CN101747059A

CN101747059A - Method for preparing low temperature co-fired microwave dielectric ceramic material

Info

Publication number: CN101747059A
Application number: CN200910200547A
Authority: CN
Inventors: 卞建江; 孔秋东; 汪亮; 吴乃贤; 景炳青; 廖林壑; 吴春红
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2009-12-22
Filing date: 2009-12-22
Publication date: 2010-06-23
Anticipated expiration: 2029-12-22
Also published as: CN101747059B

Abstract

The invention relates to a method for preparing a low temperature co-fired (LTCC) microwave dielectric ceramic material, and belongs to the technical field of special ceramic material processes. The chemical general formula of the low temperature microwave dielectric ceramic material is AWO4+xwt percent TeO2 (A=Zn, Ca or Sr; and x=2.5, 5.0, 7.5 or 10.0.). The preparation method comprises the following steps: weighing oxide raw materials in a stoichiometric ratio, and blending the oxide raw materials; performing ball milling on the blended material in a resin milling pot for 24 hours, and making a weight ratio of the material to balls to alcohol be 1:2:0.5; discharging and drying the material, and calcining the material at the temperature of between 700 and 850 DEG C to synthesize ceramic powder; grinding and performing secondary ball milling; discharging, drying and sieving the material to obtain synthetic powder; adding a certain amount of solution of polyvinylalcohol into the synthetic powder for granulation; performing dry pressing under the pressure of 120MPa for forming; and sintering the formed blocks at the temperature of between 850 and 900 DEG C for 2 hours and finally preparing the novel low temperature co-fired microwave dielectric ceramic material.

Description

A kind of preparation method of low temperature co-fired microwave dielectric ceramic material

Technical field

The present invention relates to the preparation method that a kind of new type low temperature burns (LTCC) microwave dielectric ceramic materials altogether, belong to special ceramic material Technology field.

Background technology

The universal Highgrade integration of mobile communication equipment to the microwave communication equipment, miniaturization, high reliability and low cost are had higher requirement.In addition, owing to beginning of Medium Wave Guide exists complete magnetic interface and produces radiation loss, the whole wave guide size of component is further dwindled.Use dielectric material so have only, just can make the Highgrade integration of microwave device with good microwave dielectric property, miniaturization, high reliability and cost degradation become possibility.For this reason, microwave dielectric material must have (1) high specific inductivity; (2) high quality factor (low dielectric loss); (3) near zero temperature coefficient of resonance frequency.

Along with the development of microwave technology, present mobile communication is the development of the s-generation mechanics of communication of representative through digital mobile communication system, personal digital cellular system, and 3G (Third Generation) Moblie updates.Simultaneously, along with the short distance wireless communication technology---the further investigation and the development of Bluetooth technology, wireless local area network technology develops rapidly.Therefore microwave technology develops towards higher frequency on the one hand, and expands frequency span, makes full use of frequency resource; On the other hand, mobile communication and portable terminal just develop towards miniaturization, lightweight, integrated, multi-functional, high reliability and low-cost direction, and this also proposes higher requirement to the microwave circuit components and parts based on microwave-medium ceramics.Microwave-medium ceramics is for making the critical material of these devices, and its performance index have determined the performance and the dimension limit of micro-wave communication device and system to a great extent.Present various microminiaturization, compoundization, high frequencyization, chip type, modular novel microwave dielectric components and parts arise at the historic moment, the microwave-medium ceramics relevant with new component also obtained and developed rapidly, and develops towards directions such as Gao Jie, high frequency, low-temperature sinterings.Reduce the microwave-medium ceramics sintering temperature three kinds of methods are arranged: (1) selects the low frit material.(2) preparation ultra-fine micropowder.(3) select low melting component or eutectic to do sintering aid.The present invention is chosen in AWO ₄(A=Zn, Ca, Sr) middle a certain amount of TeO that mixes ₂As research object, studied AWO respectively ₄+ xwt%TeO ₂(A=Zn, Ca, Sr; X=2.5,5.0,7.5,10.0) sintering behavior, microwave-medium performance etc.

Summary of the invention

The object of the present invention is to provide a kind of new type low temperature to burn the preparation method of (LTCC) microwave dielectric ceramic materials altogether.

For achieving the above object, the present invention adopts following technical proposals:

A kind of new type low temperature burns (LTCC) microwave dielectric ceramic materials altogether, it is characterized in that having following chemical general formula: AWO ₄+ xwt%TeO ₂, A=Zn wherein, Ca, Sr; X=2.5,5.0,7.5,10.0;

Adopt the analytical pure raw material, promptly purity is that ZnO, the purity of 99.00wt% are the CaCO of 99.50wt% ₃, purity is the SrCO of 99.50wt% ₃, purity is the WO of 99.00wt% ₃, purity is the TeO of 99.99wt% ₂

A kind of preparation method of new type low temperature co-fired microwave dielectric ceramic material is characterized in that it being that following process and step are arranged:

A. prepare burden: according to above-mentioned each chemical formula, converse the quality of required each raw material, accurate then each analytical pure raw material of weighing;

B. ball milling mixes: each raw material of accurate weighing is poured in the resin ball grinder, added alcohol and ZrO ₂Abrading-ball; Three's weight ratio is: material: ball: alcohol=1: 2: 0.5; Ball milling 24 hours mixes the back discharging, and it is dried down at 100 ℃;

C. examination is synthetic: the small quantities of powder sample is put into alumina crucible try to synthesize, and Synthetic 2 hour at a certain temperature, concrete synthesis temperature changes according to the difference of component.With the phase composite of X-ray diffraction method analysis synthetic powder sample, find out optimum synthesising temperature;

D. synthetic: as all samples to be put into alumina crucible, under optimum synthesising temperature, synthesize; Synthesis temperature is generally 700～850 ℃;

E. secondary ball milling: will synthesize good sample and grind the back with mortar and cross to pour into behind 80 mesh sieves and carry out ball milling second time in the urethane ball grinder, the interior quality of material ratio of ball milling bucket is powder: ball: dehydrated alcohol=1: 4: 0.5, ball milling 24 hours; Mix the back discharging, it is dried down at 100 ℃; Dry 80 mesh sieves and made uniformly synthetic powder;

F. granulation: polyvinyl alcohol (PVA) solution that adds 7wt% concentration and be 10wt% in above-mentioned synthetic powder carries out granulation as polymerizing agent, will synthesize powder and polyvinyl alcohol and put into mortar and grind, and evenly 40 mesh sieves are crossed in the back;

G. compressing tablet: will make that powder single face under 120MPa of grain is molded to be the cylinder of φ 10mm * 5mm;

H. binder removal: the disk after the moulding is placed on the zirconium plate, in air, rise to 600 ℃ of insulations 2 hours from room temperature, temperature rise rate is 5 ℃/min, carries out binder removal;

I. sintering: the disk behind the binder removal places on the zirconium plate, and with on the alumina crucible cover, sintering is 2 hours at a certain temperature, and temperature rise rate is 5 ℃/min; Sintering temperature is 850～900 ℃, finally makes microwave dielectric ceramic materials.

Characteristics of the present invention are: can form the raw material of low melting component or eutectic point compound owing to adopt, thus be that lower sintering temperature is arranged, but save energy, and simplified technology; The prepared microwave dielectric ceramic materials of the inventive method has higher dielectric constant and quality factor.

Description of drawings

Fig. 1 is ZnWO among the present invention ₄+ xwt%TeO ₂The XRD diffracting spectrum of (x=2.5,5.0,7.5,10.0);

Fig. 2 is CaWO among the present invention ₄+ xwt%TeO ₂The XRD diffracting spectrum of (x=2.5,5.0,7.5,10.0);

Fig. 3 is SrWO among the present invention ₄+ xwt%TeO ₂The XRD diffracting spectrum of (x=2.5,5.0,7.5,10.0).

Embodiment

Now specific embodiments of the invention are described in down.

Embodiment 1: at first according to chemical formula AWO ₄+ xwt%TeO ₂(A=Zn wherein, Ca, Sr; X=2.5,5.0,7.5,10.0) converse the quality of required each raw material, then accurate each analytical pure raw material of weighing: purity is that ZnO, the purity of 99.00wt% is the CaCO of 99.50wt% ₃, purity is the SrCO of 99.50wt% ₃, purity is the WO of 99.00wt% ₃, purity is the TeO of 99.99wt% ₂

When calculating the required quality of each raw material, considered the purity factor of raw material.In addition, chemical formula AWO ₄+ xwt%TeO ₂=100 (A=Zn wherein, Ca, Sr; X=2.5,5.0,7.5,10.0), promptly its total mass mark is used as calculating benchmark based on 100.

The preparation process and the test data of each product of present embodiment are generalized into tabulated form, referring to table 1, table 2, table 3

The preparation process of present embodiment is as follows:

Each raw material of accurate weighing is packed in the resin ball grinder, add alcohol and ZrO ₂Abrading-ball; Three's weight ratio is: material: ball: alcohol=1: 2: 0.5; Ball milling 24 hours mixes the back discharging, and it is dried down at 100 ℃; 700～850 ℃ of down calcinings 2 hours,, synthetic good above-mentioned porcelain is ground the back with mortar cross 80 mesh sieves, and then pour into and carried out secondary ball milling in the ball grinder 24 hours then with the synthesize ceramic powder; Material: ball: the constant rate of alcohol; Discharging, 80 mesh sieves are crossed in slurry oven dry back; The concentration that adds 7wt% again in the powder that obtains is that the polyvinyl alcohol solution of 10wt% carries out granulation and crosses 40 mesh sieves; The powder that granulation is good puts into that mould is dry-pressing formed under 120MPa pressure to be the cylinder block of φ 10 * 5mm; Then with the block of forming 600 ℃ of following constant temperature 2 hours to remove binding agent, its temperature rise rate is 5 ℃/min; At last with identical temperature rise rate 850～900 ℃ of following sintering 2 hours, finally make needed novel microwave dielectric ceramic material.

X-ray diffractometer and microwave dielectric property test

The employing X-ray diffractometer (Rigaku D/max2550 type, 40Kv 200mA) carries out material phase analysis to sintered sample; Network analyzer (Agilent N5230A) and relevant necessary instrument are tested its microwave dielectric property.Sample ZnWO ₄+ xwt%TeO ₂The XRD figure spectrum of (x=2.5,5.0,7.5,10.0) is as Fig. 1; Sample CaWO ₄+ xwt%TeO ₂The XRD figure spectrum of (x=2.5,5.0,7.5,10.0) is as Fig. 2; Sample SrWO ₄+ xwt%TeO ₂The XRD figure spectrum of (x=2.5,5.0,7.5,10.0) is as Fig. 3; The The performance test results of sample such as table 1, table 2 and table 3.

Table 1 ZnWO ₄+ xwt%TeO ₂(x=2.5,5.0,7.5,10.0) allocation sheet and material microwave dielectric properties

Table 2 CaWO ₄+ xwt%TeO ₂(x=2.5,5.0,7.5,10.0) allocation sheet and material microwave dielectric properties

Table 3 SrWO ₄+ xwt%TeO ₂(x=2.5,5.0,7.5,10.0) allocation sheet and material microwave dielectric properties

Claims

1. the preparation of a new type low temperature co-fired microwave dielectric ceramic material is characterized in that having following chemical general formula: AWO ₄+ xwt%TeO ₂, A=Zn wherein, Ca, Sr; X=2.5,5.0,7.5,10.0; Adopt the analytical pure raw material, promptly purity is that ZnO, the purity of 99.00wt% are the CaCO of 99.50wt% ₃, purity is the SrCO of 99.50wt% ₃, purity is the WO of 99.00wt% ₃, purity is the TeO of 99.99wt% ₂

2. the preparation method of a new type low temperature co-fired microwave dielectric ceramic material is characterized in that it being that following process and step are arranged:

E. secondary ball milling: will synthesize good sample and grind the back with mortar and cross to pour into behind 80 mesh sieves and carry out ball milling second time in the urethane ball grinder, the interior weight of material ratio of ball milling bucket is powder: ball: dehydrated alcohol=1: 4: 0.5, ball milling 24 hours; Mix the back discharging, it is dried down at 100 ℃; Dry 80 mesh sieves and made uniformly synthetic powder;