TW408090B - Low-fire dielectric ceramic compositions - Google Patents

Abstract

The present invention relates to a dielectric composition which can be densified at a temperature no higher than 1100 DEG C and can provide ceramic products with a dielectric constant in the range of 1500 to 3000 and a dielectric loss less than 5% at 1MHz. The dielectric composition comprises from 0.1 to 10 wt% BaCu02-Cu0 and from 99.9 to 90 wt% BaTi03. Laminated dielectric ceramic devices can be prepared by mixing the composition of the present invention with organic solvent, polymer binder and plasticizer, forming a green sheet from the mixture by tape casting, screen printing and laminating the green sheets, and then confirming the laminated product with Ag-Pd electrode having low Pd content.

Description

__4P809Q___ V. Description of the Invention (1) [Field of the Invention] The present invention relates to dielectric ceramic materials, and particularly relates to the dielectric materials required for application to laminated dielectric ceramic components. The dielectric Taurman composition of the present invention can be sintered and compacted at low temperature to provide products with high dielectric constant and low dielectric loss. [Background of the Invention] Barium titanate is the most commonly used ceramic material for the manufacture of ceramic capacitors. Because its sintering density is generally not lower than 1 2 50 ° c, it must be used in the production of multilayer components. A g-P d conductor paste, and due to the increase in the price of pd, the cost of manufacturing multilayer ceramic capacitors will increase, and due competitiveness will be lost. Therefore, sintering aids are used to reduce the sintering of barium titanate. Dense temperature, and further reduce the content of pd in Ag_pd conductor paste, one of the directions that must be strived by the manufacturer of the electric valley device. — Sintering aids such as Bi203 which are known in the literature to meet the above requirements,

CdO 'PbO and 103. However, these oxides will reduce the dielectric constant of barium titanate, CdO and PbO are toxic 'b2 03 will be with polyvinyl alcohol in aqueous slurry (Poly (vinyl alc〇h〇i); pVA;) Response, increasing manufacturing complexity. . Therefore, selecting an appropriate sintering aid to reduce the sintering temperature of barium titanate to Υ 1 100 ° C or lower, without the aforementioned environmental protection and process complexity issues, is what the present invention intends to disclose. [Previous skill]

Page 5__408090__ V. Description of the invention (2) The low temperature, high dielectric ceramic material disclosed in US Patent No. 5,262,368 contains BaT i03 'SrT i03' BaZr03 MnS04, W03, Mo〇3 and BaCu02 'This system The sintering temperature is 11000 ° C, and its dielectric coefficient is 800 to 1000 (iKHz) and the dielectric loss is less than 3%. The low-temperature, high-dielectric ceramic materials disclosed in U.S. Patent No. 5,4 6 1,0 1 4 contain PbCMgANb / dOs, PbTi03.PbUni / gNMdOs, "(? 61/01) 1/2) 〇3 and 3 & (: 11〇2``The sintering temperature of this system is 105 ℃, and its dielectric coefficient is 70,000 to 8,000 (ΙΚΗζ) and the dielectric loss is less than 3%. Republic of China Patent Gazette Announcement No. The high dielectrics disclosed in No. 1 5 9 8 3 0. The ceramic materials contain 卩 13 (11 light 〖/ 3 ribs 2/3) 03-? 1) 1 ^ 03-? 13 (2111/3 called / 3 ) 03, the sintering temperature of this system is lower than 1000 1 and has a dielectric coefficient of 8000 to 10000. From the foregoing description, it can be known that the industry still urgently needs dielectric ceramic materials with low sintering temperature, high dielectric constant and low dielectric loss. The present invention is developed for this need. [Summary of the Invention] The present invention provides a novel dielectric composition which can be sintered in liquid phase and sintered at low temperature to provide high dielectric constant and low dielectric loss. Dielectric ceramic material. The ceramic composition of the present invention is compatible with Ag-Pd conductors with a low Pd content due to its low-temperature sinterability, and can be co-fired and laminated with the aforementioned conductors. Process, while providing a laminated ceramic capacitor element required for the market.

408090 V. Description of the invention (3) [Detailed description of the invention] As the industry knows, pure barium titanate is the most commonly used ceramic material for ceramic capacitors made at present, because its sintering compaction temperature is generally not lower than 1 2 50 ° C 'so that when manufacturing multilayer components, you must use the Ag_Pd conductor paste containing high Pd content, and due to the rising Pd price, the cost of manufacturing multilayer ceramic capacitors will increase, and due competition will be lost. Therefore, using sintering aids to reduce the densification temperature of barium titanate and further reduce the Pd content in the Ag-Pd conductor paste will be one of the important issues that manufacturers of multilayer ceramic capacitors must work hard. The inventor of this case found that adding BaCu02-Cu0 ceramic to the BaT i 03 pottery can effectively reduce the sintering temperature to 1100 ° C or lower, and obtain co-firing with Ag-Pd conductive paste with lower Pd content. In order to prepare a multilayer ceramic capacitor element with high dielectric constant and low dielectric loss. In particular, the present invention mainly relates to a novel dielectric composition containing two ceramic components, BaCu02-Cu0 ceramics and BaT i 〇3 ceramics, which are mixed in different ratios. The ratio of the two ceramic components is not particularly limited, but调整 Adjust the nature of the required finished product. Preferably, the dielectric composition of the present invention contains 0.1 to 10% by weight BaCu02-Cu0 ceramics and 99.9 to 90% by weight BaTiOs ceramics, and more preferably 0 1 to 2.5% by weight BaCu02-Cu0 ceramics. And 99.9 to 97.5% by weight BaTi03 ceramics-In the composition of the present invention, the ceramic BaCu〇2_Cu0 system is defined as, low temperature sintering phase. "It is known from the phase diagram that the same proportion of BaCu〇2 and The eutectic temperature of the Cu0 eutectic component is 9 2 6 ° C. The BaCuO2-Cu0 ceramic component of the present invention is preferably 5 *% BaCu02 ί ^ ^-

--_ 40809〇 V. Description of the invention ⑷ '' weight% BaCu02 and 5 0.9 weight% CuO. The dielectric composition of the present invention is mainly applied to a multilayer ceramic capacitor element. -_ In this application, the dielectric composition must be mixed with an organic carrier to form a slurry, and then a green sheet can be obtained through a doctor blade forming process, followed by conventional techniques such as screen printing conductor paste, lamination and co-firing. , To obtain a multilayer ceramic capacitor element. Therefore, the present invention also relates to a paste for preparing a capacitor ceramic element, which contains: 70 to 85% by weight of a dielectric material, which contains 0; 1 to 10% by weight BaCu02-Cu0 ceramic and 99.9 to 90% by weight BaTi03 ceramic; and 30 to 15% by weight organic vehicle. 1 至 2 · 5 重量 ％ In the slurry of the present invention, the preferred dielectric material is from 0.1 to 2.5% by weight.

BaCu02-Cu0 ceramics and 99.9 to 97.5 weight percent BaTi03 ceramics. Among them, the 8-tech (: 11〇2-(^ 0 ceramics preferably contain 45 to 55 wt% 83 (: 110 and 55 to 45 wt% CuO, especially 49.1 wt% BaCu〇2). And 50, 9% by weight of CuO. The organic carrier is preferably a binder such as polyethylene glycol (pEG), polyvinyl butyral (PVB), and polyvinyl alcohol (PVA), such as n-propanol, toluene, and ethanol. Organic solvents, and plasticizers such as dibutyl phthalate (DBP). The present invention also relates to a method for preparing a dielectric ceramic element, which includes: making a slurry of the present invention into a green embryo; and the green embryo Densification is performed at a temperature not higher than 1 100 ° C. Among them, the sintering step includes two stages of degreasing and sintering, and is preferably performed in air or nitrogen / hydrogen atmosphere. As known to those skilled in the art, The degreasing stage is to remove organic binders from the raw embryo.

Page 8

--- 40 & 49Q V. Description of the invention (5) The sintering stage can make the embryo compact. In the method of the present invention, the sintering is preferably performed at a temperature of 900 to 11000 ° C for 30 to 120 minutes, and more preferably &. 1 0 0 to 1 1 0 0 ° C for 3 0 to 1 2 0 minutes. The obtained dielectric ceramic surname, 1 square meter 1 MHz has a dielectric coefficient of 1500 to 300 0 and a dielectric loss of 5%, which is a combination of the industry's dielectric constant and low dielectric loss. Regarding a method for preparing a laminated dielectric ceramic element, an aromatic method includes printing an Ag-Pd conductor electrode with a low Pd content on a ceramic green sheet, which is laminated to form a laminated ceramic green embryo, and densifying the laminated green embryo, It is characterized in that the ceramic material used to prepare the ceramic green sheet contains the following components, electrical composition: " 0.1 to 10% by weight BaCu02-Cu0 ceramic; and 99.9 to 90% by weight BaTi03 ceramics. The dielectric composition preferably contains 0.1 to 2.5% by weight BaCu02-Cu0 ceramics and 99.9 to 97.5% by weight BaTi03 ceramics. Among them, BaCu02-Cu0 ceramics preferably contain 45 to 55 wt% 仏 (: 11〇2 and 55 to 45% by weight (: 11〇 ', especially 49.1 wt% BaCu02 and 50.9 wt% CuO) The following examples are provided to further illustrate the present invention, but not to limit the scope of the present invention. Any substitutions and modifications known to those skilled in the art are still covered within the spirit and scope of the present invention. [Example 1] In this embodiment, BaCu02 + Cu0 is first prepared: at a ratio of 83: 1111 = 28:72 mole, BaCOs and CuO each having a purity of more than 99.5% are measured in 42.2 and 45,8 grams, and these ceramics are Powder added

V. Description of the invention (6) ^ 〇8〇9 (7) In a one-liter PE plastic jar containing 2000 g of Zr〇2 grinding balls' and 220 ml of isopropyl alcohol (2-propyl a 1 coho 1), ball milling for 24 hours After the same sieving, drying, and grinding steps as the ZST ball, it is calcined at 85 ° for 2 hours. The calcined powder is ground with a mortar and pestle, and then the same ball milling conditions are used for ball milling for 4 8 hours. The powder obtained after the same sieving, drying, and grinding under the conditions of grinding spider and pestle is BaCu02 + Cu0 compound ceramic powder, hereinafter referred to as BCC. In addition, BaCu02 powder is also prepared by the same process, hereinafter referred to as BC. In addition, 'BaTi03 uses commercially available powder (TICON-HPB) from TAM Ceramic Corp. (USA). Measure 20 grams of pure BaT i 03 ceramic powder and add 25cc of l-propyl alcohol. And 5wt% polyethylene glycol 200 ('PEG 200)' and 46 g of alumina grinding balls 'mixed with a three-dimensional space cantilever mixer for 2 hours' and dried at 80 ° C for 1 hour. Grinding with a pestle. Unless otherwise specified, the test pieces are measuring powder 1. 3g, 1.3 cm in diameter The circular stamper is maintained at a pressure of 9 MPa for 15 seconds, and the powder is compressed into green embryos. The prepared green embryos are sintered at 950-1100 X: 120 minutes. The sintering process is mainly divided into two stages. The first stage is degreasing. Under the heating speed of 5 C / mi η, the organic binders in the raw embryos are slowly removed. In order to completely remove the embryos, the temperature is 500 t: stay for one hour. In the second stage, it will be in an atmospheric atmosphere. The test piece is directly pushed into the furnace. After the test piece reaches the sintering temperature within 5 minutes, the sintering temperatures are 950 (1 A), 1,000 (1 B), 1 050 (1 C), and iiOO ° C (id ), Stay for another 60 minutes, clamp out the test piece, and air-cool to stop sintering. Use Archimedes' principle to measure the density of the sintered body.

Page 10 ————- i〇.8Q9jQ _____ 5. Description of the Invention (7)-The results obtained in this example are listed in Table 1. The sintered densities are all lower than 5.0, gm / cm. Scanning electron micrographs show that the micro-structure is porous, and the relative sintering densities are less than 80%. ‘[Embodiment 2] In addition to the dielectric component of this embodiment, 2.5 wt% BC and 97. 5 wt%

The remaining processes and measurement procedures outside BaT i tv are the same as those in the first embodiment. The prepared raw embryos were still divided into four groups, which were sintered at 95 (2A), 100 (2B), 1050 (2C), and 100 ° C (2D) for 60 minutes. The sintered densities are listed in Table 1. The sintered densities are all lower than 5.0 gm / cm3. Scanning electron micrographs of the fractured surface of the sintered body show that the microstructure is porous, and the relative sintered densities are both low. In 9 (3%. &Amp; [Example 3] In this example, except that the dielectric component is changed to 5wt% BC and 95wt%

The remaining processes and measurement procedures of BaT i 03 are the same as those of the first embodiment. The prepared raw embryos were still divided into four groups, which were sintered at 95 ° (3A), 1000 (3B), 105 (3C) '110 ° C (3D) for 60 minutes. The sintered density and dielectric results are listed in Table 1. 'The sintered densities are higher than 5.0 gm / cm3. The scanning electron micrographs of the fracture surface of the sintered body show that the microstructure is very dense. The sintered density is higher than 95%. The obtained dielectric ceramic element has a dielectric constant of 1100 to 1300 and a dielectric loss of 5-10%. [Example 4]

Page 11 --40809η_ V. Description of the invention (8) Except that the dielectric composition is changed to 10wt% BC and 90wt% BaTi03, the remaining processes and measurement procedures are the same as those in the first embodiment. The prepared raw embryos are still divided into four groups, sintered at 950 (4A), 1000 (4B), 1050 (40, 110 ° C (4D) for 60 minutes. The sintering density and dielectric The results are listed in Table 1. 'The sintered densities are all higher than 5.0 gm / cm3. From the scanning cat electron micrograph of the fracture surface of the sintered body, it is known that the microstructure is very dense and the relative sintered densities are higher than 95%. 5wt% BCC 与 97. 5wt% B a T The dielectric ceramic element has a dielectric coefficient of 600 to 1000 and a dielectric loss of 15-25% at 1 mHz. Except for 〇3, the rest of the manufacturing process and measurement procedures are the same as in Example 1. The prepared raw embryos are still divided into four groups, respectively at 95 0 (5A), 1000 (5B), 1050 (5C), 1100 C (5D) is sintered for 60 minutes. The sintered density and dielectric results are shown in Table 1. The sintered density is higher than 5.0 ° C and higher than 5.0 ° gm / cm3. The electron micrograph shows that the microstructure is very dense, and the relative sintering density is higher than 95%. The obtained dielectric ceramic element has a dielectric coefficient of 1 800 to 230 0 at 1 MHz and a dielectric constant of 2.5 to 3.0%. Electricity loss. [Example 6] In this example, except that the dielectric composition was changed to 5wt% BCC and 95wt% BaTi03, the remaining processes and measurement procedures were the same as in Example 1. The prepared raw embryos were still divided into four groups, each at 950 ( 6A), 1000 (6B), 105 (6C),

Page 12 V. Description of the invention (9) 408090 11 0 0 ° C (6 D) Sintering for 160 minutes. The sintered density and dielectric results are listed in Table 1. The sintered density is 1000 t: the above are all higher than 5.0 gm / cm3. The scanning electron micrographs of the fracture surface of the sintered body show that The microstructures are very dense 'and their relative sintered densities are higher than 95%. The obtained dielectric ceramic element has a dielectric constant of 1100 to 1600 and a dielectric loss of 9, 5-13.0% at 1 MHz. [Embodiment 7] In this embodiment, except that the dielectric composition is changed to 〇wt% BCC and 90wt%

The remaining processes and measurement procedures of BaT i 03 are the same as those of the first embodiment. The prepared raw embryos were still divided into four groups, sintered at 95 (7A), 1000 (7B), 1050 (7C) 'and 1100 C (7D) for 60 minutes. The sintered densities and dielectric results are listed in Table 1. Scanning electron micrographs of sintered densities above 95 ° and higher than 50 ° fracture surfaces revealed that their microstructures were non-suspended and the relative sintered densities were uniform. Above 95%. , The device has a dielectric constant of 75 0 to 1 2 00 and a dielectric loss of 4 0_0% in winter.

Page 13 inch (mtrao V. Description of the invention (10) Table test results Η Example sintered density (gm / cm7) Pak pair density (%) Sintered time (min) Dielectric coefficient (@ 1ΜΗζ) Dielectric loss (% ) (@ 1MH2) 丄 A 3.125 53.8 60--1B 3.522 60.7 60--1C 4.125 71.1 60--ID 4.485 77.3 60--2A 4.264 73.5 60--ΞΒ 4.726 81.5 60--2C 4.989 86.0 60--2D 4.916 84.7 60--3Α 5.252 90.5 60 1135 8.64 3B 5.418 93.4 60 1089 7.68 3C 5.627 97.0 60 1252 10.20 3D 5.679 97.9 60 1172 7.51 4A 5.615 96.8 60 997 16.8 4B 5.737 98.9 60 797 23.3 4C 5.792 99.8 60 709 25.3 4D 5.681 97.9 60 692 23.9 5A 3.824 65.9 60--5B 4.861 83.8 60-5C 5.776 99.5 60 2284 2.62 5D 5.756 99.2 60 1829 2.87 6A 4.684 80.7 60--6B 5.206 89.7 60--6C 5.394 93.0 60 1187 9.60 6D 5.535 95.4 60 1535 12.90 7A 5.396 93.0 60 759 8.02 7B 5.787 99.8 60 936 35.52 7C 5.745 99.1 60 丄 C62 32.85 7D 5.757 99.3 60 1153 33.15

Page 14--408000 --- 5. Description of the invention (11) In the above-mentioned embodiments (examples 1 to 7), only the fifth embodiment containing a dielectric component containing 2.5% BCC can be at low temperature (1050 ° C) Densification of more than 95% is completed, and at the same time, high dielectric constant (~ 2000) and low dielectric loss (<3%) can be achieved. Since the sintering temperature required to complete high densification is compatible with Ag-Pd conductors with low Pd content, it can be co-fired to manufacture multilayer ceramic capacitors. The sintering temperature required for the dielectric components in the fifth embodiment described above Ag-Pd conductors with low Pd content are compatible, so they can be co-fired to make multilayer ceramic capacitors. In the manufacturing process, the above-mentioned ceramic components must first be mixed with organic solvents such as toluene and ethanol, organic binders such as polyvinyl butyral (PVB) and plasticizers such as dibutyl sulfate (D BP) to form a slurry. The blade was formed into a green embryo sheet with a thickness of about 125 micrometers, and then punched into a 10 cm square green embryo sheet. A conductor paste such as Ag-Pd is made into an electrode on a green sheet by screen printing. The green-printed green embryo flakes are then stacked in order, and laminated ceramics are laminated to produce green-laminated ceramics. The conditions for lamination are 60-100. 〇With looo—300 0 psi. Finally, the laminated dielectric ceramic green body is densified and co-fired to complete densification in the air atmosphere. The dielectric components in the examples can also be made into various shapes and shapes through traditional processes such as dry pressing, cold equalizing, and hot equalizing. Ceramic bodies for different uses. Taking dry pressing as an example, 'ceramic powder can be mixed with water and a binder such as polyvinyl alcohol (pVA). After spray granulation, the powder's fluidity can be improved. Then dry pressing, degreasing and' '' sintering can be made Finished dielectric ceramic. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and decorations without departing from the spirit and scope of the present invention. Invention protection

&quot; ttWW V. Invention Description C12) Scope shall be determined by the scope of the attached patent application ΙΒΙΪ page 16

Claims (1)

Sixth, the scope of patent application «08090 1. A dielectric composition containing: ° 0.1 to 10 wt% 368 (: 110-(: 110) ceramic, the ceramic contains 45 to 55 weight:.% BaCu02 And 55 to 45% by weight of CuO; and 99.9 to 90% by weight of BaTi03 ceramics. 2. The dielectric composition as described in claim 1 of the patent application scope, which comprises:-0.1 to 2.5% by weight BaCu02-Cu0 ceramics; and 99.9 to 97.5% by weight BaTi03 ceramics. 3. The dielectric composition according to item 1 of the scope of patent application, wherein the BaCu02-CuO ceramic system contains 49.1% by weight BaCu02 and 50. 9 wt% CuO. 4. A paste for preparing a dielectric ceramic element, comprising: 70 to 85% by weight of the dielectric composition according to item 1 of the scope of patent application; and 30 to 15 % Organic carrier by weight. 5. The slurry as described in item 4 of the scope of patent application, wherein the organic carrier contains organic solvents, organic binders and organic plasticizers. 6. A method for preparing a dielectric ceramic element, Its burden will be to make green embryos according to the slurry described in item 4 of the patent application; and The raw embryo is densified at a temperature of ° C. 7. The method as described in item 6 of the patent application park, wherein the densification step includes two stages of degreasing and sintering. 8. As described in item 7 of the scope of the patent application Method, wherein the sintering stage is performed at a temperature of 900 to 1100 ° C for 15 to 150 minutes minus ° 9. The method according to item 6 of the patent application park, wherein the densification Page 17 The scope of patent application 408090 VI is in the air or nitrogen / hydrogen hydrogen atmosphere. ίο. — A method for preparing a laminated dielectric ceramic element, which comprises printing an Ag-Pd conductor electrode with a low Pd content on a ceramic 1 ceramic green sheet, laminating it to produce a laminated ceramic green embryo, and densifying the laminated green embryo, It is characterized in that the ceramic material used to prepare the ceramic green sheet is a dielectric composition containing the following components: 0.1 to 10% by weight BaCu02-Cu0 ceramic, which contains 45 to 55 weight? BaCu02 with 55 to 45% by weight CuO; and 99.9 to 90% by weight BaTi03 ceramics. 11. The method of claim 10, wherein the dielectric composition comprises 0.1 to 2.5% by weight BaCu02-Cu0 ceramics; and 99.9 to 97.5% by weight BaTi03 ceramics. 1 2. The method according to the scope of application for patent, wherein the ceramic of the dielectric composition contains 49.1% by weight BaCu02 and 50.9% by weight t% CuO. Page 18