A millimeter wave dielectric ceramic material with high thermal shock resistance and its preparation method

Abstract

The present invention discloses a millimeter wave dielectric ceramic material with high thermal shock resistance and a preparation method thereof, which relates to the technical field of electronic information functional materials. The chemical formula of the millimeter wave dielectric ceramic material of the present invention is Yb 2‑x A x Si 2‑y B y O7, A is La 3+ ,Nd 3+ ,Gd 3+ ,Lu 3+ One of the ions, B is Ti 4+ and Ge 4+ ions, 0 < x ≤ 0.12 and 0 < y ≤ 0.06. The present invention controls the content of Yb, A, Si, and B ions by regulating the values ​​of x and y, thereby stabilizing the phase of the Yb2Si2O7 ceramic and achieving high thermal shock resistance, ultimately achieving continuous operation under extreme temperature conditions. The present invention also discloses a method for preparing millimeter-wave dielectric ceramic materials, which is simple to operate, highly reliable, and amenable to industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic information functional materials, and in particular to a millimeter wave dielectric ceramic material with high thermal shock resistance and a preparation method thereof. Background Art

[0002] Millimeter-wave dielectric ceramics are ceramics used as dielectric materials in millimeter-wave (300MHz to 300GHz) frequency band circuits, fulfilling one or more functions. As a new type of electronic material, millimeter-wave dielectric ceramics are used in modern communications as resonators, filters, dielectric substrates, dielectric antennas, and dielectric waveguides, and are widely used in many areas of millimeter-wave technology.

[0003] With the implementation of fifth-generation communications technology and the development of sixth-generation communications technology, the pursuit of dielectric materials with high-speed signal transmission characteristics has become an urgent need. This urgency has greatly stimulated the development of low-dielectric-constant millimeter-wave dielectric ceramic materials (εr < 10), as the relative dielectric constant is generally considered to be inversely proportional to the signal transmission rate. In addition, driven by the rapid development of communications technology, operating frequencies have shifted to higher regions, indicating their huge potential for future application in terahertz band communication systems. Therefore, the exploration of millimeter-wave dielectric ceramic materials can be applied not only to the millimeter-wave band (low εr, high Q×f, and near-zero τf), but also to the terahertz band.

[0004] Low dielectric constant millimeter wave dielectric ceramic materials developed in recent years include silicates, molybdates and borates. Most ceramics with dielectric constants below 10 are silicate ceramics. This is because Si 4+ The ion polarizability is the smallest (0.87A 3 ), and the significant influence of silicate tetrahedrons formed by Si-O covalent bonds. For example, the Ba2ZnSi2O7 (ε r =8.09, Q×f=26,600GHz, τ f =-51.4ppm / C), Sr2MgSi2O7(ε r =8.3, Q×f=55,000GHz, τ f =-48ppm / C) and BaCo2Si2O7(ε r =9.26, Q×f=31,135GHz, τ f =-92.1ppm / cm). In addition, SrY2Si3O 10 (ε r =9.3, Q×f=64,100GHz, τ f =-31ppm / C) and Li4SrCaSi2O8(ε r=8.2, Q×f=90,094GHz, τ f =-79.6ppm / C) and other ceramics. These millimeter wave ceramics have a low relative dielectric constant. However, although the dielectric constant of the above-mentioned millimeter wave ceramics can meet the requirements of high-speed information transmission, the other two parameters are not ideal: either the quality factor is not high enough, or the frequency temperature coefficient is too large. In addition, low dielectric materials in the terahertz band are relatively rare. Moreover, in the process of comparing the failure cases of previous millimeter wave dielectric materials, it was found that the dielectric filter often cracked ceramics under high and low temperature impact. This is because in the actual working process, high-power operation generates more heat, which will increase the temperature, while low-power operation generates less heat, which will lower the temperature. The temperature change between the two will form a thermal shock effect in the material, or the natural environment temperature changes rapidly in a short period of time. Since the thermal expansion coefficient of most millimeter wave dielectric ceramics is relatively large (between 7-12), and the bending strength of the ceramics is also relatively low, the thermal stress will eventually lead to cracking and peeling of the material surface or instantaneous fracture. Therefore, the core issue is to solve the poor thermal shock resistance of millimeter wave dielectric ceramic materials and develop low dielectric constant millimeter wave dielectric materials with excellent performance to meet current needs.

[0005] Based on this, the present invention provides a new type of millimeter-wave dielectric ceramic with low dielectric constant, high quality factor, low frequency temperature coefficient, low thermal expansion coefficient, high bending strength and other excellent comprehensive properties. It can adapt to working under extreme temperature conditions and can meet the needs of 5G communication or future 6G communication industry. Summary of the Invention

[0006] The object of the present invention is to provide a millimeter wave dielectric ceramic material with high thermal shock resistance and a preparation method thereof, wherein the millimeter wave dielectric ceramic material has the advantages of a monoclinic structure, a low dielectric constant, a high quality factor and high thermal shock resistance.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A millimeter wave dielectric ceramic material with high thermal shock resistance, the chemical formula of the millimeter wave dielectric ceramic material is Yb 2-x A x Si 2-y B y O7, A is La 3+ ,Nd 3+ ,Gd 3+ ,Lu 3+ One of the ions, B is Ti 4+ and Ge 4+ One of the ions, 0<x≤0.12 and 0<y≤0.06.

[0009] Furthermore, the millimeter wave dielectric ceramic material includes SiO2, Yb2O3, A dopant and B dopant, the A dopant is one of La2O3, Nd2O3, Gd2O3, and Lu2O3, and the B dopant is one of TiO2 and GeO2.

[0010] Furthermore, the frequency temperature coefficient τ of the millimeter wave dielectric ceramic material f is -13.5±5ppm / ℃, Q×f value is 78600±500GHz, relative dielectric constant ε r It is 6.85 to 8.35.

[0011] Furthermore, the thermal expansion coefficient of the millimeter wave dielectric ceramic material is 2.8*10 -6 ~3.7*10 -6 / ℃.

[0012] Furthermore, the bending strength of the millimeter wave dielectric ceramic material is 170 to 285 MPa.

[0013] Since the fundamental reason for the failure of most filters on the market is the poor thermal shock resistance of millimeter wave dielectric ceramic materials, the present invention adds ion substitution (La 3+ 、Nd 3+ 、Gd 3+ 、Lu 3+ ;Ti 4+ 、Ge 4+ ) is doped to obtain a chemical formula of Yb 2-x A x Si 2-y B y O7 millimeter wave dielectric ceramic with high thermal shock resistance.

[0014] In order to obtain a millimeter wave dielectric ceramic material with high thermal shock resistance, effectively control the phase and stabilize the structure of Yb2Si2O7, the A-site ions must be substituted with rare earth elements of the same valence for control, and the B-site ions must be substituted with elements of the same valence for control, and A is La 3+ ,Nd 3+ ,Gd 3+ ,Lu 3+ One of the trivalent ions, B is Ti 4+ and Ge 4+The present invention also controls the content of Yb, A, Si, and B ions by comprehensively regulating the values ​​of x and y to achieve the purpose of adjusting various properties, thereby ensuring that the microstructure of the prepared millimeter wave dielectric ceramic material is highly dense, with obvious grain boundaries and no microcracks, and that its phase is stabilized in a monoclinic structure, thereby improving the thermal shock resistance of the ceramic material. The millimeter wave dielectric ceramic of the present invention also has excellent sintering temperature and millimeter wave dielectric properties, and has very excellent performance in the terahertz frequency band (ε r =8.13, Q×f=112,758GHz.), which has great application potential in future 6G communications.

[0015] A method for preparing a millimeter wave dielectric ceramic material with high thermal shock resistance comprises the following steps:

[0016] S1, according to the chemical formula Yb 2-x A x Si 2-y B y SiO2, Yb2O3, dopant A and dopant B are weighed in the stoichiometric ratio of each cationic element in O7 and mixed to form a mixture;

[0017] S2. Using zirconium dioxide balls as ball milling media, the mixture is ball milled in a mass ratio of mixture: ball milling media: industrial alcohol of 1:(6-8):(3-5) to obtain a primary milled material;

[0018] S3, drying and sieving the primary milled material to obtain a primary dry powder;

[0019] S4, placing the primary dried powder in an alumina crucible, pre-sintering at 1250-1350° C. to obtain a sintered block, and then crushing the sintered block to obtain a sintered powder;

[0020] S5. Using zirconium dioxide balls as ball milling media, the calcined powder is ball milled according to a mass ratio of calcined powder: ball milling media: industrial alcohol of 1: (4-6): (2-3) to obtain a secondary ball milling material;

[0021] S6, drying and sieving the secondary ball mill material to obtain secondary dry powder;

[0022] S7, mixing the secondary dried powder and industrial alcohol, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 5 to 10 minutes to obtain a green body;

[0023] S8. Place the green body in a sintering furnace, raise the temperature to 1450-1550° C., and sinter for 4-7 hours to obtain the millimeter wave dielectric ceramic material.

[0024] Furthermore, the ball milling time in S2 is 7 to 11 hours; the sieving mesh number in S3 is 150 mesh; and the pre-calcining time in S4 is 5 to 7 hours.

[0025] Furthermore, the ball milling time in S5 is 4 to 7 hours; the sieve mesh number in S6 is 200 mesh; the mass ratio of the secondary dried powder to industrial alcohol in S7 is 1:3; and the heating rate in S8 is 4 to 8°C / min.

[0026] The preparation method of the invention is simple, highly reliable and easy to industrialize.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The millimeter wave dielectric ceramic material of the present invention has excellent millimeter wave dielectric properties. Its densification temperature occurs between 1250 and 1350°C, and then high-density sintering is completed at a temperature of 1450 to 1550°C.

[0029] 2. In this invention, the Yb, A, Si, and B ion contents are controlled by regulating the values ​​of x and y, thereby stabilizing the Yb2Si2O7 ceramic phase and achieving high thermal shock resistance, ultimately enabling continuous operation under extreme temperature conditions. This millimeter-wave dielectric ceramic exhibits significant advantages in thermal shock resistance, effectively preventing cracking and failure, and meeting the application requirements of modern millimeter-wave devices and future 6G communications.

[0030] 3. The millimeter-wave dielectric ceramic material of the present invention does not contain volatile toxic metals such as Pb and Cd, and can be widely used in millimeter-wave devices such as dielectric resonators, filters, and oscillators in satellite communications. It is green, environmentally friendly, and pollution-free, and meets the standard requirements of the European Community's Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment and the Recycling and Treatment Management Regulations.

[0031] 4. The millimeter-wave dielectric ceramic material of the present invention has an abundant supply of raw materials and is relatively inexpensive, making it possible to produce high-performance millimeter-wave ceramics at a low cost, thus possessing significant industrial application value. Furthermore, the millimeter-wave dielectric ceramic material of the present invention has a wide sintering temperature range of 1450-1550°C, which provides good process adaptability.

[0032] 5. The raw materials used in the formula of the present invention are simple silicates and oxides, which do not require additional process synthesis. They are completely superior to raw materials that need to be synthesized separately and adopt two ball milling processes to achieve material particle size control. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the XRD analysis result of the millimeter wave dielectric ceramic material prepared in Example 3 of the present invention.

[0034] Figure 2 This is a scanning transmission electron microscope (TEM) image of the millimeter wave dielectric ceramic material prepared in Example 5 of the present invention.

[0035] Figure 3 This is a scanning electron microscope (SEM) image of the millimeter wave dielectric ceramic material prepared in Example 8 of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Example 1

[0038] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.97 La 0.03 Si 1.97 Ti 0.03 O7, that is, the A dopant is La2O3, the B dopant is TiO2, x=0.03, y=0.03.

[0039] According to the chemical formula Yb 1.97 La 0.03 Si 1.97 Ti 0.03 The stoichiometric ratios of the cationic elements in O7 are shown in Table 1 below, in terms of the mass percentages of SiO2, Yb2O3, La2O3 and TiO2.

[0040] Table 1

[0041] Material Mass percentage / % <![CDATA[SiO2]]> 75.56 <![CDATA[Yb2O3]]> 23 <![CDATA[La2O3]]> 0.95 <![CDATA[TiO2]]> 0.49

[0042] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0043] S1. Weigh SiO2, Yb2O3, La2O3 and TiO2 according to the mass percentages in Table 1 and mix them to form a mixture;

[0044] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0045] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0046] S4, placing the once dried powder in an alumina crucible, pre-calcining at 1260° C. for 5 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0047] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0048] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0049] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 10 minutes to obtain a green body;

[0050] S8, placing the green body in a sintering furnace, heating it to 1460 ° C and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.97 La 0.03 Si 1.97 Ti 0.03 O7.

[0051] Example 2

[0052] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.94 Nd 0.06 Si 1.97 Ti 0.03 O7, that is, the A dopant is Nd2O3, the B dopant is TiO2, x=0.06, y=0.03.

[0053] According to the chemical formula Yb 1.94 Nd 0.06 Si 1.97 Ti 0.03 The stoichiometric ratios of the cationic elements in O7 are shown in Table 2 below, in terms of the mass percentages of SiO2, Yb2O3, Nd2O3 and TiO2.

[0054] Table 2

[0055] Material Mass percentage / % <![CDATA[SiO2]]> 74.52 <![CDATA[Yb2O3]]> 23.05 <![CDATA[Nd2O3]]> 1.96 <![CDATA[TiO2]]> 0.47

[0056] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0057] S1. Weigh SiO2, Yb2O3, Nd2O3 and TiO2 according to the mass percentages in Table 2 and mix them to form a mixture;

[0058] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0059] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0060] S4, placing the primary dried powder in an alumina crucible, pre-calcining at 1295° C. for 3 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0061] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0062] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0063] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 8 minutes to obtain a green body;

[0064] S8, placing the green body in a sintering furnace, heating it to 1495 ° C and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.94 Nd 0.06 Si 1.97 Ti 0.03 O7.

[0065] Example 3

[0066] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.91 Gd 0.09 Si 1.97 Ti 0.03 O7, that is, the A dopant is Gd2O3, the B dopant is TiO2, x=0.09, y=0.03.

[0067] According to the chemical formula Yb 1.91 Gd 0.09 Si 1.97 Ti 0.03 The stoichiometric ratios of the cationic elements in O7, including SiO2, Yb2O3, Gd2O3 and TiO2, are shown in Table 3 below.

[0068] Table 3

[0069] Material Mass percentage / % <![CDATA[SiO2]]> 73.33 <![CDATA[Yb2O3]]> 23.04 <![CDATA[Gd2O3]]> 3.16 <![CDATA[TiO2]]> 0.47

[0070] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0071] S1. Weigh SiO2, Yb2O3, Gd2O3 and TiO2 according to the mass percentages in Table 3 and mix them to form a mixture;

[0072] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0073] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0074] S4, placing the primary dried powder in an alumina crucible, pre-calcining at 1250° C. for 3 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0075] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0076] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0077] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 5 minutes to obtain a green body;

[0078] S8, placing the green body in a sintering furnace, heating it to 1470 ° C and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.91 Gd 0.09 Si 1.97 Ti 0.03 O7.

[0079] Example 4

[0080] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.88 Lu 0.12 Si 1.97 Ti 0.03 O7, that is, the A dopant is Lu2O3, the B dopant is TiO2, x=0.12, y=0.03.

[0081] According to the chemical formula Yb 1.88 Lu 0.12 Si 1.97 Ti 0.03The stoichiometric ratios of the cationic elements in O7 are shown in Table 4 below, in terms of the mass percentages of SiO2, Yb2O3, Lu2O3 and TiO2.

[0082] Table 4

[0083] Material Mass percentage / % <![CDATA[SiO2]]> 71.94 <![CDATA[Yb2O3]]> 22.96 <![CDATA[Lu2O3]]> 4.17 <![CDATA[TiO2]]> 0.93

[0084] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0085] S1. Weigh SiO2, Yb2O3, Lu2O3 and TiO2 according to the mass percentages in Table 4 and mix them to form a mixture;

[0086] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0087] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0088] S4, placing the primary dried powder in an alumina crucible, pre-calcining at 1260° C. for 3 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0089] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0090] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0091] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 10 minutes to obtain a green body;

[0092] S8, placing the green body in a sintering furnace, heating it to 1460 ° C and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.88 Lu 0.12 Si 1.97 Ti 0.03 O7.

[0093] Example 5

[0094] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.97 La 0.03 Si 1.94 Ge 0.06O7, that is, the A dopant is La2O3, the B dopant is GeO2, x=0.03, y=0.06.

[0095] According to the chemical formula Yb 1.97 La 0.03 Si 1.94 Ge 0.06 The stoichiometric ratios of the cationic elements in O7 are shown in Table 5 below, in terms of the mass percentages of SiO2, Yb2O3, La2O3 and GeO2.

[0096] Table 5

[0097] Material Mass percentage / % <![CDATA[SiO2]]> 75.26 <![CDATA[Yb2O3]]> 22.57 <![CDATA[La2O3]]> 0.95 <![CDATA[GeO2]]> 1.22

[0098] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0099] S1. Weigh SiO2, Yb2O3, La2O3 and GeO2 according to the mass percentages in Table 5 and mix them to form a mixture;

[0100] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0101] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0102] S4, placing the primary dried powder in an alumina crucible, pre-calcining at 1250° C. for 3 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0103] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0104] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0105] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 8 minutes to obtain a green body;

[0106] S8, placing the green body in a sintering furnace, heating it to 1500℃ and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.97 La 0.03 Si 1.94 Ge 0.06 O7.

[0107] Example 6

[0108] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.94 Nd 0.06 Si 1.94 Ge 0.06 O7, that is, the A dopant is Nd2O3, the B dopant is GeO2, x=0.06, y=0.06.

[0109] According to the chemical formula Yb 1.94 Nd 0.06 Si 1.94 Ge 0.06 The stoichiometric ratios of the cationic elements in O7 are shown in Table 6 below, in terms of the mass percentages of SiO2, Yb2O3, Nd2O3 and GeO2.

[0110] Table 6

[0111] Material Mass percentage / % <![CDATA[SiO2]]> 74.22 <![CDATA[Yb2O3]]> 22.60 <![CDATA[Nd2O3]]> 1.96 <![CDATA[GeO2]]> 1.22

[0112] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0113] S1. Weigh SiO2, Yb2O3, Nd2O3 and GeO2 according to the mass percentages in Table 6 and mix them to form a mixture;

[0114] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0115] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0116] S4, placing the primary dried powder in an alumina crucible, pre-calcining at 1340° C. for 3 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0117] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0118] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0119] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 7 minutes to obtain a green body;

[0120] S8, placing the green body in a sintering furnace, heating it to 1540 ° C and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.94 Nd 0.06 Si 1.94 Ge 0.06 O7.

[0121] Example 7

[0122] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.91 Gd 0.09 Si 1.94 Ge 0.06 O7, that is, the A dopant is Gd2O3, the B dopant is GeO2, x=0.09, y=0.06.

[0123] According to the chemical formula Yb 1.91 Gd 0.09 Si 1.94 Ge 0.06 The stoichiometric ratios of the cationic elements in O7 are shown in Table 7 below, in terms of the mass percentages of SiO2, Yb2O3, Gd2O3 and GeO2.

[0124] Table 7

[0125] Material Mass percentage / % <![CDATA[SiO2]]> 73.03 <![CDATA[Yb2O3]]> 22.59 <![CDATA[Gd2O3]]> 3.16 <![CDATA[GeO2]]> 1.22

[0126] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0127] S1. Weigh SiO2, Yb2O3, Gd2O3 and GeO2 according to the mass percentages in Table 7 and mix them to form a mixture;

[0128] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0129] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0130] S4, placing the primary dried powder in an alumina crucible, pre-calcining at 1290° C. for 3 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0131] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0132] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0133] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 7 minutes to obtain a green body;

[0134] S8, placing the green body in a sintering furnace, heating it to 1490 ° C and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.91 Gd 0.09 Si 1.94 Ge 0.06 O7.

[0135] Example 8

[0136] As a preferred embodiment of the present invention, the chemical formula of a millimeter wave dielectric ceramic material with high thermal shock resistance disclosed in this embodiment is Yb 1.88 Lu 0.12 Si 1.94 Ge 0.06 O7, that is, the A dopant is Lu2O3, the B dopant is GeO2, x=0.12, y=0.06.

[0137] According to the chemical formula Yb 1.88 Lu 0.12 Si 1.94 Ge 0.06 The stoichiometric ratios of the cationic elements in O7 are shown in Table 8 below, in terms of the mass percentages of SiO2, Yb2O3, Lu2O3 and GeO2.

[0138] Table 8

[0139] Material Mass percentage / % <![CDATA[SiO2]]> 71.64 <![CDATA[Yb2O3]]> 22.52 <![CDATA[Lu2O3]]> 4.62 <![CDATA[GeO2]]> 1.22

[0140] The preparation method of the millimeter wave dielectric ceramic material in this embodiment is as follows:

[0141] S1. Weigh SiO2, Yb2O3, Lu2O3 and GeO2 according to the mass percentages in Table 8 and mix them to form a mixture;

[0142] S2. Using zirconium dioxide balls as the ball milling medium, the mixture was ball milled for 7 hours at a mass ratio of mixture: ball milling medium: industrial alcohol of 1:6:3 to obtain a primary ball milled material;

[0143] S3, drying the primary ball mill material at 70°C and passing it through a 150-mesh sieve to obtain a primary dry powder;

[0144] S4, placing the primary dried powder in an alumina crucible, pre-calcining at 1275° C. for 3 hours to obtain a calcined block, and then crushing the calcined block to obtain a calcined powder;

[0145] S5. Using zirconium dioxide balls as ball milling media, the pre-calcined powder was ball milled for 7 hours at a mass ratio of pre-calcined powder: ball milling media: industrial alcohol of 1:6:3 to obtain a secondary ball milled material;

[0146] S6, drying the secondary ball mill material at 70°C and passing it through a 200-mesh sieve to obtain a secondary dried powder;

[0147] S7, mixing the secondary dried powder and industrial alcohol in a mass ratio of 1:3, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 7 minutes to obtain a green body;

[0148] S8, placing the green body in a sintering furnace, heating it to 1475℃ and sintering it for 6 hours to obtain the millimeter wave dielectric ceramic material Yb 1.88 Lu 0.12 Si 1.94 Ge 0.06 O7.

[0149] The millimeter wave dielectric ceramic materials of Examples 1 to 8 were tested for millimeter wave dielectric properties. The test results are shown in Table 9.

[0150] Table 9

[0151]

[0152] As shown in Table 9, the relative dielectric constant εr of the millimeter wave dielectric ceramic material prepared by the present invention is between 6.85 and 8.35, the Q×f value is 78600±500GHz, and the frequency temperature coefficient τ f -13.5±5ppm / ℃, thermal expansion coefficient is 2.8~3.7*10 -6 / ℃, the flexural strength is between 170 and 285MPa, and it has excellent sintering temperature and millimeter wave dielectric properties.

[0153] Figure 1 This is the XRD analysis result of the millimeter wave dielectric ceramic material prepared in Example 3. Figure 1 It can be seen that there is no secondary phase in the prepared material, indicating that the material crystallizes as a single phase over the entire temperature range, specifically identified as a monoclinic structure with a space group of C2 / m.

[0154] Figure 2 This is a scanning transmission electron microscope (TEM) image of the millimeter wave dielectric ceramic material prepared in Example 5. Figure 2 It shows that the monoclinic structure of the ceramic material has been successfully synthesized, and the space group is determined to be C2 / m, which is consistent with the XRD observation results.

[0155] Figure 3 This is a SEM image of the millimeter wave dielectric ceramic material prepared in Example 8. Figure 3 It can be concluded that the ceramic material of the present invention has a highly dense microstructure, distinct grain boundaries and no microcracks.

[0156] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention and are intended to illustrate the technical solutions of the present invention, rather than limiting them, and certainly not limiting the patent scope of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention. In other words, any changes or refinements made to the main design concept and spirit of the present invention that have no substantive significance, provided that the technical problems they solve are still consistent with those of the present invention, should be included in the protection scope of the present invention. In addition, the direct or indirect application of the technical solutions of the present invention to other related technical fields should also be included in the patent protection scope of the present invention.

Claims

1. A millimeter wave dielectric ceramic material with high thermal shock resistance, characterized in that: The chemical formula of the millimeter wave dielectric ceramic material is Yb 2-x A x Si 2-y B y O7, A is La 3+ ,Nd 3+ ,Gd 3+ ,Lu 3+ One of the ions, B is Ti 4+ and Ge 4+ One of the ions, 0<x≤0.12 and 0<y≤0.

06.

2. The millimeter wave dielectric ceramic material with high thermal shock resistance according to claim 1, characterized in that: The millimeter wave dielectric ceramic material includes SiO2, Yb2O3, A dopant and B dopant, the A dopant is one of La2O3, Nd2O3, Gd2O3, and Lu2O3, and the B dopant is one of TiO2 and GeO2.

3. The millimeter wave dielectric ceramic material with high thermal shock resistance according to claim 1, characterized in that: The frequency temperature coefficient of the millimeter wave dielectric ceramic material is -13.5±5 ppm / °C, the Q×f value is 78600±500 GHz, and the relative dielectric constant is 6.85-8.

35.

4. The millimeter wave dielectric ceramic material with high thermal shock resistance according to claim 1, characterized in that: The thermal expansion coefficient of the millimeter wave dielectric ceramic material is 2.8*10 -6 ~3.7*10 -6 / ℃.

5. The millimeter wave dielectric ceramic material with high thermal shock resistance according to claim 1, characterized in that: The bending strength of the millimeter wave dielectric ceramic material is 170-285 MPa.

6. The method for preparing a millimeter wave dielectric ceramic material with high thermal shock resistance according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, according to the chemical formula Yb 2-x A x Si 2-y B y SiO2, Yb2O3, dopant A and dopant B are weighed in the stoichiometric ratio of each cationic element in O7 and mixed to form a mixture; S2. Using zirconium dioxide balls as ball milling media, the mixture is ball milled in a mass ratio of mixture: ball milling media: industrial alcohol of 1:(6-8):(3-5) to obtain a primary milled material; S3, drying and sieving the primary ball mill material to obtain a primary dry powder; S4, placing the primary dried powder in an alumina crucible, pre-sintering at 1250-1350° C. to obtain a sintered block, and then crushing the sintered block to obtain a sintered powder; S5. Using zirconium dioxide balls as ball milling media, the calcined powder is ball milled according to a mass ratio of calcined powder: ball milling media: industrial alcohol of 1: (4-6): (2-3) to obtain a secondary ball milling material; S6, drying and sieving the secondary ball mill material to obtain secondary dry powder; S7, mixing the secondary dried powder and industrial alcohol, pre-pressing the mixture at 2 MPa, sealing the mixture, and then pressing the mixture at a pressure of 200 MPa for 5 to 10 minutes to obtain a green body; S8. Place the green body in a sintering furnace, raise the temperature to 1450-1550° C., and sinter for 4-7 hours to obtain the millimeter wave dielectric ceramic material.

7. The method for preparing a millimeter wave dielectric ceramic material with high thermal shock resistance according to claim 6, wherein the ball milling time in S2 is 7 to 11 hours; the sieving mesh size in S3 is 150 mesh; and the pre-firing time in S4 is 5 to 7 hours.

8. The method for preparing a millimeter-wave dielectric ceramic material with high thermal shock resistance according to claim 6, wherein the ball milling time in S5 is 4 to 7 hours; the sieve mesh size in S6 is 200 mesh; the mass ratio of the secondary dried powder to industrial alcohol in S7 is 1:3; and the heating rate in S8 is 4 to 8°C / min.

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