Preparation method of tantalum oxide particles

Abstract

The invention relates to the technical field of optical evaporation materials, in particular to a preparation method of tantalum oxide particles. Comprising the following steps: S1, drying tantalum oxide and tantalum powder for later use; s2, grinding tantalum oxide, filtering feed liquid, and drying an obtained filter cake to obtain a mixture; s3, uniformly mixing the mixture with tantalum powder, pressing the mixture into blocks, and then crushing and screening the blocks to obtain mixed particles; s4, the mixed particles are put into a roller stirring tank to be stirred, and pretreated mixed particles are obtained; and S5, carrying out vacuum sintering on the pretreated mixed particles, then cooling to room temperature, and then sequentially carrying out screening, vacuum packaging and warehousing, thereby obtaining the product. The tantalum powder and the tantalum oxide are ground, so that the granulated ceramic particles are more compact, and the mechanical property of the sintered material is better; the specific surface area of the raw material is increased, the surface energy is increased, abnormal growth of grains can be effectively prevented, the activity of the raw material is increased, the sintering temperature is reduced, and the sintering time is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of optical evaporation materials, in particular to the field of IPC C23C14, and more specifically to a method for preparing tantalum oxide particles. Background Art

[0002] With the continuous development of industrial technology, optical coating materials have become an indispensable part of optical parts. Among them, tantalum oxide is a high refractive index coating material currently used in the optical communication industry. Tantalum oxide coating materials have a stable high refractive index, good chemical stability, high film firmness, and strong resistance to laser damage. It has high transmittance and reflectivity in the visible and near-infrared regions and is widely used in anti-reflection films, lasers, optical communications and other components. However, tantalum oxide granules from different manufacturers or batches are inconsistent, which affects subsequent operations.

[0003] CN115893492A provides a method for preparing tantalum oxide, comprising the following steps: A) subjecting a fluorotantalate solution to a first precipitation reaction at a pH value of 3 to 6, and subjecting a second precipitation reaction to a pH value of 8 to 10 to obtain a tantalum precipitate; B) subjecting the tantalum precipitate obtained in step A) to a staged calcination to obtain tantalum oxide. This method is suitable for mass production of hexagonal tantalum oxide powder with a powder size of 5 μm to 10 μm and a purity of more than 99.99%. However, the invention has a large particle size and a wide particle size distribution, which affects the subsequent application as a vapor deposition material. Summary of the invention

[0004] The present invention provides a method for preparing tantalum oxide particles, comprising the following steps:

[0005] S1, drying tantalum oxide and tantalum powder for later use;

[0006] S2, adding tantalum oxide, tantalum powder and dispersant into a ball mill for grinding, and drying the obtained suspension through a spray granulator to obtain a uniformly mixed material;

[0007] S3, placing the mixed particles in a drum stirring tank for spheronization to obtain pretreated mixed particles;

[0008] S4, vacuum sintering the pretreated mixed particles, cooling them to room temperature, and then sequentially screening, vacuum packaging and storing them.

[0009] The particle size of the tantalum oxide in S1 is 0.1-50 μm, and the average particle size is 5-8 μm.

[0010] The particle size of tantalum oxide D90 in S1 is 10-25 μm.

[0011] Preferably, the particle size of tantalum oxide D90 in S1 is 15-25 μm.

[0012] The grinding uses one of a horizontal planetary ball mill, a vertical planetary ball mill and a sand mill.

[0013] Preferably, the grinding uses a horizontal planetary ball mill.

[0014] The grinding rotation speed is 85-145 rpm, the solid-liquid ratio of the grinding slurry is (2-4): (6-9), and the grinding time is 30-60 hours.

[0015] The applicant has found that when the grinding speed is 85-145 rpm, the solid-liquid ratio of the grinding slurry is (2-4): (6-9), and the grinding time is 30-60 h, tantalum oxide with a D90 particle size of 1-2 μm and an average particle size of 0.95-1.05 μm can be obtained. The existing tantalum oxide raw material manufacturers have various models, large differences between different batches, and also have the characteristic of wide particle size distribution (0.1-50 μm). As a vapor deposition material, there are great limitations on its application. The applicant has explored and found during the experiment that a specific normally distributed tantalum oxide particle size can effectively improve the stability of vapor deposition. For the existing purchased tantalum oxide with a particle size of 0.1-50 μm and an average particle size of 5-8 μm, a particle size distribution that meets the requirements can be obtained by limiting the specific grinding speed, solid-liquid ratio and time, and at the same time, the stability of vapor deposition can be effectively improved.

[0016] Preferably, the grinding rotation speed is 100-130 rpm, the solid-liquid ratio of the grinding slurry is (3-4): (6-9), and the grinding time is 36-50 h.

[0017] Further preferably, the grinding rotation speed is 120 rpm, the solid-liquid ratio of the grinding slurry is 3:7, and the grinding time is 41 h.

[0018] The tantalum oxide D90 has a particle size of 0.5-3 μm and an average particle size of 0.8-1.1 μm.

[0019] Preferably, the tantalum oxide D90 has a particle size of 1-2 μm and an average particle size of 0.95-1.05 μm.

[0020] Preferably, the particle size of the pretreated mixed particulate matter includes one of the following: 1-3 mm, 2-4 mm and 3-5 mm.

[0021] The applicant has found that the weight ratio of tantalum oxide to tantalum powder is (80-100): (1-10). This may be due to the introduction of a specific mass ratio of aluminum oxide and tantalum pentoxide, which has a certain regulatory effect on the growth of titanium pentoxide crystals. In the actual coating process, it is easier to form a film with high uniformity and low stress. At the same time, in the composite process of the low-refractive index silicon dioxide film layer, it helps to increase the expansion coefficient of the silicon dioxide film, avoid cracking and film shedding under extreme conditions such as sudden cooling, ultra-low temperature, and ultra-high temperature, and expand the large-scale application of new optical coating materials in aerospace and other fields.

[0022] The weight ratio of the tantalum oxide to the tantalum powder is (80-100):(1-10).

[0023] Preferably, the weight ratio of tantalum oxide to tantalum powder is (80-90):(5-10).

[0024] Further preferably, the weight ratio of tantalum oxide to tantalum powder is 85:6.

[0025] The vacuum degree of the vacuum sintering is 0.0001-0.003Pa.

[0026] Preferably, the vacuum degree of the vacuum sintering is 0.0005-0.001Pa.

[0027] Further preferably, the vacuum degree of the vacuum sintering is 0.0008Pa.

[0028] The vacuum sintering temperature is 1700-1800° C., and the insulation time is 5-8 hours.

[0029] Preferably, the vacuum sintering temperature is 1710-1770° C., and the holding time is 5-8 hours.

[0030] Further preferably, the vacuum sintering temperature is 1750° C. and the holding time is 6 hours.

[0031] The heating rate of the vacuum sintering is 3-5°C / min, and the cooling rate of the cooling is 5-8°C / min.

[0032] Beneficial effects:

[0033] 1. The grinding speed is 85-145 rpm, the solid-liquid ratio of the grinding slurry is (2-4): (6-9), and the grinding time is 30-60 hours. Tantalum oxide with a D90 particle size of 1-2 μm and an average particle size of 0.95-1.05 μm can be obtained, which effectively improves the evaporation stability.

[0034] 2. Grind tantalum powder and tantalum oxide. The ceramic particles after granulation are denser and the mechanical properties of the material after sintering are better.

[0035] 3. The specific surface area and surface energy of the raw materials increase, which can effectively prevent abnormal grain growth. At the same time, the activity of the raw materials increases, the sintering temperature decreases, and the sintering time shortens.

[0036] 4. Through the rounding treatment, the surface of the particles has fewer sharp edges and corners (similar to the process of stones becoming pebbles through repeated friction and collision). During use (bombarded with an electron gun), there will be no uneven heating caused by the corners being bombarded accidentally (affecting the product yield). BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a particle size test diagram of Example 1 before treatment.

[0038] Figure 2 This is the particle size test diagram after treatment in Example 1. DETAILED DESCRIPTION

[0039] Example 1

[0040] A method for preparing tantalum oxide particles comprises the following steps:

[0041] S1, drying tantalum oxide and tantalum powder for later use;

[0042] S2, adding tantalum oxide, tantalum powder and dispersant into a ball mill for grinding, and drying the obtained suspension through a spray granulator to obtain a uniformly mixed material;

[0043] S3, placing the mixed particles in a drum stirring tank for spheronization to obtain pretreated mixed particles;

[0044] S4, vacuum sintering the pretreated mixed particles, cooling them to room temperature, and then sequentially screening, vacuum packaging and storing them.

[0045] The grinding was performed using a horizontal planetary ball mill.

[0046] The grinding rotation speed is 120 rpm, the solid-liquid ratio of the grinding slurry is 3:7, and the grinding time is 41 hours.

[0047] The particle size of the mixed particles is 1-3 mm.

[0048] The weight ratio of the tantalum oxide to the tantalum powder is 85:6.

[0049] The vacuum degree of the vacuum sintering is 0.0008Pa.

[0050] The vacuum sintering temperature is 1750° C. and the holding time is 6 hours.

[0051] The heating rate of the vacuum sintering is 10°C / min, and the cooling rate of the cooling is 30°C / min.

[0052] Example 2

[0053] A method for preparing tantalum oxide particles comprises the following steps:

[0054] S1, drying tantalum oxide and tantalum powder for later use;

[0055] S2, adding tantalum oxide, tantalum powder and dispersant into a ball mill for grinding, and drying the obtained suspension through a spray granulator to obtain a uniformly mixed material;

[0056] S3, placing the mixed particles in a drum stirring tank for spheronization to obtain pretreated mixed particles;

[0057] S4, vacuum sintering the pretreated mixed particles, cooling them to room temperature, and then sequentially screening, vacuum packaging and storing them.

[0058] The grinding was performed using a horizontal planetary ball mill.

[0059] The grinding rotation speed is 100 rpm, the solid-liquid ratio of the grinding slurry is 3:8, and the grinding time is 41 hours.

[0060] The particle size of the mixed particles is 1-3 mm.

[0061] The weight ratio of the tantalum oxide to the tantalum powder is 85:6.

[0062] The vacuum degree of the vacuum sintering is 0.0008Pa.

[0063] The vacuum sintering temperature is 1750° C. and the holding time is 6 hours.

[0064] The heating rate of the vacuum sintering is 8°C / min, and the cooling rate of the cooling is 25°C / min.

[0065] Example 3

[0066] A method for preparing tantalum oxide particles comprises the following steps:

[0067] S1, drying tantalum oxide and tantalum powder for later use;

[0068] S2, adding tantalum oxide, tantalum powder and dispersant into a ball mill for grinding, and drying the obtained suspension through a spray granulator to obtain a uniformly mixed material;

[0069] S3, placing the mixed particles in a drum stirring tank for spheronization to obtain pretreated mixed particles;

[0070] S4, vacuum sintering the pretreated mixed particles, cooling them to room temperature, and then sequentially screening, vacuum packaging and storing them.

[0071] The grinding was performed using a horizontal planetary ball mill.

[0072] The grinding rotation speed is 120 rpm, the solid-liquid ratio of the grinding slurry is 3:7, and the grinding time is 41 hours.

[0073] The particle size of the mixed particles is 1-3 mm.

[0074] The weight ratio of the tantalum oxide to the tantalum powder is 90:6.

[0075] The vacuum degree of the vacuum sintering is 0.0008Pa.

[0076] The vacuum sintering temperature is 1730° C. and the holding time is 6.5 h.

[0077] The heating rate of the vacuum sintering is 4°C / min, and the cooling rate of the cooling is 6°C / min.

[0078] Comparative Example 1

[0079] A method for preparing tantalum oxide particles comprises the following steps:

[0080] S1, drying tantalum oxide and tantalum powder for later use;

[0081] S2, adding tantalum oxide, tantalum powder and dispersant into a ball mill for grinding, and drying the obtained suspension through a spray granulator to obtain a uniformly mixed material;

[0082] S3, placing the mixed particles in a drum stirring tank for spheronization to obtain pretreated mixed particles;

[0083] S4, vacuum sintering the pretreated mixed particles, cooling them to room temperature, and then sequentially screening, vacuum packaging and storing them.

[0084] The grinding was performed using a horizontal planetary ball mill.

[0085] The grinding rotation speed is 80 rpm, the solid-liquid ratio of the grinding slurry is 3:5, and the grinding time is 60 hours.

[0086] The particle size of the mixed particles is 1-3 mm.

[0087] The weight ratio of the tantalum oxide to the tantalum powder is 85:6.

[0088] The vacuum degree of the vacuum sintering is 0.0008Pa.

[0089] The vacuum sintering temperature is 1750° C. and the holding time is 6 hours.

[0090] The heating rate of the vacuum sintering is 4°C / min, and the cooling rate of the cooling is 6°C / min.

[0091] Comparative Example 2

[0092] A method for preparing tantalum oxide particles comprises the following steps:

[0093] S1, drying tantalum oxide and tantalum powder for later use;

[0094] S2, adding tantalum oxide, tantalum powder and dispersant into a ball mill for grinding, and drying the obtained suspension through a spray granulator to obtain a uniformly mixed material;

[0095] S3, placing the mixed particles in a drum stirring tank for spheronization to obtain pretreated mixed particles;

[0096] S4, vacuum sintering the pretreated mixed particles, cooling them to room temperature, and then sequentially screening, vacuum packaging and storing them.

[0097] The grinding was performed using a horizontal planetary ball mill.

[0098] The grinding rotation speed is 160 rpm, the solid-liquid ratio of the grinding slurry is 2:7, and the grinding time is 35 hours.

[0099] The particle size of the mixed particles is 1-3 mm.

[0100] The weight ratio of the tantalum oxide to the tantalum powder is 85:6.

[0101] The vacuum degree of the vacuum sintering is 0.0008Pa.

[0102] The vacuum sintering temperature is 1750° C. and the holding time is 6 hours.

[0103] The heating rate of the vacuum sintering is 4°C / min, and the cooling rate of the cooling is 6°C / min.

[0104] Performance Testing Methods

[0105] The D90 particle size and average particle size of tantalum oxide in Example 1 were tested. Figure 1-2 ), the test data are listed in Table 1.

[0106] Performance test data

[0107] Table 1

[0108]

Claims

1. A method for preparing tantalum oxide particles, characterized in that: The following steps are involved: S1, drying tantalum oxide and tantalum powder for later use; S2, adding tantalum oxide, tantalum powder and dispersant into a ball mill for grinding, and drying the obtained suspension through a spray granulator to obtain a uniformly mixed material; S3, placing the mixed particles in a drum stirring tank for spheronization to obtain pretreated mixed particles; S4, vacuum sintering the pretreated mixed particles, cooling them to room temperature, and then screening, vacuum packaging and storing them in sequence.

2. The method for preparing tantalum oxide particles according to claim 1, characterized in that: The grinding uses one of a horizontal planetary ball mill, a vertical planetary ball mill and a sand mill.

3. The method for preparing tantalum oxide particles according to claim 2, characterized in that: The grinding rotation speed is 85-145 rpm, the solid-liquid ratio of the grinding slurry is (2-4): (6-9), and the grinding time is 30-60 hours.

4. The method for preparing tantalum oxide particles according to claim 3, characterized in that: The grinding rotation speed is 100-130rpm, the solid-liquid ratio of the grinding slurry is (3-4): (6-9), and the grinding time is 36-50h.

5. The method for preparing tantalum oxide particles according to claim 4, characterized in that: The particle size of the pre-treated mixed particles includes one of the following: 1-3 mm, 2-4 mm and 3-5 mm.

6. The method for preparing tantalum oxide particles according to claim 5, characterized in that: In step S2, the weight ratio of tantalum oxide to tantalum powder is (80-100): (1-10).

7. The method for preparing tantalum oxide particles according to claim 1 or 6, characterized in that: The vacuum degree of the vacuum sintering is 0.0001-0.003Pa.

8. The method for preparing tantalum oxide particles according to claim 7, characterized in that: The vacuum sintering temperature is 1700-1800° C., and the insulation time is 5-8 hours.

9. The method for preparing tantalum oxide particles according to claim 8, characterized in that: The heating rate of the vacuum sintering is 3-5°C / min.

10. The method for preparing tantalum oxide particles according to claim 9, characterized in that: The cooling rate is 5-8°C / min.

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