阅读说明：本技术 基于流化床和化学气相沉积技术的粉体颗粒包覆设备 (Powder particle coating equipment based on fluidized bed and chemical vapor deposition technology ) 是由 刘马林 刘荣正 邵友林 刘兵 常家兴 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种基于流化床和化学气相沉积技术的粉体颗粒包覆设备,包括：加热炉；流化管,流化管安装于所述加热炉的炉腔内,流化管由下至上间隔设置有下盖板、一级流化床、二级流化床和上盖板,下盖板与一级流化床之间具有流化气腔,一级流化床与所述二级流化床之间具有一级流化腔,所述二级流化床与所述上盖板之间具有二级流化腔；流化气体源通过所述流化气体管道与所述流化气腔相连通,所述第一前驱体管道将第一前驱体通入所述一级流化腔；第二前驱体管道将第二前驱体通入所述二级流化腔；尾气管道的一端与所述二级流化腔相连通,其另一端与尾气处理系统相连。其解决了粉体颗粒包覆过程中前驱体易于孔口沉积、粉体流态化不均匀的技术问题。(The invention discloses powder particle coating equipment based on a fluidized bed and a chemical vapor deposition technology, which comprises: heating furnace; the fluidized pipe is arranged in a furnace chamber of the heating furnace, a lower cover plate, a first-stage fluidized bed, a second-stage fluidized bed and an upper cover plate are arranged on the fluidized pipe at intervals from bottom to top, a fluidized air cavity is arranged between the lower cover plate and the first-stage fluidized bed, a first-stage fluidized cavity is arranged between the first-stage fluidized bed and the second-stage fluidized bed, and a second-stage fluidized cavity is arranged between the second-stage fluidized bed and the upper cover plate; a fluidizing gas source is communicated with the fluidizing gas cavity through the fluidizing gas pipeline, and a first precursor is introduced into the primary fluidizing cavity through the first precursor pipeline; a second precursor pipeline leads a second precursor into the secondary fluidization cavity; one end of the tail gas pipeline is communicated with the secondary fluidization cavity, and the other end of the tail gas pipeline is connected with a tail gas treatment system. The method solves the technical problems that the precursor is easy to deposit at the orifice and the powder is fluidized unevenly in the powder particle coating process.)

1. A powder particle coating device based on a fluidized bed and a chemical vapor deposition technology is characterized by comprising:

the heating furnace (1), the said heating furnace (1) includes the open-cover type stove outer covering (18);

the fluidized pipe is arranged in a furnace chamber of the heating furnace (1), a lower cover plate (10), a first-stage fluidized bed (9), a second-stage fluidized bed (8) and an upper cover plate (7) are arranged on the fluidized pipe at intervals from bottom to top, a fluidized air cavity (17) is arranged between the lower cover plate (10) and the first-stage fluidized bed (9), a first-stage fluidized cavity is arranged between the first-stage fluidized bed (9) and the second-stage fluidized bed (8), and a second-stage fluidized cavity is arranged between the second-stage fluidized bed (8) and the upper cover plate (7);

a fluidizing gas conduit (13) through which a source of fluidizing gas is communicated with the fluidizing gas chamber (17) for introducing fluidizing gas into the fluidizing gas chamber (17);

a first precursor conduit (15), said first precursor conduit (15) passing a first precursor into said primary fluidization chamber;

a second precursor conduit (12), said second precursor conduit (12) passing a second precursor into said secondary fluidization chamber;

and one end of the tail gas pipeline (4) is communicated with the secondary fluidization cavity, and the other end of the tail gas pipeline (4) is connected with a tail gas treatment system.

2. The powder particle coating apparatus according to claim 1, wherein a cooling water jacket is coated outside the fluidizing gas conduit (13), the first precursor conduit (15) and the second precursor conduit (12).

3. The powder particle coating apparatus of claim 1, further comprising:

the outer sleeve (2) is used for installing the fluidizing pipe in a furnace chamber of the heating furnace (1) through the outer sleeve (2), and a protective air cavity is arranged between the outer sleeve (2) and the fluidizing pipe;

one end of the exhaust pipeline (6) is communicated with the protective air cavity, and the other end of the exhaust pipeline (6) is provided with an exhaust pump;

and one end of the protective gas pipeline (14) is communicated with the protective gas cavity, and the other end of the protective gas pipeline (14) is communicated with a protective gas source.

4. The powder particle coating apparatus of claim 3, wherein the outer sleeve (2) comprises:

a pipe body;

the upper sealing plate (3) is arranged at the top end of the pipe body and seals an opening at the top end of the pipe body, the upper sealing plate (3) is connected with the heating furnace (1), and the exhaust pipeline (6) and the tail gas pipeline (4) penetrate through the upper sealing plate (3);

a lower sealing plate (16), wherein the lower sealing plate (16) is arranged at the bottom end of the tube body and seals the bottom end opening of the tube body, and the fluidizing gas pipeline (13), the first precursor pipeline (15) and the second precursor pipeline (12) all penetrate through the lower sealing plate (16).

5. The powder particle coating apparatus of claim 4, wherein the tube body is of a telescopic structure along an axial direction.

6. The powder particle coating apparatus of claim 5, wherein the tail gas conduit (4), the first precursor conduit (15) and the second precursor conduit (12) each have a bellows section (5).

7. The powder particle coating apparatus of claim 4, wherein the fluidizing gas conduit (13), the first precursor conduit (15) and the second precursor conduit (12) are respectively locked with the lower sealing plate (16) by a locking member (11).

8. The powder particle coating apparatus of claim 3, further comprising:

one end of the communicating pipeline is communicated with the tail gas pipeline (4), and the other end of the communicating pipeline is communicated with the exhaust pipeline (6);

and the switch valve (20), wherein the switch valve (20) is arranged on the communication pipeline.

9. The powder particle coating apparatus according to any one of claims 1 to 8, wherein the heating furnace (1) includes a first temperature control region, a second temperature control region, and a third temperature control region from bottom to top, and the first temperature control region, the second temperature control region, and the third temperature control region respectively adjust heating temperatures.

10. The powder particle coating apparatus according to any one of claims 1 to 8, further comprising a support (19), wherein the heating furnace (1) is placed on a support surface of the support (19).

Technical Field

The invention relates to the technical field of powder coating equipment, in particular to powder particle coating equipment based on a fluidized bed and a chemical vapor deposition technology.

Background

Powder coating is an important step of powder functionalization and surface modification. At present, the powder is coated with a plurality of reactor forms, such as a spraying method, a liquid-phase coprecipitation coating method, a sol-gel method and the like, but the coating of the traditional powder-coated reactor is not compact and has low bonding strength, and the traditional powder-coated reactor is mainly used for coating an oxide film or directly adhering substances in a liquid phase. When the compactness requirement for coating of nuclear reaction powder particles is high, a fluidized bed-chemical vapor deposition method is mostly adopted. However, in the existing fluidized bed-chemical vapor deposition powder coating equipment, because the precursor and the fluidizing gas are mixed and then synchronously pass through the gas distributor, the deposition at the orifice of the gas distributor is easily caused, the sintering plate is blocked, and the reaction is terminated. However, if the structural form of the spouted bed is adopted, the airflow is injected at a high speed when entering, and the deposition at the orifice is reduced, but the uniform fluidization is difficult to form for the nano-scale or micron-scale powder, so that the coating effect is poor, and the coating quality of the product is influenced.

Disclosure of Invention

The invention aims to provide powder particle coating equipment based on a fluidized bed and a chemical vapor deposition technology, and aims to solve the technical problems of cracking deposition at a precursor orifice and non-uniform fluidization in the powder particle coating process. The purpose is realized by the following technical scheme:

a powder particle coating device based on fluidized bed and chemical vapor deposition technology comprises:

the heating furnace comprises an open-cover furnace shell;

the fluidized pipe is arranged in a furnace chamber of the heating furnace, a lower cover plate, a first-stage fluidized bed, a second-stage fluidized bed and an upper cover plate are arranged on the fluidized pipe at intervals from bottom to top, a fluidized air cavity is formed between the lower cover plate and the first-stage fluidized bed, a first-stage fluidized cavity is formed between the first-stage fluidized bed and the second-stage fluidized bed, and a second-stage fluidized cavity is formed between the second-stage fluidized bed and the upper cover plate;

a fluidizing gas conduit through which a source of fluidizing gas is communicated with the fluidizing gas chamber for passing fluidizing gas into the fluidizing gas chamber;

a first precursor conduit for passing a first precursor into the primary fluidization chamber;

a second precursor conduit for passing a second precursor into the secondary fluidization chamber;

and one end of the tail gas pipeline is communicated with the secondary fluidization cavity, and the other end of the tail gas pipeline is connected with a tail gas treatment system.

Furthermore, the fluidizing gas pipeline, the first precursor pipeline and the second precursor pipeline are all coated with cooling water jackets.

Further, still include:

the outer sleeve is used for installing the fluidizing pipe in a furnace chamber of the heating furnace, and a protective air cavity is arranged between the outer sleeve and the fluidizing pipe;

one end of the exhaust pipeline is communicated with the protective air cavity, and the other end of the exhaust pipeline is provided with an exhaust pump;

and one end of the protective gas pipeline is communicated with the protective gas cavity, and the other end of the protective gas pipeline is communicated with a protective gas source.

Further, the outer sleeve comprises:

a pipe body;

the upper sealing plate is arranged at the top end of the pipe body and seals the opening at the top end of the pipe body, the upper sealing plate is connected with the heating furnace, and the exhaust pipeline and the tail gas pipeline both penetrate through the upper sealing plate;

and the lower sealing plate is arranged at the bottom end of the tube body and seals the bottom opening of the tube body, and the fluidizing gas pipeline, the first precursor pipeline and the second precursor pipeline all penetrate through the lower sealing plate.

Further, the body is telescopic structure along the axial.

Further, the exhaust gas conduit, the first precursor conduit and the second precursor conduit each have bellows sections.

Further, the fluidizing gas pipeline, the first precursor pipeline and the second precursor pipeline are respectively locked with the lower sealing plate through locking members.

Further, still include:

one end of the communicating pipeline is communicated with the tail gas pipeline, and the other end of the communicating pipeline is communicated with the exhaust pipeline;

and the switch valve is arranged on the communicating pipeline.

Further, the heating furnace comprises a first temperature control area, a second temperature control area and a third temperature control area from bottom to top, and the first temperature control area, the second temperature control area and the third temperature control area respectively adjust heating temperatures.

Further, the heating furnace also comprises a support, and the heating furnace is placed on the supporting surface of the support.

According to the powder particle coating equipment provided by the invention, the fluidizing gas pipeline and the two precursor pipelines are separated independently, in the working process, the precursors are conveyed into the respective fluidizing cavities through the precursor pipelines and are subjected to coating reaction with the fluidizing gases introduced into the respective fluidizing cavities, powder particles are coated and pass through the fluidized bed or the secondary fluidized bed, the precursors and the fluidized bed are not in direct contact, and the precursors do not need to pass through orifices of the fluidized bed, so that the phenomenon of orifice deposition is avoided, and the long-time operation of the coating process is facilitated.

Meanwhile, the equipment is provided with a multi-stage fluidized bed, the fluidized bed is divided into a plurality of areas by utilizing a gas channel partition plate, a lower cover plate, a first-stage fluidized bed, a second-stage fluidized bed and an upper cover plate are arranged on a fluidized pipe from bottom to top at intervals, a fluidized gas cavity is arranged between the lower cover plate and the first-stage fluidized bed, a first-stage fluidized cavity is arranged between the first-stage fluidized bed and the second-stage fluidized bed, a second-stage fluidized cavity is arranged between the second-stage fluidized bed and the upper cover plate, powder particles obtained after first-stage coating are transported to the second-stage fluidized cavity after the coating reaction of a first precursor in the first-stage fluidized cavity is finished by utilizing the characteristic that the powder is easy to transport, and the purpose of powder composite coating is realized at one time by adopting an independent transport mode and sequentially passing through the multi-stage fluidized bed in a fluidized mode, the powder particles are fluidized uniformly, thereby solving the technical problems of orifice deposition and nonuniform fluidization in the process of coating the powder particles.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like parts are designated by like reference numerals throughout the drawings. In the drawings:

fig. 1 is a schematic structural diagram of a powder particle coating apparatus according to an embodiment of the present invention.

The reference numbers are as follows:

1. a heating furnace, 2, an outer sleeve, 3, an upper sealing plate, 4 and a tail gas pipeline,

5. a corrugated pipe section 6, an exhaust pipeline 7, an upper cover plate 8, a secondary fluidized bed,

9. a first-stage fluidized bed, a lower cover plate, 11, a locking part, 12, a second precursor pipeline,

13. a fluidizing gas line, 14, a shielding gas line, 15, a first precursor line,

16. a lower sealing plate 17, a fluidizing air cavity 18, an open-cover furnace shell 19 and a bracket,

20. and (4) switching on and off the valve.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The powder particle coating equipment provided by the invention is used for coating preparation of powder particles, is particularly suitable for preparation of powder coated particles for nuclear reaction, is provided with a multistage fluidized bed, and is used for respectively feeding two precursors which are separately fed with fluidizing gas, so that the precursors and the fluidizing gas are prevented from passing through the fluidized bed simultaneously, and the orifice plate of the fluidized bed is prevented from being blocked; and the structural form of a spouted bed is abandoned, and the uniformity of powder fluidization is ensured through multi-stage fluidization.

In one embodiment, as shown in fig. 1, the powder particle coating apparatus provided by the present invention includes a heating furnace 1, a fluidizing pipe, a fluidizing gas pipe 13, a first precursor pipe 15, a second precursor pipe 12, and an exhaust gas pipe 4.

Specifically, the heating furnace 1 is an open-type heating furnace, which includes an open-type furnace shell 18, and is divided into three sections in the axial direction to control respective heating, that is, the heating furnace 1 includes a first temperature control area, a second temperature control area, and a third temperature control area from bottom to top, and the first temperature control area, the second temperature control area, and the third temperature control area respectively adjust heating temperatures. In the course of the work, the temperature of each temperature control district can be controlled alone respectively, is favorable to controlling heating temperature respectively according to the needs of precursor, can be according to the user demand, respectively with each temperature control district adjustment to under respective temperature of predetermineeing to under different course of the work, can both provide comparatively suitable reaction temperature for the precursor.

The fluidization pipe is arranged in a furnace chamber of the heating furnace 1, a lower cover plate 10, a first-stage fluidized bed 9, a second-stage fluidized bed 8 and an upper cover plate 7 are arranged on the fluidization pipe from bottom to top at intervals, a fluidization air cavity 17 is arranged between the lower cover plate 10 and the first-stage fluidized bed 9, a first-stage fluidization cavity is arranged between the first-stage fluidized bed 9 and the second-stage fluidized bed 8, and a second-stage fluidization cavity is arranged between the second-stage fluidized bed 8 and the upper cover plate 7.

Specifically, the primary fluidization chamber and the secondary fluidization chamber are powder fluidization spaces, and the powder is fluidized to a certain height, about 2/3 space or less, so that the corresponding precursors are subjected to cracking reaction therebetween to coat the powder. The first-stage fluidized bed 9 and the second-stage fluidized bed 8 are both fluidized bed gas distributors, and the first-stage fluidized bed 9 is preferably a high-temperature sintering plate so as to be suitable for fluidization of nano-sized or micron-sized powder. The secondary fluidized bed 8 is preferably a perforated plate, which allows nano-or micro-scale transport therethrough and is suitable for fluidizing the coated powder.

The bottom of the fluidizing pipe is connected with a fluidizing gas pipeline 13, a cooling water jacket can be arranged outside the fluidizing gas pipeline 13, the fluidizing gas pipeline 13 is communicated with a fluidizing gas source and a fluidizing gas cavity 17, the fluidizing gas source is communicated with the fluidizing gas cavity 17 through the fluidizing gas pipeline 13 so as to introduce fluidizing gas into the fluidizing gas cavity 17 and generate a fluidizing effect on powder through a primary fluidized bed 9.

The first precursor conduit 15 communicates a first precursor source with the primary fluidization chamber for passing the first precursor into the primary fluidization chamber; the second precursor conduit 12 communicates a second precursor source with the second fluidization chamber for passing a second precursor into the secondary fluidization chamber. The first precursor pipeline 15 and the second precursor pipeline 12 are coated with cooling water jackets so as to cool the precursors.

The top of the fluidization pipe is communicated with a tail gas pipeline 4 of chemical vapor deposition, one end of the tail gas pipeline 4 is communicated with the secondary fluidization cavity, the other end of the tail gas pipeline is connected with a tail gas treatment system, and the tail gas treatment system can be an external evacuation or liquid receiving bottle or a tail gas separation and filtration system.

Further, the powder particle coating equipment also comprises an outer sleeve 2, an exhaust pipeline 6 and a protective gas pipeline 14, wherein the fluidizing pipe is arranged in a furnace chamber of the heating furnace 1 through the outer sleeve 2, and a protective gas cavity is arranged between the outer sleeve 2 and the fluidizing pipe; one end of the exhaust pipeline 6 is communicated with the protective air cavity, and the other end of the exhaust pipeline is provided with an exhaust pump for exhausting and vacuumizing; one end of the protective gas pipeline 14 is communicated with the protective gas cavity, and the other end is communicated with a protective gas source, and is used for introducing protective gas into the protective gas cavity. The outer sleeve 2 is a vacuum outer sleeve and is used for placing a fluidization pipe, a protective gas pipeline 14 is arranged at the bottom of the outer sleeve 2 and is used for connecting protective gas, and an exhaust pipeline 6 is arranged at the top of the outer sleeve 2 and is used for vacuumizing or exhausting the protective gas.

Thus, the fluidization pipe and the reaction component therein are arranged in the outer sleeve 2, and the fluidization pipe and the reaction component therein are outside the range of vacuum pumping, so that gases related to fluidization and reactivity are integrated in the outer sleeve 2 in integral vacuum, the operation, installation and disassembly processes of the equipment are very simple, the internal connection in the outer sleeve 2 can be completely installed on a workbench from a furnace body, and therefore, the continuous coating and batch production can be realized, the aims of safety, stability, high efficiency and environmental protection are fulfilled, and the device has good economic benefit and social benefit.

Specifically, the outer sleeve 2 comprises a pipe body, an upper sealing plate 3 and a lower sealing plate 16, wherein the upper sealing plate 3 may be in the form of a flange, the upper sealing plate 3 is disposed at the top end of the pipe body and seals the top end opening of the pipe body, the upper sealing plate 3 is connected to the heating furnace 1, and the exhaust pipeline 6 and the exhaust pipeline 4 both pass through the upper sealing plate 3; the lower sealing plate 16 is disposed at the bottom end of the tube body, and seals the bottom opening of the tube body, and the fluidizing gas pipeline 13, the first precursor pipeline 15, and the second precursor pipeline 12 all penetrate through the lower sealing plate 16.

The tube body is of a telescopic structure along the axial direction, the top of the tube body is erected above the heating furnace 1 through a positioning flange (namely an upper sealing plate 3), and the lower part of the tube body can freely stretch out and draw back.

For adapting to a length-adjustable telescopic tube, the tail gas pipe 4, the first precursor pipe 15 and the second precursor pipe 12 are all provided with bellows 5, so that the tail gas pipe 4, the first precursor pipe 15 and the second precursor pipe 12 can be telescopic within a certain range, so as to offset the telescopic difference between the fluidization pipe and the outer sleeve 2 when the outer sleeve 2 is telescopic.

The fluidizing gas pipeline 13, the first precursor pipeline 15 and the second precursor pipeline 12 are respectively locked with the lower sealing plate 16 through a locking member 11, so as to improve the locking performance of each pipeline with the lower sealing plate 16.

A communicating pipeline is also arranged between the tail gas pipeline 4 and the exhaust pipeline 6, one end of the communicating pipeline is communicated with the tail gas pipeline 4, and the other end of the communicating pipeline is communicated with the exhaust pipeline 6; the communicating pipeline is provided with a switch valve 20, and the on-off state of the communicating pipeline is adjusted through the switch valve 20, and it should be noted that the switch valve 20 is opened only when the exhaust pipeline 6 is used for vacuum pumping.

In order to improve the installation convenience and reliability of the apparatus, the apparatus further comprises a bracket 19, and the heating furnace 1 is placed on a supporting surface of the bracket 19.

In the above embodiment, the powder particle coating apparatus provided by the present invention separates the fluidizing gas conduit 13 and the two precursor conduits separately, and during the operation process, the precursors are transported into the respective fluidizing chambers through the precursor conduits, and after performing the coating reaction with the fluidizing gas introduced into the respective fluidizing chambers, the powder particles are coated and pass through the fluidized bed or the secondary fluidized bed 8, while the precursors and the fluidized bed do not contact each other, and the precursors do not need to pass through the orifices of the fluidized bed, so that the phenomenon of orifice deposition is avoided, and the long-time operation of the coating process is facilitated. Meanwhile, the device is provided with a multi-stage fluidized bed, the fluidized bed is divided into a plurality of areas by utilizing a gas channel clapboard, a lower cover plate 10, a first-stage fluidized bed 9, a second-stage fluidized bed 8 and an upper cover plate 7 are arranged on a fluidized pipe from bottom to top at intervals, a fluidized air cavity 17 is arranged between the lower cover plate 10 and the first-stage fluidized bed 9, a first-stage fluidized cavity is arranged between the first-stage fluidized bed 9 and the second-stage fluidized bed 8, a second-stage fluidized cavity is arranged between the second-stage fluidized bed 8 and the upper cover plate 7, powder particles obtained after first-stage coating are transported to the second-stage fluidized cavity after the coating reaction of a first precursor in the first-stage fluidized cavity is finished by utilizing the characteristic of easy transportation of powder, and the purpose of powder composite coating is realized at one time by adopting an independent transportation mode without unloading and secondary coating through a second precursor which is independently introduced, and powder particles are uniformly liquefied through a multi-stage fluidized bed fluidization mode in sequence, so that the technical problems of orifice deposition and nonuniform fluidization in the powder particle coating process are solved.

The following briefly describes the working process of the powder particle coating apparatus provided by the present invention, taking the above specific embodiment as an example:

1) preparation work of coating apparatus

Firstly, the assembly work of the integrated outer sleeve 2 and the fluidization pipe is carried out, and proper amount of nano powder to be fluidized, pipelines, corrugated pipes, sealing rings and the like are filled in the integrated outer sleeve and the fluidization pipe, and the integration work can be independently carried out on a workbench.

After being assembled, the frame is erected above the furnace through the upper flange. Then, various checks are carried out, including whether the pressure of cooling water, various gas pressures and temperatures meet the formal production requirements or not; various settings of the precursor supply system are started.

2) Operation of cladding apparatus auxiliary system

Firstly, starting a vacuum system for vacuumizing to enable a deposition furnace and a pipeline system to reach a set vacuum degree, maintaining for 3 minutes, observing whether the line leakage rate reaches the standard, starting fluidizing gas and protective gas after the line leakage rate reaches the standard, filling argon into a pipeline as the protective gas, and starting a tail gas system to enable the argon to continuously pass through a vacuum tube, a fluidizing tube and the corresponding pipeline system; and starting the heating power supply system to enable the temperatures of the three sections to reach set values respectively and stabilize for a period of time.

3) Operation of the coating apparatus

And after the temperature is stabilized, observing the change of fluid fluidization, and determining whether to adjust the flow of argon gas according to the fluidization condition to ensure that the powder is stably fluidized to the height of 2/3 in the primary fluidizing pipe.

And introducing gas of the precursor 1 to coat the powder.

After a period of time, the coating in the primary fluidization tube is finished, the precursor 1 is closed, and the atmosphere is introduced, so that the powder is conveyed to the space of the secondary fluidization tube through the secondary distribution plate and is fluidized.

And introducing gas of the precursor 2 to coat the powder.

After a period of time, the coating in the secondary fluidized tube is finished, the precursor 2 is closed, and the large gas flow is introduced, so that the powder is transported through the tail gas pipeline 4 to carry out cyclone separation, and the composite coated powder is obtained.

And after the preparation is finished, adjusting the heating power of the power supply to zero, cooling, turning off the power supply heating system, and finishing the preparation process of the composite powder.

After the operation steps are adopted, in order to make the nano powder coating operation more clear and make the final achieved effect, the nano powder coating operation is used for the specific coating process of nano SiC powder particles, and finally SiC-Al which accords with the parameter design is prepared₂O₃The specific experimental result of the-C composite nano powder is that the first layer Al₂O₃The coating (thickness 2nm) and the second pyrolytic carbon layer (thickness 4nm) can be used as the original powder material for sintering SiC ceramics.

It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be used.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For convenience of description, spatially relative terms, such as "inner", "outer", "lower", "below", "upper", "above", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the example term "below … …" can include both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.