CN101723653A - Microwave-tuned composite ceramic material and preparation method thereof - Google Patents

Abstract

The invention discloses a microwave-tuned composite ceramic material and a preparation method thereof. The composite ceramic material consists of BaZrxTi1-xO3 and a mixture, wherein the BaZrxTi1-xO3 is 30 to 95 weight percent, and x is equal to 0.1 to 0.50; and the mixture consists of Mg2SiO4 and MgO, wherein the Mg2SiO4 in the mixture is 1 to 99 weight percent. The preparation method for the microwave-tuned composite ceramic material comprises the following steps: based on the stoichiometric proportion, preparing the BaZrxTi1-xO3 and the Mg2SiO4 respectively; obtaining the powder of the BaZrxTi1-xO3 and the powder of the Mg2SiO4 respectively by ball-milling, discharging, drying and presintering; doping the Mg2SiO4 and the MgO into the BZT powder according to the component design; and performing ball-milling, drying, pelleting, molding, batching out, then sintering at the furnace temperature if between 1,200 and 1,400 DEG C for 2 to 4 hours, and obtaining the needed material. The microwave-tuned composite ceramic material has the characteristics of proper dielectric constant, low dielectric loss, high tuning rate, and high performance and low sintering temperature. The microwave-tuned composite ceramic material can be applied to a phase shifter, an adjustable filter, a delay line, an oscillator, a resonator, a phased-array antenna, and other microwave devices.

Description

A kind of microwave-tuned composite ceramic material and preparation method thereof

Technical field

The invention belongs to the microwave ceramic material technology, be specifically related to a kind of BaZr _xTi _1-xO ₃-MgO-Mg ₂SiO ₄Microwave-tuned composite ceramic material and preparation method thereof.

Background technology

Adjustable filter, retarding line, phase shifter, vibrator, microwave devices such as syntonizer and phased array antenna are the important devices in micro-wave communication field, use but too high cost has limited its wide range of commercial.Low-cost tunable technology will cause the revolution of microwave component and antenna industry.

The specific inductivity of microwave-tuned material can change with impressed voltage.Be applied to the microwave communication field, can change the operating frequency of element by impressed voltage, as allowing a wave filter produce frequency agility, this broadband communications to future is extremely important, because can realize that like this several users is at a common frequency range transmission and received signal.The tuning material of novel microwave can reduce the cost of phased array antenna greatly, with the application that makes phased array antenna by present military extend to civilian.The speed of phased array antenna, precision and reliability are all than corresponding mechanical handling antenna height.

Microwave-tuned material can be used for making phase shifter.Present phase shifter mainly is ferrite phase shifter and semiconductor diode phase shifter.But under high frequency, PIN diode exists loss big, and power is low, needs the logical circuit control phase to move, can not continuous tuning etc. shortcoming; Ferrite is low in the above loss of 3GHz, and power is big, but the costing an arm and a leg of its tuning circuit, and volume is big, heaviness, power consumption is big, only is used for military field, in addition, the loss ratio of ferrite when 1-2GHz is big when 10GHz, is not suitable for cell phone and person-to-person communication service.Ferrite phase shifter is difficult to make two dimensional structure.

The microwave-tuned material of electric field controls mainly is the ferroelectric material of perovskite structure, with strontium-barium titanate (Ba, Sr) TiO ₃And composite studies is maximum.Zirconium barium titanate BaZr _xTi _1-xO ₃(BZT) have the high tuning rate, simultaneously, Zr ⁴⁺Compare Ti ⁴⁺Chemically more stable, and BaZr _xTi _1-xO ₃Temperature stability at paraelectric phase is better than (Ba, Sr) TiO ₃The specific inductivity of zirconium barium titanate is too high, and the microwave dielectric loss height need improve material.In addition, too big specific inductivity can cause too big insertion loss, with circuit coupling difficulty.Therefore, how to obtain having moderate specific inductivity, the zirconium barium titanate of higher tuning rate is technological difficulties.

Summary of the invention

The present invention is in order to overcome the deficiencies in the prior art, a kind of microwave-tuned composite ceramic material to be provided, and this this material dielectric constant is moderate, and dielectric loss is low, and the tuning rate height is particularly useful for microwave-tuned element; The present invention also provides this preparation methods.

For achieving the above object, microwave-tuned composite ceramic material provided by the invention is by BaZr _xTi _1-xO ₃Constitute with mixture, wherein, BaZr _xTi _1-xO ₃Mass percent be 30-95%, x=0.1-0.50, described mixture is by Mg ₂SiO ₄Constitute with MgO, wherein, Mg ₂SiO ₄Mass percentage content in mixture is 1-99%.

The preparation method of above-mentioned microwave-tuned composite ceramic material comprises the steps:

(1) preparation BaZr _xTi _1-xO ₃And Mg ₂SiO ₄Powder

With pulverous BaCO ₃, ZrO2 and TiO ₂Be mixed in proportion as one group of raw material, with pulverous SiO ₂Be mixed in proportion as another group raw material with MgO, with two groups of raw materials wet ball grindings 6-24 hour respectively, discharging then, oven dry in 1000 ℃ of-1300 ℃ of scopes pre-burning 2-6 hour again, obtain BaZr respectively _xTi _1-xO ₃And Mg ₂SiO ₄Powder;

(2) according to proportioning at BaZr _xTi _1-xO ₃Mix the Mg of powdered in the powder ₂SiO ₄And MgO, oven dry after wet ball grinding 6-24 hour;

(3) polyvinyl alcohol (PVA) granulation of adding 3-8wt%, compression moulding green compact again in the material after oven dry;

(4) green compact are heated to 400-800 ℃, heat-up rate is incubated 2-4 hour then smaller or equal to 30 ℃/minute, gets rid of the organic substance in the green compact;

(5) sintering in 1200 ℃ of-1400 ℃ of scopes is incubated 2-4 hour again, obtains microwave-tuned composite ceramic material.

The invention has the advantages that by material prescription of the present invention, can be in 1200 ℃ of-1400 ℃ of scopes sintering, and this material to have a specific inductivity moderate, dielectric loss is low, the tuning rate height waits excellent properties, has obtained the result that high-performance and sintering temperature and low have both simultaneously.By regulating the Mg in the component ₂SiO ₄With MgO doping, Mg ₂SiO ₄With MgO content ratio and Zr/Ti ratio, can change the Curie temperature of material, adjust and design relevant dielectric properties, especially specific inductivity, dielectric loss and the tuning rate etc. of composite ceramic material, widened the range of application of material.This composite ceramic material composition is with BaZr _xTi _1-xO ₃, Mg ₂SiO ₄Exist with MgO three-phase composite thing, do not have impurity to exist mutually.Adopt traditional electronic ceramic technology, technology is simple, and cost is low, the side effect of material system environment-protecting asepsis.Material of the present invention can be widely used in variable condenser, adjustable filter, phase shifter, variable delay line, voltage-controlled vibrator, adjustable dielectric resonator, adjustable microwave devices such as adjustable impedance coupling device.Wherein phase shifter is the important devices of phased array antenna, directly determines the cost and the performance of phased array antenna.This material can replace the ferrite of the costliness of using in the phased array antenna, makes the phased array antenna smaller volume, and weight lightens, and it is cheap that price becomes.

Description of drawings

Fig. 1 is BaZr _xTi _1-xO ₃-MgO-Mg ₂SiO ₄The XRD spectrum of composite ceramics.

Fig. 2 is BaZr _xTi _1-xO ₃-MgO-Mg ₂SiO ₄The relation curve of the specific inductivity of composite ceramics and loss and temperature.

Fig. 3 is BaZr _xTi _1-xO ₃-MgO-Mg ₂SiO ₄The relation curve of the tuning rate of composite ceramics and external dc field intensity.

Embodiment

Below by by embodiment the present invention being described in further detail, but following examples only are illustrative, and protection scope of the present invention is not subjected to the restriction of these embodiment.

Example 1-5:

With pulverous BaCO ₃, ZrO ₂, TiO ₂, SiO ₂With MgO be raw material, prepare BaZr respectively by stoichiometric ratio _xTi _1-xO ₃(x=0.2) and Mg ₂SiO ₄, in raw material, add dehydrated alcohol or deionized water, be ball-milling medium with agate ball or zirconium dioxide, behind the wet ball grinding 6h, discharging, oven dry, powder obtains BaZr respectively at 1100 ℃ of following pre-burning 2h _xTi _1-xO ₃(x=0.2) and Mg ₂SiO ₄Powder.Press the prescription of table 1, with BaZr _xTi _1-xO ₃(x=0.2), Mg ₂SiO ₄Mix with MgO, wet ball grinding 6h, discharging, oven dry, the polyvinyl alcohol that adopts 5wt% is as the tackiness agent granulation, under the pressure of 150MPa with the pressed by powder moulding; After 600 ℃ of binder removals are handled, in air atmosphere,, obtain BaZr in 1320 ℃ of sintering 3h _0.2Ti _0.8O ₃-MgO-Mg ₂SiO ₄Composite ceramics.Sample after burning till is processed through fine grinding, after the ultrasonic cleaning, goes up silver electrode again, can be used for the dielectric properties test.

Table 1

	??BaZr 0.2Ti 0.8O 3(Wt％)	?Mg 2SiO 4(Wt％)	?MgO(Wt％)
				Embodiment 1	??40	?48	?12
Embodiment 2	??40	?36	?24
				Embodiment 3	??40	?30	?30
Embodiment 4	??40	?24	?36
				Embodiment 5	??40	?12	?48

BaZr _xTi _1-xO ₃-MgO-Mg ₂SiO ₄Specific inductivity and the dielectric loss of composite ceramics under 1MHz sees Table 2

Table 2

	Specific inductivity (1MHz)	Dielectric loss
			Embodiment
1	??125.36	??0.00121
			Embodiment 2	??144.54	??0.000986
Embodiment 3	??129.03	??0.0011
			Embodiment 4	??141.48	??0.00102
Embodiment 5	??183.19	??0.00162

The BaZr of embodiment 1-5 prescription gained _xTi _1-xO ₃-MgO-Mg ₂SiO ₄The XRD spectrum of composite ceramics.Composite ceramic material is by BaZr _xTi _1-xO ₃(x=0.2), MgO and Mg ₂SiO ₄Three phase composites.Embodiment 1,3, the BaZr of 5 prescription gained _xTi _1-xO ₃-MgO-Mg ₂SiO ₄The relation curve of the specific inductivity of composite ceramics and dielectric loss and temperature as shown in Figure 2.The BaZr of embodiment 1-5 prescription gained _xTi _1-xO ₃-MgO-Mg ₂SiO ₄The tuning rate of composite ceramics under different DC electric field intensity as shown in Figure 3.Reduce MgO content, BaZr _xTi _1-xO ₃-MgO-Mg ₂SiO ₄The specific inductivity of composite ceramics reduces, but Mg ₂SiO ₄Tuning rate increased on the contrary to some extent after content surpassed 30wt%.This provides a specific inductivity that reduces material, and improves the method for the tuning rate of material.In the prior art, the reduction of tuning rate is often followed in the reduction of ceramic dielectric constant.By adjusting Zr/Ti ratio, MgO-Mg ₂SiO ₄Content and MgO/Mg ₂SiO ₄Ratio can obtain the series material of differing dielectric constant and tuning rate.

Example 6:x=0.1, BaZr _xTi _1-xO ₃Mass percent be 30%, Mg ₂SiO ₄Mass percentage content in mixture is 1%;

Example 7:x=0.3, BaZr _xTi _1-xO ₃Mass percent be 50%, Mg ₂SiO ₄Mass percentage content in mixture is 30%;

Example 8:x=0.5, BaZr _xTi _1-xO ₃Mass percent be 95%, Mg ₂SiO ₄Mass percentage content in mixture is 99%;

With described material of above-mentioned example 6-8 and stoicheiometry, prepare microwave-tuned composite ceramic material according to following process, resulting material all can reach technique effect of the present invention.

(1) prepares BaZr respectively by stoichiometric ratio _xTi _1-xO ₃And Mg ₂SiO ₄,

Raw material adopts pulverous BaCO ₃, ZrO2, TiO ₂, SiO ₂And MgO, add dehydrated alcohol or deionized water then, be ball-milling medium with agate ball or zirconium dioxide, behind the ball milling 6h-24h, discharging, oven dry, powder is pre-burning 2h-6h in 1000 ℃ of-1300 ℃ of scopes, obtains BaZr respectively _xTi _1-xO ₃And Mg ₂SiO ₄Powder;

(2) according to forming proportioning, at BaZr _xTi _1-xO ₃Mix Mg in the powder ₂SiO ₄And MgO, to add dehydrated alcohol or deionized water then, be ball-milling medium with agate ball or zirconium dioxide, ball milling 6h-24h;

(3) polyvinyl alcohol granulation and the compression moulding green compact of adding 3-8wt% in the mixture after oven dry;

(4) be warmed up to 800 ℃ below the temperature, insulation 2-4 hour, to get rid of the organic substance in the green compact, the heat-up rate of binder removal process is not higher than 30 ℃/min;

(5) green compact sintering in 1200 ℃ of-1400 ℃ of scopes is incubated 2h-4h, obtains the bulk of required excellent performance.

Embodiment among the present invention only is used for that the present invention will be described, does not constitute the restriction to the claim scope, and other substituting of being equal in fact that those skilled in that art can expect are all at protection domain of the present invention.

Claims (2)

1. a microwave-tuned composite ceramic material is characterized in that it is by BaZr _xTi _1-xO ₃Constitute with mixture, wherein, BaZr _xTi _1-xO ₃Mass percent be 30-95%, x=0.1-0.50, described mixture is by Mg ₂SiO ₄Constitute with MgO, wherein, Mg ₂SiO ₄Mass percentage content in mixture is 1-99%.

2. the preparation method of the described microwave-tuned composite ceramic material of claim 1 is characterized in that, this preparation method comprises the steps:

(1) preparation BaZr _xTi _1-xO ₃And Mg ₂SiO ₄Powder:

With pulverous BaCO ₃, ZrO2 and TiO ₂Be mixed in proportion as one group of raw material, with pulverous SiO ₂Be mixed in proportion as another group raw material with MgO, with two groups of raw materials wet ball grindings 6-24 hour respectively, discharging then, oven dry in 1000 ℃ of-1300 ℃ of scopes pre-burning 2-6 hour again, obtain BaZr respectively _xTi _1-xO ₃And Mg ₂SiO ₄Powder;

(2) according to proportioning at BaZr _xTi _1-xO ₃Mix the Mg of powdered in the powder ₂SiO ₄And MgO, oven dry after wet ball grinding 6-24 hour;

(3) the polyvinyl alcohol granulation of adding 3-8wt%, compression moulding green compact again in the material after oven dry;

(4) green compact are heated to 400-800 ℃, heat-up rate is incubated 2-4 hour then smaller or equal to 30 ℃/minute, gets rid of the organic substance in the green compact;

(5) sintering in 1200 ℃ of-1400 ℃ of scopes is incubated 2-4 hour again, obtains microwave-tuned composite ceramic material.

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