Preparation method of silicon carbide ceramic part

Abstract

The invention belongs to the technical field of silicon carbide ceramic part processing, and discloses a preparation method of a silicon carbide ceramic part. The preparation method of the silicon carbide ceramic part comprises the following steps: S1, raw material preparation: adding silicon carbide powder, boron powder and carbon powder into mixing granulation equipment to obtain ceramic powder, S2, material molding: putting mixed particles obtained in the S1 into an injection molding machine, injecting the mixed particles into a mold for molding, S3, sintering molding: carrying out low-temperature degreasing treatment on a material blank, and carrying out heat treatment to obtain the silicon carbide ceramic part. And S4, processing the silicon carbide ceramic material, and carrying out rough machining and finish machining to obtain the silicon carbide ceramic part. According to the preparation method of the silicon carbide ceramic part, the silicon carbide ceramic part is processed in an injection molding mode, the ceramic powder obtained through sufficient mixing is subjected to injection molding and ultrahigh-temperature and high-pressure hot isostatic pressing treatment, the material is compact in structure, high in strength and excellent in mechanical property, and the problems proposed in the background technology are solved.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide ceramic part processing, in particular to a method for preparing a silicon carbide ceramic part. Background Art

[0002] Silicon carbide ceramics have excellent properties such as high high-temperature strength, strong oxidation resistance, good wear resistance, excellent thermal stability, small thermal expansion coefficient, high thermal conductivity, high hardness, and resistance to thermal shock and chemical corrosion. They are widely used in precision bearings, seals, gas turbine rotors, nozzles, heat exchanger components and nuclear reactor materials, especially in the manufacture of special ceramic products such as ceramic valves and ceramic cylinder valve plates.

[0003] The silicon carbide ceramic material process mainly involves raw material mixing (mixing silicon carbide with additives). The molding methods include compression molding and injection molding, followed by sintering, and finally processing and trimming. This process is accompanied by an ultra-high pressure and ultra-high temperature environment, which also creates the excellent performance of silicon carbide ceramic materials. The performance of silicon carbide ceramic products is restricted by their preparation process, especially the raw material mixing stage. It is necessary to ensure sufficient mixing degree to ensure the uniformity of the material in subsequent processing. Therefore, we propose a preparation method for silicon carbide ceramic parts. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing a silicon carbide ceramic part, which solves the problems raised in the background technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a method for preparing a silicon carbide ceramic part, the preparation method comprising the following steps:

[0006] S1. Raw material preparation:

[0007] Adding silicon carbide powder, boron powder and carbon powder into a mixing and granulating device to obtain ceramic powder;

[0008] Add ceramic powder, binder and oxide sintering aid into a mixing granulation device and mix for 2 to 6 hours to obtain mixed particles;

[0009] The ceramic powder accounts for 50% to 60% of the volume of the mixed particles, the binder accounts for 25% to 40%, and the sintering aid accounts for 0.1% to 15% of the mass of the mixed powder;

[0010] The mixing and granulating equipment includes an equipment body, a shell is fixedly installed inside the equipment body, a feeding pipe is fixedly connected to the top of the shell, a mixing structure is provided inside the equipment body, a partition is fixedly connected to the inner wall of the shell, a first discharge pipe is fixedly connected to the inner wall of the partition, a granulating structure is provided inside the shell near the bottom of the first discharge pipe, a collecting box is fixedly installed on the bottom of the inner wall of the shell, a slide is fixedly connected to the inner wall of the collecting box, and a third discharge pipe is fixedly connected to the right side of the collecting box;

[0011] The mixing structure includes a first motor, the bottom of the first motor is fixedly mounted on the top of the housing, the interior of the first motor is fixedly connected to a rotating shaft, the outer wall of the rotating shaft is rotatably connected to a first bearing, the outer wall of the rotating shaft is fixedly connected to a fixed sleeve, the outer wall of the fixed sleeve is welded to a stirring frame, the outer wall of the stirring frame is fixedly connected to a U-shaped rod, and the interior of the stirring frame is fixedly connected to a stirring rod;

[0012] S2, material molding, putting the mixed particles obtained in S1 into an injection molding machine, injecting into a mold for molding, the injection molding machine barrel temperature is 240℃~300℃, the nozzle temperature is 200℃~220℃, and the injection pressure is 50MPa~120MPa, to obtain a blank;

[0013] S3, sintering molding, the blank is subjected to low-temperature degreasing treatment to evaporate the adhesive in the blank;

[0014] Then hot isostatic pressing is performed to obtain dense silicon carbide ceramic material;

[0015] The temperature of the low-temperature degreasing treatment is 500°C to 800°C, and the time is 2 to 4 hours;

[0016] The hot isostatic pressing treatment is performed at a temperature of 2000° C. to 2200° C., a pressure of 100 MPa to 200 MPa, and a time of 3 to 6 hours.

[0017] S4. Processing of silicon carbide ceramic materials: obtaining silicon carbide ceramic parts after rough and fine processing.

[0018] Preferably, the oxide sintering aid is aluminum oxide, yttrium oxide or a mixture of the two.

[0019] Preferably, the ceramic powder is composed of 1-2% boron powder, 0.5%-1% carbon powder and the balance silicon carbide powder according to volume ratio.

[0020] Preferably, the granulation structure includes a fixed frame, the outer wall of the fixed frame is fixedly connected to the inner wall of the outer shell, a rotating structure is provided inside the fixed frame, the left bottom of the fixed frame is fixedly connected to the second discharge pipe, a snap-in groove is provided at the bottom of the inner wall of the fixed frame, a sliding groove is provided inside the fixed frame near the bottom of the snap-in groove, and a sliding structure is provided inside the sliding groove.

[0021] Preferably, the rotating structure includes a rotating shaft, which is movably installed inside the fixed frame, a sleeve is fixedly installed on the outer wall of the rotating shaft, a groove is provided on the outer wall of the sleeve, a through hole is provided inside the groove, a push plate is movably connected inside the through hole, the left end of the rotating shaft is rotatably connected to the second bearing, and the right end of the rotating shaft is fixedly connected to the second motor.

[0022] Preferably, the sliding structure includes a sliding plate, which is movably connected to the inside of the sliding groove, a rectangular groove is provided inside the sliding plate, a spring is fixedly connected to the inside of the rectangular groove, the top of the spring is fixedly connected to a baffle, a movable groove is provided inside the baffle, the top of the sliding plate is fixedly connected to a pin seat, the inside of the pin seat is movably connected to a push rod through a pin shaft, the right outer wall of the push rod is fixedly connected to a tension spring, the right end of the sliding plate is fixedly connected to the output end of the electric hydraulic cylinder, and the bottom of the sliding plate is movably connected to a pulley.

[0023] Preferably, the outer wall of the rotating shaft is fixedly connected to a push plate, the left end of the second bearing is fixedly installed on the left inner side of the fixed frame, the left side of the second motor is fixedly installed on the right outer wall of the fixed frame, the size of the baffle matches the size of the rectangular groove, the movable groove is movably connected to a tension spring, and the bottom end of the tension spring is fixedly connected to the bottom of the inner wall of the rectangular groove.

[0024] Preferably, the electric hydraulic cylinder is fixedly installed at the right end of the sliding groove, the bottom of the pulley is slidably connected to the inside of the sliding groove, the left side of the second motor is fixedly installed on the right outer wall of the outer shell, the third discharge pipe is fixedly installed on the right side of the outer shell, the bottom of the first discharge pipe is fixedly connected to the inside of the top of the fixed frame, the bottom of the second discharge pipe is fixedly connected to the inside of the top of the collecting box, and the first bearing is fixedly installed inside the top of the outer shell.

[0025] By adopting the above technical solution, the beneficial effects of the present invention are:

[0026] 1. The preparation method of the silicon carbide ceramic parts adopts injection molding to process the silicon carbide ceramic parts. The ceramic powder obtained by thorough mixing is injection molded and then subjected to hot isostatic pressing treatment at ultra-high temperature and high pressure. The material itself has a dense structure, high strength and excellent mechanical properties, which solves the problems raised in the background technology.

[0027] 2. The preparation method of the silicon carbide ceramic part, through the design of the mixing structure, is driven by the first motor to rotate the rotating shaft, so that the fixed sleeve fixedly connected to the outer wall of the rotating shaft drives the stirring frame to rotate, and the materials are mixed and stirred to ensure that the materials are fully mixed, thereby solving the problems raised in the background technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a three-dimensional diagram of the present invention;

[0029] Figure 2 It is a schematic diagram of the structure of the present invention;

[0030] Figure 3 For the present invention Figure 2 A magnified view of the structure at center A;

[0031] Figure 4 It is a schematic diagram of the sliding structure of the present invention.

[0032] In the figure: 1. Equipment body; 2. Housing; 3. Feed pipe; 4. Mixing structure; 41. First motor; 42. Rotating shaft; 43. First bearing; 44. Fixed sleeve; 45. Stirring frame; 46. U-shaped rod; 47. Stirring rod; 5. Partition; 6. First discharge pipe; 7. Granulating structure; 71. Fixed frame; 72. Rotating structure; 721. Rotating shaft; 722. Sleeve; 723. Groove; 724. Through hole; 725. Push plate; 72 6. Second bearing; 727. Second motor; 73. Second discharge pipe; 74. Snap-in groove; 75. Sliding groove; 76. Sliding structure; 761. Sliding plate; 762. Rectangular groove; 763. Spring; 764. Baffle; 765. Movable groove; 766. Pin seat; 767. Push rod; 768. Tension spring; 769. Electric hydraulic cylinder; 7610. Pulley; 8. Collection box; 9. Slide plate; 10. Third discharge pipe; 11. Support leg. DETAILED DESCRIPTION

[0033] See also Figure 1-4 The present invention provides a technical solution: a method for preparing a silicon carbide ceramic part, the preparation method comprising the following steps:

[0034] S1. Raw material preparation:

[0035] Adding silicon carbide powder, boron powder and carbon powder into a mixing and granulating device to obtain ceramic powder;

[0036] Add ceramic powder, binder and oxide sintering aid into a mixing granulation device and mix for 2 to 6 hours to obtain mixed particles;

[0037] The ceramic powder accounts for 50% to 60% of the volume of the mixed particles, the binder accounts for 25% to 40%, and the sintering aid accounts for 0.1% to 15% of the mass of the mixed powder;

[0038] The mixing and granulating equipment includes an equipment body 1, an outer shell 2 is fixedly installed inside the equipment body 1, a feed pipe 3 is fixedly connected to the top of the outer shell 2, a mixing structure 4 is provided inside the equipment body 1, a partition 5 is fixedly connected to the inner wall of the outer shell 2, a first discharge pipe 6 is fixedly connected to the inner wall of the partition 5, a granulating structure 7 is provided at the bottom of the inner wall of the outer shell 2 near the first discharge pipe 6, a collecting box 8 is fixedly installed at the bottom of the inner wall of the outer shell 2, a slide 9 is fixedly connected to the inner wall of the collecting box 8, and a third discharge pipe 10 is fixedly connected to the right side of the collecting box 8;

[0039] The mixing structure 4 includes a first motor 41. The bottom of the first motor 41 is fixedly mounted on the top of the housing 2. A rotating shaft 42 is fixedly connected to the interior of the first motor 41. A first bearing 43 is rotatably connected to the outer wall of the rotating shaft 42. A fixed sleeve 44 is fixedly connected to the outer wall of the rotating shaft 42. A stirring frame 45 is welded to the outer wall of the fixed sleeve 44. A U-shaped rod 46 is fixedly connected to the outer wall of the stirring frame 45. A stirring rod 47 is fixedly connected to the interior of the stirring frame 45.

[0040] S2, material molding, putting the mixed particles obtained in S1 into an injection molding machine, injecting into a mold for molding, the injection molding machine barrel temperature is 240℃~300℃, the nozzle temperature is 200℃~220℃, and the injection pressure is 50MPa~120MPa, to obtain a blank;

[0041] S3, sintering molding, the blank is subjected to low-temperature degreasing treatment to evaporate the adhesive in the blank;

[0042] Then hot isostatic pressing is performed to obtain dense silicon carbide ceramic material;

[0043] The temperature of low-temperature degreasing treatment is 500℃~800℃, and the time is 2~4h;

[0044] The temperature of the hot isostatic pressing treatment is 2000° C. to 2200° C., the pressure is 100 MPa to 200 MPa, and the time is 3 to 6 hours.

[0045] S4. Processing of silicon carbide ceramic materials: obtaining silicon carbide ceramic parts after rough and fine processing.

[0046] The oxide sintering aid is aluminum oxide, yttrium oxide or a mixture of the two.

[0047] The ceramic powder is composed of 1-2% boron powder, 0.5%-1% carbon powder and the balance silicon carbide powder according to volume ratio.

[0048] The granulation structure 7 includes a fixed frame 71, the outer wall of the fixed frame 71 is fixedly connected to the inner wall of the outer shell 2, a rotating structure 72 is provided inside the fixed frame 71, the left bottom of the fixed frame 71 is fixedly connected to a second discharge pipe 73, a snap-in groove 74 is provided at the bottom of the inner wall of the fixed frame 71, a sliding groove 75 is provided inside the fixed frame 71 near the bottom of the snap-in groove 74, and a sliding structure 76 is provided inside the sliding groove 75.

[0049] The rotating structure 72 includes a rotating shaft 721, which is movably installed inside the fixed frame 71. A sleeve 722 is fixedly installed on the outer wall of the rotating shaft 721. A groove 723 is provided on the outer wall of the sleeve 722. A through hole 724 is provided inside the groove 723. A push plate 725 is movably connected inside the through hole 724. The left end of the rotating shaft 721 is rotatably connected to the second bearing 726, and the right end of the rotating shaft 721 is fixedly connected to the second motor 727.

[0050] The sliding structure 76 includes a sliding plate 761, which is movably connected to the inside of the sliding groove 75. A rectangular groove 762 is provided inside the sliding plate 761. A spring 763 is fixedly connected to the inside of the rectangular groove 762. The top of the spring 763 is fixedly connected to a baffle 764. A movable groove 765 is provided inside the baffle 764. The top of the sliding plate 761 is fixedly connected to a pin seat 766. The inside of the pin seat 766 is movably connected to a push rod 767 through a pin shaft. The right outer wall of the push rod 767 is fixedly connected to a tension spring 768. The right end of the sliding plate 761 is fixedly connected to the output end of the electric hydraulic cylinder 769. The bottom of the sliding plate 761 is movably connected to a pulley 7610.

[0051] The outer wall of the rotating shaft 721 is fixedly connected to the pushing plate 725, the left end of the second bearing 726 is fixedly installed on the left inner side of the fixed frame 71, the left side of the second motor 727 is fixedly installed on the right end outer wall of the fixed frame 71, the size of the baffle 764 matches the size of the rectangular groove 762, and the internal movability of the movable groove 765 is connected to the tension spring 768, and the bottom end of the tension spring 768 is fixedly connected to the bottom of the inner wall of the rectangular groove 762.

[0052] The electric hydraulic cylinder 769 is fixedly installed at the right end of the sliding groove 75, the bottom of the pulley 7610 is slidably connected to the inside of the sliding groove 75, the left side of the second motor 727 is fixedly installed on the right outer wall of the outer shell 2, the third discharge pipe 10 is fixedly installed on the right side of the outer shell 2, the bottom of the first discharge pipe 6 is fixedly connected to the top inside of the fixed frame 71, the bottom of the second discharge pipe 73 is fixedly connected to the top inside of the collecting box 8, and the first bearing 43 is fixedly installed inside the top inside of the outer shell 2.

[0053] Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a silicon carbide ceramic part, characterized in that: The preparation method comprises the following steps: S1. Raw material preparation: Adding silicon carbide powder, boron powder and carbon powder into a mixing and granulating device to obtain ceramic powder; Add ceramic powder, binder and oxide sintering aid into a mixing granulation device and mix for 2 to 6 hours to obtain mixed particles; The ceramic powder accounts for 50% to 60% of the volume of the mixed particles, the binder accounts for 25% to 40%, and the sintering aid accounts for 0.1% to 15% of the mass of the mixed powder; The mixing and granulating equipment comprises an equipment body (1), a shell (2) is fixedly installed inside the equipment body (1), a feed pipe (3) is fixedly connected to the top of the shell (2), a mixing structure (4) is provided inside the equipment body (1), a partition (5) is fixedly connected to the inner wall of the shell (2), a first discharge pipe (6) is fixedly connected to the inside of the partition (5), a granulating structure (7) is provided near the bottom of the first discharge pipe (6) inside the shell (2), a collecting box (8) is fixedly installed at the bottom of the inner wall of the shell (2), a slide plate (9) is fixedly connected to the inside of the collecting box (8), and a third discharge pipe (10) is fixedly connected to the right side of the collecting box (8); The mixing structure (4) comprises a first motor (41), the bottom of the first motor (41) is fixedly mounted on the top of the housing (2), the interior of the first motor (41) is fixedly connected to a rotating shaft (42), the outer wall of the rotating shaft (42) is rotatably connected to a first bearing (43), the outer wall of the rotating shaft (42) is fixedly connected to a fixed sleeve (44), the outer wall of the fixed sleeve (44) is welded to a stirring frame (45), the outer wall of the stirring frame (45) is fixedly connected to a U-shaped rod (46), and the interior of the stirring frame (45) is fixedly connected to a stirring rod (47); S2, material molding, putting the mixed particles obtained in S1 into an injection molding machine, injecting into a mold for molding, the injection molding machine barrel temperature is 240℃~300℃, the nozzle temperature is 200℃~220℃, and the injection pressure is 50MPa~120MPa, to obtain a blank; S3, sintering molding, the blank is subjected to low-temperature degreasing treatment to evaporate the adhesive in the blank; Then hot isostatic pressing is performed to obtain dense silicon carbide ceramic material; The temperature of the low-temperature degreasing treatment is 500°C to 800°C, and the time is 2 to 4 hours; The hot isostatic pressing treatment is performed at a temperature of 2000° C. to 2200° C., a pressure of 100 MPa to 200 MPa, and a time of 3 to 6 hours. S4. Processing of silicon carbide ceramic materials: obtaining silicon carbide ceramic parts after rough and fine processing.

2. The method for preparing a silicon carbide ceramic part according to claim 1, wherein: The oxide sintering aid is aluminum oxide, yttrium oxide or a mixture of the two.

3. The method for preparing a silicon carbide ceramic part according to claim 2, wherein: The ceramic powder is composed of 1-2% boron powder, 0.5%-1% carbon powder and the balance silicon carbide powder according to volume ratio.

4. The method for preparing a silicon carbide ceramic part according to claim 1, wherein: The granulation structure (7) includes a fixed frame (71), the outer wall of the fixed frame (71) is fixedly connected to the inner wall of the outer shell (2), a rotating structure (72) is provided inside the fixed frame (71), the left bottom of the fixed frame (71) is fixedly connected to a second discharge pipe (73), a clamping groove (74) is provided at the bottom of the inner wall of the fixed frame (71), a sliding groove (75) is provided inside the fixed frame (71) near the bottom of the clamping groove (74), and a sliding structure (76) is provided inside the sliding groove (75).

5. The method for preparing a silicon carbide ceramic part according to claim 4, characterized in that: The rotating structure (72) includes a rotating shaft (721), which is movably mounted inside the fixed frame (71); a sleeve (722) is fixedly mounted on the outer wall of the rotating shaft (721); a groove (723) is provided on the outer wall of the sleeve (722); a through hole (724) is provided inside the groove (723); a pushing plate (725) is movably connected inside the through hole (724); a second bearing (726) is rotatably connected to the left end of the rotating shaft (721); and a second motor (727) is fixedly connected to the right end of the rotating shaft (721).

6. The method for preparing a silicon carbide ceramic part according to claim 5, characterized in that: The sliding structure (76) includes a sliding plate (761), the sliding plate (761) is movably connected to the inside of the sliding groove (75), a rectangular groove (762) is provided inside the sliding plate (761), a spring (763) is fixedly connected to the inside of the rectangular groove (762), the top of the spring (763) is fixedly connected to a baffle (764), a movable groove (765) is provided inside the baffle (764), the top of the sliding plate (761) is fixedly connected to a pin seat (766), the inside of the pin seat (766) is movably connected to a push rod (767) through a pin shaft, the right outer wall of the push rod (767) is fixedly connected to a tension spring (768), the right end of the sliding plate (761) is fixedly connected to the output end of the electric hydraulic cylinder (769), and the bottom of the sliding plate (761) is movably connected to a pulley (7610).

7. The method for preparing a silicon carbide ceramic part according to claim 6, wherein: The outer wall of the rotating shaft (721) is fixedly connected to a pushing plate (725), the left end of the second bearing (726) is fixedly installed inside the left side of the fixed frame (71), and the left side of the second motor (727) is fixedly installed on the outer wall of the right end of the fixed frame (71). The size of the baffle (764) matches the size of the rectangular groove (762), and the interior of the movable groove (765) is movably connected to a tension spring (768), and the bottom end of the tension spring (768) is fixedly connected to the bottom of the inner wall of the rectangular groove (762).

8. The method for preparing a silicon carbide ceramic part according to claim 7, wherein: The electric hydraulic cylinder (769) is fixedly mounted on the right end of the sliding groove (75), the bottom of the pulley (7610) is slidably connected to the inside of the sliding groove (75), the left side of the second motor (727) is fixedly mounted on the right outer wall of the housing (2), the third discharge pipe (10) is fixedly mounted on the right side of the housing (2), the bottom of the first discharge pipe (6) is fixedly connected to the inside of the top of the fixed frame (71), the bottom of the second discharge pipe (73) is fixedly connected to the inside of the top of the collection box (8), and the first bearing (43) is fixedly mounted on the inside of the top of the housing (2).

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