98% alumina photovoltaic insulating ceramics

Abstract

This invention relates to the field of ceramic materials, specifically 98% alumina photovoltaic insulating ceramics. The 98% alumina photovoltaic insulating ceramics are prepared by the following steps: preparation of a toughening agent; airflow mixing of alumina powder and a composite sintering agent; preparation of a ceramic composite slurry; and sintering of the ceramic composite slurry. This invention prepares a toughening agent with single-walled carbon nanotubes, silicon nitride, and zirconium dioxide as its main components. The modified single-walled carbon nanotubes possess excellent mechanical properties and thermal conductivity. The system formed by silicon nitride, zirconium dioxide, and ethyl cellulose simultaneously enhances the stability of the toughening agent. During subsequent sintering, the decomposition products of ethyl cellulose prevent the decomposition of silicon nitride, allowing silicon nitride and zirconium dioxide to better inhibit the growth of alumina grains, thus significantly improving the toughness of the alumina ceramic. Adding this toughening agent to alumina ceramics can greatly hinder the generation and propagation of ceramic cracks, thereby improving the toughness of the 98% alumina photovoltaic insulating ceramics.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials, specifically 98% alumina photovoltaic insulating ceramics. Background Technology

[0002] Photovoltaic systems, also known as solar photovoltaic power generation systems, are often used outdoors to convert solar energy into electrical energy to provide power to people. Photovoltaic insulation materials refer to the insulation materials and components used in photovoltaic systems. They are widely used in various parts of photovoltaic systems, including photovoltaic modules, junction boxes, tracking systems, inverters, etc. The main function of photovoltaic insulation materials is to protect the photovoltaic system from electrical faults such as electric shock, leakage, and short circuits, while providing good mechanical support and wear resistance.

[0003] Therefore, photovoltaic insulating materials typically need to possess high mechanical properties, high weather resistance, high mechanical strength, and chemical corrosion resistance simultaneously. Ceramic materials not only meet these characteristics well, but also have abundant raw material sources and low production costs, making them commonly used photovoltaic insulating materials, such as alumina ceramics. However, most existing alumina ceramics have high hardness but low toughness, resulting in high brittleness. Furthermore, since photovoltaic systems are often installed outdoors, alumina ceramics are prone to cracking when subjected to forces from wind and rain, which significantly reduces their mechanical properties and makes photovoltaic systems susceptible to electrical failures.

[0004] To address the aforementioned technological challenges, this invention researches a 98% alumina photovoltaic insulating ceramic with high toughness, which is less prone to cracking when protecting photovoltaic systems. Summary of the Invention

[0005] To address the aforementioned technical deficiencies, this invention researches a 98% alumina photovoltaic insulating ceramic that exhibits high toughness, making it less prone to cracking when protecting photovoltaic systems.

[0006] The preparation process of 98% alumina photovoltaic insulating ceramic includes the following steps:

[0007] S1: Preparation of toughening agent

[0008] Single-walled carbon nanotubes were ultrasonically cleaned and then vacuum dried to obtain pretreated single-walled carbon nanotubes. Aluminate coupling agent and pretreated single-walled carbon nanotubes were added to a mixer, a protective gas was introduced into the mixer, and the temperature was raised for stirring to obtain modified single-walled carbon nanotubes. Silicon nitride, zirconium dioxide, ethyl cellulose and anhydrous ethanol were mixed and ball-milled. The resulting mixed powder and modified single-walled carbon nanotubes were poured into a planetary ball mill for ball milling and drying to obtain a toughening agent.

[0009] S2: Gas flow mixing of alumina powder and composite sintering agent

[0010] Fluorinated graphite, ZnO, and montmorillonite are mixed in a mixer to obtain a composite sintering agent. Nano-alumina and the composite sintering agent are then added to an air jet mill for air jet mixing to obtain alumina sintered powder.

[0011] S3: Preparation of ceramic composite slurry

[0012] Acetylacetone and tetrabutyl titanate were added to a container and mixed evenly. The resulting mixture was then magnetically stirred to obtain an acetylacetone-tetrabutyl titanate solution. Xylene was then mixed with the acetylacetone-tetrabutyl titanate solution and added to the container. Alumina sintering powder was then added to the container and stirred to obtain a mixed solution. Toughening agent and silane coupling agent were added to the container and stirred at high speed to obtain a ceramic composite slurry.

[0013] S4: Sintering of ceramic composite slurry

[0014] The ceramic composite slurry is poured onto a casting machine, and the parameters are adjusted to obtain an alumina ceramic film of a certain thickness. The alumina ceramic film is then placed in a high-temperature sintering furnace. The furnace temperature is first raised at a relatively fast rate and then held for a period of time. The furnace temperature is then raised at a slower rate and held for sintering for a period of time to obtain 98% alumina photovoltaic insulating ceramic.

[0015] Furthermore, the preparation of the toughening agent in step S1 specifically includes the following steps:

[0016] S1.1: Place 5-6 portions of single-walled carbon nanotubes in an ultrasonic cleaner, set the ultrasonic frequency to 30-40 kHz, and ultrasonically clean for 20-25 minutes. Place the cleaned single-walled carbon nanotubes in a vacuum drying oven and adjust the vacuum degree inside the oven to 10. -3 -5×10 -3 Pa, at a temperature of 545-550℃, is dried and impurities removed for 30-35 minutes to obtain pretreated single-walled carbon nanotubes;

[0017] S1.2: Take 0.4-0.5 parts of aluminate coupling agent and pretreated single-walled carbon nanotubes and add them to a mixer. Introduce a protective gas into the mixer until the ambient atmosphere becomes a protective atmosphere. Adjust the stirring temperature to 50-55℃ and the speed to 100-120rpm. Stir for 50-55 minutes to obtain modified single-walled carbon nanotubes.

[0018] S1.3: Place 3-4 parts silicon nitride, 1.5-2 parts zirconium dioxide, 0.4-0.5 parts ethyl cellulose and 3-4 parts anhydrous ethanol in a ball mill and mill at 450-500 rpm for 1.5-2 hours. Pour the resulting mixed powder and modified single-walled carbon nanotubes into a planetary ball mill and mill at 550-600 rpm for 30-35 minutes. Collect the mixed powder and place it in a drying oven to dry at 80-85℃ for 2-3 hours to obtain the toughening agent.

[0019] Further, the mixing of alumina powder and composite sintering agent in step S2 specifically includes the following steps:

[0020] S2.1: Mix 1-2 parts of fluorinated graphite, 3-4 parts of ZnO and 2-3 parts of montmorillonite using a mixer to obtain a composite sintering agent;

[0021] S2.2: Add 1000-1050 parts of nano-alumina and composite sintering agent to an air jet mill, adjust the mill power to 200-220 kW, and the gas consumption to 25-30 m³ / h. 3 At a gas pressure of 0.6-0.8 MPa, nano-alumina and composite sintering agent are mixed by airflow for 25-30 minutes to obtain alumina sintered powder.

[0022] Furthermore, the preparation of the ceramic composite slurry in step S3 specifically includes the following steps:

[0023] S3.1: Add acetylacetone and tetrabutyl titanate to a container and mix well. Stir the resulting mixture with a magnetic stirrer at 300-320 rpm for 1.5-2 hours to obtain an acetylacetone-tetrabutyl titanate solution.

[0024] S3.2: Mix xylene with acetylacetone-tetrabutyl titanate solution and add to a container, then add alumina sintered powder to the container and stir for 10-15 minutes to obtain a mixed solution;

[0025] S3.3: Add toughening agent and 1-1.2% of the volume of the resulting mixed solution of silane coupling agent to the container, and stir at high speed of 1600-1800 rpm for 20-25 minutes using a digital display cantilever constant speed high-power electric mixer to obtain ceramic composite slurry.

[0026] Furthermore, the sintering of the ceramic composite slurry in step S4 specifically includes the following steps:

[0027] S4.1: Pour the ceramic composite slurry onto the casting machine, adjust the casting speed to 0.6-0.8 m / min, and the casting temperature to 70-75℃ to obtain an alumina ceramic film with a thickness of 2-3 mm;

[0028] S4.2: Place the alumina ceramic film in a high-temperature sintering furnace. First, raise the furnace temperature to 690-700℃ at a heating rate of 8-10℃ / min and hold for 25-30 minutes. Then, raise the furnace temperature to 1600-1650℃ at a heating rate of 4-5℃ / min and hold for sintering for 2.5-3 hours to obtain 98 alumina photovoltaic insulating ceramic.

[0029] Furthermore, the protective gas in step S1.2 is nitrogen.

[0030] Furthermore, in step S1.3, the grinding balls in the ball mill are alumina balls with a particle size of 2-3 mm.

[0031] Furthermore, in step S3.1, the molar ratio of acetylacetone to tetrabutyl titanate is 1:(1-1.2).

[0032] Further, in step S3.2, the volume ratio of xylene to acetylacetone-butyl titanate solution is 1:(1-1.05).

[0033] Furthermore, the silane coupling agent in step S3.3 is trimethyltrimethoxysilane.

[0034] The beneficial effects are as follows: 1. This invention prepares a toughening agent with single-walled carbon nanotubes, silicon nitride, and zirconium dioxide as the main components. The single-walled carbon nanotubes modified with an aluminate coupling agent under a nitrogen atmosphere not only have excellent mechanical properties and thermal conductivity, but also can better combine with alumina. The silicon nitride, zirconium dioxide, and ethyl cellulose are mixed and ball-milled to form a silicon nitride, zirconium dioxide, and ethyl cellulose system. This not only increases the stability of the toughening agent when preparing ceramic composite slurry, but also allows the decomposition products of ethyl cellulose to adhere to the surface of silicon nitride during the subsequent sintering process, preventing the decomposition of silicon nitride. This allows silicon nitride and zirconium dioxide to better inhibit the growth of alumina grains, which can significantly improve the toughness of alumina ceramics. Adding this toughening agent to alumina ceramics can greatly hinder the generation and propagation of ceramic cracks and improve the toughness of 98 alumina photovoltaic insulating ceramics.

[0035] 2. This invention uses an airflow pulverizer to prepare alumina sintering powder from fluorinated graphite, ZnO, and montmorillonite. The resulting alumina sintering powder has a more uniform composition, and the powder particles collide and bond tightly during the formation process. This not only helps the alumina ceramic particles to better agglomerate and sinter during the sintering process of 98% alumina photovoltaic insulating ceramics, increasing the density of the ceramic material and thus improving its mechanical properties, but also the high thermal conductivity of fluorinated graphite and ZnO can improve the thermal conductivity of 98% alumina photovoltaic insulating ceramics to a certain extent, preventing heat accumulation and extending its service life.

[0036] 3. In this invention, alumina ceramic film is first prepared by casting ceramic composite slurry onto a casting machine. Then, the alumina ceramic film is subjected to a two-stage heating process at a certain speed. The first stage allows the alumina ceramic film to be degummed better, and the second stage sinters the alumina ceramic film, making the components of the sintered 98 alumina photovoltaic insulating ceramic more compact, thereby further improving its mechanical properties. Attached Figure Description

[0037] Figure 1 The flowchart shows the process for preparing 98% alumina photovoltaic insulating ceramics used in the embodiments of the present invention.

[0038] Figure 2 This is a table comparing the fracture toughness of 98% alumina photovoltaic insulating ceramic and 98% alumina ceramic tube prepared in the embodiment of Comparative Example 1 of the present invention.

[0039] Figure 3 This is a comparative table showing the fracture toughness of the 98 alumina photovoltaic insulating ceramic prepared in Example 2 of the present invention and the 98 alumina photovoltaic insulating ceramic prepared in Example 1 (with step S1 removed). Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all 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.

[0041] Example 1

[0042] The preparation process of 98% alumina photovoltaic insulating ceramics, such as Figure 1 As shown, the specific steps include:

[0043] S1: Preparation of toughening agent

[0044] S1.1: Place 5 portions of single-walled carbon nanotubes in an ultrasonic cleaner, set the ultrasonic frequency to 35 kHz, and perform ultrasonic cleaning for 20 minutes. Then place the cleaned single-walled carbon nanotubes in a vacuum drying oven and adjust the vacuum degree inside the oven to 10. - 3 Pa, temperature 545℃, drying and impurity removal for 30 minutes to obtain pretreated single-walled carbon nanotubes;

[0045] S1.2: Take 0.4 parts of aluminate coupling agent and pretreated single-walled carbon nanotubes and add them to a mixer. Pour nitrogen into the mixer until the ambient atmosphere becomes nitrogen. Adjust the stirring temperature to 50℃ and the speed to 100 rpm. Stir for 50 minutes to obtain modified single-walled carbon nanotubes, which have excellent mechanical properties and thermal conductivity, and can also better combine with alumina.

[0046] S1.3: Place 3 parts silicon nitride, 1.5 parts zirconium dioxide, 0.4 parts ethyl cellulose and 3 parts anhydrous ethanol in a ball mill. Silicon nitride and zirconium dioxide can inhibit the growth of alumina grains and significantly improve the toughness of alumina ceramics. Adjust the speed to 450 rpm and ball mill for 1.5 hours. Pour the resulting mixed powder and modified single-walled carbon nanotubes into a planetary ball mill and ball mill at 550 rpm for 30 minutes. Collect the mixed powder and place it in a drying oven to dry at 80°C for 2 hours to obtain a toughening agent. Adding this toughening agent to alumina ceramics can greatly hinder the generation and propagation of ceramic cracks and improve the toughness of 98 alumina photovoltaic insulating ceramics.

[0047] S2: Gas flow mixing of alumina powder and composite sintering agent

[0048] S2.1: Mix 1 part fluorinated graphite, 3 parts ZnO and 2 parts montmorillonite in a mixer to obtain a composite sintering agent, which helps alumina ceramic particles to agglomerate and sinter better, increases the density of ceramic materials, thereby improving their mechanical properties. In addition, fluorinated graphite and ZnO also have high thermal conductivity, which can improve the thermal conductivity of 98 alumina photovoltaic insulating ceramics to a certain extent, prevent heat accumulation, and extend their service life.

[0049] S2.2: Add 1000 parts of nano-alumina and composite sintering agent to an air jet mill, adjust the mill power to 200 kW and the gas consumption to 25 m³ / s. 3 At a gas pressure of 0.6 MPa, nano-alumina and composite sintering agent are mixed by airflow for 25 minutes to obtain alumina sintered powder. The resulting alumina sintered powder has a more uniform composition, and the powder particles collide and bond tightly during the formation process.

[0050] S3: Preparation of ceramic composite slurry

[0051] S3.1: Add acetylacetone and tetrabutyl titanate to a container at a 1:1 molar ratio and mix thoroughly. Stir the resulting mixture with a magnetic stirrer at 300 rpm for 1.5 hours to obtain an acetylacetone-tetrabutyl titanate solution.

[0052] S3.2: Mix xylene and acetylacetone-tetrabutyl titanate solution in a 1:1 volume ratio and add them to a container. Then add alumina sintered powder to the container and stir for 10 minutes to obtain a mixed solution.

[0053] S3.3: Add toughening agent and 1% (by volume) of trimethyltrimethoxysilane to the container, and stir at 1600 rpm for 20 minutes using a digital display cantilever constant speed high-power electric mixer to obtain ceramic composite slurry.

[0054] S4: Sintering of ceramic composite slurry

[0055] S4.1: The ceramic composite slurry is poured onto the casting machine, the casting speed is adjusted to 0.6m / min, the casting temperature is 70℃, and an alumina ceramic film with a thickness of 2mm is obtained.

[0056] S4.2: The alumina ceramic film is placed in a high-temperature sintering furnace. The furnace temperature is first raised to 690℃ at a heating rate of 8℃ / min to facilitate debinding of the alumina ceramic film. The temperature is held for 25 minutes, and then the furnace temperature is raised to 1600℃ at a heating rate of 4℃ / min. The temperature is held for sintering for 2.5 hours to make the components of the sintered 98 alumina photovoltaic insulating ceramic more compact, thereby further improving its mechanical properties and obtaining 98 alumina photovoltaic insulating ceramic.

[0057] Example 2

[0058] The preparation process of 98% alumina photovoltaic insulating ceramics, such as Figure 1 As shown, the specific steps include:

[0059] S1: Preparation of toughening agent

[0060] S1.1: Place 6 portions of single-walled carbon nanotubes in an ultrasonic cleaner, set the ultrasonic frequency to 35 kHz, and perform ultrasonic cleaning for 20 minutes. Then place the cleaned single-walled carbon nanotubes in a vacuum drying oven and adjust the vacuum degree inside the oven to 10. - 3 Pa, temperature 545℃, drying and impurity removal for 30 minutes to obtain pretreated single-walled carbon nanotubes;

[0061] S1.2: Take 0.5 parts of aluminate coupling agent and pretreated single-walled carbon nanotubes and add them to a mixer. Pour nitrogen into the mixer until the ambient atmosphere becomes nitrogen. Adjust the stirring temperature to 50℃ and the speed to 100 rpm. Stir for 50 minutes to obtain modified single-walled carbon nanotubes, which have excellent mechanical properties and thermal conductivity, and can also better combine with alumina.

[0062] S1.3: Place 4 parts silicon nitride, 2 parts zirconium dioxide, 0.5 parts ethyl cellulose and 4 parts anhydrous ethanol in a ball mill. Silicon nitride and zirconium dioxide can inhibit the growth of alumina grains and significantly improve the toughness of alumina ceramics. Adjust the speed to 450 rpm and ball mill for 1.5 hours. Pour the resulting mixed powder and modified single-walled carbon nanotubes into a planetary ball mill and ball mill at 550 rpm for 30 minutes. Collect the mixed powder and place it in a drying oven to dry at 80°C for 2 hours to obtain a toughening agent. Adding this toughening agent to alumina ceramics can greatly hinder the generation and propagation of ceramic cracks and improve the toughness of 98 alumina photovoltaic insulating ceramics.

[0063] S2: Gas flow mixing of alumina powder and composite sintering agent

[0064] S2.1: Mix 2 parts fluorinated graphite, 4 parts ZnO and 3 parts montmorillonite in a mixer to obtain a composite sintering agent, which helps alumina ceramic particles to agglomerate and sinter better, increases the density of ceramic materials, thereby improving their mechanical properties. In addition, fluorinated graphite and ZnO also have high thermal conductivity, which can improve the thermal conductivity of 98 alumina photovoltaic insulating ceramics to a certain extent, prevent heat accumulation, and extend their service life.

[0065] S2.2: Add 1050 parts of nano-alumina and composite sintering agent to an air jet mill, adjust the mill power to 200 kW and the gas consumption to 25 m³ / s. 3 At a gas pressure of 0.6 MPa, nano-alumina and composite sintering agent are mixed by airflow for 25 minutes to obtain alumina sintered powder. The resulting alumina sintered powder has a more uniform composition, and the powder particles collide and bond tightly during the formation process.

[0066] S3: Preparation of ceramic composite slurry

[0067] S3.1: Add acetylacetone and tetrabutyl titanate to a container at a molar ratio of 1:1.2 and mix well. Stir the resulting mixture with a magnetic stirrer at 300 rpm for 1.5 hours to obtain an acetylacetone-tetrabutyl titanate solution.

[0068] S3.2: Mix xylene and acetylacetone-tetrabutyl titanate solution in a volume ratio of 1:1.05 and add them into a container. Then add alumina sintered powder into the container and stir for 10 minutes to obtain a mixed solution.

[0069] S3.3: Add toughening agent and 1.2% (by volume) of trimethyltrimethoxysilane to the container, and stir at 1600 rpm for 20 minutes using a digital display cantilever constant speed high-power electric mixer to obtain ceramic composite slurry.

[0070] S4: Sintering of ceramic composite slurry

[0071] S4.1: The ceramic composite slurry is poured onto the casting machine, the casting speed is adjusted to 0.6m / min, the casting temperature is 70℃, and an alumina ceramic film with a thickness of 3mm is obtained;

[0072] S4.2: The alumina ceramic film is placed in a high-temperature sintering furnace. The furnace temperature is first raised to 690℃ at a heating rate of 8℃ / min to facilitate debinding of the alumina ceramic film. The temperature is held for 25 minutes, and then the furnace temperature is raised to 1600℃ at a heating rate of 4℃ / min. The temperature is held for sintering for 2.5 hours to make the components of the sintered 98 alumina photovoltaic insulating ceramic more compact, thereby further improving its mechanical properties and obtaining 98 alumina photovoltaic insulating ceramic.

[0073] Example 3

[0074] The preparation process of 98% alumina photovoltaic insulating ceramics, such as Figure 1 As shown, the specific steps include:

[0075] S1: Preparation of toughening agent

[0076] S1.1: Place 5 portions of single-walled carbon nanotubes in an ultrasonic cleaner, set the ultrasonic frequency to 40 kHz, and perform ultrasonic cleaning for 25 minutes. Then place the cleaned single-walled carbon nanotubes in a vacuum drying oven and adjust the vacuum degree inside the oven to 5 × 10⁻⁶. -3 Pa, temperature 550℃, drying and impurity removal for 35 minutes to obtain pretreated single-walled carbon nanotubes;

[0077] S1.2: Take 0.4 parts of aluminate coupling agent and pretreated single-walled carbon nanotubes and add them to a mixer. Pour nitrogen into the mixer until the ambient atmosphere becomes nitrogen. Adjust the stirring temperature to 55℃ and the speed to 120 rpm. Stir for 55 minutes to obtain modified single-walled carbon nanotubes, which have excellent mechanical properties and thermal conductivity, and can also better combine with alumina.

[0078] S1.3: Place 3 parts silicon nitride, 1.5 parts zirconium dioxide, 0.4 parts ethyl cellulose and 3 parts anhydrous ethanol in a ball mill. Silicon nitride and zirconium dioxide can inhibit the growth of alumina grains and significantly improve the toughness of alumina ceramics. Adjust the speed to 500 rpm and ball mill for 2 hours. Pour the resulting mixed powder and modified single-walled carbon nanotubes into a planetary ball mill and ball mill at 600 rpm for 35 minutes. Collect the mixed powder and place it in a drying oven to dry at 85°C for 3 hours to obtain a toughening agent. Adding this toughening agent to alumina ceramics can greatly hinder the generation and propagation of ceramic cracks and improve the toughness of 98 alumina photovoltaic insulating ceramics.

[0079] S2: Gas flow mixing of alumina powder and composite sintering agent

[0080] S2.1: Mix 1 part fluorinated graphite, 3 parts ZnO and 2 parts montmorillonite in a mixer to obtain a composite sintering agent, which helps alumina ceramic particles to agglomerate and sinter better, increases the density of ceramic materials, thereby improving their mechanical properties. In addition, fluorinated graphite and ZnO also have high thermal conductivity, which can improve the thermal conductivity of 98 alumina photovoltaic insulating ceramics to a certain extent, prevent heat accumulation, and extend their service life.

[0081] S2.2: Add 1000 parts of nano-alumina and composite sintering agent to an air jet mill, adjust the mill power to 220 kW and the gas consumption to 30 m³ / s. 3 At a gas pressure of 0.8 MPa, nano-alumina and composite sintering agent are mixed by airflow for 30 minutes to obtain alumina sintered powder. The resulting alumina sintered powder has a more uniform composition, and the powder particles collide and bond tightly with each other during the formation process.

[0082] S3: Preparation of ceramic composite slurry

[0083] S3.1: Add acetylacetone and tetrabutyl titanate to a container at a 1:1 molar ratio and mix well. Stir the resulting mixture with a magnetic stirrer at 320 rpm for 2 hours to obtain an acetylacetone-tetrabutyl titanate solution.

[0084] S3.2: Mix xylene and acetylacetone-tetrabutyl titanate solution in a 1:1 volume ratio and add them to a container. Then add alumina sintered powder to the container and stir for 15 minutes to obtain a mixed solution.

[0085] S3.3: Add toughening agent and 1% (by volume) of trimethyltrimethoxysilane to the container, and stir at 1800 rpm for 25 minutes using a digital display cantilever constant speed high-power electric mixer to obtain ceramic composite slurry.

[0086] S4: Sintering of ceramic composite slurry

[0087] S4.1: The ceramic composite slurry is poured onto the casting machine, the casting speed is adjusted to 0.8m / min, the casting temperature is 75℃, and an alumina ceramic film with a thickness of 2mm is obtained.

[0088] S4.2: The alumina ceramic film is placed in a high-temperature sintering furnace. The furnace temperature is first raised to 700℃ at a heating rate of 10℃ / min to facilitate debinding of the alumina ceramic film. The temperature is held for 30 minutes, and then the furnace temperature is raised to 1650℃ at a heating rate of 5℃ / min. The temperature is held for sintering for 3 hours to make the components of the sintered 98 alumina photovoltaic insulating ceramic more compact, thereby further improving its mechanical properties and obtaining 98 alumina photovoltaic insulating ceramic.

[0089] Comparative Example 1

[0090] Compared with Example 1, Comparative Example 1 differs in that Comparative Example 1 uses a 98% alumina ceramic tube, specifically a 98% alumina ceramic tube purchased from Yixing Luoda New Materials Co., Ltd.

[0091] The fracture toughness of the 98% alumina photovoltaic insulating ceramics prepared in Examples 1, 2, and 3, as well as Comparative Example 1, was tested using the single-sided pre-cracked beam (SEPB) method, according to GB / T23806-2009, "Test Method for Fracture Toughness of Fine Ceramics". Fracture toughness reflects the toughness of a material; higher fracture toughness indicates higher material toughness. The test was repeated three times, and the data were recorded and tabulated. Figure 2 As can be seen, the fracture toughness of the 98 alumina photovoltaic insulating ceramics prepared in Examples 1, 2 and 3 is higher than that of Comparative Example 1, which proves that the examples prepared 98 alumina photovoltaic insulating ceramics with high toughness, which are not easy to crack when protecting the photovoltaic system.

[0092] Comparative Example 2

[0093] Compared with Example 1, Comparative Example 2 differs in that step S1 is removed, while the remaining steps are the same as in Example 1.

[0094] The fracture toughness of the 98% alumina photovoltaic insulating ceramics prepared in Examples 1, 2, 3, and Comparative Example 2 was tested using the single-sided pre-cracked beam (SEPB) method, as per GB / T23806-2009, "Test Method for Fracture Toughness of Fine Ceramics". Data were recorded and tabulated, as follows: Figure 3 As can be seen, the fracture toughness of the 98 alumina photovoltaic insulating ceramics prepared in Examples 1, 2 and 3 is higher than that of the 98 alumina photovoltaic insulating ceramics prepared in Comparative Example 2, which proves that this process prepares a toughening agent that can improve the toughness of alumina ceramics.

[0095] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. 98 alumina photovoltaic insulating ceramic, characterized in that, Its preparation process specifically includes the following steps: S1: Preparation of toughening agent S1.1: Place 5-6 portions of single-walled carbon nanotubes in an ultrasonic cleaner, set the ultrasonic frequency to 30-40 kHz, and ultrasonically clean for 20-25 minutes. Place the cleaned single-walled carbon nanotubes in a vacuum drying oven and adjust the vacuum degree inside the oven to 10. -3 -5×10 -3 Pa, at a temperature of 545-550℃, is dried and impurities removed for 30-35 minutes to obtain pretreated single-walled carbon nanotubes; S1.2: Take 0.4-0.5 parts of aluminate coupling agent and pretreated single-walled carbon nanotubes and add them to a mixer. Introduce a protective gas into the mixer until the ambient atmosphere becomes a protective atmosphere. Adjust the stirring temperature to 50-55℃ and the speed to 100-120rpm. Stir for 50-55 minutes to obtain modified single-walled carbon nanotubes. S1.3: Place 3-4 parts silicon nitride, 1.5-2 parts zirconium dioxide, 0.4-0.5 parts ethyl cellulose and 3-4 parts anhydrous ethanol in a ball mill and mill at 450-500 rpm for 1.5-2 hours. Pour the resulting mixed powder and modified single-walled carbon nanotubes into a planetary ball mill and mill at 550-600 rpm for 30-35 minutes. Collect the mixed powder and place it in a drying oven to dry at 80-85℃ for 2-3 hours to obtain the toughening agent. S2: Gas flow mixing of alumina powder and composite sintering agent S2.1: Mix 1-2 parts of fluorinated graphite, 3-4 parts of ZnO and 2-3 parts of montmorillonite using a mixer to obtain a composite sintering agent; S2.2: Add 1000-1050 parts of nano-alumina and composite sintering agent to an air jet mill, adjust the mill power to 200-220 kW, and the gas consumption to 25-30 m³ / h. 3 At a gas pressure of 0.6-0.8 MPa, nano-alumina and composite sintering agent are mixed by airflow for 25-30 minutes to obtain alumina sintered powder. S3: Preparation of ceramic composite slurry Acetylacetone and tetrabutyl titanate were added to a container and mixed evenly. The resulting mixture was magnetically stirred to obtain an acetylacetone-tetrabutyl titanate solution. Xylene was first mixed with the acetylacetone-tetrabutyl titanate solution and added to the container. Then, alumina sintering powder was added to the container and stirred to obtain a mixed solution. Toughening agent and silane coupling agent were added to the container and stirred at high speed to obtain a ceramic composite slurry. S4: Sintering of ceramic composite slurry The ceramic composite slurry is poured onto a casting machine, and the parameters are adjusted to obtain an alumina ceramic film of a certain thickness. The alumina ceramic film is then placed in a high-temperature sintering furnace. The furnace temperature is first raised at a relatively fast rate and then held for a period of time. The furnace temperature is then raised at a slower rate and held for sintering for a period of time to obtain 98% alumina photovoltaic insulating ceramic.

2. The 98% alumina photovoltaic insulating ceramic according to claim 1, characterized in that, Step S3, the preparation of the ceramic composite slurry, specifically includes the following steps: S3.1: Add acetylacetone and tetrabutyl titanate to a container and mix well. Stir the resulting mixture with a magnetic stirrer at 300-320 rpm for 1.5-2 hours to obtain an acetylacetone-tetrabutyl titanate solution. S3.2: Mix xylene with acetylacetone-tetrabutyl titanate solution and add to a container, then add alumina sintered powder to the container and stir for 10-15 minutes to obtain a mixed solution; S3.3: Add toughening agent and 1-1.2% of the volume of the resulting mixed solution of silane coupling agent to the container, and stir at high speed of 1600-1800 rpm for 20-25 minutes using a digital display cantilever constant speed high-power electric mixer to obtain ceramic composite slurry.

3. The 98% alumina photovoltaic insulating ceramic according to claim 1, characterized in that, Step S4, sintering of the ceramic composite slurry, specifically includes the following steps: S4.1: Pour the ceramic composite slurry onto the casting machine, adjust the casting speed to 0.6-0.8 m / min, and the casting temperature to 70-75℃ to obtain an alumina ceramic film with a thickness of 2-3 mm; S4.2: Place the alumina ceramic film in a high-temperature sintering furnace. First, raise the furnace temperature to 690-700℃ at a heating rate of 8-10℃ / min and hold for 25-30 minutes. Then, raise the furnace temperature to 1600-1650℃ at a heating rate of 4-5℃ / min and hold for sintering for 2.5-3 hours to obtain 98 alumina photovoltaic insulating ceramic.

4. The 98% alumina photovoltaic insulating ceramic according to claim 1, characterized in that, The protective gas in step S1.2 is nitrogen.

5. The 98% alumina photovoltaic insulating ceramic according to claim 1, characterized in that, In step S1.3, the grinding balls in the ball mill are alumina balls with a particle size of 2-3 mm.

6. The 98% alumina photovoltaic insulating ceramic according to claim 2, characterized in that, In step S3.1, the molar ratio of acetylacetone to tetrabutyl titanate is 1:(1-1.2).

7. The 98% alumina photovoltaic insulating ceramic according to claim 2, characterized in that, In step S3.2, the volume ratio of xylene to acetylacetone-butyl titanate solution is 1:(1-1.05).

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