Low dielectric loss YIG substrate material for LTCF circulator and preparation method thereof

Abstract

The invention discloses a low-dielectric-loss YIG substrate material for an LTCF circulator and a preparation method of the low-dielectric-loss YIG substrate material, and belongs to the technical field of electronic ceramic materials. The substrate material comprises a main material and an inducer, wherein the main material comprises the following components: 60.53 mol% of Fe2O3, 28.1 mol% of Y2O3, 11.11 mol% of Bi2O3, 0.13 mol% of V2O5 and 0.13 mol% of Li2CO3; the inducer is BZB glass. The substrate material provided by the invention has low sintering temperature (Tlt; 920 DEG C), high density ([rho] gt; 5.3 g / cm < 3 >), a narrow ferromagnetic resonance linewidth ([delta] Hlt; 300Oe), low dielectric loss (tan [delta] [epsilon] lt; 1 * 10 <-3 >), high dielectric constant (epsilon'gt; 20), a high spin wave line width ([delta] Hkgt; 20Oe), a high saturation magnetization (4pi Msgt; 1600 Gauss) and a high Curie temperature (Tcgt; 300 DEG C).

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic ceramic materials, and in particular relates to a low dielectric loss YIG substrate material for an X-band LTCF circulator and a preparation method thereof. Background Art

[0002] Due to its advantages such as narrow ferromagnetic resonance linewidth and low microwave dielectric loss, YIG ferrite is widely used as a substrate material for X-band circulators. With the development of phased array radar technology, the key component, the circulator, is moving towards low loss, miniaturization and integration. Low-temperature co-fired ferrite (LTCF) technology provides an effective solution for the miniaturization and integration of microwave ferrite devices. The currently commonly used ion substitution modification scheme is difficult to take into account the low-temperature sintering (T≤920℃) and excellent electromagnetic properties of YIG ferrite, high ferromagnetic resonance linewidth ΔH and microwave dielectric loss tanδ ε The latter, in particular, can lead to excessive insertion loss and return loss, severe heat generation, and other problems in YIG ferrite devices. Therefore, controlling the microwave electromagnetic loss of low-temperature sintered YIG ferrite is a difficult problem that needs to be solved in order to realize the application of LTCF devices.

[0003] At present, the research on low temperature sintering and electromagnetic properties of YIG ferrite mainly focuses on two aspects: multi-ion substitution and low melting point oxide / glass doping modification. The invention patent with application number 202110324952.9 discloses a low temperature sintering YIG ferrite material and its preparation method. 3+ Ions partially replace the Y in the c position of YIG ferrite 3+ ions, through Zn 2+ 、V 5+ ions replace Fe at a and d positions respectively 3+ions, the sample sintered at 960℃ obtained a ferromagnetic resonance linewidth of 380Oe. The sintering temperature of the material prepared by this method is still too high, the ferromagnetic resonance linewidth is too large, and there is no report on the microwave dielectric properties. "Zong Bo, Liu Wenjun, Zhao Datian, et al. Study on low-temperature sintering of yttrium ferrite doped with Li2O-B2O3-ZnO glass and its magnetic properties [J]. Thermal Processing Technology, 2013, 42(24): 54-56." The article used LBZ glass to reduce the sintering temperature of YIG ferrite and improve its magnetic properties. The ferromagnetic resonance linewidth of YIG ferrite sintered at 1100℃ was 160Oe. The sintering temperature of the sample prepared by this method is still too high, and there is no test result of microwave dielectric properties. "Fu R, Li Y, Peng R, etal. High Dielectric Constant YIG Ferrites with Low Sintering Temperature[J]. Journal of Materials Science: Materials in Electronics, 2022, 33(8): 4914-4923." The article uses Bi 3+ and Ca 2+ Replace c position Y 3+ , using Sn 4+ ions and Zr 4+ ions jointly replace Fe at the a position 3+ , which reduces the sintering temperature of YIG ferrite to 950℃ and reduces the ferromagnetic resonance linewidth to 190Oe. However, no test data on microwave dielectric properties are available, and the dielectric loss in the RF band is still high (4×10 -3 In summary, to meet the demands of small-scale integration and high-performance applications in LTCF circulators, a better solution is urgently needed to improve the comprehensive performance of YIG ferrite substrate materials, especially to significantly reduce the dielectric loss of low-heat materials. Summary of the Invention

[0004] The purpose of the present invention is to address the problem of high microwave electromagnetic loss in existing low-temperature sintered YIG ferrites and to propose a low dielectric loss YIG substrate material for LTCF circulators and a preparation method thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A low dielectric loss YIG substrate material for LTCF circulators is prepared by low-temperature co-sintering of a main material of YIG ferrite and an inducer of BZB glass, wherein the inducer accounts for 0.30 to 0.60 wt.% of the main material mass; the main material comprises: Fe2O360.53 mol%, Y2O3 28.1 mol%, Bi2O3 11.11 mol%, V2O5 0.13 mol%, and Li2CO3 0.13 mol%; the inducer is Bi2O3-ZnO-B2O3 (BZB) glass, and the molar ratio of the raw materials is:

[0007] A method for preparing a low dielectric loss YIG substrate material for an LTCF circulator comprises the following steps:

[0008] Step 1: Pre-burning material preparation:

[0009] 1.1 Analytically pure lithium carbonate (Li2CO3), vanadium pentoxide (V2O5), yttrium trioxide (Y2O3), ferric oxide (Fe2O3), and bismuth trioxide (Bi2O3) were weighed in the ratio of "Fe2O3 60.53 mol%, Y2O3 28.1 mol%, Bi2O3 11.11 mol%, V2O5 0.13 mol%, and Li2CO3 0.13 mol%". The raw materials were then transferred to a planetary ball mill and milled for 5-7 h to obtain a primary slurry.

[0010] 1.2 The primary slurry obtained in step 1.1 is dried and sieved, and then pre-calcined in an oxygen furnace at 800-850°C for 2.5-3.5 hours. After cooling to room temperature in the furnace, the slurry is taken out to obtain a pre-calcined material;

[0011] Step 2: Secondary ball milling:

[0012] After sieving the pre-calcined material obtained in step 1, an inducer equivalent to 0.30-0.60 wt.% of the mass of the pre-calcined material is added, and the resulting mixture is placed in a planetary ball mill for secondary ball milling for 8-10 hours to obtain a secondary slurry, which is then dried to obtain a YIG ferrite secondary abrasive;

[0013] Step 3: Molding and sintering:

[0014] 3.1 After the YIG ferrite secondary abrasive obtained in step 2 is passed through an 80-mesh sieve, 8-12 wt.% of polyvinyl alcohol (PVA) binder is added to granulate the abrasive, and then pressed into a green sample using a hydraulic press;

[0015] 3.2 The green sample obtained in step 3.1 is placed in a sintering furnace, heated to 880-920°C at a rate of 1-3°C / min, and kept warm for 3 hours. After sintering, the green sample is naturally cooled to room temperature in the furnace to obtain the YIG ferrite material.

[0016] Furthermore, the inducing agent in step 2 is Bi2O3-ZnO-B2O3 (BZB) glass additive, and the molar ratio of the raw materials is

[0017] The present invention provides a low dielectric loss YIG substrate material for LTCF circulators. The main material is Bi-Li-V co-doped YIG ferrite. On the one hand, the low-temperature sintering of the composite ferrite is improved by reducing the lattice activation energy of the main crystal phase; on the other hand, the presence of a perovskite intermediate phase in the reaction process of YIG ferrite provides an environment for the formation of cubic double perovskite. Secondly, a trace amount of BZB glass is introduced to regulate the microwave electromagnetic properties of the material: 1) Bi-rich induced formation of 3+ The cubic double perovskite second phase and the multiphase composite ferrite are beneficial to suppress the low-valence Fe 2+ 、V 4+ The generated electron migration reduces the dielectric loss of the composite ferrite; 2) the addition of an appropriate amount of sintering aid promotes the densification process of the ferrite, which is beneficial to narrowing the ferromagnetic resonance linewidth of the composite ferrite while improving its dielectric constant.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. Based on the Bi-Li-V co-doped YIG ferrite formula, the present invention adds a trace amount of BZB glass to promote the densification process. The reduction of porosity is beneficial to narrowing the ferromagnetic resonance linewidth and improving the dielectric constant.

[0020] 2. The present invention controls the reaction process of YIG ferrite by introducing an appropriate amount of BZB glass to induce Bi-rich 3+ The formation of a cubic double perovskite phase and the multiphase composite structure weaken the ferrite lattice relaxation loss, thereby significantly reducing the dielectric loss of the YIG substrate material; at the same time, a relatively high spin wave linewidth is maintained, which is expected to be applied to high-power microwave systems.

[0021] 3. The low dielectric loss YIG substrate material for LTCF circulator prepared by the present invention has a low sintering temperature (T < 920 ° C) and a high density (ρ > 5.3g / cm 3 ), narrow ferromagnetic resonance linewidth (ΔH<300Oe), low dielectric loss (tanδ ε <1×10 -3 ), high dielectric constant (ε'>20), high spin wave linewidth (ΔH k>20Oe), high saturation magnetization (4πM s >1600Gauss) and high Curie temperature (T c The obtained multiphase composite ferrite not only meets the requirements of LTCF process, but also has the excellent magnetic properties of the key substrate material required for realizing microwave devices such as low-loss circulators. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the SEM image of the comparative example sample;

[0023] Figure 2 These are the SEM images and EDS point scanning test results of the sample in Example 3; among them, (a) is the secondary electron microscopy structure, (b) is the backscattered electron microscopy structure, (c) is the EDS point scanning result of the perovskite phase, and (d) is the EDS point scanning result of the garnet phase. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0025] A low-dielectric-loss YIG substrate material for LTCF circulators is developed. Based on a Bi-Li-V co-doped low-fired formula, a trace amount of BZB glass is introduced to regulate the composition and microstructure of the composite ferrite, resulting in a narrow ferromagnetic resonance linewidth, low dielectric loss, high spin wave linewidth, high saturation magnetization, and high Curie temperature.

[0026] Example 1

[0027] Step 1: Pre-burning material preparation:

[0028] 1.1 Analytically pure lithium carbonate (Li2CO3), vanadium pentoxide (V2O5), yttrium trioxide (Y2O3), ferric oxide (Fe2O3), and bismuth trioxide (Bi2O3) were weighed in the ratio of "Fe2O3 60.53 mol%, Y2O3 28.1 mol%, Bi2O3 11.11 mol%, V2O5 0.13 mol%, Li2CO3 0.13 mol%", and then transferred to a planetary ball mill and milled for 6 h.

[0029] 1.2 The primary slurry obtained in step 1.1 is dried and sieved, and then pre-calcined at 850°C in an oxygen atmosphere for 3 hours. After cooling to room temperature, the slurry is taken out to obtain a pre-calcined material;

[0030] Step 2: Add inducer for secondary ball milling:

[0031] The calcined material obtained in step 1 was sieved, and an inducer (BZB glass) equivalent to 0.30 wt.% of the calcined material was added. The resulting mixture was placed in a planetary ball mill for secondary ball milling for 12 h. The secondary slurry was dried to obtain a second abrasive.

[0032] Step 3: Molding and sintering:

[0033] 3.1 After the second abrasive obtained in step 2 is passed through an 80-mesh sieve, a polyvinyl alcohol binder equivalent to 10 wt.% of the powder mass is added to granulate the abrasive, and then pressed into a green sample using a hydraulic press;

[0034] 3.2 Place the green sample obtained in step 3.1 into a sintering furnace, heat it to 900°C at a rate of 2°C / min, and keep it warm for 3 hours. After sintering, cool it naturally to room temperature in the furnace to obtain the multi-phase composite low-loss YIG substrate material for the LTCF circulator.

[0035] The properties of the YIG ferrite material prepared in Example 1 are as follows: density ρ = 5.33 g / cm 3 Ferromagnetic resonance linewidth ΔH = 283 Oe @ 9.3 GHz; dielectric constant ε' = 20.60, dielectric loss tangent tanδ ε =8.20×10 -4 @10.6GHz; spin wave linewidth ΔH k =29.8Oe@9.3GHz; saturation magnetization 4πM s =1659.02Gauss; Curie temperature T c =309.7℃.

[0036] Example 2

[0037] The difference between this embodiment and embodiment 1 is that the inducer added in step 2 is equivalent to 0.45 wt.% of the mass of the pre-burned main material, and the remaining steps are the same as those in embodiment 1.

[0038] The properties of the YIG ferrite material prepared in Example 2 are as follows: density ρ = 5.43 g / cm 3 Ferromagnetic resonance linewidth ΔH = 262 Oe @ 9.3 GHz; dielectric constant ε' = 21.30, dielectric loss tangent tanδ ε =6.50×10 -4 @10.6GHz; spin wave linewidth ΔH k =29.0Oe@9.3GHz; saturation magnetization 4πM s =1688.39 Gauss; Curie temperature T c =310.2℃.

[0039] Example 3

[0040] The difference between this embodiment and embodiment 1 is that the inducer added in step 2 is equivalent to 0.60 wt.% of the mass of the pre-burned main material, and the remaining steps are the same as those in embodiment 1.

[0041] The properties of the YIG ferrite material prepared in Example 3 are as follows: density ρ = 5.43 g / cm 3 Ferromagnetic resonance linewidth ΔH = 260 Oe @ 9.3 GHz; dielectric constant ε' = 21.38, dielectric loss tangent tanδ ε =6.42×10 -4 @10.6GHz; spin wave linewidth ΔH k =21.5Oe@9.3GHz; saturation magnetization 4πM s =1684.43Gauss; Curie temperature T c =309.6℃.

[0042] Comparative Example

[0043] The difference between the comparative example and Example 1 is that no inducer is added in step 2, and the remaining steps are the same as those in Example 1.

[0044] The properties of the YIG ferrite material prepared in the comparative example are: density ρ = 5.23 g / cm 3 Ferromagnetic resonance linewidth ΔH = 330 Oe @ 9.3 GHz; dielectric constant ε' = 20.18, dielectric loss tangent tanδ ε =3.89×10 -3 @10.6GHz; spin wave linewidth ΔH k =32.1Oe@9.3GHz; saturation magnetization 4πM s =1632.40Gauss; Curie temperature T c =309.3℃.

[0045] Figure 1 is the SEM image of the comparative sample. Figure 2 The SEM image and EDS point scanning test results of the sample of Example 3. Table 1 summarizes the performance parameters of the comparative example and the embodiment. It can be seen from the figure that due to the liquid phase mass transfer effect that promotes the sintering of the composite ferrite, the average grain size of the embodiment sample with the addition of BZB glass increases and the porosity decreases significantly compared with the comparative example sample. A second phase of layered structure was also observed in the SEM image of Example 3. The reason for this is that there is a perovskite intermediate phase YIP in the reaction process of YIG ferrite. When the doping concentration of BZB glass is high, a part of the unreacted YIP phase and Fe2O3 are induced through the "dissolution-precipitation" process to form a Bi-rich phase. 3+This multiphase composite structure significantly improves the microwave loss characteristics of YIG ferrite substrate materials: the dielectric loss tangent is reduced by 78.9% to 83.5%, and the ferromagnetic resonance linewidth is reduced by 14.2% to 21.2%.

[0046] Table 1 Performance parameters of comparative examples and embodiments

[0047]

Claims

1. A low dielectric loss YIG substrate material for LTCF circulator, characterized in that: The YIG substrate material includes a main material and an inducer, wherein the inducer accounts for 0.30-0.60 wt.% of the main material; the components of the main material are: Fe2O360.53 mol%, Y2O3 28.1 mol%, Bi2O3 11.11 mol%, V2O5 0.13 mol%, and Li2CO3 0.13 mol%; the inducer is Bi2O3-ZnO-B2O3 glass.

2. The low dielectric loss YIG substrate material for LTCF circulator according to claim 1, characterized in that: The molar ratio of each raw material in Bi2O3-ZnO-B2O3 glass is n Bi2O3 :n ZnO :n B2O3 =1:1:

1.

3. A method for preparing a low dielectric loss YIG substrate material for LTCF circulator, characterized in that: The following steps are involved: Step 1: Pre-burning material preparation: 1.1 Li2CO3, V2O5, Y2O3, Fe2O3, and Bi2O3 were weighed in the ratio of "Fe2O3 60.53 mol%, Y2O3 28.1 mol%, Bi2O3 11.11 mol%, V2O5 0.13 mol%, and Li2CO3 0.13 mol%" and ball-milled to obtain a primary slurry. 1.2 The primary slurry obtained in step 1.1 is dried and sieved, and then pre-calcined in an oxygen furnace at 800-850°C for 2.5-3.5 hours. After cooling to room temperature in the furnace, the slurry is taken out to obtain a pre-calcined material; Step 2: Secondary ball milling: After sieving the pre-burned material obtained in step 1, an inducer equivalent to 0.30-0.60 wt.% of the mass of the pre-burned material is added, and the obtained mixture is ball-milled for the second time and dried to obtain a YIG ferrite secondary abrasive; Step 3: Molding and sintering: 3.1 The YIG ferrite abrasive obtained in step 2 was sieved, granulated, and pressed into green samples; 3.2 The green sample obtained in step 3.1 is placed in a sintering furnace and kept at 880-920° C. for 3 hours. After sintering, it is naturally cooled to room temperature in the furnace to obtain the YIG ferrite material.

4. The method for preparing a low dielectric loss YIG substrate material for a LTCF circulator according to claim 2, wherein: The inducing agent in step 2 is Bi2O3-ZnO-B2O3 glass additive, and the molar ratio of the raw materials is n Bi2O3 :n ZnO :n B2O3 =1:1:1.

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