. At this time, a specified protective atmosphere is selected as the gas source, such as nitrogen, argon, hydrogen, etc.

[0066] In this embodiment of the invention, in step C, the temperature is raised to 650-920℃ (e.g., 650℃, 655℃, 660℃, 665℃, 670℃, 675℃, 680℃, 700℃, 750℃, 800℃, 900℃, 920℃) and held for 180-400 min (e.g., 180 min, 200 min, 220 min, 240 min, 280 min, 300 min, 310 min, 320 min, 330 min, 340 min, 350 min, 360 min, 370 min, 380 min, 390 min, 400 min).

[0067] The following are some examples of a sintering method for agglomerated powder provided by the present invention.

[0068] First, agglomerated powders are prepared using existing technologies such as gas atomization, plasma torch method, rotating electrode atomization method, mechanical alloying method, and physical pulverization method. Examples of such powders include spherical diamond agglomerated powder, MCrAlY alloy powder, boron nitride and binder mixed powder, Ni-WC coated diamond powder, and WC-NiCrBSi smelted powder.

[0069] Example 1

[0070] A. Place 200g of the spherical diamond agglomerate powder prepared above into the container 3, and heat it through the heating device 4 to perform pre-sintering and debinding treatment. The heating rate during sintering is 4℃ / min, and the temperature is maintained at 120℃, 330℃ and 550℃ for 120min respectively.

[0071] B. Rotate container 3 to pour out the powder, turn on the air supply device 2, and introduce compressed air at a flow rate of 30 sccm; then slowly tilt container 3 containing agglomerated powder (by manually rotating the shaft connected to the container, slowly releasing it at an angular velocity of 0.2 r / min), so that the agglomerated powder is poured out and blown up by the upward flowing gas and kept dispersed.

[0072] C. Raise the temperature to 650℃ and hold for 200 minutes;

[0073] D. Stop heating, turn off the air supply device 2, and wait for it to cool to room temperature. Collect the aggregated powder product in the lower part of the cavity 11 of the sintering chamber 1.

[0074] Example 2

[0075] A. Place 200g of the spherical diamond agglomerate powder prepared above into the container 3, and heat it through the heating device 4 to perform pre-sintering and debinding treatment. The heating rate during sintering is 4℃ / min, and the temperature is maintained at 120℃, 330℃ and 550℃ for 120min respectively.

[0076] B. Rotate container 3 to pour out the powder, turn on the air supply device 2, and introduce compressed air at a flow rate of 50 sccm; then slowly tilt the container 3 containing the agglomerated powder (by manually rotating the shaft connected to the container at an angular velocity of 0.5 r / min), so that the agglomerated powder is poured out and blown up by the upward-flowing gas and kept dispersed.

[0077] C. Raise the temperature to 680℃ and hold for 300 minutes;

[0078] D. Stop heating, turn off the air supply device 2, and wait for it to cool to room temperature. Collect the aggregated powder product in the lower part of the cavity 11 of the sintering chamber 1.

[0079] Example 3

[0080] A. Place 200g of the Ni-WC coated diamond powder prepared above into the container 3, introduce argon gas at a flow rate of 20sccm, and heat it through the heating device 4 to perform pre-sintering and debinding treatment. The heating rate during sintering is 4℃ / min, and the temperature is maintained at 120℃, 330℃, 550℃, and 700℃ for 60min respectively.

[0081] B. Rotate container 3 to pour out the powder, turn on the air supply device 2, and introduce argon gas at a flow rate of 50 sccm; then slowly tilt container 3 containing agglomerated powder (by manually rotating the shaft connected to the container at an angular velocity of 0.3 r / min), so that the agglomerated powder is poured out and blown up by the upward flow of gas and kept dispersed.

[0082] C. Raise the temperature to 920℃ and hold for 180 minutes;

[0083] D. Stop heating, turn off the air supply device 2, and wait for it to cool to room temperature. Collect the aggregated powder product in the lower part of the cavity 11 of the sintering chamber 1.

[0084] Comparative Example 1

[0085] A. Place 200g of the spherical diamond agglomerate powder prepared above into a muffle furnace, heat it up through a heating device, and perform pre-sintering and debinding treatment. The heating rate during sintering is 4℃ / min, and the temperature is held at 120℃, 330℃ and 550℃ for 120min respectively.

[0086] B. Raise the temperature to 580℃ and hold for 200 minutes;

[0087] C. Stop heating.

[0088] Comparative Example 2

[0089] A. Place 200g of the spherical diamond agglomerate powder prepared above into a muffle furnace, heat it up through a heating device, and perform pre-sintering and debinding treatment. The heating rate during sintering is 4℃ / min, and the temperature is held at 120℃, 330℃ and 550℃ for 120min respectively.

[0090] B. Raise the temperature to 680℃ and hold for 200 minutes;

[0091] C. Stop heating.

[0092] By comparison, such as Figure 5 As shown, Examples 1-3 can prepare high-strength spherical powder with a single particle compressive strength of 35 kgf; Comparative Example 1, due to the low sintering temperature, prepares spherical powder with a single particle compressive strength of 20 kgf, but the prepared powder is spherical; Comparative Example 2, due to the excessively high temperature, melts into a block and cannot be used to prepare high-strength spherical powder.

[0093] The apparatus and method for sintering agglomerated powder provided in this invention release the agglomerated powder from the container and blown up by an upward airflow during sintering. This results in high dispersion of the agglomerated powder during sintering, rapid and uniform heat transfer, and prevents the agglomerated powder from sintering together. After sintering, the agglomerated powder retains its original shape (e.g., spherical multi-edged) and size (e.g., particle size). Furthermore, the apparatus and method for sintering agglomerated powder provided in this invention allow for high-temperature sintering without lowering the sintering temperature, thus maximizing the strength of the agglomerated powder during sintering.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sintering method for agglomerated powders, characterized in that, Using equipment for sintering agglomerated powder, the equipment for sintering agglomerated powder includes a sintering chamber and an air supply device; The sintering chamber has a cavity, and the cavity is equipped with a container for placing agglomerated powder, which can release the agglomerated powder inside; the cavity is also equipped with a heating device. The air outlet of the air supply device is connected to the bottom of the sintering chamber, so that the gas supplied by the air supply device can blow the released agglomerated powder upward and keep it dispersed. The container is an open-top container, and the container is connected to a rotating shaft that allows the top opening of the container to rotate downwards; the rotating shaft passes through the side wall of the sintering chamber and its end is located outside the sintering chamber; the end of the rotating shaft is connected to a rotation drive device through a transmission mechanism. The sintering method includes the following steps: A. The agglomerated powder is placed in the container and heated by the heating device to pre-sinter and degumme the agglomerated powder in the container; B. Gas flowing upwards is introduced into the cavity of the sintering chamber through the air supply device, and then the agglomerated powder in the container is released downwards at an angular velocity of 0.2 to 0.5 r / min, so that the agglomerated powder is blown up by the upward-flowing gas and kept dispersed. C. Continue to increase the temperature and maintain the heat for the predetermined time; D. Stop heating, the air supply device stops supplying air, and collect the powder product after it has cooled to room temperature.

2. The method for sintering agglomerated powder according to claim 1, characterized in that, The rotating shaft passes through the side wall of the sintering chamber and its end is located outside the sintering chamber; the end of the rotating shaft is connected to an operating handle; or The end of the rotating shaft is connected to a rotation drive device via a transmission mechanism.

3. The method for sintering agglomerated powder according to claim 1, characterized in that, The container is an open-bottom container, and the bottom opening of the container is provided with an openable baffle; the baffle is hinged to the bottom of the container, and a push-pull rod is provided between the bottom of the baffle and the side wall of the sintering chamber.

4. The method for sintering agglomerated powder according to claim 1, characterized in that, The bottom of the sintering chamber is provided with a collection section, and the air outlet of the air supply device is connected to the bottom end of the collection section.

5. The method for sintering agglomerated powder according to claim 4, characterized in that, The inner diameter of the collecting section gradually decreases, and a screen is provided at the bottom of the collecting section.

6. The method for sintering agglomerated powder according to claim 4, characterized in that, The air supply device is a cyclone generator, which includes a housing with an air chamber inside. The top of the housing is provided with an air outlet communicating with the air chamber. The side wall of the housing is provided with several air inlets communicating with the air chamber, and each air inlet is connected to an air source through a pipeline.

7. The method for sintering agglomerated powder according to claim 6, characterized in that, The housing includes an upper housing and a lower housing. The upper housing is fixedly connected to the collecting part, and the lower housing is detachably connected to the upper housing.

8. The method for sintering agglomerated powder according to claim 1, characterized in that, The equipment for sintering agglomerated powder also includes a vacuum device connected to the sintering chamber; The sintering chamber wall is equipped with a temperature measuring device mounting section; The sintering chamber is equipped with an exhaust valve that communicates with the cavity.

9. The sintering method for agglomerated powder according to claim 1, characterized in that, In step A, the heating rate during pre-sintering is 4-8℃ / min, and the temperature is held for 60-180 min at 100-120℃, 300-330℃, and 500-700℃ respectively.

10. The sintering method for agglomerated powder according to claim 1, characterized in that, In step A, before pre-sintering, the cavity of the sintering chamber is evacuated by a vacuum pumping device, and a protective atmosphere is introduced into the cavity of the sintering chamber by an air supply device.

11. The sintering method for agglomerated powder according to claim 9, characterized in that, In step B, the gas delivered by the air supply device is sintering gas; The sintering gas is one or more of compressed air, nitrogen, argon, hydrogen, methane, and ammonia. The air supply device delivers gas at a flow rate of 40-100 sccm.

12. The sintering method for agglomerated powder according to claim 11, characterized in that, In step C, the temperature is raised to 650-920℃ and held for 180-400 min.

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