Integrated photochromic casting ceramic backboard material and preparation method thereof

Abstract

The invention relates to the technical field of ceramic back plates, in particular to an integrated photochromic casting ceramic back plate material and a preparation method thereof. The chemical formula of the ceramic backboard material is BaMgSiO4EuxFey, wherein 0 lt; x is less than or equal to 0.01, 0lt; and y < = 0.01. The rare earth element Eu and the transition metal element Fe are cooperatively doped, so that the color change contrast ratio and the hardness of the ceramic are remarkably improved; x and y meet the following requirements: 0.002 lt; x is less than or equal to 0.008, 0.002 lt; y is less than or equal to 0.008, so that the color-changing contrast ratio and the hardness of the ceramic back plate material can be further improved, the color-changing contrast ratio is more than 90%, and the Vickers hardness is more than 600Hv; the response time of the ceramic backboard material is prolonged to be less than 8 s, the color change fatigue resistance is high, the chemical stability is good, and the structure supporting and photochromic functions are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic backplates, and specifically, to an integrated photochromic casting ceramic backplate material and a preparation method thereof. Background Art

[0002] In today's smartphone market, the backplate material not only affects the aesthetic appearance of the mobile phone but also directly impacts its performance. Currently, the mainstream options include materials such as glass, metal, or ordinary ceramics. Glass backplates are advantageous for their aesthetic appeal and color presentation capabilities, but their fragility and limited strength restrict mobile phone design and durability. Metal backplates are strong and durable, but their single color and signal shielding limit their applications in 5G communication and wireless charging technologies. Ordinary ceramic backplates have made progress in enhancing the appearance texture, but their functions are limited to the surface and cannot fully meet consumers' diverse demands for the appearance and functions of mobile phones. To meet consumers' demands for personalization and functional diversity, the research and development of backplates with unique properties have become an industry trend.

[0003] Chinese Utility Model Patent CN221381000U discloses a photochromic ceramic plate and a mobile phone back cover. The photochromic ceramic plate includes a support layer and a photochromic layer. The support layer can be any one of a ceramic substrate, a metal substrate, or a glass substrate; the photochromic layer is disposed on the surface of the support layer; the photochromic layer is formed by photochromic ceramics; by disposing the photochromic layer on the surface of the support layer of the ceramic substrate, metal substrate, or glass substrate, this photochromic ceramic plate can have a photochromic effect; thereby expanding the richness of products; however, it does not involve research on the photochromic effect and the mechanical properties of the backplate. Summary of the Invention

[0004] In the first aspect of the present invention, an integrated photochromic casting ceramic backplate material is provided, and the chemical formula of the ceramic backplate material is: BaMgSiO4Eu x Fe y , where 0 < x ≤ 0.01 and 0 < y ≤ 0.01.

[0005] Optionally, x and y satisfy the following requirements: 0.002 < x ≤ 0.008 and 0.002 < y ≤ 0.008.

[0006] Optionally, x and y satisfy the following requirements: 0.004 < x ≤ 0.008 and 0.002 < y ≤ 0.008.

[0007] The preparation raw materials of the ceramic include powders, and the powders include: BaCO3, SiO2, MgO, Eu2O3, Fe2O3.

[0008] The preparation raw materials of the ceramic further include: a solvent, a plasticizer, a dispersant, a binder, and a defoaming agent.

[0009] Optionally, by weight percentage, the raw materials for ceramic preparation include: 40-60% solvent, 0.5-8% plasticizer, 0.5-5% dispersant, 5-10% binder, 1-5% defoamer, and the balance is made up with powder.

[0010] Optionally, the solvent includes at least one of toluene, ethyl acetate, ethanol, and cyclohexanone.

[0011] Optionally, the solvent includes toluene and ethanol, and the mass ratio of toluene to ethanol is 2-5:1.

[0012] Optionally, the solvent includes toluene and ethanol, and the mass ratio of toluene to ethanol is 2-4:1.

[0013] Optionally, the plasticizer includes at least one of polyethylene glycol, dibutyl phthalate, and diethyl sebacate.

[0014] Optionally, the plasticizer includes dibutyl phthalate and polyethylene glycol, and the mass ratio of dibutyl phthalate to polyethylene glycol is 1-5:1.

[0015] Optionally, the mass ratio of dibutyl phthalate to polyethylene glycol is 2-4:1.

[0016] Optionally, the dispersant includes at least one of tributyl phosphate, castor oil, and triethanolamine.

[0017] Optionally, the binder includes at least one of polyvinyl butyral and methyl cellulose.

[0018] Optionally, the defoamer includes at least one of polydimethylsiloxane and n-butanol.

[0019] The color change contrast of the integrated photochromic tape-cast ceramic backplane material is 55-93%, and the Vickers hardness is 570-750 Hv.

[0020] The second aspect of the present invention provides a method for preparing an integrated photochromic tape-cast ceramic backplane material, including the following steps: S1, weighing the corresponding powder; S2, after mixing the powder, performing ball milling, drying, and grinding treatments, then performing pre-sintering treatment, and then performing ball milling to obtain the basic ceramic powder; S3, mixing the basic ceramic powder with a solvent and a dispersant, adding a plasticizer, a binder, and a defoamer after primary ball milling, and obtaining a ceramic tape-casting slurry after secondary ball milling; S4, casting the tape-casting slurry using a tape-casting machine to obtain a tape-cast film; S5, sequentially slicing, punching, and laminating the tape-cast film to obtain a ceramic green body; S6, dewax the ceramic green body, perform reduction sintering, cutting and grinding.

[0021] The ball milling is carried out by mixing according to the mass ratio of powder: zirconia balls: ethanol of 1: (1 - 2): (1 - 2).

[0022] Optionally, the ball milling is carried out by mixing according to the mass ratio of powder: zirconia balls: ethanol of 1: 1.5: 1.5.

[0023] In the step S2, the pre - sintering treatment adopts the direct pre - sintering method.

[0024] Optionally, the temperature of the pre - sintering is 950 - 1150 °C, the heating rate is 2 - 8 °C / min, the cooling rate is 4 - 10 °C / min, and the holding time is 2 - 5 h.

[0025] Optionally, the temperature of the pre - sintering is 950 - 1050 °C, the heating rate is 2 - 5 °C / min, the cooling rate is 4 - 6 °C / min, and the holding time is 3 - 5 h.

[0026] Optionally, the pre - sintering temperature is 1000 °C, the heating rate is 3 °C / min, the cooling rate is 5 °C / min, and the holding time is 4 h.

[0027] In the step S3, the time of the first ball milling is 8 - 14 h, and the time of the second ball milling is 4 - 8 h.

[0028] Optionally, in the step S3, the time of the first ball milling is 10 - 12 h, and the time of the second ball milling is 6 - 8 h.

[0029] In the step S4, the thickness of the cast film is 30 - 60 μm.

[0030] Optionally, in the step S4, the thickness of the cast film is 40 - 50 μm.

[0031] In the step S5, the hot - pressing temperature is 45 - 70 °C, the hot - pressing pressure is 10 - 30 MPa; the cold isostatic pressing pressure is 150 - 250 MPa, and the pressure - holding time is 5 - 30 min.

[0032] Optionally, in the step S5, the hot - pressing temperature is 50 - 65 °C, the hot - pressing pressure is 10 - 20 MPa; the cold isostatic pressing pressure is 180 - 200 MPa, and the pressure - holding time is 10 - 20 min.

[0033] Optionally, the size of the ceramic green body is 12 - 20 cm in length, 5 - 10 cm in width, and 15 - 40 mm in thickness.

[0034] The size of the ceramic green body is 13 - 15 cm in length, 6 - 8 cm in width, and 20 - 35 mm in thickness.

[0035] In the step S6, the debinding temperature is 550-650 °C, the heating rate is 0.5-3 °C / min, and the heat preservation time is 5-8 h.

[0036] Optionally, the debinding temperature is 550-600 °C, the heating rate is 0.5-1 °C / min, and the heat preservation time is 5-7 h.

[0037] In the step S6, the reduction sintering temperature is 1300-1450 °C, the heating rate is 2-8 °C / min, the cooling rate is 4-10 °C / min, and the heat preservation time is 2-4 h.

[0038] Optionally, the sintering temperature is 1300-1350 °C, the heating rate is 3-5 °C / min, the cooling rate is 4-6 °C / min, and the heat preservation time is 2-4 h.

[0039] The reducing atmosphere includes H2 and N2.

[0040] By volume ratio, the reducing atmosphere contains 3-8% of H2.

[0041] Optionally, by volume ratio, the reducing atmosphere contains 4-6% of H2.

[0042] The applicant's research found that the chemical formula of the ceramic backplane material is: BaMgSiO4Eu x Fe y , where 0 < x ≤ 0.01 and 0 < y ≤ 0.01. The co-doping of rare earth element Eu and transition metal element Fe significantly improves the color change contrast and hardness of the ceramic. It may be that Fe can form a composite structure with Eu, introduce vacancy-related defects, increase the trap concentration and depth, thereby enhancing the light absorption ability, promoting the transfer and capture of electrons, and thus improving the efficiency of photochromism. At the same time, the doping of Fe can also improve the hardness and stability of the material, making it not easy to undergo structural damage during the photochromic process. The doping of Eu can introduce oxygen vacancies, and these oxygen vacancies serve as electron capture centers. When ultraviolet light is absorbed, electrons are excited and enter the oxygen vacancies, forming color centers, resulting in color changes.

[0043] Beneficial effects 1. The chemical formula of the ceramic backplane material is: BaMgSiO4Eu x Fe y , where 0 < x ≤ 0.01 and 0 < y ≤ 0.01. The co-doping of rare earth element Eu and transition metal element Fe significantly improves the color change contrast and hardness of the ceramic.

[0044] 2. The x and y satisfy the following requirements: 0.002 < x ≤ 0.008, 0.002 < y ≤ 0.008, which can further improve the color change contrast and hardness of the ceramic backplane material, making the color change contrast > 90% and the Vickers hardness > 600 Hv.

[0045] 3. The photochromic tape-cast ceramic backplane material prepared in this application has a response time < 8 s, high color change anti-fatigue property, and good chemical stability.

[0046] 4. Through a specific tape-casting preparation method, the ceramic material prepared in this application has a simple composition and low economic cost, and has both structural support and photochromic functions, which can meet the preparation of large-size ceramics and broaden the application scope of ceramics.

[0047] 5. The ceramic backplane material prepared in this application helps to achieve large-scale production operations, can be used in the field of mobile phone backplanes, and broadens the application scenarios of photochromic materials. Description of the Drawings

[0048] Figure 1 It is the XRD pattern of the ceramic backplane materials of the examples and the comparative examples, where JCPDS 16-0573 is the spectrum of the barium magnesium silicate standard card.

[0049] Figure 2 It is the diffuse reflection spectra of Example 1 before irradiation and after irradiation with 365 nm ultraviolet light and sunlight.

[0050] Figure 3 It is the diffuse reflection spectra of Example 2 before irradiation and after irradiation with 365 nm ultraviolet light and sunlight.

[0051] Figure 4 It is the diffuse reflection spectra of Example 3 before irradiation and after irradiation with 365 nm ultraviolet light and sunlight.

[0052] Figure 5 It is the diffuse reflection spectra of Comparative Example 1 before irradiation and after irradiation with 365 nm ultraviolet light and sunlight.

[0053] Figure 6 It is the diffuse reflection spectra of Comparative Example 2 before irradiation and after irradiation with 365 nm ultraviolet light and sunlight.

[0054] Figure 7 It is the schematic diagram of the backplane of different sizes of Example 1 before and after color change, where a is before color change and b is after color change.

[0055] Figure 8 It is the summary chart of the color change contrast and response time of the examples and the comparative examples. Detailed Embodiments

[0056] Example 1 An integrated photochromic cast ceramic backplane material, the chemical formula of the ceramic backplane material being: BaMgSiO4Eu x Fe y , where x = 0.005 and y = 0.005.

[0057] By weight percentage, the raw materials for preparing the ceramic are: 42% solvent (toluene: ethanol weight ratio 3:1), 5% plasticizer (polyethylene glycol: dibutyl phthalate weight ratio 3:1), 3% dispersant (tributyl phosphate), 7.5% binder (polyvinyl butyral, Sinopharm Chemical Reagent Co., Ltd.), 2.4% defoamer (n-butanol), and the powder makes up the balance. Polyethylene glycol: HuShi, Sinopharm Chemical Reagent Co., Ltd.

[0058] The powder is: BaCO3, SiO2, MgO, Eu2O3 and Fe2O3.

[0059] The molar ratio of BaCO3, SiO2, MgO, Eu2O3 and Fe2O3 is 0.995:1:0.995:0.0025:0.0025.

[0060] A preparation method of an integrated photochromic cast ceramic backplane material, which is the following steps: S1, according to the stoichiometric ratio of each element in the chemical formula of the ceramic backplane material, weigh the corresponding powder; S2, mix the powder by wet high-energy ball milling method, according to the mass ratio of powder: zirconia balls: ethanol 1:1.5:1.5, the mixing time is 24h, and each component is fully mixed; after drying and grinding, pass through a 60-mesh sieve, place it in a crucible, compact it, and then use the direct pre-sintering method. The specific method is that the pre-sintering temperature is 1000°C, the heating rate is 3°C / min, keep warm for 4h, the cooling rate is 5°C / min, and cool down to room temperature to obtain the basic ceramic powder; S3, weigh the basic ceramic powder, solvent and dispersant in proportion, first ball mill for 12h to mix the slurry, and then add the plasticizer, binder and defoamer to the slurry obtained from the first ball mill in proportion, and ball mill for 6h to mix the slurry for the second time to obtain a uniform and stable ceramic casting slurry; S4, use a casting machine to cast the prepared casting slurry into a casting film with a thickness of 40μm; S5, cut the cast film into large pieces of 14×7cm and punch holes. First, hot press and bond 60 layers of cast film at 55°C and 20MPa to form a sheet with a fixed size, then evacuate and seal the sheet, and perform cold isostatic pressing at 200MPa for 15min to form a ceramic green body; S6. Place the green body in a muffle furnace for debinding at a heating rate of 0.5 °C / min, a holding time of 6 h, and a debinding temperature of 600 °C. After debinding, perform reduction sintering. The specific method is to use a tube furnace to sinter at a sintering temperature of 1350 °C, a heating rate of 4 °C / min, a holding time of 3 h, a cooling rate of 5 °C / min, and in a reducing atmosphere (volume ratio: 3% H2, 97% N2). Cut and polish according to the required size to obtain the product.

[0061] Example 2: An integrated photochromic tape-cast ceramic backplane material, the chemical formula of the ceramic backplane material is: BaMgSiO4Eu x Fe y , where x = 0.005 and y = 0.0025.

[0062] By weight percentage, the raw materials for preparing the ceramic are: 45% solvent (toluene: ethanol weight ratio is 3:1), 5% plasticizer (polyethylene glycol: dibutyl phthalate weight ratio is 3:1), 3% dispersant (tributyl phosphate), 7.5% binder (polyvinyl butyral), 2.4% defoamer (n-butanol), and the powder makes up the balance.

[0063] The powder is: BaCO3, SiO2, MgO, Eu2O3, and Fe2O3.

[0064] The molar ratio of BaCO3, SiO2, MgO, Eu2O3, and Fe2O3 is 0.995:1:0.9975:0.0025:0.00125.

[0065] A preparation method of an integrated photochromic tape-cast ceramic backplane material, comprising the following steps: S1. Weigh the corresponding powders according to the stoichiometric ratios of the elements in the chemical formula of the ceramic backplane material. S2. Mix the powders by wet high-energy ball milling method. According to the mass ratio of powder: zirconia balls: ethanol of 1:1.5:1.5, the mixing time is 24 h, and each component is fully mixed. After drying and grinding, pass through a 60-mesh sieve, place in a crucible, compact, and then use the direct pre-sintering method. The specific method is a pre-sintering temperature of 1000 °C, a heating rate of 3 °C / min, a holding time of 4 h, a cooling rate of 5 °C / min, and cool down to room temperature to obtain the basic ceramic powder. S3. Weigh the basic ceramic powder, solvent, and dispersant in proportion, perform primary ball milling for 12 h to mix the slurry, and then add the plasticizer, adhesive, and defoamer to the slurry obtained from the primary ball milling in proportion, and perform ball milling for 6 h to mix the slurry for the second time to obtain a uniform and stable ceramic tape-casting slurry. S4. Cast the prepared tape-casting slurry into a tape-cast film with a thickness of 45 μm using a tape-casting machine. S5. The cast film is cut into large pieces of 14×7 cm and punched. First, 60 layers of cast film are hot-pressed and bonded into a sheet of fixed size at 55 °C and 20 MPa, and then the sheet is evacuated and sealed, and cold isostatic pressing is carried out at 200 MPa for 15 min to form a ceramic green body. S6. The green body is put into a muffle furnace for debinding at a heating rate of 0.5 °C / min, a holding time of 6 h, and a debinding temperature of 550 °C. After debinding, reduction sintering is carried out. The specific method is to use a tube furnace to sinter at a sintering temperature of 1300 °C, a heating rate of 4 °C / min, a holding time of 3 h, and a cooling rate of 5 °C / min in a reducing atmosphere (volume ratio, 3% H2, 97% N2), and then cut and polished according to the required size to obtain the product.

[0066] Example 3: An integrated photochromic cast ceramic backplane material, the chemical formula of the ceramic backplane material is: BaMgSiO4Eu x Fe y , where x = 0.005 and y = 0.0075.

[0067] By weight percentage, the raw materials for preparing the ceramic are: 45% solvent (toluene: ethanol weight ratio is 3:1), 5% plasticizer (polyethylene glycol: dibutyl phthalate weight ratio is 3:1), 3% dispersant (tributyl phosphate), 7.5% binder (polyvinyl butyral), 2.4% defoamer (n-butanol), and the powder makes up the balance.

[0068] The powder is: BaCO3, SiO2, MgO, Eu2O3 and Fe2O3.

[0069] The molar ratio of BaCO3, PSiO2, MgO, Eu2O3 and Fe2O3 is 0.995:1:0.9925:0.0025:0.00375.

[0070] A preparation method of an integrated photochromic cast ceramic backplane material, which comprises the following steps: S1. Weigh the corresponding powders according to the stoichiometric ratio of each element in the chemical formula of the ceramic backplane material. S2. The powders are mixed by the wet high-energy ball milling method. According to the mass ratio of powder: zirconia ball: ethanol of 1:1.5:1.5, the mixing time is 24 h, and each component is fully mixed. After drying and grinding, it is passed through a 60-mesh sieve, placed in a crucible, compacted, and then directly pre-sintered. The specific method is a pre-sintering temperature of 1000 °C, a heating rate of 3 °C / min, a holding time of 4 h, a cooling rate of 5 °C / min, and cooled to room temperature to obtain the basic ceramic powder. S3. Weigh the basic ceramic powder, solvent, and dispersant in proportion, and perform the first ball milling for 12 h to mix the slurry. Then, add plasticizer, binder, and defoamer to the slurry obtained from the first ball milling in proportion, and perform ball milling for 6 h to mix the slurry for the second time, obtaining a uniform and stable ceramic casting slurry. S4. Cast the prepared casting slurry into a casting film with a thickness of 40 μm using a casting machine. S5. Cut the cast film into large pieces with a size of 14×7 cm and punch holes. First, hot press and bond 60 layers of casting film at 50 °C and 20 MPa to form a sheet with a fixed size. Then, evacuate and seal the sheet, and perform cold isostatic pressing at 200 MPa for 15 min to form a ceramic green body. S6. Place the green body in a muffle furnace for debinding at a heating rate of 0.5 °C / min, a holding time of 6 h, and a debinding temperature of 600 °C. After debinding, perform reduction sintering. The specific method is to use a tube furnace for sintering at a sintering temperature of 1350 °C, a heating rate of 4 °C / min, a holding time of 3 h, and a cooling rate of 5 °C / min under a reducing atmosphere (volume ratio: 3% H2, 97% N2). Cut and polish according to the required size to obtain the product.

[0071] Comparative Example 1: An integrated photochromic casting ceramic backplane material, the chemical formula of the ceramic backplane material is: BaMgSiO4Eu x , where x = 0.005.

[0072] By weight percentage, the raw materials for preparing the ceramic are: 45% solvent (toluene: ethanol weight ratio is 3:1), 5% plasticizer (polyethylene glycol: dibutyl phthalate weight ratio is 3:1), 3% dispersant (tributyl phosphate), 7.5% binder (polyvinyl butyral), 2.4% defoamer (n-butanol), and the powder makes up the balance.

[0073] The powder is: BaCO3, SiO2, MgO, and Eu2O3.

[0074] The molar ratio of BaCO3, SiO2, MgO, and Eu2O3 is 0.99:1:1:0.005.

[0075] A preparation method of an integrated photochromic casting ceramic backplane material, which comprises the following steps: S1. Weigh the corresponding powders according to the stoichiometric ratios of the elements in the chemical formula of the ceramic backplane material. S2. Mix the powders by wet high-energy ball milling. According to the mass ratio of powder:zirconia balls:ethanol of 1:1.5:1.5, mix for 24 hours to fully mix all components. After drying and grinding, pass through a 60-mesh sieve, place in a crucible, compact, and then use the direct pre-sintering method. The specific method is a pre-sintering temperature of 1000 °C, a heating rate of 3 °C / min, hold for 4 hours, and a cooling rate of 5 °C / min to obtain the basic ceramic powder. S3. Weigh the basic ceramic powder, solvent, and dispersant in proportion. First, ball mill for 12 hours to mix the slurry. Then, add a plasticizer, binder, and defoamer to the slurry obtained from the first ball milling in proportion and ball mill for 6 hours to mix the slurry for the second time, obtaining a uniform and stable ceramic tape-casting slurry. S4. Cast the prepared tape-casting slurry into a tape-casting film with a thickness of 45 μm using a tape-casting machine. S5. Cut the cast film into large pieces of 14×7 cm and punch holes. First, hot press and bond 60 layers of the tape-casting film at 55 °C and 20 MPa to form a sheet with a fixed size. Then, evacuate and seal the sheet, and perform cold isostatic pressing at 200 MPa for 15 minutes to form a ceramic green body. S6. Place the green body in a muffle furnace for debinding at a heating rate of 0.5 °C / min, a holding time of 6 hours, and a debinding temperature of 600 °C. After debinding, perform reduction sintering. The specific method is to use a tube furnace for sintering at a sintering temperature of 1300 °C, a heating rate of 3 °C / min, a holding time of 2 hours, and a cooling rate of 5 °C / min under a reducing atmosphere of 5% H2 and 95% N2. Cut and polish according to the required size to obtain the product.

[0076] Comparative Example 2 An integrated photochromic tape-casting ceramic backplane material, the chemical formula of the ceramic backplane material is: BaMgSiO4Fe x , where x = 0.005.

[0077] By weight percentage, the raw materials for preparing the ceramic are: 45% solvent (toluene:ethanol weight ratio of 3:1), 5% plasticizer (polyethylene glycol:dibutyl phthalate weight ratio of 3:1), 3% dispersant (tributyl phosphate), 7.5% binder (polyvinyl butyral), 2.4% defoamer (n-butanol), and the powder makes up the balance.

[0078] The powder is: BaCO3, SiO2, MgO, and Fe2O3.

[0079] The molar ratio of BaCO3, SiO2, MgO, and Fe2O3 is 0.99:1:1:0.005.

[0080] A preparation method of an integrated photochromic tape-casting ceramic backplane material, which is the following steps: S1. Weigh the corresponding powders according to the stoichiometric ratios of the elements in the chemical formula of the ceramic backplane material. S2. Mix the powders by wet high-energy ball milling. According to the mass ratio of powder: zirconia balls: ethanol of 1:1.5:1.5 and a mixing time of 24 h, mix all components thoroughly. After drying and grinding, sieve through a 60-mesh sieve, place in a crucible, compact, and then use the direct pre-sintering method. The specific method is a pre-sintering temperature of 1000 °C, a heating rate of 3 °C / min, a holding time of 4 h, and a cooling rate of 5 °C / min to obtain the basic ceramic powder. S3. Weigh the basic ceramic powder, solvent, and dispersant in proportion. First, ball mill for 12 h to mix the slurry, and then add plasticizer, binder, and defoamer to the slurry obtained from the first ball milling in proportion and ball mill for 6 h to mix the slurry for the second time to obtain a uniform and stable ceramic tape-casting slurry. S4. Cast the prepared tape-casting slurry into a tape-casting film with a thickness of 45 μm using a tape-casting machine. S5. Cut the cast film into large pieces of 14×7 cm and punch holes. First, thermally press and bond 60 layers of the tape-casting film at 55 °C and 20 MPa to form a sheet with a fixed size, then evacuate and seal the sheet, and perform cold isostatic pressing at 200 MPa for 15 min to form a ceramic green body. S6. Place the green body in a muffle furnace for debinding at a heating rate of 0.5 °C / min, a holding time of 6 h, and a debinding temperature of 600 °C. After debinding, perform reduction sintering. The specific method is to use a tubular furnace for sintering at a sintering temperature of 1300 °C, a heating rate of 3 °C / min, a holding time of 2 h, a cooling rate of 5 °C / min, and a reduction atmosphere of 5% H2 and 95% N2. Cut and polish according to the required size to obtain the product.

[0081] Performance testing methods and data Perform the following performance tests on the photochromic tape-casting ceramic backplane materials prepared in the examples and comparative examples. The test data are listed in Table 1.

[0082] 1) Phase structure test: Use an X-ray diffractometer to analyze the crystal structure and phase composition of the prepared ceramic backplane. Figure 1 The XRD pattern of the prepared backplane is basically consistent with the barium magnesium silicate standard card. Since the doping content of Fe and Eu is very small and they dissolve into the lattice, there is no obvious difference in XRD between the examples and the comparative examples.

[0083] 2) Hardness test: Use a Vickers hardness tester to test the hardness of the prepared ceramic backplane material.

[0084] 3) Photochromic performance test: The photochromic cast ceramic backplane material of the present application turns from the original milky white to pink when irradiated with ultraviolet light in the wavelength range of 255 - 365 nm; the ceramic restores its original color when irradiated with green light in the range of 520 - 550 nm or after heating and reduction at 200 °C.

[0085] Contrast test: Use an ultraviolet-visible-near-infrared spectrophotometer to measure the change in diffuse reflectance R% of the backplane before and after irradiation with a 365 nm light source, and calculate the color change contrast, as Figures 2 - 4 It shows that the ceramic backplane materials prepared in Examples 2 - 4 have a relatively high contrast. Figure 5 、 6 It shows that the contrast of the ceramic backplane materials prepared in Comparative Examples 1 and 2 is significantly lower than that of Examples 1 - 3.

[0086] Response time test: Record the time required to reach the maximum color change and maximum contrast. Figure 7 It shows that there are obvious differences in the ceramic backplane material before and after color change.

[0087] As Figure 8 shown, there are obvious differences in the photochromic performance tests between Examples 1 - 3 and Comparative Examples 1 and 2, indicating that the raw material composition of the ceramic backplane material has a significant impact on the photochromic performance.

[0088] Table 1 Vickers hardness (Hv) Contrast ratio (%) Response time (s) Comparative Example 1 570 55.7 10.2 Comparative Example 2 610 77.7 8.8 Example 1 750 92.2 5.4 Example 2 680 90.3 6.2 Example 3 690 90.2 7.6 From the data in Table 1, it can be seen that the ceramic backplane materials prepared in Examples 1 - 3 have high hardness, good wear and scratch resistance, and at the same time, the contrast > 90%, the response time < 8 s, high color change fatigue resistance, and good chemical stability.

Claims

1. An integrated photochromic cast ceramic backplane material, characterized in that, The chemical formula of the ceramic backplane material is: BaMgSiO4Eu x Fe y , where 0 < x ≤ 0.01 and 0 < y ≤ 0.

01.

2. The integrated photochromic cast ceramic backplane material according to claim 1, wherein x and y meet the following requirements: 0.002 < x ≤ 0.008, 0.002 < y ≤ 0.

008.

3. The integrated photochromic cast ceramic backplane material according to claim 1 or 2, characterized in that, The raw materials for preparing the ceramic backplane material include powders, and the powders include BaCO3, SiO2, MgO, Eu2O3 and Fe2O3.

4. The integrated photochromic cast ceramic backplane material according to claim 3, characterized in that, The raw materials for preparing the ceramic backplane material further include a solvent, a plasticizer, a dispersant, a binder and a defoaming agent.

5. A preparation method of the integrated photochromic cast ceramic backplane material according to claim 4, comprising the following steps: Weigh the corresponding powders; after mixing the powders and performing ball milling, drying and grinding treatments, conduct pre-sintering treatment, and then perform ball milling to obtain basic ceramic powders; mix the basic ceramic powders with a solvent and a dispersant, add a plasticizer, a binder and a defoaming agent after the first ball milling, and obtain a ceramic casting slurry after the second ball milling; cast the casting slurry using a casting machine to obtain a cast film; successively slice, punch and stack the cast film to obtain a ceramic green body; perform debinding, reduction sintering, cutting and polishing on the ceramic green body.

6. The preparation method of the integrated photochromic cast ceramic backplane material according to claim 5, characterized in that, The temperature of the pre-sintering is 950 - 1150 °C, the heating rate is 2 - 8 °C / min, the cooling rate is 4 - 10 °C / min, and the holding time is 2 - 5 h.

7. The preparation method of the integrated photochromic cast ceramic backplane material according to claim 5, characterized in that, The temperature of the debinding is 550 - 650 °C, the heating rate is 0.5 - 3 °C / min, and the holding time is 5 - 8 h.

8. The preparation method of the integrated photochromic cast ceramic backplane material according to claim 5, characterized in that, The temperature of the reduction sintering is 1300 - 1450 °C, the heating rate is 2 - 8 °C / min, the cooling rate is 4 - 10 °C / min, and the holding time is 2 - 4 h.

9. The preparation method of the integrated photochromic cast ceramic backplane material according to claim 8, characterized in that, The stacking pressure successively includes hot pressing and cold isostatic pressing.

10. The preparation method of the integrated photochromic cast ceramic backplane material according to claim 9, characterized in that, The temperature of the hot pressing is 50 - 65 °C, the pressure is 10 - 20 MPa; the pressure of the cold isostatic pressing is 180 - 200 MPa, and the pressure holding time is 10 - 20 min.

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