Pretreatment method of silicon-aluminum mixture
By first firing and heat treating the silicon-aluminum mixture, and then wet ball milling with alumina, the problem of sharp edges and angles on the surface of the silicon-aluminum mixture during the evaporation process is solved, and the stability of the evaporated material and the bonding force of the film are improved. , achieving better evaporation effect.
Patent Information
- Application Number
- CN202411145451.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-20
- Publication Date
- 2024-12-13
AI Technical Summary
During the evaporation process, the existing silicon-aluminum mixtures have splashing problems due to sharp edges and angles on the surface of the particles, and the bonding force with the plastic substrate is poor, resulting in the film layer being easily shedded and cracked.
First, the silicon-aluminum mixture is fired and heat-treated to form mullite, then mixed with alumina for wet ball milling, and through spray drying, sintering and annealing, particles with high roundness and smoothness are prepared to reduce spraying. Splash risk and improve evaporation stability.
It effectively reduces the edges and angles of particles, improves the roundness and smoothness of particles, enhances the stability of the evaporated material, avoids splashing, and improves the wipe performance of the film layer.
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Figure HDA0005002073840000011
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of evaporation materials, in particular to the field of IPCC04B35, and more specifically to a pretreatment method for a silicon-aluminum mixture. Background Art
[0002] Silicon dioxide is the most basic evaporation material widely used in the field of optical coating. At present, the coating material of plastic substrate is mostly evaporation of silicon dioxide, but due to the poor bonding between silicon dioxide film and plastic substrate, the film layer is easy to fall off and crack. Adding appropriate aluminum oxide to silicon oxide evaporation material can significantly improve the above problems. At present, the silicon oxide and aluminum oxide evaporation materials used in the market are all granular materials, which are uneven and have edges and corners. They are directly sublimated from solid to gas during the evaporation process, which is easy to splash during use.
[0003] CN107285753A discloses a method for preparing a low refractive index evaporation material, including preparing ingredients, mixing ingredients, drying slurry, tableting, preparing sintered bodies, and cleaning and packaging. This method directly wet-mills the raw materials to obtain a slurry with uniform composition, but does not effectively remove the edges and corners of the silicon-aluminum mixture, which will cause splashing during use to a certain extent. Summary of the invention
[0004] The present invention provides a method for pretreating a silicon-aluminum mixture, comprising the following steps:
[0005] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0006] S2, firing the mixture, grinding and screening, heat treating, and cooling to obtain mullite;
[0007] S3, adding alumina to mullite, mixing evenly, adding solvent, wet ball milling and spray drying to obtain a powder raw material;
[0008] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0009] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0010] The applicant has found that the silicon-aluminum mixture is first fired and heat-treated, and then wet-milled, which can effectively reduce the edges and corners of the prepared particles and improve the roundness of the particles, thereby solving the problem of easy splashing of the prepared evaporation material, and then improving the stability of evaporation. In the prior art, the silicon-aluminum mixture is usually ball-milled first, but due to the uneven mixing and the large difference in physical properties between aluminum oxide and silicon oxide, the problem of sharp edges and corners on the surface of the particles cannot be effectively solved. The silicon-aluminum mixture is first fired and heat-treated, and then wet-milled after mixing with aluminum oxide, which can solve the problem of sharp edges and corners on the surface of the particles. It may be that mullite with high hardness and stability is obtained in advance, which is similar to the physical properties of aluminum oxide, and promotes the effect of co-grinding. Further research has found that the weight ratio of aluminum oxide to mullite is 1: (2-40), and the material-ball ratio is (1-3): 1. The ball milling process with a ball milling time of 10-14h can further improve the smoothness of the particles while avoiding the occurrence of pitting.
[0011] In step S2, the aluminum oxide accounts for 74-78% of the mixture by mass.
[0012] Preferably, in step S2, alumina accounts for 75-76% of the mixture by mass.
[0013] Further preferably, in step S2, aluminum oxide accounts for 75% of the mixture by mass.
[0014] The firing temperature is 1600-1680° C., and the firing time is 4-6 hours.
[0015] Preferably, the firing temperature is 1650-1680° C., and the firing time is 4-6 hours.
[0016] More preferably, the firing temperature is 1650° C. and the firing time is 5 hours.
[0017] The heat treatment temperature is 1100-1300° C. and the time is 10-15 hours.
[0018] Preferably, the heat treatment temperature is 1200° C. and the time is 12 hours.
[0019] The specific cooling process is: cooling at 25-35°C / min, keeping at 750-820°C for 1.5-3h, cooling to 280-320°C at 15-25°C / min, and finally cooling to 20-40°C.
[0020] Preferably, the specific cooling process is: cooling at 28-35°C / min, keeping at 750-820°C for 1.5-3h, then cooling to 280-320°C at 15-23°C / min, and finally cooling to 20-40°C.
[0021] Further preferably, the specific cooling process is: cooling at 30°C / min, keeping at 800°C for 2h, then cooling to 300°C at 20°C / min, and finally cooling to 25°C.
[0022] The weight ratio of silicon oxide to mullite is 1:(2-40).
[0023] Preferably, the weight ratio of silicon oxide to mullite is 1:(4-16).
[0024] Further preferably, the weight ratio of silicon oxide to mullite is 1:8.
[0025] The material-ball ratio of the wet ball milling is (1-3):1, and the wet ball milling time is 10-14h.
[0026] Preferably, the material-ball ratio of the wet ball milling is 1:1, and the wet ball milling time is 12 hours.
[0027] The average particle size of the particles is 1-4 mm.
[0028] Preferably, the average particle size of the particles is one of 1-3 mm, 2-4 mm and 1-2 mm.
[0029] The stirring speed in S5 is 20-45 rpm, and the stirring time is 20-45 min.
[0030] Preferably, the stirring speed in S5 is 30-45 rpm, and the stirring time is 20-45 min.
[0031] More preferably, the stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0032] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0033] The diameter of the spherical powder is 40 to 60 μm.
[0034] Preferably, the diameter of the spherical powder is 40-50 μm.
[0035] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1300-1550° C., keeping the temperature for 5-7 hours, and then naturally cooling to 20-40° C.
[0036] Preferably, the sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500°C, keeping the temperature for 6 hours, and then naturally cooling to 25°C.
[0037] Beneficial effects:
[0038] 1. First, the silicon-aluminum mixture is fired and heat-treated, and then wet-milled, which can effectively reduce the edges and corners of the prepared particles and improve the roundness of the particles, thereby solving the problem of easy splashing of the prepared evaporation material and improving the evaporation stability.
[0039] 2. The weight ratio of silicon oxide to mullite is 1:(2-40), and the material-ball ratio is (1-3):1. The ball milling process with a ball milling time of 10-14 hours can further improve the smoothness of the particles while avoiding the occurrence of pitting.
[0040] 3. The specific cooling process is: cooling at 25-35°C / min, keeping at 750-820°C for 1.5-3h, cooling to 280-320°C at 15-25°C / min, and finally cooling to 20-40°C, while maintaining the stability of evaporation, having good film wiping performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] Figure 1 This is a flow chart of the pretreatment of the silicon-aluminum mixture in Example 1. DETAILED DESCRIPTION
[0042] Example 1
[0043] A pretreatment method for a silicon-aluminum mixture, such as Figure 1 As shown, the following steps are:
[0044] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0045] S2, firing the mixture, grinding and screening, heat treating, and cooling to obtain mullite;
[0046] S3, taking silicon oxide and adding it to mullite, mixing them evenly, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0047] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0048] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0049] The weight ratio of silicon oxide to mullite is 1:8.
[0050] In step S2, aluminum oxide accounts for 75% of the mixture by mass.
[0051] The firing temperature is 1650° C. and the firing time is 5 hours.
[0052] The heat treatment temperature is 1200° C. and the time is 12 hours.
[0053] The specific cooling process is: cooling at 30°C / min, keeping at 800°C for 2h, cooling to 300°C at 20°C / min, and finally cooling to 25°C.
[0054] The material-to-ball ratio of the wet ball milling is 1:1, and the wet ball milling time is 12 hours.
[0055] The stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0056] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0057] The diameter of the spherical powder is 40 to 50 μm.
[0058] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0059] Example 2
[0060] A pretreatment method for a silicon-aluminum mixture comprises the following steps:
[0061] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0062] S2, firing the mixture, grinding and sieving, heat treating, and cooling to obtain mullite;
[0063] S3, taking silicon oxide and adding it to mullite, mixing them evenly, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0064] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0065] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0066] The weight ratio of silicon oxide to mullite is 1:8.
[0067] In step S2, aluminum oxide accounts for 75% of the mass of the mixture.
[0068] The firing temperature is 1650° C. and the firing time is 5 hours.
[0069] The heat treatment temperature is 1300° C. and the time is 11 hours.
[0070] The specific cooling process is: cooling at 25°C / min, keeping at 800°C for 2h, cooling to 300°C at 23°C / min, and finally cooling to 25°C.
[0071] The material-to-ball ratio of the wet ball milling is 1:1, and the wet ball milling time is 12 hours.
[0072] The stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0073] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0074] The diameter of the spherical powder is 40 to 50 μm.
[0075] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0076] Example 3
[0077] A pretreatment method for a silicon-aluminum mixture comprises the following steps:
[0078] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0079] S2, firing the mixture, grinding and screening, heat treating, and cooling to obtain mullite;
[0080] S3, taking silicon oxide and adding it to mullite, mixing them evenly, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0081] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0082] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0083] The weight ratio of silicon oxide to mullite is 1:12.
[0084] In step S2, aluminum oxide accounts for 75% of the mixture by mass.
[0085] The firing temperature is 1650° C. and the firing time is 5 hours.
[0086] The heat treatment temperature is 1200° C. and the time is 12 hours.
[0087] The specific cooling process is: cooling at 30°C / min, keeping at 800°C for 2h, cooling to 300°C at 20°C / min, and finally cooling to 25°C.
[0088] The material-to-ball ratio of the wet ball milling is 2:1, and the wet ball milling time is 12 hours.
[0089] The stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0090] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0091] The diameter of the spherical powder is 40 to 50 μm.
[0092] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0093] Example 4
[0094] A pretreatment method for a silicon-aluminum mixture comprises the following steps:
[0095] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0096] S2, firing the mixture, grinding and sieving, heat treating, and cooling to obtain mullite;
[0097] S3, taking silicon oxide and adding it to mullite, mixing them evenly, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0098] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0099] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0100] The weight ratio of silicon oxide to mullite is 1:16.
[0101] In step S2, aluminum oxide accounts for 75% of the mass of the mixture.
[0102] The firing temperature is 1650° C. and the firing time is 5 hours.
[0103] The heat treatment temperature is 1200° C. and the time is 12 hours.
[0104] The specific cooling process is: cooling at 30°C / min, keeping at 800°C for 2h, cooling to 300°C at 20°C / min, and finally cooling to 25°C.
[0105] The material-to-ball ratio of the wet ball milling is 1:1, and the wet ball milling time is 12 hours.
[0106] The stirring speed in S5 is 40 rpm, and the stirring time is 25 min.
[0107] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0108] The diameter of the spherical powder is 40 to 50 μm.
[0109] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0110] Comparative Example 1
[0111] A pretreatment method for a silicon-aluminum mixture comprises the following steps:
[0112] S1, drying aluminum oxide and silicon oxide separately, mixing them evenly to obtain a mixture, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0113] S2, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0114] S3, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0115] The weight ratio of aluminum oxide to silicon oxide is 1:2.
[0116] In step S2, aluminum oxide accounts for 75% of the mixture by mass.
[0117] The material-to-ball ratio of the wet ball milling is 1:1, and the wet ball milling time is 12 hours.
[0118] The stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0119] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0120] The diameter of the spherical powder is 40 to 50 μm.
[0121] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0122] Comparative Example 2
[0123] A pretreatment method for a silicon-aluminum mixture comprises the following steps:
[0124] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0125] S2, firing the mixture, grinding and screening, heat treating, and cooling to obtain mullite;
[0126] S3, taking silicon oxide and adding it to mullite, mixing them evenly, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0127] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0128] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0129] The weight ratio of silicon oxide to mullite is 1:1.
[0130] In step S2, aluminum oxide accounts for 75% of the mixture by mass.
[0131] The firing temperature is 1650° C. and the firing time is 5 hours.
[0132] The heat treatment temperature is 1200° C. and the time is 12 hours.
[0133] The specific cooling process is: cooling at 30°C / min, keeping at 800°C for 2h, cooling to 300°C at 20°C / min, and finally cooling to 25°C.
[0134] The material-to-ball ratio of the wet ball milling is 1:1, and the wet ball milling time is 12 hours.
[0135] The stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0136] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0137] The diameter of the spherical powder is 40 to 50 μm.
[0138] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0139] Comparative Example 3
[0140] A pretreatment method for a silicon-aluminum mixture comprises the following steps:
[0141] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0142] S2, firing the mixture, grinding and screening, heat treating, and cooling to obtain mullite;
[0143] S3, taking silicon oxide and adding it to mullite, mixing them evenly, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0144] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0145] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0146] The weight ratio of silicon oxide to mullite is 1:8.
[0147] In step S2, aluminum oxide accounts for 75% of the mixture by mass.
[0148] The firing temperature is 1650° C. and the firing time is 5 hours.
[0149] The heat treatment temperature is 1200° C. and the time is 12 hours.
[0150] The specific cooling process is: cooling at 30°C / min, keeping at 800°C for 2h, cooling to 300°C at 20°C / min, and finally cooling to 25°C.
[0151] The material-to-ball ratio of the wet ball milling is 4:1, and the wet ball milling time is 15 hours.
[0152] The stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0153] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0154] The diameter of the spherical powder is 40 to 50 μm.
[0155] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0156] Comparative Example 4
[0157] A pretreatment method for a silicon-aluminum mixture comprises the following steps:
[0158] S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture;
[0159] S2, firing the mixture, grinding and screening, heat treating, and cooling to obtain mullite;
[0160] S3, taking silicon oxide and adding it to mullite, mixing them evenly, adding a solvent, wet ball milling and spray drying to obtain a powder raw material;
[0161] S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening;
[0162] S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
[0163] The weight ratio of silicon oxide to mullite is 1:8.
[0164] In step S2, aluminum oxide accounts for 75% of the mixture by mass.
[0165] The firing temperature is 1650° C. and the firing time is 5 hours.
[0166] The heat treatment temperature is 1200° C. and the time is 12 hours.
[0167] The specific cooling process is: cooling to 25°C at 30°C / min.
[0168] The material-to-ball ratio of the wet ball milling is 1:1, and the wet ball milling time is 12 hours.
[0169] The stirring speed in S5 is 30 rpm, and the stirring time is 30 min.
[0170] The specific steps of the spray drying are: putting the ball-milled material into a spray granulator to prepare spherical powder.
[0171] The diameter of the spherical powder is 40 to 50 μm.
[0172] The sintering annealing step is: placing the particles in a sintering furnace in an oxygen environment, heating to 1500° C., keeping the temperature for 6 hours, and then naturally cooling to 25° C.
[0173] Performance Testing Methods
[0174] 1. Particle smoothness: randomly inspect 50 particles, observe the surface of the particles, and count the number of particles with sharp angles less than 45°. If the number is no more than 3, it is excellent; if the number is more than 3 and no more than 6, it is good; if the number is more than 6, it is poor.
[0175] 2. Evaporation performance test, sample preparation: the particles prepared in the example are placed in a crucible, and an optical film on the surface of a plastic substrate is subjected to evaporation processing, and the relevant evaporation performance is tested as follows.
[0176] (1) Evaporation stability: the fluctuation of the evaporation rate of the thin film during the evaporation process.
[0177] (2) Pit phenomenon: After the evaporation is completed, the surface of the evaporation material collapses and becomes uneven, which will cause the evaporation angle to change during the evaporation process.
[0178] (3) Wipeability of the film: After the evaporation is completed, wipe the surface of the film with high-purity alcohol to see if there are any marks left.
[0179] Performance test data
[0180] Table 1
[0181] Particle smoothness Evaporation stability The pit phenomenon Wipeability of film Example 1 excellent No fluctuation none No residue Example 2 excellent No fluctuation none No residue Example 3 excellent No fluctuation none No residue Example 4 excellent No fluctuation none No residue Comparative Example 1 Difference There are fluctuations have There is a residue Comparative Example 2 good There are fluctuations none There is a residue Comparative Example 3 good There are fluctuations have There is a residue Comparative Example 4 excellent There are fluctuations none No residue
Claims
1. A method for pretreating a silicon-aluminum mixture, characterized in that: The following steps are involved: S1, drying aluminum oxide and silicon oxide respectively, and mixing them uniformly to obtain a mixture; S2, firing the mixture, grinding and screening, heat treating, and cooling to obtain mullite; S3, adding silicon oxide to mullite, mixing evenly, adding solvent, wet ball milling and spray drying to obtain a powder raw material; S4, pressing the powder raw material into blocks by a hydraulic press, and obtaining granules after crushing and screening; S5, the particles are placed in a drum mixing tank and stirred, and then sintered and annealed, dust removed, inspected and packaged, and stored.
2. The pretreatment method of a silicon-aluminum mixture according to claim 1, characterized in that: Alumina in the S2 accounts for 74-78% of the mixture by mass.
3. The pretreatment method of a silicon-aluminum mixture according to claim 2, characterized in that: The firing temperature is 1600-1680° C., and the firing time is 4-6 hours.
4. The method for pretreating a silicon-aluminum mixture according to claim 3, characterized in that: The heat treatment temperature is 1100-1300° C. and the time is 10-15 hours.
5. The method for pretreating a silicon-aluminum mixture according to claim 4, characterized in that: The specific cooling process is: cooling at 25-35°C / min, keeping at 750-820°C for 1.5-3h, cooling to 280-320°C at 15-25°C / min, and finally cooling to 20-40°C.
6. A method for pretreating a silicon-aluminum mixture according to claim 1 or 5, characterized in that: The weight ratio of silicon oxide to mullite in the S3 is 1:(2-40).
7. The method for pretreating a silicon-aluminum mixture according to claim 6, characterized in that: The weight ratio of silicon oxide to mullite is 1:(4-16).
8. The method for pretreating a silicon-aluminum mixture according to claim 1, characterized in that: The material-ball ratio of the wet ball milling is (1-3):1, and the wet ball milling time is 10-14h.
9. The method for pretreating a silicon-aluminum mixture according to claim 8, characterized in that: The average particle size of the particles is 1-4 mm.
10. A method for pretreating a silicon-aluminum mixture according to claim 1 or 9, characterized in that: The stirring speed in S5 is 20-45 rpm, and the stirring time is 20-45 min.