CN109503163A

CN109503163A - One kind having ultrahigh Q-value tantalic acid magnesium media ceramic and preparation method thereof

Info

Publication number: CN109503163A
Application number: CN201811563982.XA
Authority: CN
Inventors: 党明召; 林慧兴; 姜少虎; 张奕; 姚晓刚; 何飞; 赵相毓; 顾忠元
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2018-12-20
Filing date: 2018-12-20
Publication date: 2019-03-22

Abstract

The present invention relates to one kind to have ultrahigh Q-value tantalic acid magnesium media ceramic and preparation method thereof, and the chemical composition of the tantalic acid magnesium media ceramic is MgTa₂O₆- x mol% A, wherein A is at least one of the oxide of B, the oxide of Zn, the oxide of Mg, the oxide of Ga, the oxide of W, the oxide of Sn, the oxide of Zr, the oxide of Al and oxide of Mn, 0 < x < 2.

Description

One kind having ultrahigh Q-value tantalic acid magnesium media ceramic and preparation method thereof

Technical field

The microwave dielectric material of ultrahigh Q-value and preparation method thereof that the present invention relates to a kind of applied to microwave communication, belongs to Function ceramics field.

Background technique

Microwave-medium ceramics (Microwave Dielectric Ceramics, abbreviation MWDC) refer to applied to Microwave Frequency As dielectric material and the ceramics of one or more functions are completed in section (mainly uhf band, SHF frequency range) circuit.20th century Later period, with the fast development of wireless Internet, wideband backbone network and global position system GPS, as microwave filter, resonance The high performance microwave media ceramic of the wireless communications devices such as device and oscillator has become the coke of international academic community extensive concern Point material.

With mobile 5G communication and satellite communication technology to development, communication frequency is gradually increased, bandwidth increases, traditional The devices such as cavity body filter have been unable to meet the performance requirement of microwave telecommunication devices, and the development of microwave dielectric properties is to dielectric material More stringent requirements are proposed --- high Q value and nearly zero temperature coefficient of resonance frequency.However, in existing microwave-medium ceramics In, most of ceramics need to reach above-mentioned requirements by certain Material composition design it is impossible to meet above-mentioned requirements.Most often It is by the opposite two media ceramics of temperature coefficient of resonance frequency according to certain change with generally also most effective design method Metering ratio is learned to be mixed and be sintered, therefore, the two media pottery that the Q value being typically chosen is high, temperature coefficient of resonance frequency is opposite Porcelain achieves the goal.But in existing report, high q-factor microwave-medium ceramics generally have negative temperature coefficient of resonance frequency, For example Al₂O₃、Mg₄Ta₂O₉, ZnAl₂O₄..., need the positive temperature coefficient of resonance frequency of suitable high q-factor meet mixing require, The ceramic systems of existing composite demand concentrate on TiO₂、CaTiO₃、SrTiO₃In, these ceramics Q values are relatively low, are not able to satisfy substantially The following high q-factor ceramics demand.Reported literature points out MgTa₂O₆Media ceramic has excellent microwave dielectric property, and its resonance Frequency-temperature coefficient is positive value, is expected to meet application demand；But the material system haves the characteristics that sintering character is poor, mainly The reason is that since there are micro Ta in the MT powder of preparation₂O₅, mutually there is phase transformation in this, cause material fine and close during the sintering process It is difficult.

Summary of the invention

In view of the above-mentioned problems, the object of the present invention is to provide a kind of ultrahigh Q-value that dielectric properties are stable and positive frequencys Tantalic acid magnesium media ceramic of temperature coefficient and preparation method thereof.

On the one hand, the present invention provides a kind of tantalic acid magnesium media ceramic with ultrahigh Q-value, the tantalic acid magnesium media ceramic Chemical composition be MgTa₂O₆- x mol%A, wherein A be the oxide of B, the oxide of Zn, Mg oxide, Ga oxidation At least one of object, the oxide of W, the oxide of Sn, the oxide of Zr, the oxide of Al and oxide of Mn, 0 < x < 2。

Preferably, the dielectric constant of the tantalic acid magnesium media ceramic is 26~28, and superelevation Qf > 150000GHz, resonance frequency Rate temperature coefficient is at 50~60ppm/ DEG C.

On the other hand, the present invention provides a kind of preparations of tantalic acid magnesium media ceramic with ultrahigh Q-value as described above Method, comprising:

By MgO, Ta₂O₅With the source A according to chemical composition MgTa₂O₆- x mol%A is weighed and is mixed, and obtains material powder；

Gained material powder is not less than 8 hours in 1000~1250 DEG C of calcinings, synthesizes MT powder；

By gained MT powder through granulation, molding and sintering, the tantalic acid magnesium media ceramic with ultrahigh Q-value is obtained.

Due to there is a small amount of residual Ta in MT powder synthesis process₂O₅The phenomenon that phase, hinders ceramic densifying.For this purpose, this Application is by the way that by a small amount of source A, (oxycompound containing at least one of B, Zn, Mg, Ga, W, Sn, Zr, Al, Mn element divides Solution product is containing the compound for limiting oxide) directly it is added when MT powder synthesizes, a small amount of source A is required to and Ta₂O₅Hair Raw reaction is dissolved into MT lattice structure, and playing can significantly inhibit or reduce in MT powder since solid phase reaction is not thorough Bottom and remaining micro Ta₂O₅, promote ceramic densifying.

Preferably, the purity of the MgO is greater than 99%, the Ta₂O₅Purity be greater than 99%

Preferably, the source A be the oxide of B, the oxide of Zn, the oxide of Mg, the oxide of Ga, W oxide, The oxide of Sn, the oxide of Zr, at least one of the oxide of the oxide of Al and Mn or/and high-temperature decomposition product be containing The compound of at least one above-mentioned restriction oxide (A).

Preferably, the D of the MT powder₅₀2 μm of <.

Preferably, binder used in the granulation be polyvinyl alcohol, polyvinyl formal, in carboxymethyl cellulose extremely Few one kind.

Also, preferably, the quality of the binder is 1~3wt% of material powder.

Preferably, the sintering is after being sintered 4~12 hours at 1500~1600 DEG C in Mg atmosphere, with 1~2 DEG C/ Minute cooling rate is down to 1000~1200 DEG C, then cools to room temperature with the furnace.Due to MT powder sintering temperature it is high (about 1500~ 1600 DEG C), at a temperature of this Mg volatilization it is more serious, by the sintering process in Mg atmosphere at 1500~1600 DEG C sintering 4~ After 12 hours, 1000~1200 DEG C are down to 1~2 DEG C/min of cooling rate, then cooling to room temperature availability with the furnace can be best Ceramics.

Also, preferably, being warming up to 1500~1600 DEG C with 5~10 DEG C/min of heating rate.

The present invention controls Ta in MT powder by the way that the source A is added₂O₅Content, to prepare compactness good MT pottery Porcelain.

Detailed description of the invention

Fig. 1 is to add the source A after the addition source A (element is B, Mg in selection A), powder synthesis when being not added with the source A, powder synthesis The object phase composition of the tantalic acid magnesium media ceramic of (choosing element in A is B, Mg).

Specific embodiment

The present invention is further illustrated below by way of following embodiments, it should be appreciated that following embodiments are merely to illustrate this Invention, is not intended to limit the present invention.

In the present invention, the chemical composition of the tantalic acid magnesium media ceramic with ultrahigh Q-value can be MgTa₂O₆- x mol%A, Middle component A is mainly the oxide containing one or more of B, Zn, Mg, Ga, W, Sn, Zr, Al, Mn element, the value model of x It encloses for 0 < x < 2.Wherein, MgTa₂O₆The dielectric constant of media ceramic (tantalic acid magnesium media ceramic) can be 26~28, superelevation Qf > 150000GHz, temperature coefficient of resonance frequency are 50~60ppm/ DEG C.

In one embodiment of the present invention, the tantalic acid magnesium media ceramic with ultrahigh Q-value is to utilize a kind of special process The MgTa of method preparation₂O₆Powder sintering forms.Illustrate to following exemplary the system of the tantalic acid magnesium media ceramic with ultrahigh Q-value Preparation Method.

By MgO, Ta₂O₅With the source A according to chemical composition MgTa₂O₆- x mol%A is weighed and is mixed, and obtains material powder.Its In, the purity of MgO is greater than 99%, Ta₂O₅Purity be greater than 99%.Wherein the additive amount of A and MgO molar ratio are xmol%, wherein 0 < x < 2.When the source A, additional amount is excessive, it will generates new low Qf value ceramic phase, influences the performance of tantalic acid magnesium ceramics.

Material powder is not less than 8 hours in 1000~1250 DEG C of calcinings, synthesizes MT powder (MgTa₂O₆- x mol%A powder Body).Gained MT powder is crushed, its particle size after cracking D is controlled₅₀2 μm of <.

The example that MT powder is prepared as one, by high-purity (> 99%) MgO, Ta₂O₅And the source A is according to chemical formula MgTa₂O₆- x mol%A is weighed, and is then placed in the nylon tank for being previously added zirconium ball, and deionized water is added and carries out wet-milling, material: water =1:2 is placed in drying in 130 DEG C of baking ovens, is put into alumina crucible and is calcined after powder drying, forged after mixing Burning temperature is 1000~1250 DEG C, and preferably 1100 DEG C, calcination time is not less than 8h, synthesizes MgTa₂O₆- x mol%A (is denoted as MT) Powder.

By MT powder through granulation, molding and sintering, the tantalic acid magnesium media ceramic with ultrahigh Q-value is obtained.Wherein make Binder used in grain can in polyvinyl alcohol (PVA), polyvinyl formal (PVB) or carboxymethyl cellulose (CMC) at least One kind, preferably PVA.The molding mode can be dry-pressing formed etc..The system of the sintering includes: first by 5~10 DEG C/min 1500~1600 DEG C (preferably 1550 DEG C) 4~12h of heat preservation are warming up to, then are down to 1000~1200 DEG C by 1~2 DEG C/min, and protect Hold the tantalic acid magnesium media ceramic under the sintering schedule of Mg atmosphere, obtaining having ultrahigh Q-value in sintering furnace.

Enumerate embodiment further below with the present invention will be described in detail.It will similarly be understood that following embodiment is served only for this Invention is further described, and should not be understood as limiting the scope of the invention, those skilled in the art is according to this hair Some nonessential modifications and adaptations that bright above content is made all belong to the scope of protection of the present invention.Following examples are specific Technological parameter etc. is also only an example in OK range, i.e. those skilled in the art can be done properly by the explanation of this paper In the range of select, and do not really want to be defined in hereafter exemplary specific value.

Embodiment 1

(1) MgO and Ta that purity is greater than 99% are accurately weighed₂O₅Each 0.1mol, then weigh the source 0.001mol or 0.002mol A (source A is respectively H₃BO₃、ZnO、MgO、GaO_3/2(Ga₂O₃)、WO₃、SnO₂、ZrO₂、AlO_3/2(Al₂O₃)、MnO₂One of), add Enter in the nylon tank of addition zirconia ball in advance, pour into deionized water, weight ratio is material: water=1:2；After ball milling, put Enter baking oven, dries 8h at a temperature of 130 DEG C.The powder of drying is fitted into corundum sagger, after calcining 8~12h at 1100 DEG C, MT powder is made；

(2) the MT powder of calcining is added in the nylon tank of addition zirconia ball in advance, deionized water is added and is crushed, expects: Water=1:1, as 2 μm of particle size after cracking D50 <, taking-up is dried at 130 DEG C；Select polyvinyl alcohol (PVA) water of 3% mass fraction Solution is granulated powder；It is pressed into diameter 6mm after granulation, is highly the small column of 4mm, is put in the horse for being pre-placed MgO Not in furnace, 1500~1550 DEG C are warming up to by 5 DEG C/min, keeps the temperature 6h, then be down to 1000 DEG C by 1 DEG C/min, subsequent furnace cooling To room temperature, microwave dielectric material is made, performance is shown in Table 1.

1 embodiment of table, 1 properties of sample list

(note: it is GaO that the source A is added in above-mentioned example_3/2、AlO_3/2、H₃BO₃Molar content calculate, then the Ga being added₂O₃、 Al₂O₃、B₂O₃Content be respectively 0.0005mol and 0.001mol).

Embodiment 2

H (is chosen into the source A in embodiment 1₃BO₃、ZnO、SnO₂、AlO_3/2, MgO is as representing) addition in MT powder prepared it It (is namely added afterwards in sintering stage), for remaining step with embodiment 1, performance is shown in Table 2.

Table 2 is properties of sample list prepared by embodiment 2:

Fig. 1 gives the source A that is not added with, in MgTa₂O₆Powder synthesize when addition the source A (choose A in element be B, Mg, i.e., 1mol%H₃BO₃And 1mol%MgO) and in MgTa₂O₆Powder synthesis after add again the source A (choose A in element be B, Mg, i.e., 1mol%H₃BO₃And 1mol%MgO), the MgTa being sintered out₂O₆The composition of ceramics, it can be seen that the source A addition before powder synthesizes Obvious inhibition can be played or eliminate Ta₂O₅Phase, this high-performance MgTa fine and close to preparation₂O₆Media ceramic has important Directive significance.It is added, does not play bright if can also be seen that for additive to be placed on after MT powder synthesizes by Fig. 1, Tables 1 and 2 Aobvious inhibition Ta₂O₅The effect of crystal transition, ceramics are still fine and close difficult.

Claims

1. a magnesium tantalate dielectric ceramic with ultra-high Q value, characterized in that the chemical composition of the magnesium tantalate dielectric ceramic is MgTa ₂ O ₆ -x mol% A, wherein A is the oxide of B, Zn At least one of oxides of Mg, oxides of Ga, oxides of W, oxides of Sn, oxides of Zr, oxides of Al and oxides of Mn, 0<x<2.

2. The magnesium tantalate dielectric ceramic with ultra-high Q value according to claim 1, wherein the dielectric constant of the magnesium tantalate dielectric ceramic is 26-28, the ultra-high Qf >150000GHz, and the resonant frequency temperature The coefficient is 50 to 60 ppm/°C.

3. a preparation method of the magnesium tantalate dielectric ceramic with ultra-high Q value as claimed in claim 1 or 2, is characterized in that, comprising:

MgO, Ta ₂ O ₅ and A source are weighed and mixed according to the chemical composition MgTa ₂ O ₆ -x mol% A to obtain raw material powder;

The obtained raw material powder is calcined at 1000-1250 ℃ for not less than 8 hours to synthesize MT powder;

The obtained MT powder is granulated, shaped and sintered to obtain the magnesium tantalate dielectric ceramic with ultra-high Q value.

4 . The preparation method according to claim 3 , wherein the purity of the MgO is greater than 99%, and the purity of the Ta ₂ O ₅ is greater than 99%. 5 .

5. The preparation method according to claim 3 or 4, wherein the A source is B oxide, Zn oxide, Mg oxide, Ga oxide, W oxide, Sn oxide At least one of oxides, Zr oxides, Al oxides and Mn oxides or/and the pyrolysis product is a compound of A.

6 . The preparation method according to claim 3 , wherein D ₅₀ of the MT powder is less than 2 μm. 7 .

7. The preparation method according to any one of claims 3-6, wherein the binder used in the granulation is at least one of polyvinyl alcohol, polyvinyl formal, and carboxymethyl cellulose. kind.

8 . The preparation method according to claim 7 , wherein the mass of the binder is 1-3 wt % of the raw material powder. 9 .

9 . The preparation method according to claim 3 , wherein the sintering is performed by sintering at 1500 to 1600° C. for 4 to 12 hours in a Mg atmosphere at a rate of 1 to 2° C./min. 10 . The cooling rate was reduced to 1000-1200°C, followed by furnace cooling to room temperature.

10 . The preparation method according to claim 9 , wherein the temperature is raised to 1500 to 1600° C. at a heating rate of 5 to 10° C./min. 11 .