A terbium-doped cesium cadmium chloride microcrystalline powder and a preparation method thereof

Abstract

The application discloses a terbium-doped cesium cadmium chloride microcrystalline powder and a preparation method thereof. 1‑x Tb x Cl3, wherein x=0.05-0.30. The application relates to the technical field of metal powder material preparation, and has the beneficial effect that the crystallinity of the powder is effectively improved, the particle agglomeration is significantly reduced, and the microcrystalline powder with irregular morphology is obtained through mechanical grinding, the chlorine elements provided by pyridine chloride and hydrochloric acid, the dispersion effect of polyethylene, and slow cooling treatment.

Description

Technical Field

[0001] This invention relates to the field of metal powder material preparation, and in particular to a terbium-doped cesium cadmium chloride microcrystalline powder and its preparation method. Background Technology

[0002] Metal halides, as an important class of inorganic functional materials, possess excellent photoelectric properties due to their rich composition and structural diversity. In particular, halides containing rare earth elements exhibit superior luminescence properties due to their unique electronic structure, showing broad application prospects. Optimizing the performance of these materials largely depends on efficient and controllable synthesis methods to prepare microcrystalline powders with high crystallinity and good dispersibility.

[0003] In the field of microcrystalline powder preparation, there have always been technical challenges such as uneven particle size distribution, lack of hard agglomerates, and obtaining uniform particle morphology. Currently, research into methods for synthesizing rare earth-doped metal halides is ongoing, and efficient preparation methods such as high-temperature solid-state methods, hydrothermal synthesis methods, and mechanical ball milling have been developed. However, these methods also have several drawbacks. For example, the high-temperature solid-state method promotes atomic or ion diffusion and crystallization by sintering precursors at high temperatures for extended periods, resulting in crystals with high crystallinity. However, the high temperature can lead to severe particle agglomeration and uneven component distribution, and it consumes a lot of energy in practical applications, which is not conducive to industrial production. The hydrothermal synthesis method allows for obtaining crystals with regular morphology at lower temperatures, but it also suffers from drawbacks such as high requirements for experimental equipment, limited yield, and poor batch repeatability. Mechanical ball milling relies on mechanical energy to induce precursor reactions, making it simple to operate and with mild reaction conditions. However, during traditional ball milling, microcrystalline powders are prone to moisture absorption and agglomeration, leading to reduced product crystallinity and limiting the improvement of the final powder product quality. Overall, existing methods for preparing metal halide microcrystalline powders generally face the problem of insufficient control over the physical properties of the powder (such as morphology, particle size and dispersibility), while also needing to address the challenges of energy consumption, efficiency and large-scale production.

[0004] Therefore, developing a synthesis method for preparing terbium-doped cesium cadmium chloride microcrystalline powder with high crystallinity and low agglomeration characteristics under mild conditions is of great significance for promoting the practical application of this type of functional powder material. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems by designing a terbium-doped cesium cadmium chloride microcrystalline powder and its preparation method.

[0006] The technical solution of the present invention to achieve the above objectives is a terbium-doped cesium cadmium chloride microcrystalline powder and its preparation method, the chemical composition of which is CsCd. 1-x Tb x Cl3, where x = 0.05~0.30;

[0007] The powder consists of amorphous particles with a particle size distribution in the range of 0.5-2μm, and the particles have irregular morphology and local aggregation.

[0008] This invention also provides a method for preparing the above-mentioned terbium-doped cesium cadmium chloride microcrystalline powder, comprising the following steps: Step S1: Cesium chloride, cadmium chloride, and terbium trichloride are mixed in a molar ratio of 1:0.95:x (x=0.05~0.30) and placed in a wear-resistant ball mill jar; Step S2: Pyridine chloride and hydrochloric acid are added, with the amount being 0.15 mmol of pyridine chloride and 0.10 mmol of hydrochloric acid per 1 mmol of CsCl, to form a precursor; Step S3: Polyethylene is added, with the amount being 0.01~0.02 g of polyethylene per 1 g of precursor, to obtain mixture a; Step S4: The above mixture a is ball-milled in a planetary ball mill at a speed of 300 rpm for 2 hours to obtain mixture b; Step S5: After ball milling, the obtained mixture b is cooled and dried, first slowly cooled to room temperature to obtain mixture c; Step S6: Place the mixture c in a vacuum drying oven and sublimate it under a vacuum of -0.04 MPa for 12 hours to obtain the terbium-doped cesium cadmium chloride microcrystalline powder.

[0009] In step S2, the amount of pyridine chloride and hydrochloric acid added is 0.15 mmol of pyridine chloride and 0.10 mmol of hydrochloric acid per 1 mmol of CsCl. The pyridine chloride is used to ensure uniform dispersion, and the hydrochloric acid is used to facilitate crystallization.

[0010] In step S3, the amount of polyethylene used is 0.02g per 1g of precursor. Polyethylene, as a dispersant, has good dispersion effect and anti-agglomeration effect.

[0011] In step S5, the mixture is slowly cooled to 20°C to obtain mixture c, which forms a stable and ordered structure. It is then sublimated under a vacuum of -0.04 MPa for 12 hours to remove most of the solvent and ensure that the powder morphology is uniform.

[0012] The present invention discloses a terbium-doped cesium cadmium chloride microcrystalline powder and its preparation method. By combining mechanical grinding with chlorine provided by pyridine chloride and hydrochloric acid, the dispersing effect of polyethylene, and slow cooling treatment, the crystallinity of the powder is effectively improved, particle agglomeration is significantly reduced, and microcrystalline powder with irregular morphology is obtained. Attached Figure Description

[0013] Figure 1 This is the XRD pattern of the terbium-doped cesium cadmium chloride microcrystalline powder material prepared in Example 1.

[0014] Figure 2 This is a TEM image of the terbium-doped cesium cadmium chloride microcrystalline powder material prepared in Example 1.

[0015] Figure 3 This is an elemental surface distribution diagram of the terbium-doped cesium cadmium chloride microcrystalline powder material prepared in Example 1.

[0016] Figure 4 This is an image of the terbium-doped cesium cadmium chloride microcrystalline powder material prepared in Example 1 under a 365nm ultraviolet light. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings, such as... Figure 1-4 As shown, a terbium-doped cesium-cadmium chloride microcrystalline powder and its preparation method are disclosed. The preparation process of the terbium-doped cesium-cadmium chloride microcrystalline powder is as follows: Cesium chloride (CsCl), cadmium chloride (CdCl2), and terbium trichloride (TbCl3) are mixed in a molar ratio of 1:0.95:x (x=0.05~0.30) and placed in a wear-resistant ball mill jar. To ensure sufficient chlorine supply in the reaction system and improve powder dispersibility, pyridine chloride and hydrochloric acid are further added, with the dosage being 0.15 mmol of pyridine chloride and 0.10 mmol of hydrochloric acid per 1 mmol of CsCl, forming a precursor. Polyethylene is also added, with the dosage being 0.015 g of polyethylene per 1 g of precursor, resulting in mixture a. This mixture is adsorbed onto the particle surface during grinding, thereby preventing agglomeration and improving grinding uniformity. A planetary ball mill (QM-3SP04) was used to ball mill the above precursor at 300 rpm for 2 hours to ensure thorough mixing and the formation of a homogeneous material, yielding mixture b. After ball milling, mixture b was slowly cooled to room temperature to obtain mixture c. Mixture c was then sublimated under a vacuum of -0.04 MPa for 12 hours to remove most of the solvent, thereby obtaining well-crystallized terbium-doped cesium cadmium chloride microcrystalline powder.

[0018] The obtained powder was characterized by transmission electron microscopy (TEM), and the results are as follows: Figure 2 As shown in the figure, the powder sample consists of a large number of uniformly shaped particles with amorphous characteristics. The particle size is mainly distributed in the range of 0.5-2 μm, exhibiting a relatively loose micro-aggregate structure. This loose amorphous structure is beneficial for increasing the specific surface area and improving the dispersibility between particles, thereby providing better interfacial contact conditions for subsequent processing or reactions, demonstrating the potential of the method of this invention in the control of powder microstructure.

[0019] Performance tests on the product showed that it emitted yellow fluorescence under ultraviolet light. Figure 4 As shown, the XRD analysis is as follows: Figure 1 As shown, the crystal structure of the product was confirmed, and the elemental distribution test results were as follows: Figure 3 As shown, this indicates that each element is uniformly distributed in the material.

[0020] In the preparation method of the present invention, in order to ensure a sufficient supply of chlorine in the reaction system, the amount of pyridine chloride and hydrochloric acid added is 0.15 mmol of pyridine chloride and 0.10 mmol of hydrochloric acid per 1 mmol of CsCl.

[0021] In the preparation method of the present invention, the amount of polyethylene used is 0.02g per 1g of precursor, in order to improve the uniformity of ball milling and inhibit particle agglomeration.

[0022] In the preparation method of the present invention, the product is slowly cooled to room temperature and sublimated under a vacuum of -0.04 MPa for 12 h to remove most of the solvent, so as to ensure that the product forms a stable and ordered structure with good morphology.

[0023] Example 1: 1 mmol of cesium chloride (CsCl), 0.95 mmol of cadmium chloride (CdCl2), and 0.05 mmol of terbium trichloride (TbCl3) were accurately weighed and placed in a 25 mL agate ball mill jar. 0.15 mmol of pyridine chloride and 0.10 mmol of hydrochloric acid were added to ensure sufficient chlorine supply to the system. Simultaneously, 0.02 g of polyethylene was added to improve powder dispersibility and inhibit particle agglomeration. Then, 25 agate balls with a diameter of 6 mm were added, and the ball mill jar was placed in a planetary ball mill (QM-3SP04) and ball-milled at 300 rpm for 2 hours to ensure thorough mixing and homogenization of the material. After ball milling, the resulting mixture b was slowly cooled to room temperature and then sublimated under a vacuum of -0.04 MPa for 12 hours to remove most of the solvent and maintain crystal structure stability, thereby obtaining terbium-doped cesium-cadmium chloride microcrystalline powder, i.e., TbCl3. 3+ Doped with CsCdCl3.

[0024] Characterization of the obtained powder showed that it mainly consisted of amorphous particles in a loosely aggregated state. XRD analysis was performed as follows. Figure 1 As shown, its crystal structure was confirmed, and the elemental distribution test results were as follows: Figure 3 As shown, this indicates that the elements are uniformly distributed in the material.

[0025] Example 2: Based on Example 1, to ensure sufficient chlorine supply and precise control of crystal structure in the ball milling system, pyridine chloride and hydrochloric acid were added to the system, with the amounts adjusted to 0.05 mmol, 0.1 mmol, 0.15 mmol, and 0.2 mmol, respectively. The results showed that the powder exhibited the best dispersibility and overall performance when the amount of pyridine chloride was 0.15 mmol and the amount of hydrochloric acid was 0.10 mmol.

[0026] Example 3: Based on Example 1, the amount of polyethylene was adjusted to 0.5 wt% (0.005 g), 1.0 wt% (0.010 g), 1.5 wt% (0.015 g), and 2.0 wt% (0.020 g) of the total precursor mass, respectively, to improve powder dispersibility and inhibit particle agglomeration. The results showed that when the amount of polyethylene was 2.0 wt% (0.02 g) of the total precursor mass, the dispersibility and overall performance of the resulting powder were optimal.

[0027] The above technical solutions only illustrate preferred embodiments of the present invention. For those skilled in the art, any adjustments they may make to certain parts still embody the principles of the present invention and fall within the scope of protection of the present invention. The above technical solutions only embody preferred technical solutions of the present invention, and any modifications that those skilled in the art may make to certain parts embody the principles of the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing terbium-doped cesium cadmium chloride microcrystalline powder, characterized in that, The chemical composition of terbium-doped cesium cadmium chloride microcrystalline powder is Tb 3+ Doping CsCdCl3 includes the following steps: Step S1: Cesium chloride, cadmium chloride and terbium trichloride are mixed in a molar ratio of 1:0.95:x, where x = 0.05~0.30, and then placed in a wear-resistant ball mill jar; Step S2: Add pyridine chloride and hydrochloric acid, using 0.15 mmol of pyridine chloride and 0.10 mmol of hydrochloric acid per 1 mmol of CsCl to form a precursor; Step S3: Add polyethylene, using 0.01~0.02g of polyethylene per 1g of precursor, to obtain mixture a; Step S4: The above mixture a is ball-milled in a planetary ball mill at a speed of 300 rpm for 2 hours to obtain mixture b; Step S5: After ball milling, the resulting mixture b is cooled and dried. First, it is slowly cooled to room temperature to obtain mixture c. Step S6: Sublimate the mixture c under a vacuum of -0.04 MPa for 12 h to obtain the terbium-doped cesium cadmium chloride microcrystalline powder; The powder consists of amorphous particles with a particle size distribution in the range of 0.5-2μm, and the particles have irregular morphology and local aggregation.

2. The method according to claim 1, characterized in that, In step S3, polyethylene is used as a dispersant, and the dosage is 0.02g of polyethylene per 1g of precursor.

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