Ceramic composite bearing and method for manufacturing same

Abstract

The application relates to a ceramic composite material bearing and a preparation method thereof. The inner and outer rings of the bearing are integrally designed and prepared by using continuous fiber reinforced ceramic composite material, woven fiber cloth is wound to the outer surfaces of the inner and outer ring molds to obtain a preform, and an interface layer and a ceramic matrix are sequentially deposited on the surface of the fiber preform. Through the thermal and physical compatibility matching design of the inner and outer rings of the bearing and the ceramic roller, the ceramic composite material bearing with the comprehensive performances of high temperature resistance, high toughness and high wear resistance is obtained. The bearing structure is simple, and accessories such as supporting frames, dust covers and lubricating grease are not needed. The application further discloses a preparation method of the bearing. The preparation method can realize the preparation of a large-size ceramic bearing, and can significantly improve the impact resistance of the bearing in a high-temperature and complex load environment.

Description

Technical Field

[0001] This invention belongs to the field of new material bearing technology, and relates to a ceramic composite bearing and its preparation method, specifically a high-toughness ceramic composite bearing suitable for high-temperature environments. Background Technology

[0002] Bearings are crucial components in mechanical equipment, widely used in the national economy and defense industry. Currently, the rapid development of high-tech fields such as aviation, aerospace, nuclear energy, and photovoltaics has created an urgent need for bearings that can withstand high temperatures and corrosive environments. Ceramic bearings, with their excellent properties such as wear resistance, acid and alkali resistance, high temperature resistance, and long service life, have been widely used in various industrial sectors. However, due to the inherent brittleness of ceramic materials, the ceramic inner and outer ring structures used in conventional ceramic bearings are relatively small, making it difficult to manufacture large-scale bearings and apply them in complex working conditions. Furthermore, although conventional ceramic bearings can withstand the high temperatures caused by rapid rotation, their support frames or dust covers still use polymer materials, or still require grease for lubrication. These materials can volatilize, coke, or even carbonize at high temperatures, making it impossible for the bearing to operate normally for extended periods in high-temperature environments. Summary of the Invention

[0003] Technical problems to be solved

[0004] To avoid the shortcomings of existing technologies, this invention proposes a ceramic composite bearing and its preparation method.

[0005] Technical solution

[0006] A ceramic composite bearing is characterized in that: the inner ring 4 and the outer ring 1 of the bearing are made of continuous fiber reinforced ceramic composite material, and the outer side of the inner ring 4 and the inner side of the outer ring 1 are provided with grooved annular parts; the two grooves are integrated and a roller 2 is provided inside; the roller 2 is made of bulk pure ceramic material; the inner ring and the outer ring of the bearing are an integrated structure; the side of the inner ring 4 of the bearing is provided with an inner ring filling port 3, and the side of the outer ring 1 is provided with an outer ring filling port 5, and the two filling ports form a circular hole for filling the roller 2.

[0007] The fibers in the continuous fiber reinforced ceramic composite material include, but are not limited to, silicon carbide fibers or carbon fibers; the ceramics include, but are not limited to, silicon carbide or silicon nitride.

[0008] The bulk pure ceramics include, but are not limited to: silicon nitride, silicon carbide, zirconium oxide, or boron nitride.

[0009] The roller is a ball roller or a cylindrical roller.

[0010] A method for preparing the ceramic composite bearing, characterized by the following steps:

[0011] Step 1, Mold Design and Manufacturing: Using electrode graphite or high-strength graphite, a cylindrical mold blank is machined according to the inner surface of the outer ring of the bearing, and a cylindrical mold blank is machined according to the inner surface of the inner ring of the bearing.

[0012] The core of the mold blank is removed by machining to form a cylinder with a wall thickness of 2-5mm;

[0013] Ventilation holes with a diameter of 3-8mm are machined along the normal direction of the cylindrical surface, with a spacing of 12-30mm between the ventilation holes, to obtain the outer ring and the mold for the outer ring.

[0014] Step 2, Preparation of continuous fiber preform: The woven fiber cloth is wound onto the outer surface of the outer ring mold and onto the outer surface of the inner ring mold. Carbon fiber or silicon carbide fiber is used as stitching thread to sew the woven fiber cloth wound on the inner mold to obtain the outer ring and inner ring preforms.

[0015] The thickness of the interface layer is 100-600 nm;

[0016] The interface layer material is pyrolytic carbon or boron nitride;

[0017] The ceramic matrix is ​​silicon carbide or silicon nitride;

[0018] Step 3, Densification and Processing of Fiber Preform: Using chemical vapor deposition, an interface layer and a ceramic matrix are sequentially deposited on the surface of the fiber preform, and then the mold is removed; it is processed to the designed dimensions to obtain the inner and outer rings of the ceramic composite material;

[0019] Step 4, Groove Polishing: Use a diamond grinding head to grind the grooves of the inner and outer rings. During the grinding process, apply diamond polishing paste to the surface of the grinding head and the grooves, and perform rough polishing, semi-fine polishing and fine polishing respectively.

[0020] Step 5, Bearing Assembly: Fix the inner and outer rings of the bearing on the centering fixture, so that the inner and outer rings are coaxial and their two end faces are flush; adjust the circumferential angle of the inner and outer rings to align the filling ports; insert the rollers through the filling ports in sequence; remove the bearing after filling the rollers from the fixture to obtain the ceramic composite bearing.

[0021] The preparation process of the pyrolytic carbon interface layer is as follows: under a pressure of 100-2000 Pa, the temperature is raised to 800-1000℃ and held for 5-8 hours. Then, a mixed gas of propylene and hydrogen is introduced and deposited for 5-18 hours. After that, the temperature is held for another 1-2 hours and then cooled to room temperature. Then, under vacuum conditions, the temperature is heat-treated at 1800-1950℃ for 20-30 hours. The flow ratio of propylene to hydrogen is 1:1-5. The process is repeated 1-3 times.

[0022] The preparation process of the boron nitride interface layer is as follows: under a pressure of 50-1000 Pa, the temperature is raised to 600-900℃ and held for 3-5 hours. Then, a mixed gas of argon, hydrogen, ammonia and boron trichloride is introduced. After deposition for 5-12 hours, the temperature is held for another 1-2 hours and then cooled to room temperature. The flow rate ratio of argon, hydrogen, ammonia and boron trichloride is 1:4-6:2-8:2-8. The process is repeated 1-3 times.

[0023] When the ceramic matrix is ​​silicon carbide, the preparation process is as follows: under a pressure of 200-2000 Pa, the temperature is raised to 800-1100℃, and after holding at that temperature for 3-5 hours, a mixed gas of trichloromethylsilane, hydrogen, and argon is introduced. After deposition for 15-25 hours, the temperature is held for another 1-2 hours, and then cooled to room temperature. The flow rate ratio of trichloromethylsilane, hydrogen, and argon is 1:5-25:10-25. The process is repeated 4-12 times.

[0024] When the ceramic matrix is ​​silicon nitride, its preparation process is as follows: under a pressure of 200-4000 Pa, the temperature is raised to 700-1100℃ and held for 1-2 hours. Then, a mixture of hydrogen, argon, trichloromethylsilane and ammonia is deposited for 10-20 hours, followed by holding for another 1-2 hours and then cooling to room temperature. The flow rate ratio of hydrogen, argon, trichloromethylsilane and ammonia is 1:1:5-50:5-50. The process is repeated 6-10 times.

[0025] The raw materials for the woven fiber fabric can be carbon fiber, silicon carbide fiber, or a combination of both. The weaving method for the woven fiber fabric is two-dimensional plain weave, two-dimensional satin weave, two-dimensional twill weave, 2.5-dimensional weave, or three-dimensional needle punching.

[0026] Beneficial effects

[0027] This invention proposes a ceramic composite bearing and its preparation method. The bearing's inner and outer rings are integrally designed and prepared from continuous fiber-reinforced ceramic composite materials. A preform is obtained by winding woven fiber cloth onto the outer surface of the mold for both the outer and inner rings. An interface layer and a ceramic matrix are then sequentially deposited on the surface of the fiber preform. Through the thermal and physical compatibility matching design of the bearing's inner and outer rings and ceramic rollers, a ceramic composite bearing with comprehensive properties such as high temperature resistance, high toughness, and high wear resistance is obtained. The bearing structure is simple and requires no accessories such as support frames, dust covers, or lubricating grease. This invention also discloses the preparation method of the above-mentioned bearing. This preparation method can realize the preparation of larger-sized ceramic bearings and can significantly improve the impact resistance of bearings under high temperature and complex load environments.

[0028] The ceramic composite bearing involved in this invention has the following advantages: it uses a ceramic composite material with high fracture toughness as the main material of the inner and outer rings of the bearing, which can significantly improve the bearing's resistance to impact loads compared with conventional ceramic bearings; the use of a rolling pair of ceramic composite inner and outer rings and ceramic rollers can eliminate the need for support frames and lubrication measures, simplifying the bearing structure and enabling the bearing to work in high-temperature environments for a long time.

[0029] I. The inner and outer rings of the ceramic composite material, designed and prepared in an integrated manner through the above approach, exhibit a fracture toughness of 15-27 MPa·m. 1 / 2 The yield is 2-5 times higher than that of silicon nitride and silicon carbide materials used in the inner and outer rings of existing ceramic bearings. Therefore, the technology of this invention can realize the fabrication of bearings with larger dimensions (outer diameter Φ>80mm) and can significantly improve the bearing's resistance to impact loads in complex operating environments.

[0030] II. The inner and outer rings of the ceramic composite material prepared by this technology possess wear resistance, high temperature resistance, and corrosion resistance, and exhibit excellent physical and chemical compatibility with the ceramic rollers used in this technology. Therefore, bearings prepared using this technology do not require polymer material support frames or dust covers, nor do they require grease for auxiliary lubrication, enabling long-term use in high-temperature environments. When using silicon nitride rollers, the long-term temperature resistance of the bearing can reach 1350℃; when using silicon carbide rollers, the long-term temperature resistance of the bearing can reach 1600℃. Attached Figure Description

[0031] Figure 1 : Exploded view of a ceramic composite bearing component;

[0032] Figure 2 : Structural assembly drawing of ceramic composite bearing

[0033] 1-Outer ring, 2-Roller, 3-Inner ring, 4-Inner ring filling port, 5-Outer ring filling port, 6-Groove. Detailed Implementation

[0034] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0035] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods; the reagents and raw materials described are commercially available unless otherwise specified.

[0036] Example 1

[0037] The bearing's inner and outer rings are integrally designed and fabricated using a continuous silicon carbide fiber-reinforced silicon carbide ceramic composite material. The bearing has an outer diameter of 95 mm, an inner diameter of 60 mm, and a thickness of 17.5 mm. The rollers are made of silicon nitride ceramic balls with a diameter of 8 mm. The fabrication method includes the following steps:

[0038] Step 1: Mold Design and Manufacturing. Using electrode graphite as the raw material, cylindrical mold blanks are machined with reference to the inner surfaces of the outer and inner rings of the bearing. The core of the mold blank is removed to form a cylinder with a wall thickness of 5mm. Vent holes with a diameter of 6mm are machined along the normal direction of the cylindrical surface, with a spacing of 18mm between the vent holes. The molds for the outer ring and the outer ring are thus obtained.

[0039] Step 2: Preparation of continuous fiber preforms. Two-dimensional plain-weave silicon carbide fiber cloth is wound onto the outer surface of the outer and inner ring molds, and silicon carbide fibers are used as stitching thread to sew the woven fiber cloth wound on the inner mold. This yields the outer and inner ring preforms.

[0040] Step 3: Densification and processing of the fiber preform. A boron nitride interface layer and a silicon carbide ceramic matrix are sequentially deposited on the surface of the fiber preform, and then the mold is removed; it is then processed to the designed dimensions to obtain the inner and outer rings of the ceramic composite material.

[0041] The preparation process of the boron nitride interface layer is as follows: under a pressure of 200 Pa, the temperature is raised to 700 °C and held for 5 h. Then, a mixture of argon, hydrogen, ammonia and boron trichloride gas is introduced. After deposition for 12 h, the temperature is held for another 2 h and then cooled to room temperature. The flow rate ratio of argon, hydrogen, ammonia and boron trichloride is 1:4:6:5. The process is repeated 3 times.

[0042] The preparation process of silicon carbide ceramic matrix is ​​as follows: under a pressure of 300 Pa, the temperature is raised to 950℃ and held for 4 hours. Then, a mixed gas of trichloromethylsilane, hydrogen and argon is introduced. After deposition for 20 hours, the temperature is held for another 2 hours and then cooled to room temperature. The flow rate ratio of trichloromethylsilane, hydrogen and argon is 1:15:15. The process is repeated 12 times.

[0043] Step 4: Groove Polishing. The grooves on the inner and outer rings are ground using a diamond grinding head. During grinding, diamond polishing paste is applied to the grinding head and groove surfaces, and rough polishing, semi-finish polishing, and finish polishing are performed respectively.

[0044] During rough polishing, the grinding paste particle size is 24μm; during semi-fine polishing, the grinding paste particle size is 6μm; during fine polishing, the grinding paste particle size is 2μm; the grinding head particle size and the grinding paste particle size are matched.

[0045] Step 5: Bearing assembly. Fix the inner and outer rings of the bearing on the centering fixture, making the inner and outer rings coaxial and their end faces flush; adjust the circumferential angle of the inner and outer rings to align the filling ports; insert the rollers through the filling ports one by one; remove the bearing after filling the rollers from the fixture to obtain the ceramic composite bearing.

[0046] The ceramic composite bearings prepared using the above steps were tested using the following standards: "Test Method for Tensile Properties of Continuous Fiber Reinforced Ceramic Matrix Composites at Room Temperature" (GJB 6475-2008), "Test Method for Compression Properties of Continuous Fiber Reinforced Ceramic Matrix Composites at Room Temperature" (GJB 6476-2008), and "Test Method for Fracture Toughness of Fine Ceramics - Single-Sided Precracked Beam (SEPB) Method" (GB / T 23806-2009). The tensile strength of the inner and outer ring materials was 260 MPa, the compressive strength was 500 MPa, and the fracture toughness was 22 MPa·m. 1 / 2 After placing the bearing in a muffle furnace and exposing it to air at 1200℃ for 100 hours, the weight change rate was less than 1%, indicating that the bearing's rolling function was normal.

[0047] Example 2

[0048] The bearing's inner and outer rings are integrally designed and fabricated using continuous carbon fiber reinforced silicon carbide ceramic composite materials. The bearing has an outer diameter of 130 mm, an inner diameter of 80 mm, and a thickness of 28 mm. The rollers are made of silicon carbide ceramic cylinders with a diameter of 10 mm. The fabrication method includes the following steps:

[0049] Step 1: Mold Design and Manufacturing. Using high-strength graphite as the raw material, cylindrical mold blanks are machined with reference to the inner surfaces of the outer and inner rings of the bearing. The core of the mold blank is removed to form a cylinder with a wall thickness of 4mm. Vent holes with a diameter of 5mm are machined along the normal direction of the cylindrical surface, with a spacing of 12mm between the vent holes. The molds for the outer ring and the outer ring are thus produced.

[0050] Step 2: Preparation of continuous fiber preforms. Three-dimensional needle-punched carbon fibers are wound onto the outer surfaces of the outer and inner ring molds, and carbon fibers are used as stitching thread to sew the fibers wound on the inner mold. This yields the outer and inner ring preforms.

[0051] Step 3: Densification and processing of the fiber preform. A pyrolytic carbon interface layer and a silicon carbide ceramic matrix are sequentially deposited on the surface of the fiber preform, and then the mold is removed; it is then processed to the designed dimensions to obtain the inner and outer rings of the ceramic composite material.

[0052] The preparation process of the pyrolytic carbon interface layer is as follows: under a pressure of 280 Pa, the temperature is raised to 1000℃ and held for 3 hours. Then, a mixed gas of propylene and hydrogen is introduced and deposited for 12 hours. After that, the temperature is held for another 2 hours and then cooled to room temperature. Then, under vacuum conditions, it is heat-treated at 1850℃ for 30 hours. The flow rate ratio of propylene to hydrogen is 1:5. The process is repeated 3 times.

[0053] The preparation process of silicon carbide ceramic matrix is ​​as follows: under a pressure of 200-2000 Pa, the temperature is raised to 1050℃ and held for 3 hours. Then, a mixed gas of trichloromethylsilane, hydrogen and argon is introduced. After deposition for 24 hours, the temperature is held for another 2 hours and then cooled to room temperature. The flow rate ratio of trichloromethylsilane, hydrogen and argon is 1:20:15. The process is repeated 10 times.

[0054] Step 4: Groove Polishing. The grooves on the inner and outer rings are ground using a diamond grinding head. During grinding, diamond polishing paste is applied to the grinding head and groove surfaces, and rough polishing, semi-finish polishing, and finish polishing are performed respectively.

[0055] During rough polishing, the grinding paste particle size is 20μm; during semi-fine polishing, the grinding paste particle size is 5μm; during fine polishing, the grinding paste particle size is 1μm; the grinding head particle size and the grinding paste particle size are matched.

[0056] Step 5: Bearing assembly. Fix the inner and outer rings of the bearing on the centering fixture, making the inner and outer rings coaxial and their end faces flush; adjust the circumferential angle of the inner and outer rings to align the filling ports; insert the rollers through the filling ports one by one; remove the bearing after filling the rollers from the fixture to obtain the ceramic composite bearing.

[0057] The ceramic composite bearings prepared using the above steps were tested using the following standards: "Test Method for Tensile Properties of Continuous Fiber Reinforced Ceramic Matrix Composites at Room Temperature" (GJB 6475-2008), "Test Method for Compression Properties of Continuous Fiber Reinforced Ceramic Matrix Composites at Room Temperature" (GJB 6476-2008), and "Test Method for Fracture Toughness of Fine Ceramics - Single-Sided Precracked Beam (SEPB) Method" (GB / T 23806-2009). The tensile strength of the inner and outer ring materials was 224 MPa, the compressive strength was 387 MPa, and the fracture toughness was 18 MPa·m. 1 / 2 After placing the bearing in a muffle furnace and exposing it to air at 1500℃ for 100 hours, the weight change rate was less than 1%, indicating that the bearing's rolling function was normal.

Claims

1. A method for preparing a ceramic composite bearing, characterized in that: The bearing inner ring (4) and outer ring (1) are made of continuous fiber reinforced ceramic composite material, and the outer side of the inner ring (4) and the inner side of the outer ring (1) are provided with grooved annular parts; the two grooves are integrated and a roller (2) is provided inside; the roller (2) is made of bulk pure ceramic material; the bearing inner ring and outer ring are integrated structures; the inner ring (4) is provided with an inner ring filling port (3) on the side, and the outer ring (1) is provided with an outer ring filling port (5) on the side, and the two filling ports form a circular hole for filling the roller (2); The method includes: Step 1, Mold Design and Manufacturing: Using electrode graphite or high-strength graphite, a cylindrical mold blank is machined according to the inner surface of the outer ring of the bearing, and a cylindrical mold blank is machined according to the inner surface of the inner ring of the bearing. The core of the mold blank is removed by machining to form a cylinder with a wall thickness of 2-5 mm; Ventilation holes with a diameter of 3-8 mm are machined along the normal direction of the cylindrical surface, with a spacing of 12-30 mm between the ventilation holes, to obtain the outer ring and the mold for the outer ring. Step 2, Preparation of continuous fiber preform: The woven fiber cloth is wound onto the outer surface of the outer ring mold and onto the outer surface of the inner ring mold. Carbon fiber or silicon carbide fiber is used as stitching thread to sew the woven fiber cloth wound on the inner mold to obtain the outer ring and inner ring preforms. Step 3, Densification and Processing of Fiber Preform: Using chemical vapor deposition, an interface layer and a ceramic matrix are sequentially deposited on the surface of the fiber preform, and then the mold is removed; it is processed to the designed dimensions to obtain the inner and outer rings of the ceramic composite material; The thickness of the interface layer is 100-600 nm; The interface layer material is pyrolytic carbon or boron nitride; The ceramic matrix is ​​silicon carbide or silicon nitride; Step 4, Groove Polishing: Use a diamond grinding head to grind the grooves of the inner and outer rings. During the grinding process, apply diamond polishing paste to the surface of the grinding head and the grooves, and perform rough polishing, semi-fine polishing and fine polishing respectively. Step 5, Bearing Assembly: Fix the inner and outer rings of the bearing on the centering fixture, so that the inner and outer rings are coaxial and the two end faces are flush; adjust the circumferential angle of the inner and outer rings to align the filling ports; insert the rollers through the filling ports one by one; remove the bearing after filling the rollers from the fixture to obtain the ceramic composite bearing. The preparation process of the pyrolytic carbon interface layer is as follows: under a pressure of 100-2000 Pa, the temperature is raised to 800-1000℃ and held for 5-8 hours. Then, a mixed gas of propylene and hydrogen is introduced, and after deposition for 5-18 hours, the temperature is held for another 1-2 hours and then cooled to room temperature. Then, under vacuum conditions, it is heat-treated at 1800-1950℃ for 20-30 hours. The flow ratio of propylene to hydrogen is 1:1-5. The process is repeated 1-3 times. The preparation process of the boron nitride interface layer is as follows: under a pressure of 50-1000 Pa, the temperature is raised to 600-900℃ and held for 3-5 hours. Then, a mixed gas of argon, hydrogen, ammonia, and boron trichloride is introduced. After deposition for 5-12 hours, the temperature is held for another 1-2 hours and then cooled to room temperature. The flow rate ratio of argon, hydrogen, ammonia, and boron trichloride is 1:4-6:2-8:2-8. This process is repeated 1-3 times. When the ceramic matrix is ​​silicon carbide, the preparation process is as follows: under a pressure of 200-2000 Pa, the temperature is raised to 800-1100℃, and after holding at that temperature for 3-5 hours, a mixed gas of trichloromethylsilane, hydrogen, and argon is introduced. After deposition for 15-25 hours, the temperature is held for another 1-2 hours, and then cooled to room temperature. The flow rate ratio of trichloromethylsilane, hydrogen, and argon is 1:5-25:10-25. This process is repeated 4-12 times. When the ceramic matrix is ​​silicon nitride, its preparation process is as follows: under a pressure of 200-4000 Pa, the temperature is raised to 700-1100℃ and held for 1-2 hours. Then, a mixture of hydrogen, argon, trichloromethylsilane and ammonia is deposited for 10-20 hours, followed by holding for another 1-2 hours and then cooling to room temperature. The flow rate ratio of hydrogen, argon, trichloromethylsilane and ammonia is 1:1:5-50:5-50. The process is repeated 6-10 times.

2. The method for preparing the ceramic composite bearing according to claim 1, characterized in that: The fibers in the continuous fiber-reinforced ceramic composite material include silicon carbide fibers or carbon fibers; the ceramics include silicon carbide or silicon nitride.

3. The method for preparing the ceramic composite bearing according to claim 1, characterized in that: The bulk pure ceramic includes silicon nitride, silicon carbide, zirconium oxide, or boron nitride.

4. The method for preparing the ceramic composite bearing according to claim 1, characterized in that: The roller is a ball roller or a cylindrical roller.

5. The method according to claim 1, characterized in that: The raw material of the woven fiber cloth is carbon fiber, silicon carbide fiber, or a combination of carbon fiber and silicon carbide fiber; the weaving method of the woven fiber cloth is two-dimensional plain weave, two-dimensional satin weave, two-dimensional twill weave, 2.5-dimensional weave, or three-dimensional needle punching.

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