Rare earth element gadolinium substituted LiZnTi ferrite material and preparation method thereof

Abstract

The invention discloses a rare earth element gadolinium substituted LiZnTi ferrite material and a preparation method thereof, and belongs to the technical field of ferrite materials, the molecular formula of the material is Li < 0.43 > Zn < 0.27 > Ti < 0.13 > Gd < x > Fe < 2.17-x > O < 4 >, the preparation method is a solid-phase reaction method and comprises the steps of material preparation, primary ball milling, pre-sintering, secondary ball milling, granulation forming, sintering and the like. Through substitution of a proper amount of Gd ions, the compactness of the prepared ferrite material is greatly improved, and the problem of large ferromagnetic resonance line width in the prior art is solved; by optimizing the raw material ratio and sintering temperature, the LiZnTi ferrite material with excellent gyromagnetic performance and good compactness is successfully prepared, the actual density of the material reaches 4.782 g / cm < 3 >, and the ferromagnetic resonance line width is reduced to 270 Oe.

Description

Technical Field

[0001] The invention relates to the technical field of ferrite materials, and in particular to a rare earth element gadolinium-substituted LiZnTi ferrite material and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology, microwave devices have been widely used in radar, artificial intelligence, satellite communications and other fields, which has led to a growing demand for high-performance ferrite materials. Gyromagnetic ferrite has become one of the key materials for microwave devices due to its excellent electromagnetic properties, especially high permeability and low loss at high frequencies.

[0003] The densification of materials helps to improve the magnetic properties of materials and reduce the magnetic loss of materials, making them more efficient and durable in electronic devices, communication equipment and power systems. Low ferromagnetic resonance linewidth can reduce microwave losses and improve the signal transmission efficiency of devices. By promoting the densification of materials and reducing the ferromagnetic resonance linewidth, the working efficiency and performance of microwave devices can be effectively improved, especially in applications under high-frequency conditions. Therefore, how to reduce the ferromagnetic resonance linewidth of Li-based ferrite materials while maintaining good densification has become a key issue that urgently needs to be solved. Summary of the invention

[0004] One of the purposes of the present invention is to provide a LiZnTi ferrite material substituted with the rare earth element gadolinium to solve the above-mentioned problems.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a rare earth element gadolinium substituted LiZnTi ferrite material, the molecular formula of which is Li 0.43 Zn 0.27 Ti 0.13 G x Fe 2.17-x O4, where 0 <x≤0.10。

[0006] As a preferred technical solution, x=0.04. When x is 0.04, the density of the material is higher, the ferromagnetic resonance line width is lower, and the comprehensive performance of the material is better.

[0007] The second object of the present invention is to provide a method for preparing the above-mentioned rare earth element gadolinium-substituted LiZnTi ferrite material, the technical scheme adopted is, comprising the following steps: S1. Ingredients: Li2CO3, ZnO, TiO2 and Fe2O3 are used as the main materials, Gd2O3 is used as the ion substitute, according to the molecular formula Li 0.43 Zn 0.27 Ti 0.13 G x Fe2.17-x Calculate and weigh the raw materials, where 0 < x ≤ 0.10; from this, the mass ratio of the main material to the ion substitute is converted to (43.41 - 45.11)∶(0.73 - 3.66); S2. Primary ball milling: Ball mill the raw materials weighed in step S1. After the ball milling is completed, obtain the primary ball milled material; S3. Pre-sintering: Dry and screen the primary ball milled material obtained in step S2, then place it in a box furnace, raise the temperature and hold for a certain time, and cool down to room temperature with the furnace to obtain the pre-sintered material; S4. Secondary ball milling: Ball mill the pre-sintered material obtained in step S3. After the ball milling is completed, obtain the secondary ball milled material; S5. Granulation and forming: Dry and screen the secondary ball milled material obtained in step S4, then add a binder for granulation, and press it into a sample; S6. Sintering: Sinter the sample obtained in step S5. After the sintering is completed, cool down to room temperature with the furnace to obtain the LiZnTi ferrite material substituted by the rare earth element gadolinium.

[0008] As a preferred technical solution, in step S2, the primary ball milling is carried out at a rotation speed of 240 - 300 r / min; As a preferred technical solution, in step S3, the temperature is raised at a rate of 2 - 5 °C / min to 650 - 850 °C, and the holding time is 2 - 6 h.

[0009] As a preferred technical solution, in step S5, the binder is PVA glue with a concentration of 10 wt.% - 15 wt.%. PVA glue plays a role in increasing the viscosity during granulation. When PVA glue is added to the glue, the adhesion between materials is improved, thereby enhancing the bonding strength and enabling the materials to be better pressed into shape.

[0010] As a preferred technical solution, in step S5, the pressure during pressing is 10 - 15 Mpa.

[0011] As a preferred technical solution, in step S6, the sintering parameters are: first degrease at a temperature of 500 - 650 °C for 1 - 2 h, and then sinter at a temperature of 1000 - 1100 °C for 4 - 8 h.

[0012] The synthesis method of the present invention is novel. First, the main components and the substitute are mixed evenly and subjected to primary ball milling. After drying, a suitable pre-sintering temperature is adopted in a box furnace, the temperature is 650 - 850 °C, and the holding time is 2 - 6 h; then the material is taken for secondary ball milling, dried and then added with a binder for granulation. After the granulation is completed, it is dry pressed into a cylindrical sample, and finally a suitable sintering temperature is selected to prepare a ferrite with good densification and low ferromagnetic resonance linewidth.

[0013] The present invention uses a main formula (Li2CO3, Fe2O3, ZnO and TiO2) and a substituent (Gd2O3) in combination, adopts a suitable pre-sintering temperature (650-850 ℃) and grinding time, and a suitable sintering temperature (1000-1100 ℃) to synthesize a new LiZnTiGd ferrite material with good densification and low ferromagnetic resonance line width; its density can reach 4.782 g / cm 3 , D H As low as 270 Oe.

[0014] Compared with the prior art, the advantages of the present invention are as follows: the present invention solves the problems of poor densification and large ferromagnetic resonance line in the prior art by replacing an appropriate amount of Gd ions; firstly, the main material and the replacement material are mixed and ball milled once, dried and pre-fired after ball milling, a suitable pre-fired temperature is selected for pre-fired, ball milled twice after pre-fired, a binder is added after ball milling and drying, granulated and pressed into a cylindrical sample, and finally a suitable temperature is selected for sintering, and a LiZnTi ferrite material with excellent gyromagnetic properties and good density is successfully prepared, and the density of the material reaches 4.782 g / cm 3 , and the ferromagnetic resonance linewidth is reduced to 270Oe. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a process flow chart for preparing the LiZnTi ferrite material substituted with the rare earth element gadolinium according to the present invention; Figure 2 XRD diagram of LiZnTiGd ferrite materials prepared in Examples 1, 2, 3, 4, and 5 of the present invention; Figure 3 This is a density trend diagram of the LiZnTiGd ferrite prepared in Examples 1, 2, 3, 4, and 5 of the present invention; Figure 4 (a) is a SEM image of a reference standard, (b) to (f) are SEM images of LiZnTiGd ferrites prepared in Examples 1, 2, 3, 4, and 5 of the present invention; Figure 5 (a) is a line width fitting diagram of a reference standard, and (b) to (f) are line width fitting diagrams of LiZnTiGd ferrites prepared in Examples 1, 2, 3, 4, and 5 of the present invention. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with the accompanying drawings. Example

[0017] A rare earth element gadolinium-substituted LiZnTi ferrite material, the preparation method of which comprises the following steps: S1. Ingredients: According to Li0.43 Zn 0.27 Ti 0.13 G x Fe 2.17-x O4 molecular formula: Li2CO3, Fe2O3, ZnO and TiO2 are weighed as main materials, and the substituent material is Gd2O3, where x = 0.02, and the mass of Gd2O3 is 0.7323 g; S2. First ball milling: The powder weighed in step S1 was subjected to a ball milling for a ball milling time of 4-6 h; S3. Pre-sintering: After taking the material, dry it in an oven at 100 °C, sieve it with an 80-mesh sieve, put the sieved powder into a sintering furnace, heat it to 650-850 °C at a rate of 2-5 °C / min and keep it at that temperature for 2-6 h, then cool it to 600 °C at a rate of 2-5 °C / min, and then naturally cool it to room temperature to obtain a pre-sintered material; S4 secondary ball milling: The quality of the pre-sintered material obtained in step S3 was used as a reference for secondary ball milling, the milling time was 4-6 h, the milling speed was 240-300 r / min, after the milling was completed, the secondary milling material was obtained; S5 granulation molding: The secondary ball mill obtained in step S4 is dried and sieved, a binder is added for granulation, and pressed into a cylindrical sample at a pressure of 10 to 15 Mpa; S6. Sintering: Sintering the sample obtained in step S5, first debinding at 500-650°C for 1-2 h, then sintering at 1000-1100°C for 4-8 h, and then cooling to room temperature in the furnace to obtain the gadolinium-substituted LiZnTi ferrite material. Example

[0018] A rare earth element gadolinium-substituted LiZnTi ferrite material and a preparation method thereof are substantially the same as those in Example 1, except that: in step S1, x=0.04 is weighed, and the mass of Gd2O3 is 1.4646 g; Example

[0019] A rare earth element gadolinium-substituted LiZnTi ferrite material and a preparation method thereof are substantially the same as those in Example 1, except that: in step S1, x=0.06 is weighed, and 2.1970 g of Gd2O3 is weighed; Example

[0020] A rare earth element gadolinium-substituted LiZnTi ferrite material and a preparation method thereof are substantially the same as those in Example 1, except that: in step S1, x=0.08 is weighed, and the mass of Gd2O3 is 2.9293 g; Example

[0021] A rare earth element gadolinium-substituted LiZnTi ferrite material and a preparation method thereof are substantially the same as those in Example 1, except that: in step S1, x=0.10 is weighed, and the mass of Gd2O3 is 3.6616 g; Reference standards: A rare earth element gadolinium-substituted LiZnTi ferrite material and a preparation method thereof are substantially the same as those in Example 1, except that in step S1, weighing x=0.00, i.e., Gd2O3 is not weighed, and the rest is the same as in Example 1.

[0022] Comparative Example 1 A rare earth element gadolinium-substituted LiZnTi ferrite material and a preparation method thereof are substantially the same as those in Example 3, except that the sintering temperature in step S6 is 1000°C.

[0023] The density trend diagram of the materials obtained in the above embodiments and comparative examples is as follows: Figure 3 As shown in the SEM images Figure 4 As shown, the line width fitting diagram is Figure 5 As shown; Its performance test data is shown in Table 1: Table 1 Density and ferromagnetic resonance line width of materials obtained in different embodiments and comparative examples

[0024] The sintering temperature of Comparative Example 1 is different from that of Example 2. The results show that the sintering density decreases, the ferromagnetic resonance line width increases, the density is low, and the line width is large, which does not meet the process requirements.

[0025] The preparation process flow chart of a rare earth element gadolinium-substituted LiZnTi ferrite material and its preparation method of the present invention is as follows: Figure 1 shown.

[0026] The XRD results of the gadolinium-substituted LiZnTi gyromagnetic ferrite materials prepared in Examples 1, 2, 3, 4, and 5 are as follows: Figure 2 As shown in Figure 2, when x < 0.06, the sample exhibits a consistent spinel phase; when x ≥ 0.06, the spinel phase and the GdFeO3 phase are observed. The generation of the GdFeO3 phase may be caused by the unreacted Gd ions due to the high doping concentration. As the concentration of Gd ions increases, the dilution effect of the rare earth elements decreases, resulting in an insufficient dilution effect. Therefore, if the doping concentration of the rare earth element exceeds the specific limit of a particular element, an impurity phase will appear in the sample.

[0027] As shown in Table 1, the ferromagnetic resonance line width values ​​of the ferrite materials obtained in Examples 1, 2, 3, 4, 5 of the present invention and Comparative Example 1. It can be seen from Table 1 that the ferromagnetic resonance line width of Example 2 is the lowest, Δ H It is 270 Oe.

[0028] As can be seen from Table 1, compared with the reference standard, the performance standard of Example 2 adopts the rare earth element gadolinium substitution and the appropriate sintering temperature. The experimental results show that the density increases and the densification is good; the ferromagnetic resonance line width Δ H Reduce and meet the process requirements.

[0029] Those skilled in the art can make various modifications and changes within the spirit and scope of the present invention. Therefore, any solution with equivalent technical effects should be regarded as within the protection scope of the present invention. The actual protection scope of the present invention should be defined by the attached claims.

Claims

1. A rare earth element gadolinium-substituted LiZnTi ferrite material, characterized in that: The molecular formula of the material is Li 0.43 Zn 0.27 Ti 0.13 G x Fe 2.17-x O4, where 0 <x≤0.10。 2. The rare earth element gadolinium-substituted LiZnTi ferrite material according to claim 1, characterized in that: Said x=0.

04.

3. The method for preparing the rare earth element gadolinium-substituted LiZnTi ferrite material according to claim 1 or 2, characterized in that: The steps include: S1. Ingredients: Li2CO3, ZnO, TiO2, Gd2O3 and Fe2O3 are used as raw materials, according to the molecular formula Li 0.43 Zn 0.27 Ti 0.13 G x Fe 2.17-x O4 calculate and weigh the raw materials, of which 0 <x≤0.10; S2. A ball milling: The raw material weighed in step S1 is subjected to a ball milling, and after the ball milling is completed, a ball milling material is obtained; S3 pre-burning: The once-milled material obtained in step S2 is dried, sieved and placed in a box furnace, heated and kept warm, and the furnace is cooled to room temperature to obtain a pre-burned material; S4 secondary ball milling: The pre-sintered material obtained in step S3 was subjected to secondary ball milling, and after the ball milling was completed, a secondary ball milling material was obtained; S5 granulation molding: The secondary ball mill obtained in step S4 is dried and sieved, a binder is added to granulate and pressed into a sample; S6. Sintering: Sintering the sample obtained in step S5. After sintering, the sample is cooled to room temperature in the furnace to obtain the rare earth element gadolinium-substituted LiZnTi ferrite material.

4. The preparation method according to claim 3, characterized in that In step S2, the first ball milling is performed at a rotation speed of 240-300 r / min.

5. The preparation method according to claim 3, characterized in that In step S3, the temperature is raised to 650-850°C at a rate of 2-5°C / min, and the holding time is 2-6 h.

6. The preparation method according to claim 3, characterized in that In step S5, the adhesive is PVA glue with a concentration of 10 wt.% to 15 wt.%.

7. The preparation method according to claim 3, characterized in that In step S5, the pressure during pressing is 10-15 Mpa.

8. The preparation method according to claim 3, characterized in that In step S6, the sintering parameters are: first debinding at 500-650°C for 1-2 h, and then sintering at 1000-1100°C for 4-8 h.

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