GB2026466A - Ceramic capacitor composition - Google Patents
Ceramic capacitor composition Download PDFInfo
- Publication number
- GB2026466A GB2026466A GB7919035A GB7919035A GB2026466A GB 2026466 A GB2026466 A GB 2026466A GB 7919035 A GB7919035 A GB 7919035A GB 7919035 A GB7919035 A GB 7919035A GB 2026466 A GB2026466 A GB 2026466A
- Authority
- GB
- United Kingdom
- Prior art keywords
- mol
- ceramic
- samples
- temperature
- parts
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003985 ceramic capacitor Substances 0.000 title claims abstract description 20
- 239000000203 mixture Substances 0.000 title claims abstract description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 24
- WMWLMWRWZQELOS-UHFFFAOYSA-N bismuth(iii) oxide Chemical compound O=[Bi]O[Bi]=O WMWLMWRWZQELOS-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052681 coesite Inorganic materials 0.000 claims abstract description 12
- 229910052906 cristobalite Inorganic materials 0.000 claims abstract description 12
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 12
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 12
- 229910052682 stishovite Inorganic materials 0.000 claims abstract description 12
- 229910052905 tridymite Inorganic materials 0.000 claims abstract description 12
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000000919 ceramic Substances 0.000 claims description 34
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 18
- BERDEBHAJNAUOM-UHFFFAOYSA-N copper(I) oxide Inorganic materials [Cu]O[Cu] BERDEBHAJNAUOM-UHFFFAOYSA-N 0.000 claims description 12
- KRFJLUBVMFXRPN-UHFFFAOYSA-N cuprous oxide Chemical compound [O-2].[Cu+].[Cu+] KRFJLUBVMFXRPN-UHFFFAOYSA-N 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 10
- 238000005245 sintering Methods 0.000 claims description 9
- 238000009413 insulation Methods 0.000 claims description 8
- 230000000694 effects Effects 0.000 claims description 5
- 230000002829 reductive effect Effects 0.000 claims description 4
- 239000011248 coating agent Substances 0.000 claims 2
- 238000000576 coating method Methods 0.000 claims 2
- 238000010438 heat treatment Methods 0.000 claims 2
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Chemical compound O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 abstract description 8
- 239000000523 sample Substances 0.000 description 17
- 239000003990 capacitor Substances 0.000 description 15
- 238000007669 thermal treatment Methods 0.000 description 6
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- 239000000654 additive Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910002370 SrTiO3 Inorganic materials 0.000 description 3
- 229910002113 barium titanate Inorganic materials 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 235000010216 calcium carbonate Nutrition 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910000018 strontium carbonate Inorganic materials 0.000 description 2
- LEDMRZGFZIAGGB-UHFFFAOYSA-L strontium carbonate Chemical compound [Sr+2].[O-]C([O-])=O LEDMRZGFZIAGGB-UHFFFAOYSA-L 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910004481 Ta2O3 Inorganic materials 0.000 description 1
- -1 Tea205 Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000005324 grain boundary diffusion Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000003534 oscillatory effect Effects 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 238000009966 trimming Methods 0.000 description 1
- 210000000707 wrist Anatomy 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/018—Dielectrics
- H01G4/06—Solid dielectrics
- H01G4/08—Inorganic dielectrics
- H01G4/12—Ceramic dielectrics
- H01G4/1272—Semiconductive ceramic capacitors
- H01G4/1281—Semiconductive ceramic capacitors with grain boundary layer
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
- C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
- C04B35/465—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates
- C04B35/47—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on strontium titanates
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Ceramic Capacitors (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Inorganic Insulating Materials (AREA)
Abstract
A semiconductive ceramic capacitor composition has a main component consisting of 14-21 mol% CaO, 29-36 mol% of SrO and 49.5-51 mol% of Ti2O2 which contains 0.05-1 mol part of at least one of Ta2O5 and Nb2O5, 0.5-6 parts of SiO2 and 0.5-6 parts of Bi2O3 per 100 mol parts of the main component.
Description
SPECIFICATION
Ceramic capacitor composition
The present invention relates to a semiconductive ceramic capacitor and the method for making the same.
More particularly, the present invention relates to CaTiO3rTiO3 type semiconductive ceramic capacitor which has high dielectric constant, very small rate of change in the dielectric constant with temperature, as well as low dielectric loss (tans) at 10 KHz and at 100 KHz, and the method for making the same.
Hitherto, a trimmer ceramic capacitor has been used in the oscillatory circuit of quarz type wrist watch for adjusting a delay or advance of time by controlling the capacitance of the trimmer capacitor. In accordance with the recent tendencies in miniaturization of watches, the trimmer capacitors used therein are also required to be miniaturized. For this reason, advent of semiconductive ceramic capacitor materials having high dielectric constant are expected. However, the dielectric constant of conventional ceramic capacitor materials are only in the range of about 100 to 300. In this respect, it has been known that the dielectric constant of BaTiO3 is relatively higher and is about 2,000.However, such BaTiO3-type ceramic is not suitable for use in afore-said purpose, since BaTiO3-type ceramic has temperature-dependent hysteresis of capacitance and has high dielectric loss (tan 5) for the reason that it is a ferroelectrics.
Among semiconductive ceramic capacitors in the prior art, hitherto have been known, include capacitors made of BaTiO3 or SrTiO3 as the main component, and the apparent dielectric constants of these capacitors are in the order of about several ten thousands.
Such an extent of the apparent dielectric constant of these capacitors is too large value for the use in trimmer capacitors. Hence, said semiconductive ceramic capacitors could not have been used for trimmer capacitors, since they have difficulties in controlling the capacitance because relatively large change in capacitance per rotation angle of rotor in the trimming operation. The rate of change of capacitance with temperature of BaTiO3 semiconductive capacitor is +15 to 40% and that of SrTiO3 semiconductive capacitor is i1 O to 15% as compared with their respective capacitances at 20"C as the standard, and these values are considered to be too large.
The object of the present invention is to provide semiconductive ceramic capacitor which satisfies the three requirements necessary for a trimmer capacitor, which are (1) the dielectric constant should be within the range from 1,000 to 3,500, (2) the dielectric losses (tan 5) at 10 KHz and at 100 KHz should be lower than 1%, respectively, and, (3) the rate of change of capacitance with temperature should be within +8%.
Another object of the present invention is to provide method for making said semiconductive ceramic capacitor.
A semiconductive ceramic capacitor of the present invention is consist of a solid solution of CaTiO3-SrTiO3 as the main component, in addition thereto Nb205 or Ta205 is added as a source of the element which effects the ceramic to change into a semiconductor, furthermore SiO2 and Bi203 are added as additives. In making the semiconductive ceramic capacitor, each of these starting materials are mixed together, and the mixture is calcined and shaped into the predetermined form. Then the shaped article is sintered in N2-gas or in a mixture of N2-H2 gas4s to obtain a semiconductive ceramic. Next, Cu2O or B203 is coated on the surface of the semiconductive ceramic, and is subjected to a thermal treatment to effect that the only grain boundaries therein are changed to an insulator.Thus, according to the present invention, a powdery mixture being prepared as the starting material for a semiconductive ceramic capacitor containing 100 mol parts of the main component consisting of 14 to 21 mol % of CaO, 29 to 36 mol % of SrO and 49.5 to 51 mol % ofTiO2; 0.5 to 1.0 mol part of one or more of Ti205 and Nub205; 0.5 to 6.0 mol parts of SiO2 and 0.5 to 6.0 mol parts of Bi203 is calcined at 900" to 1200 C, then the calcined article is pulverized and shaped, then is sintered at a temperature of 12700 to 138000 in a neutral or reductive atmosphere.The thus obtained ceramic is provided with 0.1 to 2.5 mg of Cu2O per 1 gram of the ceramic and is subjected to thermal treatment at a temperature of 1,000 to 1,200"C or with 0.3 to 6.0 mg of B203 per 1 gram of the ceramic and is subjected to thermal treatment at a temperature of 950" to 1,2000C. Then the ceramic is provided with two electrodes on the both side of the surface thereof to complete the semiconductive ceramic capacitor of the present invention. The reasons for the restriction of the composition of the respective starting materials and for the restriction of the method of making the ceramic will be explained in detail by way of showing the following examples.
Example 1.
Technical grades of SrCO3, CaCO3, TiO2, Nb205, Tea205, SiO2 and Bi203 are mixed together in the ratio shown in Table 1.
Table 1
Additional components
Sample Main components (mol parts) per 100
No. (mol %) parts of the main
components
SrCO3 CaCO3 TiO2 Nb203 Ta2O3 SiO2 Bi203 1* 37 13 50 0.4 0 0 0 2* 36 14 50 0.4 0 0 0 3* 34 16 50 0.4 0 0 0 4* 32 18 50 0.4 0 0 0 5* 30 20 50 0.4 0 0 0 6* 29 21 50 0.4 0 0 0 7* 28 22 50 0.4 0 0 0 8* 32 18 50 0.4 0 1 0 t9* 32 18 50 0.4 0 3 0 10* 32 18 50 0.4 0 0 1 11* 32 18 50 0.4 0 0 3 12* 36 14 50 0.4 0 1 0 13* 36 14 50 0.4 0 0 1 14* 29 21 50 0.4 0 1 0 15* 29 21 50 0.4 0 0 1 16* 32 18 50 0.4 0 0.1 0.1 17 32 18 50 0.4 0 0.5 0.5 18 32 18 50 0.4 0 1 1 19 32 18 50 0.4 0 3 1 20 32 18 50 0.4 0 6 1 21* 32 18 50 0.4 0 8 1 22 32 18 50 0.4 0 3 3 23 32 18 50 0.4 0 1 3 24 32 18 50 0.4 0 6 6 25* 32 18 50 0.4 0 1 8 26 32 18 50 0.4 0.4 1 1 27* 37 13 50 0.4 0 1 1 28 36 14 50 0.4 0 1 1 29 29 21 50 0.4 0 1 1 30* 28 22 50 0.4 0 1 1 31* 32 18 49 0.4 0 1 1 32 32 18 49.5 0.4 0 1 1 33 32 18 50.5 0.4 0 1 1 34 32 18 51 0.4 0 1 1 35* 32 18 52 0.4 0 1 1 36* 32 18 50.5 0.01 0 1 1 37 32 18 50.5 0.05 0 1 1 38 32 18 50.5 0.1 0 1 1 39 32 18 50.5 0.6 0 1 1 40 32 18 50.5 1.0 0 1 1 41* 32 18 50.5 1.2 0 1 1 42 32 18 50.5 0 0.1 1 1 43 32 18 50.5 0 0.6 1 1
[* Referential examples]
Each of the samples is respectively wet-mixed, then is provisionally shaped by pressing under a pressure of 300 kg/cm2, calcined at 1,1 000C for 2 hours, pulverized in wet condition and shaped into a plate having 12 mm in iameterwith 0.6 mm in thickness by pressing a pressure of 1,000 kg/cm2.Each of the shaped articles is then sintered at 1,320"C for 4 hours in a mixed gas of 90% N2-1 0% H2 to obtain a ceramic. The surface of the ceramic is coated with 1.5 mg of Cu2O per 1 g of the ceramic, and is subjected to a thermal treatment at 1,080 C for 2 hours. Then both side of the surfaces of the ceramic body is coated with silver paste and glazed at 800 C for 15 min. The apparent dielectric constant, dielectric loss (tan b) and the rate of change of capacitance with temperature of the respective ceramic capacitors are shown in Table 2.
Table 2
Apparent Rate of change of
Sample dielectric Dielectric loss capacitance with
No. constant [tan 8j (%) temperature (%)
10 KHz 100 KHz -25 ~ 20 C 20"-85"C 1* 2500 0.40 1.03 8.3 -7.9 2* 2300 0.42 1.15 6.0 -5.7 3* 2100 0.47 1.19 4.1 -4.0 4* 2100 0.50 1.24 2.5 -2.3 5* 2000 0.56 1.29 3.9 -3.5 6* 1900 0.63 1.37 5.0 -4.6 7* 1900 0.88 1.54 7.2 -6.8 8* 1800 0.52 1.02 2.6 -2.5 9* 1500 0.62 1.10 2.6 -2.4 10* 2000 0.47 1.20 2.7 -2.5 11* 1900 0.50 1.18 2.5 -2.4 12* 2100 0.45 1.15 6.1 -5.8 13* 2200 0.43 1.15 6.0 -5.5 14* 1700 0.60 1.35 5.1 -4.8 15* 1700 0.55 1.30 5.2 -5.0 16* 2100 0.50 1.06 2.5 -2.4 17 2000 0.40 0.65 2.6 -2.5 18 1700 0.25 0.30 2.5 -2.5 19 1450 0.28 0.33 2.4 -2.6 20 1200 0.45 0.70 2.6 -2.6 21* 900 1.20 1.8 2.5 -2.8 22 1400 0.30 0.45 2.7 -2.6 23 1250 0.28 0.58 2.5 -2.9 24 1100 0.55 0.77 2.3 -2.5 25* 1250 0.47 0.86 2.9 -2.7 26 1750 0.30 0.33 2.7 -2.9 27* 2300 0.22 0.29 8.5 -8.2 28 2200 0.25 0.27 6.1 -6.3 29 1750 0.39 0.80 5.2 -4.8 30* 1800 0.44 0.88 7.2 -7.1 31* 1750 0.93 1.20 -2.7 -2.8 32 2200 0.54 0.85 -2.7 -2.7 33 2600 0.25 0.33 -2.6 -2.5 34 2500 0.62 0.95 -2.5 -2.5 35* 2000 1.25 1.87 -2.5 -2.4 36* 1900 2.5 4.9 -2.4 -2.2 37 1800 0.59 0.92 -2.5 -2.4 38 1700 0.46 0.73 -2.5 -2.4 39 1900 0.60 0.86 -2.4 -2.3 40 1600 0.67 0.90 -2.4 -2.3 41* 1000 1.22 2.58 -2.6 -2.7 42 1600 0.48 0.79 -2.7 -2.6 43 1800 0.65 0.91 -2.9 -2.7
[* Referential examples]
Samples Nos. 1 to 7 show the properties of the ceramics in which the content of Nb205 as a semiconductive element is kept as 0.4 mol parts and varies the ratio of Sr/Ca.The dielectric loss (tan b) at 100
KHz of these samples are all greater than 1% and therefore they cannot be used as trimmer capacitors. The apparent capacitance of these samples are all within the range of 1,000 to 3,500. The rate of capacitance change with temperature of these samples except sample No. 1 are all lower than 8%. The capacitancetemperature characteristics of the respective samples varies depend on the ratio of Sr/Ca.
Samples Nos. 8 to 15 show the properties of the ceramics having the rate of change of capacitance with temperature are within +8%, of which the ratio of Sr/Ca are within the range of Sr/Ca = 36/14 to 29/21, and
SiO2 or Bi203 is added thereto.
Even if the type and the amounts of said additives are varied, the most of the properties of these samples in case of the presence of these additives are not affected as compared with the cases of the absence of the additives.
Samples Nos. 16 to 30 show the properties of the ceramics when both of SiO2 and Bi203 are added. Thus, when SiO2 and Bi203 are respectively added to the ceramics within the range of 0.5 to 6 mol parts, the dielectric loss (tan 6) are improved greatly that is tan 6 at 10 KHz and 100 KHz decreased to less than 1%. The temperature-capacitance characteristics of the samples are all most not changed as compared with those of samples without added the above-mentioned additional components. The apparent dielectric constants of these samples are shown to be slightly small, however these samples will no problem to be used as trimmer capacitor.
Samples Nos. 31 to 35 show the relationship between the excessiveness of TiO2 and the various properties. Sample No.31 contains 1 mol % lesser amount of TiO2 and Sample No.35 contains 2 mol % excessive amount of TiO2, and the dielectric loss (tan b) of these samples exceed over 1%. Therefore the respective samples containing 0.5 mol % lesser amount of TiO2 to 1 mole % excessive amount of TiO2 can satisfy all the properties required for the capacitor.
Samples Nos. 36 to 43 show the relationship between the added amount of Nb205 or Ta205 as the element effective to change the ceramic to semiconductor and the various properties. The effect of Nb205 is almost equivalent to that of Ta205. The amount of Nb205 or Ta205 to be added may be of within the range of 0.5 to 1.0 mol part, and if the amount exceeds this range, the dielectric loss (tan b) will be increased over 1%.
Example 2
The relationship between the sintering temperatures and various properties is investigated with respect to ceramic samples which were prepared to have the same composition as in Samples Nos. 18,24,28 and 29 in
Example 1 (hereinafter referred to as Composition Nos. 18, 24,28 and 29). The sintering temperature are shown in Table 3 and the each samples were sintered at respective temperatures for 4 hours. The conditions for making the samples are the same as disclosed in Example 1. Samples Nos. 101 to 116 were sintered in an atmosphere of 90% N2-10% H2 and Samples No. 117 to 120 were sintered in an atmosphere of N2.
Table 3
Rate of chang of
Sintering Apparent tan # (%) capacitance With
Composi- Sample temperature dielectric temperature (%) tion No. constant
No. ( C) 10 KHz 100 KHz -25 ~ 20 C 20 ~ 85 C 18 101 1250 400 1.55 3.78 2.9 -2.7 18 102 1270 1100 0.30 0.35 2.5 -2.3 18 103 1380 2500 0.41 0.62 2.4 -2.3 18 104 1400 2700 0.95 1.43 2.4 -2.4 24 105 1250 450 1.03 1.96 2.6 -2.5 24 106 1270 700 0.34 0.42 2.5 -2.5 24 107 1360 1350 0.50 0.73 2.4 -2.2 24 108 1380 - - - 28 109 1250 500 1.27 2.13 6.5 -6.2 28 110 1270 1400 0.48 0.65 6.4 -6.1 28 111 1380 3200 0.59 0.83 6.2 -6.1 28 112 1400 3500 1.41 2.32 6.3 -6.2 29 113 1250 350 1.10 1.75 5.5 -5.2 29 114 1270 1000 0.55 0.79 5.3 435.1 29 115 1380 2500 0.71 0.96 5.2 -4.9 29 116 1400 2800 0.94 1.12 5.2 -4.9 18 117 * 1270 350 2.1 4.3 2.8 -2.8 18 118 * 1290 1000 0.62 0.89 2.4 -2.3 18 119 * 1380 1900 0.51 0.75 2.4 -2.3 18 120 * 1400 2000 0.99 1.38 2.7 -2.5 Ceramics of sample No. 108 were fused to each other in the sintering step and the properties thereof could not be examined.
Compositions in which respectively 1 mol part of SiO2 and Bi203 are added thereto and sintered at 1,270 to 1,380"C in a reductive atmosphere show predetermined properties. Other compositions in which SiO2 and Bi203 were added in excess amount such as 6 mol parts, which show the upper limit of sintering temperature is slightly lower and those of sintered at 1,270 to 1,360"C show good properties. Those samples of sintered at lower than 1,250"C are considered that they are sintered incompletely and result insufficient solid-solidification of the semiconductive elements and is reoxidized in the step of grain-boundary diffusion of Cu2O.
Alternatively, samples sintered at a temperature over 1,400"C, a ceramic thus obtained is considered as over-sintered, and a ceramic having a dense structure cannot be obtained, the dielectric loss (tans) value thereof is increased.
Sintering in an atmosphere of N2 gas increase the sintering temperature as compared with the case of using a reductive atmosphere and obtain ceramics having slightly lower quality, however such ceramics satisfy the properties for use in trimmer capacitors.
Example 3
Materials for making ceramics having the same compositions respectively in Samples No. 18, 24, 28 and 29 as disclosed in Example 1 were prepared. Cu2O is coated in the amount as shown in Table 4 respectively and the samples were thermally treated at 1,080 C for 2 hours.
Samples Nos. 221 to 225 having the same composition as sample No. 18 as shown in Example 1, were respectively coated with B203 in varying the amount and were subjected to thermal treatment. The results are shown in Table 4.
Every samples show good properties with respect to the dielectric constant and to the capacitance temperature relationship. Samples coated with 0.1 to 2.5 mg of Cu2O per 1 g of sample and with 0.3 to 6 mg of B205 per 1 g of sample show less than 1% of tan 5.
Table 4
Amount of Rate of chang of
Composi- Sample Cu2O coated Apparent capacitance With tion No. (mg/lg of dielectric tan # (%) temporature (%)
No. sample) constant 10 KHz 100 KHz -25 ~ 20 C 20 ~ 85 C 18 201 0.05 1500 0.73 1.16 2.7 -2.6 18 202 0.1 1750 0.32 0.49 2.5 -2.5 18 203 1.5 1700 0.25 0.30 2.5 -2.5 18 204 2.5 1650 0.40 0.67 2.4 -2.3 18 205 5 1700 0.88 1.42 2.1 -2.0 24 206 0.05 1050 0.85 1.33 2.9 -2.7 24 207 0.1 1250 0.41 0.57 2.6 -2.5 24 208 1.5 1100 0.55 0.77 2.3 -2.5 24 209 2.5 1000 0.62 0.83 2.3 -2.2 24 210 5 1200 1.05 1.72 2.0 -1.9 28 211 0.05 2000 0.70 1.05 6.5 -6.2 28 212 0.1 2400 0.31 0.45 6.2 -6.0 28 213 1.5 2200 0.25 0.27 6.1 -6.3 28 214 2.5 1900 0.37 0.65 6.0 -6.0 28 215 5 2300 0.30 1.22 5.9 -5.6 29 216 0.05 1700 0.86 1.35 5.6 -5.3 29 217 0.1 1850 0.48 0.61 5.3 -5.1 29 218 1.5 1750 0.39 0.80 5.2 -4.8 29 219 2.5 1600 0.53 0.89 5.2 -4.8 29 220 5 1750 1.07 1.69 5.0 -4.5 18 221 0.1 1500 0.89 1.34 2.7 -2.5 18 222 0.3 1600 0.42 0.57 2.6 -2.5 18 223 2 1550 0.30 0.46 -2.6 -2.5 18 224 6 1300 0.52 0.85 -2.9 -2.6 18 225 10 1200 1.55 2.18 -2.9 -2.7 [Samples Nos. 221 to 225 were coated with Bi2O3] Example 4
Shaped ceramics having the same composition as in Sample No. 18 in Example 1 were sintered at 1,320 C for 4 hours in an atmosphere of 90 % N2-10% H2. Then 1.5 mg of Cu2O per 1 g of the sample or 2 mg of B203 per 1 g of the sample was coated on the respective samples and the coated samples were subjected to thermal treatment at various temperatures as shown in Table 5 for 2 hours. The results are shown in Table 5.
Samples Nos. 301 to 307 were coated with Cu2O and Samples Nos. 308 to 318 were coated with B203 respectively.
Table 5
Temperature Apparent Rate of change of
Sample of thermal dielectric tan # (%) capacitance With
No. treatment constant temperature (%) ( C) 10 KHz 100 KHz -25 ~ 20 C 20 ~ 85 C 301 950 3750 2.55 3.76 2.4 -2.4 302 1000 2100 0.45 0.87 2.4 -2.2 303 1050 1800 0.25 0.29 2.5 -2.4 304 1100 1600 0.27 0.33 2.5 -2.5 305 1150 1450 0.43 0.73 2.5 -2.4 306 1200 1250 0.67 0.95 2.7 -2.5 307 1250 800 1.44 2.25 2.7 -2.7 308 900 4050 1.92 2.71 2.6 -2.5 309 950 2900 0.53 0.96 2.6 -2.4 310 1000 2450 0.47 0.76 2.5 -2.4 311 1100 1500 0.35 0.48 2.6 -2.5 312 1200 1100 0.53 0.71 2.7 -2.6 313 1250 900 0.76 1.10 2.9 -2.6 As can be seen clearly from the Table 5, the range of diffusion temperature of Cu2O is slightly different from that of B2O3, that is the former is 1,000 to 1 ,200 C and the latter is 950" to 1 ,200 C.
As can clearly be understood from the aforementioned explanation, composition of material for semiconductive ceramic capacitor which is suitabie for making a miniaturized capacitor having excellent capacitance-temperature characteristics can be prepared by the method of the present invention.
As to the diffusion layer for changing the crystalline boundary-layer of the semiconductive ceramic to the insulator, Cu2O or B203 can be coated not only singly but also in the form of a mixture, and can be diffused.
The insulation resistivity of the barrier-layer in the semiconductive ceramics obtained in the Examples are all 1011 ohms or higher.
Claims (7)
1. A semiconductive ceramic capacitor characterized by containing in the ratio of 0.05 to 1.0 mol part of at least one of Ta205 and Nub205, 0.5 to 6 parts of SiO2 and 0.5 to 6 parts of Bi203 per 100 mol parts of the main component consisting of 14 to 21 mol % of CaO, 20 to 36 mol % of SrO, and 49.5 to 51 mol % of TiO2.
2. A method for making a semiconductive ceramic capacitor characterized by sintering a composition containing 0.05 to 1.0 mol part of at least one of Ta205 and Nb205r 0.5 to 6 mol parts of SiO2 and 0.5 to 6 mol parts of Bi203 per 100 mol parts of the main component consisting of 14to 21 moi % of CaO, 29 to 36 mol % of SrO and 49.5 to 51 mol % of TiO2, in a nuetral atmosphere or a reductive atmosphere to obtain a semiconductive ceramic, and changing crystalline grain-boundary layers to an insulation layer.
3. A method according to claim 2, wherein the sintering of the composition is carried out at a temperature of 1,2700 to 1,380"C.
4. A method according to claim 2, wherein the changing of crystalline grain-boundary layer to an insulation layer is carried out by coating Cu2O in the rate of 0.1 to 2.5 mg per 1 g of the ceramic and heating the coated ceramic in the air to effect the only crystalline grain-boundary layer is changed to the insulation layer.
5. A method according to claim 4, wherein the changing of crystalline grain-boundary layer to the insulation layer is carried out at a temperature of 1,000 to 1,200"C.
6. A method according to claim 2, wherein the changing of crystalline grain-boundary layer to an insulation layer is carried out by coating B203 in the rate of 0.3 to 6 mg per 1 g of the ceramic and heating the coated ceramic in the air to effect the only crystalline grain-boundary is changed to the insulation layer.
7. A method according to claim 6, wherein the changing of the crystalline grain-boundary layer to the insulation layer is carried out at a temperature of 950" to 1,200"C.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6638478A JPS54157300A (en) | 1978-06-01 | 1978-06-01 | Semi-conductor porcelain capacitorsigma element manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2026466A true GB2026466A (en) | 1980-02-06 |
| GB2026466B GB2026466B (en) | 1982-07-14 |
Family
ID=13314266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7919035A Expired GB2026466B (en) | 1978-06-01 | 1979-05-31 | Ceramic capacitor composition |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS54157300A (en) |
| CH (1) | CH638948B (en) |
| DE (1) | DE2921807A1 (en) |
| GB (1) | GB2026466B (en) |
| HK (1) | HK20885A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0038044A1 (en) * | 1980-04-11 | 1981-10-21 | Matsushita Electric Industrial Co., Ltd. | Grain boundary layer dielectric ceramic compositions |
| EP0047815A1 (en) * | 1980-08-20 | 1982-03-24 | Matsushita Electric Industrial Co., Ltd. | Grain boundary layer dielectric ceramic compositions |
| DE3212071A1 (en) * | 1981-04-06 | 1982-11-11 | North American Philips Corp., 10017 New York, N.Y. | INTERGRANULAR INSULATING TYPE DIELECTRIC BODY AND METHOD OF MANUFACTURING THE SAME |
| GB2124204A (en) * | 1982-07-26 | 1984-02-15 | Murata Manufacturing Co | Dielectric composition |
| FR2645850A1 (en) * | 1989-04-17 | 1990-10-19 | Commissariat Energie Atomique | FERRITE-BASED DIELECTRIC CERAMIC COMPOSITION AND METHOD FOR MANUFACTURING THE SAME |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3035793C2 (en) * | 1980-09-23 | 1985-11-07 | Murata Manufacturing Co., Ltd., Nagaokakyo, Kyoto | Process for the production of boundary layer semiconductor ceramic capacitors |
| US4347167A (en) * | 1980-10-01 | 1982-08-31 | University Of Illinois Foundation | Fine-grain semiconducting ceramic compositions |
-
1978
- 1978-06-01 JP JP6638478A patent/JPS54157300A/en active Granted
-
1979
- 1979-05-29 DE DE19792921807 patent/DE2921807A1/en not_active Ceased
- 1979-05-31 CH CH509379A patent/CH638948B/en unknown
- 1979-05-31 GB GB7919035A patent/GB2026466B/en not_active Expired
-
1985
- 1985-03-21 HK HK208/85A patent/HK20885A/en unknown
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0038044A1 (en) * | 1980-04-11 | 1981-10-21 | Matsushita Electric Industrial Co., Ltd. | Grain boundary layer dielectric ceramic compositions |
| EP0047815A1 (en) * | 1980-08-20 | 1982-03-24 | Matsushita Electric Industrial Co., Ltd. | Grain boundary layer dielectric ceramic compositions |
| DE3212071A1 (en) * | 1981-04-06 | 1982-11-11 | North American Philips Corp., 10017 New York, N.Y. | INTERGRANULAR INSULATING TYPE DIELECTRIC BODY AND METHOD OF MANUFACTURING THE SAME |
| GB2124204A (en) * | 1982-07-26 | 1984-02-15 | Murata Manufacturing Co | Dielectric composition |
| FR2645850A1 (en) * | 1989-04-17 | 1990-10-19 | Commissariat Energie Atomique | FERRITE-BASED DIELECTRIC CERAMIC COMPOSITION AND METHOD FOR MANUFACTURING THE SAME |
| EP0394107A1 (en) * | 1989-04-17 | 1990-10-24 | Commissariat A L'energie Atomique | Dielectric ceramic composition based on ferrites and process for its production |
Also Published As
| Publication number | Publication date |
|---|---|
| CH638948B (en) | |
| GB2026466B (en) | 1982-07-14 |
| HK20885A (en) | 1985-03-29 |
| JPS6159525B2 (en) | 1986-12-17 |
| DE2921807A1 (en) | 1979-12-06 |
| CH638948GA3 (en) | 1983-10-31 |
| JPS54157300A (en) | 1979-12-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR920003027B1 (en) | Semiconductive ceramic composition | |
| GB2026466A (en) | Ceramic capacitor composition | |
| US4367265A (en) | Intergranular insulation type semiconductive ceramic and method of producing same | |
| CN100364924C (en) | Titanium barium base ceramic medium materials and capacitor made thereform | |
| US4552853A (en) | Dielectric ceramic composition | |
| CA1058842A (en) | Method for making a glass-reacted-ceramic | |
| GB2027008A (en) | Ceramic Dielectrics | |
| JPS5820133B2 (en) | Porcelain for semiconductor porcelain capacitors and manufacturing method thereof | |
| CA1296880C (en) | Method for making a bismuth doped neodymium barium titanate | |
| US5250481A (en) | High dielectric ceramic composition | |
| US4820670A (en) | Dielectric ceramic composition | |
| US4697222A (en) | Composition for dielectric porcelain and dielectric porcelain and capacitor by use of said composition | |
| US5006957A (en) | Semiconductor porcelain substrate, dielectric porcelain substrate and capacitor employing the composition | |
| JP3179830B2 (en) | Dielectric porcelain composition | |
| JPS6043651B2 (en) | Composition for semiconductor ceramic capacitors | |
| GB2080789A (en) | Heterophasic semiconducting ceramic compositions | |
| JPS5951094B2 (en) | dielectric porcelain composition | |
| US4388415A (en) | High voltage dielectric (SRT I03) | |
| JPH0361287B2 (en) | ||
| US4769354A (en) | Type I dielectric composition based on neodymium titanate | |
| KR970001061B1 (en) | Dielectric magnetic composition using condensor and manufacturing method thereof | |
| JPH0734415B2 (en) | Grain boundary insulation type semiconductor porcelain composition | |
| KR100474249B1 (en) | Dielectric ceramic composition and manufacture method | |
| JPH03274606A (en) | Dielectric cramic composite | |
| JPS6312373B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930531 |