CN1397957A

CN1397957A - Multi-layer ceramic capacitor material with ultrahigh dielectric constant and temp stability and its preparing process

Info

Publication number: CN1397957A
Application number: CN 02125720
Authority: CN
Inventors: 王晓慧; 陈仁政; 桂治轮; 李詜; 李龙土
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2002-08-14
Filing date: 2002-08-14
Publication date: 2003-02-19
Anticipated expiration: 2022-08-14
Also published as: CN1172321C

Abstract

The invention discloses an ultra-high dielectric constant, temperature-stable multilayer ceramic capacitor material and a preparation method, which belong to the preparation technology of ceramic materials. The main components of the material are barium titanate, metal powder, cobalt oxide, niobium oxide and secondary additives of rare earth oxides. The barium titanate is prepared by a solid phase synthesis method and a chemical synthesis method, mixed with metal powder and secondary additives, pressurized and sintered to form a multilayer ceramic capacitor material. There is no need to add a sintering aid in the preparation process, which can significantly reduce the synthesis and sintering temperature. The room-temperature dielectric constant of the material can be controlled between 4000 and 42000, and the capacity temperature change rate is ≤±15%. The sintering temperature can be controlled below 1280°C. It is a high-performance multilayer ceramic capacitor material with wide application prospects.

Description

Ultra-high dielectric coefficient, temperature-stable multilayer ceramic capacitor material and preparation method thereof

Technical field

The invention belongs to the capacitor material preparing technical field, particularly have a kind of ultra-high dielectric coefficient, temperature-stable multilayer ceramic capacitor material of ultra-high dielectric coefficient, temperature stabilization and preparation method thereof.

Technical background

Multilayer ceramic capacitor is that electrode material is replaced in parallel being superimposed together with ceramic body with multilayer, and burns till an integral body simultaneously.According to the international EIA of Electronic Industries Association standard.Its capacitance is meant that the capacitance with 25 ℃ is a benchmark, within the scope of from-55 to+125 ℃ of temperature, and temperature coefficient of capacitance＜± 15%, dielectric loss (DF)≤2.5%.Multilayer ceramic capacitor is divided into two big classes by composition: a class is made up of leaded ferroelectric, and is another kind of with BaTiO ₃The ferroelectric of the non-plumbous system of base is formed.And the latter is because environmentally safe, and mechanical strength and reliability be better than the former, and therefore non-lead is BaTiO ₃Base has broad application prospects.Traditional non-lead is that the composition of multi-layer ceramic capacitor material mainly is with BaTiO ₃Be base-material, suitably adding niobium (Nb), tantalum (Ta), magnesium (Mg), transition elements cobalt (Co), manganese (Mn) etc. and other element is modifier (secondary additive), and general sintering temperature height is all more than 1300 ℃.Some also adds silica (SiO ₂), bismuth oxide (Bi ₂O ₃) wait sintering aid to reduce sintering temperature.Preparation technology passes through solid-phase synthesis.Processing step comprise weighing-batch mixing-high temperature synthetic-pulverizing-secondary interpolation-screening-moulding-sintering etc.There is the component skewness in this technology, and the synthesis temperature height is subject to contaminating impurity, shortcomings such as reproducibility difference.And the sintering temperature height, the energy consumption height is unfavorable for technology controlling and process.Room temperature dielectric constant with the ceramic material of barium phthalate base multilayer ceramic capacitor does not surpass 5000.Comparatively Cheng Shu product is as United States Patent (USP), U.S Pat.No5571767, (Wilson) the Wilson invention with BaTiO ₃Be major ingredient, add neodymia, with Bi ₂O ₃, TiO ₂And glassy phase PbO, Bi ₂O ₃, SiO ₂, TiO ₂, Al ₂O ₃Be sintering aid, under 1100 ℃, the multi-layer ceramic capacitor material of sintering preparation, dielectric constant is 3200 to the maximum.U.S. material is researched and analysed the BaTiO that the low fever has been reported in the laboratory ₃Quito layer ceramic capacitor material, its dielectric constant reaches 4400, but the sintering process complexity, needs strict control, burns till sintering temperature～1110 ℃ for three times.

Summary of the invention

The purpose of this invention is to provide a kind of ultra-high dielectric coefficient, temperature-stable multilayer ceramic capacitor material and preparation method thereof, described multi-layer ceramic capacitor material mainly is made up of barium titanate, metal dust and secondary additive.Described multi-layer capacity modulator material is to be major ingredient with the barium titanate, adds to be used to improve the metal powder of dielectric property, and the secondary additive that is used to improve temperature performance, with the prescription of mol ratio is:

X ([100-(a+b+c)] BaTiO ₃+ a Nb ₂O ₅+ b Co ₃O ₄+ c Re ₂O ₃+ d MnO ₂The Me of)+(1-x), 0.5≤x≤1.0 wherein, 0.1≤a≤3.0,0.1≤b≤1.5,0.1≤c≤1.2,1.0≤a/b≤5.0, Me represents argent (Ag), palladium (Pd), silver palladium alloy (Ag-Pd), Re represents yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), dysprosium (Dy), erbium (Er) and ytterbium (Yb), wherein manganese oxide (MnO ₂) add in right amount or do not add and all can.

Described major ingredient BaTiO ₃Shared molal quantity is 50-99%; The shared molal quantity of described metal dust is 0-49%; Be the 1-3 kind of silver, palladium, silver palladium alloy, the consumption of secondary additive accounts for the 0.5-4mol% of total amount of material.Its secondary additive comprises niobium oxide (Nb ₂O ₅), cobalt sesquioxide (Co ₂O ₃) or cobaltosic oxide (Co ₃O ₄) and rare earth oxide yittrium oxide (Y ₂O ₃), cerium oxide (CeO ₂), praseodymium oxide (Pr ₂O ₃), neodymia (Nd ₂O ₃), samarium oxide (Sm ₂O ₃), dysprosia (Dy ₂O ₃), ytterbium oxide (Yb ₂O ₃) in the 1-3 kind.

Described ultra-high dielectric coefficient, temperature-stable multilayer ceramic capacitor preparation methods are: preparation major ingredient BaTiO ₃, again by prescription x ([100-(a+b+c)] BaTiO ₃+ a Nb ₂O ₅+ b Co ₃O ₄+ c Re ₂O ₃+ dMnO ₂The Me of)+(1-x), ball milling, drying, moulding, sintering formed after proportioning was mixed.

Step of preparation process is as follows:

1. solid phase method synthesizes BaTiO ₃Material: with initial feed TiO ₂, and BaCO ₃By the stoichiometric proportion weighing, be medium mixing and ball milling 24 hours with water, reach its granularity less than 1 μ m after, under 70～120 ℃ of temperature, dry by the fire 6 hours, again under 1200 ℃ of temperature, solid phase reaction is synthesized BaTiO in 6 hours ₃

2. also pressing formula rate and add metal dust, secondary additive mixing, is medium ball milling 24-72 hour with water;

3. under 70～120 ℃ of temperature, dry moulding in 6 hours;

4 sintering are 1150～1300 ℃ temperature range, and sintering 30～240 minutes promptly gets multi-layer ceramic capacitor material behind the natural cooling.

Described barium titanate BaTiO ₃Be to adopt butyl titanate (Ti (OC ₄H ₉) ₄), barium nitrate (Ba (NO ₃) ₂), barium acetate (Ba (CH ₃COO) ₂) chemically synthetic.Its synthesis technique is: by the stoichiometric proportion wiring solution-forming, Ti or Ba ion concentration are between 0.1～5M in the solution with three kinds of raw materials; With oxalic acid is that precipitation reagent carries out co-precipitation, forms the barium titanium oxalate white depositions, 10～80 ℃ of precipitation reaction temperature, and the reaction time is 2～4 hours; Sediment earlier with behind the deionized water wash several, is washed for several times with ethanol again, under 70～120 ℃, dried through 10～24 hours; And 700～1100 ℃ of calcinings down, be incubated after 0.5～2 hour, obtain the material B aTiO of superfine powder ₃With secondary additive, metal dust and its even mixing, be medium ball milling 24～72 hours then with water; Under 70～120 ℃ after 10～24 hours dryings, extrusion forming, sintering, natural cooling promptly get ultra-high dielectric coefficient, temperature-stable multilayer ceramic capacitor material.

Described BaTiO ₃Major ingredient directly and metal dust, additive mix, be medium ball milling 24-72 hour with the absolute ethyl alcohol; Under 50～70 ℃, after 10～24 hours dryings, extrusion forming, and under 1150～1300 ℃, through 30～240 minutes sintering, natural cooling promptly got ultra-high dielectric coefficient, temperature-stable multilayer ceramic capacitor material.

Described BaTiO ₃Salt, additive that major ingredient and metal oxide or other easily are decomposed into metal mix, and are medium ball milling 24～72 hours with the absolute ethyl alcohol; Under 50～70 ℃, through 10～24 hours dryings; Under 300 ~ 500 ℃, this kind of pre-burning powder makes wherein metal oxide or slaine decomposite metal dust, extrusion forming then; Under 1150～1300 ℃, through 30～240 minutes sintering, natural cooling promptly got multi-layer ceramic capacitor material.Described metal dust is that metal oxide or other labile slaine are silver oxide (Ag ₂O), silver carbonate (Ag ₂CO ₃), silver nitrate (AgNO ₃).

The invention has the beneficial effects as follows, use technology of the present invention to need not to add any sintering agent, just can go out ultra-high dielectric coefficient, the temperature-stable multilayer ceramic capacitor material of excellent performance at≤1280 ℃ sintering temperature, the room temperature dielectric constant of material can be controlled between 4400～42000, temperature coefficient of capacitance＜± 15% in-55 ℃～+ 125 ℃ scopes, and have 10 ¹²～10 ¹³The high insulation resistivity of Ω CM, stable performance, puncture voltage is greater than 5KV/mm, and dielectric loss is little, and mechanical strength is big, characteristics such as reliability height, good uniformity.Preparation technology of the present invention is easy, utilizes the advantage of material self to reduce sintering temperature, and firing range is wide, and it is simply adjustable to fill a prescription, and sintering process is easily controlled.

Description of drawings

Fig. 1 is the characteristic curve corresponding to the sample dielectric constant with temperature variation of embodiment 1.

Fig. 2 is the temperature variant characteristic curve of sample percentage of capacitance variation with temperature corresponding to embodiment 1.

Fig. 3 is the characteristic curve corresponding to the sample dielectric constant with temperature variation of embodiment 2.

Fig. 4 is the temperature variant characteristic curve of sample percentage of capacitance variation with temperature corresponding to embodiment 2.

Fig. 5 is the characteristic curve corresponding to the sample dielectric constant with temperature variation of embodiment 3.

Fig. 6 is the temperature variant characteristic curve of sample percentage of capacitance variation with temperature corresponding to embodiment 3.

Fig. 7 is the characteristic curve corresponding to the sample dielectric constant with temperature variation of embodiment 4.

Fig. 8 is the temperature variant characteristic curve of sample percentage of capacitance variation with temperature corresponding to embodiment 4.

Fig. 9 is the characteristic curve corresponding to the sample dielectric constant with temperature variation of embodiment 5.

Figure 10 is the temperature variant characteristic curve of sample percentage of capacitance variation with temperature corresponding to embodiment 5.

Embodiment

Fig. 1～Figure 10 shows that is according to each sample (shown in the table 1-table 5) temperature characteristics of dielectric constant and the temperature curve that electric capacity varies with temperature rate of the embodiment 1～5 that preparation method of the present invention did.Its probe temperature is-60 ℃～130 ℃.ε is the dielectric constant of material in the table; TCC: temperature coefficient of capacitance;

Tg δ (25 ℃): dielectric loss during room temperature;

TCC(T)％＝100×(ε(T)-ε(25℃))/ε(25℃)。

In conjunction with top test curve figure, exemplify following embodiment and respectively the present invention illustrated:

Embodiment 1, is example with Nh, Co, Nd element doping.Fixedly additive Nb, Co consumption are 1.0mol%.Nb∶Co＝2.5。Barium titanate BaTiO ₃Major ingredient adopts chemical synthesis process to produce its initial feed butyl titanate (Ti (OC ₄H ₉) ₄) 102.1g is dissolved in ethanol, barium acetate (Ba (CH ₃COO) ₂) be that 76.64g is water-soluble, oxalic acid (H ₂C ₂O ₄2H ₂O) be dissolved in ethanol for 83.2g.Earlier the butyl titanate ethanolic solution is added in the oxalic acid ethanolic solution, stir, then the barium acetate aqueous solution is slowly added, form the white precipitate of barium titanium oxalate.Sediment is earlier with the washed with de-ionized water several, and with after the ethanol cleaning for several times, drying is calcined, and obtains white barium carbonate powder material again.In barium carbonate powder material 20g, add secondary additive by prescription respectively, the content of niobium oxide and cobalt oxide is 1.0mol% in the prescription, the content of neodymia is respectively 0.3,0.5,0.7,0.8,0.9 and 1.0mol%, is designated as 1-1,1-2,1-3,1-4,1-5,1-6.Batching is mixed through ball milling, after the drying, and compression moulding under 2MPa pressure, diameter is 10mm, thickness is 1mm.In 1240 ℃ of sintering 4h.Programming rate is 6 ℃/min.The ceramics that burns till is measured its dielectric property behind the silver ink firing up and down.The dielectric property parameter of the ceramic print that is obtained sees Table 1.What Fig. 1 curve provided is the dielectric temperature characteristic curve of sample.Fig. 2 provides the temperature coefficient of capacitance curve of sample.

Embodiment 2: fixing prescription major ingredient barium titanate is 98mol%, and the content of niobium oxide and cobalt oxide is 1.0mol%, and neodymia is 1.0mol%.Barium titanate adopts the chemical synthesis of embodiment 1 to produce.Press embodiment 1 prescription respectively and add secondary additive in barium carbonate powder material 20g, batching is mixed through ball milling, after the drying, and compression moulding under 2MPa pressure, diameter is 10mm, thickness is 1mm.Respectively at 1200 ℃, 1220 ℃, 1240 ℃, 1250 ℃, 1260 ℃, 1280 ℃ of sintering 2h.Programming rate is 6 ℃/min.Measure its dielectric property behind the ceramics upper and lower surface silver ink firing that burns till.The dielectric property parameter of the ceramic print that is obtained sees Table 2.What Fig. 3 curve provided is the dielectric temperature characteristic curve of sample.Fig. 4 provides the temperature coefficient of capacitance curve of sample.

Embodiment 3: use three groups of 20g barium titanates of weighing, add secondary additive according to embodiment 1 prescription, add 0.2g, 1.0g, 2.0g silver powder then respectively, be designated as 3-, 3-2,3-3, batching is mixed through the alcohol ball milling, after the drying, behind the 2MPa forming under the pressure, at 1240 ℃ of sintering, temperature retention time is 2 hours.Its dielectric property of test behind the ceramics sample silver ink firing that is obtained.Table 3 is listed under 1240 ℃ of sintering, the dielectric property parameter of different metal Ag powder addition ceramics sample.Fig. 5 and Fig. 6 are respectively the dielectric temperature characteristic curve and the temperature coefficient of capacitance curve of sample.

Embodiment 4: use the pure barium titanate powder of embodiment 2 preparations, three groups of 20g barium titanates of weighing add secondary additive according to embodiment 1 prescription, add 4.72g, 6.30g, 7.24g silver nitrate (AgNO then respectively ₃), being designated as 4-1,4-2,4-3, batching is mixed through the alcohol ball milling, after the drying, heat-treats under 350 ℃, and temperature retention time is 2 hours.Silver nitrate is decomposed into argent simple substance after the preliminary treatment.Then with this powder behind the 2MPa forming under the pressure, at 1250 ℃ of sintering, temperature retention time is 2 hours.Its dielectric property of test behind the ceramics sample silver ink firing that is obtained.Table 4 is listed under 1250 ℃ of sintering, the dielectric property parameter of different silver nitrate addition ceramics samples.Fig. 7 and Fig. 8 are respectively the dielectric temperature characteristic curve and the temperature coefficient of capacitance curve of sample.

Embodiment 5: to the pure barium titanate powder of the embodiment of the invention two preparations, three groups of 20g barium titanates of weighing add secondary additive according to prescription, add 6.39g, 7.16g, 7.67g silver carbonate (Ag then respectively ₂CO ₃), being designated as 5-1,5-2,5-3, batching is mixed through the alcohol ball milling, after the drying, heat-treats under 300 ℃, and temperature retention time is 2 hours.Silver carbonate is decomposed into argent simple substance after the preliminary treatment.Then with this powder behind the 2MPa forming under the pressure, at 1240 ℃ of sintering, temperature retention time is 2 hours.Its dielectric property of test behind the ceramics sample silver ink firing that is obtained.Table 5 is listed under 1240 ℃ of sintering, the dielectric property parameter of different silver carbonate addition ceramics samples.Fig. 9 and Figure 10 are respectively the dielectric temperature characteristic curve and the temperature coefficient of capacitance curve of sample.

In addition, the insulation resistance of ceramic material and puncture voltage test result see Table 6.

Above-mentioned experimental result explanation by the adjustment of prescription, technology and metal addition, at 1200 ~ 1250 ℃, does not add under the condition of sintering aid, can obtain the barium phthalate base multi-layer ceramic capacitor material of ultra-high dielectric coefficient (up to 42000) temperature-stable.

The room temperature dielectric constant of sample can be controlled between 4000 to 42000, and temperature coefficient of capacitance is less than ± 15%, and dielectric loss is less than 2.5%.Insulation resistivity is 10 ¹²~ 10 ¹³Ω CM, puncture voltage is greater than 5KV/mm.Utilize prescription of the present invention and technology, chemical method preparation technology particularly, it is low to obtain sintering temperature, and performance is adjustable, and sintering range is wide, the multi-layer ceramic capacitor material of the barium phthalate base that stability and reproducibility are good.And the uniform crystal particles of material, particle diameter is less than 1 micron, and mechanical strength is good, the reliability height, anti-breakdown characteristics is strong, can be applied to big capacity multilayer ceramic capacitor, is a kind of ultra-high dielectric coefficient, temperature-stable multilayer ceramic capacitor material with wide application prospect.

Table 1

??SAMPLE	??CONDITION	????E	????TCC(％)	????E ??(25℃)	????E	????T ??CC(％)	????TGδ ????(25 ??℃)(％)
		????E	????TCC(％)		????E	????T ??CC(％)		??????????-55℃		???????????125℃
		????1-1	?1240℃/4h		????2981	????-13.9		??????????-55℃		???????????125℃		????3462	????4213	????21.7	????2.76
????1-2	?1240℃/4h	????1-1	?1240℃/4h	????4053	????2981	????-13.9	????-2.33	????4150	????4601	????10.9	????1.31	????3462	????4213	????21.7	????2.76
????1-2	?1240℃/4h	????1-3	?1240℃/4h	????4053	????4488	????2.61	????-2.33	????4150	????4601	????10.9	????1.31	????4374	????4366	????-0.18	????1.50
????1-4	?1240℃/4h	????1-3	?1240℃/4h	????4356	????4488	????2.61	????2.93	????4232	????3946	????-6.75	????1.55	????4374	????4366	????-0.18	????1.50
????1-4	?1240℃/4h	????1-5	?1240℃/4h	????4356	????4290	????0.92	????2.93	????4232	????3946	????-6.75	????1.55	????4251	????4186	????-1.53	????1.38
????1-6	?1240℃/4h	????1-5	?1240℃/4h	????4273	????4290	????0.92	????2.10	????4185	????3783	????-9.60	????1.32	????4251	????4186	????-1.53	????1.38

Table 2

?SAMPLE	?CONDITION	????E	??TCC(％)	????E ??(25℃)	????E	?TCC(％)	????TGΔ (25℃)(％)
		????E	??TCC(％)		????E	?TCC(％)		?????????-55℃		???????????125℃
		??2-1	?1200℃/2h		????2557	????-11.8		?????????-55℃		???????????125℃		????2901	????3226	????11.2	????6.18
??2-2	?1220℃/2h	??2-1	?1200℃/2h	????3147	????2557	????-11.8	????-7.69	????3409	????3843	????12.7	????1.91	????2901	????3226	????11.2	????6.18
??2-2	?1220℃/2h	??2-3	?1240℃/2h	????3147	????3677	????-0.59	????-7.69	????3409	????3843	????12.7	????1.91	????3799	????4080	????7.4	????1.86
??2-4	?1250℃/2h	??2-3	?1240℃/2h	????3908	????3677	????-0.59	????0.51	????3850	????4273	????10.2	????1.70	????3799	????4080	????7.4	????1.86
??2-4	?1250℃/2h	??2-5	?1260℃/2h	????3908	????4571	????2.21	????0.51	????3850	????4273	????10.2	????1.70	????4472	????4306	????-3.7	????1.68
??2-6	?1280℃/2h	??2-5	?1260℃/2h	????4470	????4571	????2.21	????-2.57	????4588	????4262	????-7.1	????1.45	????4472	????4306	????-3.7	????1.68

Table 3

?SAMPLE	??CONDITION	????E	????TCC(％)	????E ??(25℃)	????E	??TCC(％)	????TGΔ (25℃)(％)
		????E	????TCC(％)		????E	??TCC(％)		?????????????-55℃		?????????????125℃
		??3-1	??1240℃/2h		????4154	????-5.65		?????????????-55℃		?????????????125℃		????4403	????4649	??5.58	????0.84
??3-2	??1240℃/2h	??3-1	??1240℃/2h	????4750	????4154	????-5.65	????-7.52	????5136	????5222	??1.67	????0.869	????4403	????4649	??5.58	????0.84
??3-2	??1240℃/2h	??3-3	??1240℃/2h	????4750	????5825	????-10.40	????-7.52	????5136	????5222	??1.67	????0.869	????6501	????6286	??3.30	????1.21

Table 4

?SAMPLE	??CONDITION	????E	????TCC(％)	????E ??(25℃)	????E	??TCC(％)	????TGΔ (25℃)(％)
		????E	????TCC(％)		????E	??TCC(％)		??????????????-55℃		????????????125℃
		??4-1	??1250℃/2h		????7202	??-12.53		??????????????-55℃		????????????125℃		????8234	??7694	??-6.56	????1.48
??4-2	??1250℃/2h	??4-1	??1250℃/2h	????10140	????7202	??-12.53	??-14.50	????11860	??10760	??-9.27	????2.06	????8234	??7694	??-6.56	????1.48
??4-2	??1250℃/2h	??4-3	??1250℃/2h	????10140	????16590	??-15.62	??-14.50	????11860	??10760	??-9.27	????2.06	????19710	??17540	??-11.01	????1.97

Table 5

?SAMPLE	??CONDITION	????E	??TCC(％)	????E ??(25℃)	????E	??TCC(％)	????TGΔ (25℃)(％)
		????E	??TCC(％)		????E	??TCC(％)		????????????-55℃		?????????????125℃
		??5-1	??1240℃/2h		????15630	??-15.65		????????????-55℃		?????????????125℃		????18530	??16420	??-11.38	????1.91
??5-2	??1240℃/2h	??5-1	??1240℃/2h	????29160	????15630	??-15.65	??-15.72	????34600	??29730	??-14.07	????2.28	????18530	??16420	??-11.38	????1.91
??5-2	??1240℃/2h	??5-3	??1240℃/2h	????29160	????35800	??-14.25	??-15.72	????34600	??29730	??-14.07	????2.28	????41750	??35630	??-14.65	????2.21

Table 6

?Sample	??Sintering?Condition	????ρ ??(×10 ¹²Ω·cm)	????Breaking?Down?Voltage ????(Kv/mm)
?Sample	??Sintering?Condition	????ρ ??(×10 ¹²Ω·cm)	????Breaking?Down?Voltage ????(Kv/mm)	??1-3	????1240℃-4h	????14.5	????11.6
??1-4	????1240℃-4h	????20.3	????11.0	??1-3	????1240℃-4h	????14.5	????11.6
??1-4	????1240℃-4h	????20.3	????11.0	??4-2	????1240℃-2h	????12.7	????5.8

Claims

1. A super high dielectric constant, temperature stable multilayer ceramic capacitor material, mainly composed of barium titanate, metal powder and secondary additives, characterized in that: said multilayer capacitor material is based on barium titanate Material, adding metal powder for improving dielectric properties, and secondary additives for improving temperature performance, the formula in molar ratio is:

x([100-(a+b+c)]BaTiO ₃ +a Nb ₂ O ₅ +b Co ₃ O ₄ +c Re ₂ O ₃ +d MnO ₂ )+(1-x)Me, where 0.5≤x ≤1.0, 0.1≤a≤3.0, 0.1≤b≤1.5, 0.1≤c≤1.2, 1.0≤a/b≤5.0, Me stands for metal silver (Ag), palladium (Pd), silver-palladium alloy (Ag-Pd) , Re represents yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), dysprosium (Dy), erbium (Er) and ytterbium (Yb), where the oxide Manganese (MnO ₂ ) can be added or not added in an appropriate amount.

2. according to the described ultra-high dielectric constant of claim 1, temperature stable multilayer ceramic capacitor material, it is characterized in that: the molar number that the main material _BaTiO occupies is 50-99%; The molar number is 0-49%, which includes 1-3 kinds of silver, palladium, silver-palladium alloy; the amount of secondary additives accounts for 0.5-4mol% of the total material, and its secondary additives include niobium oxide (Nb ₂ O ₅ ), cobalt trioxide (Co ₂ O ₃ ), or tricobalt tetroxide (Co ₃ O ₄ ) and rare earth oxides yttrium oxide (Y ₂ O ₃ ), cerium oxide (CeO ₂ ), praseodymium oxide (Pr ₂ O ₃ ) 1-3 of , neodymium oxide (Nd ₂ O ₃ ), samarium oxide (Sm ₂ O ₃ ), dysprosium oxide (Dy ₂ O ₃ ), and ytterbium oxide (Yb ₂ O ₃ ).

3. a preparation method for preparing the described ultra-high dielectric constant and temperature-stable multilayer ceramic capacitor material of claim 1, is characterized in that: the preparation method of the multilayer ceramic capacitor material is to prepare major ingredient _BaTiO3 , according to formula x([100-(a+b+c)]BaTiO ₃ +a Nb ₂ O ₅ +b Co ₃ O ₄ +c Re ₂ O ₃ +d MnO ₂ )+(1-x)Me It is made by ball milling, drying, molding and sintering after mixing. The preparation process steps are as follows:

1). BaTiO ₃ was synthesized by solid-phase method. The initial raw material TiO ₂ and BaCO ₃ were weighed according to the stoichiometric ratio, mixed with water and ball-milled for 24 hours to achieve a particle size of less than 1 μm, and then at a temperature of 70-120°C, Bake for 6 hours, then synthesize BaTiO ₃ by solid state reaction at 1200°C within 6 hours;

2). Add metal powder and secondary additives according to the formula ratio, and use water as the medium for ball milling for 24-72 hours;

3). Dry for 6 hours at a temperature of 70-120°C;

4). Sintering in the temperature range of 1150-1300°C, sintering for 30-240 minutes, and cooling naturally to obtain a multilayer ceramic capacitor material.

4. a kind of preparation method of ultra-high dielectric constant described in claim 1, temperature-stable multilayer ceramic capacitor material is characterized in that: described barium titanate BaTiO ₃ adopts tetrabutyl titanate (Ti(OC ₄ H ₉ ) ₄ ), barium nitrate (Ba(NO ₃ ) ₂ ), and barium acetate (Ba(CH ₃ COO) ₂ ) are chemically synthesized; solution, so that the concentration of Ti or Ba ions in the solution is between 0.1 and 5M; add precipitant oxalic acid for co-precipitation to form a white precipitate of barium titanyl oxalate, the precipitation reaction temperature is 10-80°C, and the reaction time is 2-4 hours; Wash the precipitate several times with deionized water, then wash it several times with ethanol, dry it at 70-120°C for 10-24 hours; calcinate at 700-1100°C, keep it warm for 0.5-2 hours That is to obtain the superfine powder material BaTiO ₃ ; then mix the secondary additives and metal powder uniformly according to the formula, and ball mill with water for 24-72 hours; after drying at 70-120°C for 10-24 hours, add Compression molding, sintering into a multilayer ceramic capacitor material.

5. a preparation method for preparing the described ultra-high dielectric constant _of claim 1, temperature-stable multilayer ceramic capacitor material, is characterized in that: described BaTiO main material directly mixes with metal powder, secondary additive, with After ball milling with absolute ethanol as the medium for 24-72 hours, drying at 50-70° C. for 10-24 hours, press molding and sintering to form a multilayer ceramic capacitor material.

6. a kind of preparation method of ultra-high dielectric constant described in claim 1, temperature-stable multilayer ceramic capacitor material is characterized in that: described _BaTiO Main material and metal oxide or other easily decomposable metal salts, The secondary additives are mixed evenly, ball milled with absolute ethanol for 24-72 hours, dried at 50-70°C for 10-24 hours, and pre-calcined at 300-500°C to make the powder Metal oxides or metal salts are decomposed into metal powders, which are then press-molded and sintered into multilayer ceramic capacitor materials.

7. according to the preparation method of the described ultra-high dielectric constant of claim 6, temperature-stable multilayer ceramic capacitor material, it is characterized in that: described metal oxide or other easily decomposable metal salts are silver oxide (Ag ₂ O) , silver carbonate (Ag ₂ CO ₃ ), silver nitrate (AgNO ₃ ).