JP2799916B2 - Conductive metal-coated ceramic powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is advantageously used for manufacturing electrodes.
Concerning conductive metal-coated ceramic powder that can be used
It is. [0002] 2. Description of the Related Art Conventionally, a substrate and a substrate are provided on the substrate.
The substrate with an electrode layer having a unit structure consisting of
It is used as a part of various kinds of electric equipment and electronic equipment.
Such a substrate with an electrode layer is, for example, a ceramic core.
Capacitor, thermistor, varistor, various resistors, CR
Composite parts, IC boards, and conductive patterns for printed wiring
It is used for [0003] As a conductive material of the electrode layer for these purposes,
The most commonly used are silver, gold and palladium.
Metals or noble metals such as platinum or alloys thereof. This
These precious metals have high conductivity and are excellent materials for electrodes
However, because it is very expensive,
This is a major obstacle to reducing strikes. For this reason, noble metals are used as materials for electrodes.
Measures to use inexpensive base metals instead of
Or fine-grained base metal or ceramic powder
Conductive coating consisting of noble metal coated powder obtained by coating with noble metal
Use of precious metals by using pastes
Measures to reduce the
ing. [0005] As a material for electrodes, copper,
The former measure using a base metal such as nickel
In the manufacture of ceramic capacitors, IC substrates, etc.
Has been put to practical use. However, these base metals
If used, baking work on the substrate
Must be performed in an inert atmosphere such as a nitrogen atmosphere
Therefore, the implementation is characterized by controlled atmosphere.
There is a problem that a special firing furnace is required. [0006] In addition, laminated cores which have been rapidly spreading recently.
Capacitors, laminated varistors manufactured in a similar manner,
When manufacturing laminated coils and multilayer IC packages
Are the substrate for the capacitor, the substrate for the varistor, etc.
Simultaneous firing of electrode materials at high temperature
Therefore, electrode materials must be stable even at high temperatures.
Is done. Generally, base metals can be used in special atmospheres at high temperatures.
Is unstable unless placed on a
Including the simultaneous firing process of
Electrode material (conductive metal material) for manufacturing child parts
In general, platinum, palladium,
Precious metals such as silver and their alloys are used. Further, the same applies when a noble metal powder is used.
However, the base metal powder is applied to the ceramic in the form of a conductive paint.
When applied to a glass substrate and fired at the same time,
There is a difference in expansion and contraction curves between metals and ceramics
Or various factors caused by differences in the sintering start temperature
When the structural defects occur, the electrical characteristics of
There is a problem that the mechanical strength is often reduced. On the other hand, as described above, there is a fine base metal.
Noble metal coating obtained by coating ceramic powder with noble metal
Use conductive paint made of over-coated powder instead of precious metal
By reducing the use of precious metals
Measures have been considered and published. However, conventionally known
Such as chemical plating which is a method of coating powder
According to the method, the noble metal coating layer to be formed
Metal or ceramic components
There is a title. For this reason, such coated particle powder was used.
The electrode layer manufactured by firing the conductive paint on the surface of the substrate,
The conductivity is very low compared to the conductivity of the noble metal used.
It will show electrical conductivity, and as an electrode used for electronic parts
Not practically available. [0009] SUMMARY OF THE INVENTION The present invention relates to an electrode material.
The electrical properties of conductive metal materials used as
An electrode that can reduce the amount of conductive metal material used without any
Conductive metals particularly useful for producing substrates with layers
The main purpose is to provide coated ceramic powder
You. The present invention relates to a conductive material used as a material for an electrode.
The machine without reducing the electrical properties of the metal material
Having an electrode layer with improved electrical characteristics and solder resistance
Conductive metallized ceramics especially useful for manufacturing plates
To provide powdered powder
is there. [0011] Means for Solving the Problems The present invention provides:Ceramic
No contamination and no exposureMade of conductive metal material only
The average particle diameter covered by the coating layer1.5Mi
Fine ceramic powder (less than carbon)
The weight of the Lamix part is 90 to 10 weight of the whole coating powder
%) In the conductive metal-coated ceramics
In powder. The present inventionCoating layer contains ceramic components
And no exposure,Electrical characteristics such as the conductivity of the coating layer
Of the conductive metal material used to form the coating layer
CharacteristicChanges that cause problems in practical use
Will not wake up. [0013] A high purity metal coating such as the conductive powder of the present invention.
The coating powder is covered by a conventionally known chemical plating method or the like.
It cannot be manufactured by the overcoating method, while
Utilize the reaction for forming the coating layer via such a gelled state
Thus, it can be easily manufactured. A reaction for forming a coating layer via a gelation state is performed.
The following methods should be mentioned as typical methods
Can be. (A) Fine-grained ceramic present in a uniformly dispersed state
Powder, (B) a coating present in a uniformly dispersed state
A conductive metal salt forming a layer, and (C) in a dissolved state
Containing ions of a conductive metal forming an existing coating layer
Add a reducing agent such as hydrazine to the aqueous suspension with stirring
Conductivity on the surface of fine ceramic powder
After forming the metal coating layer, collect and dry it
Way. [0015] Alternatively, similarly, an
As another method using the reaction for forming the covering layer, the following method is used.
Can be mentioned. Of conductive metal ions and supersaturation
Aqueous gelation liquid containing conductive metal chelate compound, and it
Of conductive metal ions and conductive metal chelate compounds
Amount of peroxide sufficient to reduce
A state in which hydrogen and fine ceramic powder are uniformly dispersed
The aqueous dispersion, and the alkalinizing agent
At the same time as eliminating the gel state of the aqueous gelling solution.
In addition, conductive metal powder is applied to the surface of fine ceramic powder.
After depositing the body to form a conductive metal coating layer,
A method of collecting and drying it. [0016] Similarly, a coating layer form via a gel state
Other methods that utilize the commercial reaction include the following:
I can do it. Conductive metal compounds, non-metallic
Monium (such as ammonium chloride) and aqueous ammonia
Into a gelled aqueous solution of pH 5-10 containing
A reducing agent is added to the dispersion in which Lamix powder is uniformly dispersed.
The gel state of the aqueous gelling solution is obtained by adding
At the same time as eliminating fine ceramic powder
Conductive metal coating layer by depositing simple conductive metal on the surface
After forming, a method of collecting and drying it. Production of high-purity metal-coated powder as described above
The manufacturing method is a method invented by the inventor prior to the present invention.
For further details on these manufacturing methods, see
Japanese Patent Application Nos. 55-51516 and 55-55
No. 116482, No. 56-133314, No. 56-1
No. 33315 is disclosed in the specification of the patent application. The metal used as the conductive metal material in the present invention
Examples of platinum, gold, silver, palladium, etc.
Noble metals, or molybdenum, nickel, cobalt,
Iron, copper, zinc, tin, antimony, tungsten, manga
In air such as titanium, vanadium, chromium, etc.
Base metals that can exist almost stably can be mentioned. This
These metals can be used alone or in alloys.
Can be The fine-grained ceramic used in the present invention
Examples of silica powder include silicon dioxide and zirconium oxide.
System, aluminum oxide, titanium dioxide, ferric oxide, acid
Oxides such as calcium iodide and barium titanate
Ceramics, tungsten carbide, silicon carbide
At least two or more atoms such as silicon, titanium nitride, etc.
The average particle size of non-oxide ceramics containing1.
5Submicron powders can be mentioned. Also eyes
Depending on the target, fine particles with an average particle size of 1 micron or less
In some cases, it is preferable to use
is there. The average of such powder having a particularly small average particle size is
One and high-purity coatings are made by conventional chemical plating.
Although the method was not practically possible,
Uniform and high purity by using the coating method via
Can be formed. The core of the high-purity metal-coated powder of the present invention is
The ceramic powder that forms and the coating layer that forms
Weight ratio of high-purity metal is 90:10 to 10:90.
Preferably within the range of 75:25 to 25:75
Adjust to Conductive powder produced by the production method of the present invention
The end is a ceramic substrate and the electrodes provided on the substrate.
It is particularly advantageous for the production of substrates with electrode layers from electrode layers.
You. The ceramic substrate is made of, for example,
Silicon, zirconium oxide, aluminum oxide, dioxide
Titanium, ferric oxide, calcium oxide, barium titanate
Mainly composed of oxide ceramics such as
Or tungsten carbide, silicon carbide, titanium nitride
Non-oxide ceramics such as tan
This is a substrate formed by: These ceramic substrates
The main ones are already ceramic capacitors, thermistors
Data, varistors, various resistors, CR composite parts, IC base
Electronic components such as boards and conductive patterns for printed wiring
Multilayer capacitor, multilayer varistor, multilayer coil, multilayer IC
Used as a substrate for electronic components such as packages
Or attempts to use it. That is, it is manufactured by the method as described above.
The high purity metal-coated powder of the present invention is used in the form of a conductive paint.
Forming electrode layer by baking on Lamix substrate
can do. The preparation of the conductive paint is carried out by using a conventional conductive metal unit.
Of the conductive paint using the powder.
I can. That is, appropriate addition to high-purity coated powder
A conductive paint is prepared by adding an agent, a solvent, and the like. The formation of the electrodes on the ceramic substrate is performed by
For example, ceramic substrate by screen printing
After applying conductive paint to the surface, baking in a baking furnace, etc.
It can be carried out by the method described above. Firing method, firing strip
The same gold as the metal forming the coating layer.
Method and conditions for firing conductive paints composed of metals
Can be determined. An electrode layer is formed using the high-purity coated particles of the present invention.
When forming, the ceramic material of the ceramic substrate
And fine-grained ceramic powder present inside the electrode layer
It is advantageous to use the same ceramic material
It is. That is, the conventional method of baking conductive paint on a substrate
In the method, the coefficient of expansion between the metal of the conductive paint and the material of the substrate
Are different from each other before firing.
Apply conductive paint to the fired substrate and then fire
It was common to take the law. However, the high purity of the present invention
If coated particles are used, the ceramic
And the fine particles present inside the electrode layer
The same as the ceramic material of the ceramic powder or
Same type (for example, do not use both as oxide-based ceramics)
Etc.) can be selected for such materials
If you select the material, the unfired ceramic
Apply a conductive paint directly to the substrate and bake as it is
The operation to be performed, that is, simultaneous firing, becomes possible. [0028] The conductive metal-coated ceramic powder of the present invention
The end is, for example, various electric parts, electronic parts, electric appliances
Specializes in the manufacture of substrates with electrode layers that are incorporated into fixtures and electronic components.
It can be used advantageously. For example, the conductive metal coating of the present invention
Substrate with electrode layer obtained using coated ceramic powder
Is the ceramic substrate and the electrodes provided on the substrate
Layered electronic components with lead wires
Electronic parts in the form of child parts and those electronic parts laminated
Products, such as electronic components whose layers take the form of a spiral
It can be taken as a form. Examples of specific products
Ceramic capacitors, thermistors, varistors,
Various resistors, CR composite parts, IC boards, printed wiring
Electronic components such as conductive patterns and multilayer capacitors,
Multi-layer varistor, multi-layer coil, multi-layer IC package, BL
A ceramic capacitor and the like can be given. The electronic component as described above is used as the conductive material according to the present invention.
By manufacturing using metal-coated ceramic powder
The electrical characteristics of conductive metal materials used as electrode materials
Reduction of the amount of conductive metal material used without lowering the performance
Not only is possible, but also its mechanical properties and
Various properties such as flexibility can also be improved. For example, the mechanical strength of electronic parts is large.
Among the structural properties that affect it, delamination (layer
There is a phenomenon called "interlaminar separation". This delamination
Means that the substrate with the electrode layer is manufactured by the simultaneous firing method
The expansion between the conductive material used and the ceramic substrate
The difference between the tension and shrinkage curves, or the
Difference, conductive material, binder, solvent, ceramic base
Ignition phenomena caused by reactions between plates, etc., electrode materials
Changes in the electrode volume due to oxidation or reduction of
Is a phenomenon in which a thin crack occurs between the electrode layer and the substrate.
You. If this delamination occurs, the electronics
Product properties, especially mechanical strength,
Have been. The conductive metal-coated ceramic powder of the present invention
The substrate with electrode layer obtained by using
Hardly occurs, so that the conductive metal coating of the present invention
Substrate with electrode layer obtained by using coated ceramic powder
It shows particularly high mechanical strength. [Example 1] (I) Production of silver-coated barium titanate powder An aqueous solution of 10 g of silver nitrate dissolved in 50 ml of water;
Disodium salt of diaminetetraacetic acid (EDTA)
An aqueous solution in which 15 g is dissolved in 200 ml of water is stirred.
The mixture was mixed to obtain a gelled solution. Reduced viscosity of this gel state
Another 50 ml of water was added to
100 ml of aqueous hydrogen peroxide solution (30% aqueous solution)
Was added. Separately, barium titanate powder (average particle size:
(1.4μ) 6g was added to 150ml of water and the dispersion was uniformly dispersed.
Prepare and disperse this dispersion into a gelling liquid (with hydrogen peroxide added).
) And thoroughly stirred. Gelation obtained
While stirring the solution vigorously, add aqueous sodium hydroxide
100 ml of liquid (NaOH 5 g / 25 ml water)
The gel state disappears and the silver on the surface of the barium titanate powder
Was precipitated. Add 150 ml of hydrogen peroxide to the reaction system.
An aqueous solution (30% aqueous solution) was added to complete the reaction. The obtained silver-coated barium titanate powder is filtered.
It was removed by filtration, washing, and drying.
It shows a light gray color after drying, and the yield is 11.7 g (theoretical yield).
12g), and the barium titanate / silver weight ratio in the powder is 5
It was 0/50. By observation with a scanning electron microscope
And the surface coating layer of this silver-coated barium titanate powder is silver
Only from ceramic powder
No non-uniformity due to outflow was observed. (II) Ceramic capacitor electrode Silver-coated barium titanate powder obtained by the above (I)
A mixture having the following composition including powder was prepared. Silver-coated barium titanate powder 10 g Lead borosilicate glass frit 0.2g 1.0 g of ethyl cellulose 2.5 g of ethyl cellosolve 2.5 g of butyl carbitol This mixture is further mixed well using a three-roll kneader.
After kneading, a conductive paint for an electrode was obtained. The obtained conductive paint is used for screen printing.
And sintered barium titanate ceramic condenser
Sensor (diameter 13.0 mm, thickness 0.5 mm)
The plate was printed on both sides and baked at 800 ° C. This
Electrical properties and mechanical properties of baked products (silver-coated powder electrodes)
Table 1 shows the results of measuring the physical properties and the solder resistance.
You. For comparison, silver-coated powder was used instead of silver-coated powder.
Using the same amount of silver simple powder as the powder, similarly fired and manufactured
The same measurement was performed for the silver electrode. The result is also
Also shown in Table 1. [0036]                                   Table 1                  Characteristics Silver coated powder electrode Silver electrode              Electrical characteristics           εs 6500 6420       tan δ (%) 1.5 1.6       Lead wire tensile strength 2.5kg 1.8kg       Solder bite No bite Peripheral bite       Solderability All surface solder wet Same as left        The above measurement was performed as follows.
Capacitance (εs) and dielectric loss tangent (tan δ) are 25 ° C.
In, YHP digital LCR meter model 4274A
Use, measurement voltage 1.0Vrms, measurement frequency 1.0K
Hz. The tensile strength of the lead wire was determined by burning the electrode.
Then, the solder was melted in advance using a solder (Senju Metal Co., Ltd. S
-356, containing 3.5% of Ag).
5mm solder-plated annealed copper wire (MLT manufactured by Kyowa Electric Cable Co., Ltd.)
-122) and attached to Intesco Universal Material Testing Machine)
It was measured. The solder erosion and solderability are determined by the temperature.
Temperature controlled to 230 ° C (S-Sumi Metal Co., Ltd. S-
356, containing 3.5% of Ag).
Observation was made using a stereoscopic microscope at × magnification. [Embodiment 2] (I) Production of silver-coated ferric oxide powder Ferric oxide instead of barium titanate powder (average particle size:
1.5 μ) The same method as in Example 1 except that 6 g was used.
As a result, a silver-coated ferric oxide powder was produced. Yield 1
1.6 g (theoretical yield 12 g) of the ferric oxide /
The silver weight ratio was 50/50. Scanning electron microscope
According to the observation, the surface coating layer of this silver-coated ferric oxide powder
Is made of silver only, and
No non-uniformity due to penetration or exposure was observed. (II) Varistor electrode Including the silver-coated ferric oxide powder obtained by the above (I)
A mixture having the following composition was prepared. Silver-coated ferric oxide powder 10 g Lead borosilicate glass frit 0.2g 1.0 g of ethyl cellulose 2.5 g of ethyl cellosolve 2.5 g of butyl carbitol This mixture is further mixed well using a three-roll kneader.
After kneading, a conductive paint for an electrode was obtained. The obtained conductive paint is used for screen printing.
And the sintered varistor element (Fe_TwoO_Three 85 mol%
La_Two O_Three 5 mol% · CaO 10 mol%, diameter 13.0
mm, thickness 0.5mm) Print on both sides of (substrate), 80
The firing was performed at 0 ° C. This fired product (silver-coated powder
Pole) electrical characteristics, mechanical characteristics and solder resistance
Table 2 shows the results of measuring the properties. For comparison,
Instead of silver-coated powder, use the same amount of silver simple powder as silver-coated powder.
The same applies to silver electrodes manufactured and fired in the same manner.
A measurement was made. Table 2 also shows the results. [0043]                                   Table 2                  Characteristics Silver coated powder electrode Silver electrode              Electrical characteristics           α 55           E_Ten                12V 12V       Lead wire tensile strength 2.6kg 2.0kg       Solder bite No bite Peripheral bite       Solderability All surface solder wet Same as left        Voltage non-linear coefficient α and when 10 mA is applied
Terminal voltage E_TenAre mechatronic at 25 ° C
Model 592C and Iwasaki Communication Equipment Co., Ltd. VO
It was measured using AC757. Lead wire tensile strength, solder
The bite and solderability are the same as in Example 1.
Measured and judged by the method. [Embodiment 3] (I) Production of palladium-coated barium titanate powder Palladium solution (50 g of palladium metal in aqua regia 700 m
1) ammonium chloride 12 in 700 ml
0 g (1.2 equivalent times based on palladium) was added.
An orange gel solution was obtained. Add ammonia water to this solution
(25% aqueous solution) By adding 450 ml, the solution becomes
It becomes a pink gel-like solution, and the pH of the solution becomes about 7.
Was. To this solution was added barium titanate powder (average
Particle size: 1.5 μ) 50 g is added, and while stirring sufficiently, water is added.
10% aqueous sodium borohydride solution (0.75% by weight)
When 00ml was added, the gel state disappeared and black powder
Generated. The liquid phase is removed by decantation and
Using decantation operation with water and hot water
After washing 10 times, drying at 65 ° C
Thus, palladium-coated barium titanate powder was produced.
The yield is 99g (theoretical yield 100g).
The barium acid / palladium weight ratio was 50/50.
According to observation with a scanning electron microscope, this palladium coating
The surface coating layer of barium titanate powder is only palladium
It is formed from
No unevenness was found at all. (II) Internal electrode of multilayer capacitor The palladium-coated titanate obtained by the above (I)
A mixture having the following composition was prepared containing the lithium powder. Palladium (Pd) coating Barium titanate powder 45 g 3.8 g of ethyl cellulose 3.8 g of dibutyl phthalate 42.5 g of butyl carbitol This mixture is further mixed well using a three-roll kneader.
After kneading, a conductive paint for an electrode was obtained. The obtained conductive paint and barium titanate
Using the element (substrate) and the simultaneous condensation method
[35 layers, electrode spacing 16 μm (after firing)]
Was. Electrical characteristics and structure of this multilayer capacitor
Table 3 shows the results of measurement of the dynamic characteristics. Also for comparison
Instead of palladium (Pd) -coated powder, Pd-coated powder
Using the same amount of palladium (Pd) simple powder as the powder,
The same measurement was performed on the fired Pd electrode.
Was. Table 3 also shows the results. [0049]                                   Table 3                  Characteristics Pd coated powder electrode Pd electrode              Electrical characteristics           C 239 nF 234 nF           εs 9790 9600       tan δ (%) 0.58 0.51           IR 3.5X10^TenΩ 3.5X10^TenΩ           V_B                 620V 650V       Temperature characteristics (ΔC / C)         MAX (%) 11.2 18.0         MIN (%) -72.0 -73.1         Tc (° C) 20 20       Structural properties       Delamination 0/50 50/50       Cracked, chipped 0 out of 50 2 out of 50        The capacitance (εs) and the dielectric loss tangent (tan
δ) was measured in the same manner as in Example 1. Insulation resistance
(IR) using YHP insulation resistance meter model 4329A
And measure the value after one minute at 25 V and measure the breakdown voltage (V_B ) Is
Measured using Nissin Electric Co., Ltd. model NS-3150
Was. Temperature characteristics (ΔC / C) from -25 ° C to 85 ° C
Measure the maximum and minimum values of the rate of change
Temperature 25 ° C), and the temperature at which the maximum value
Posted. The delamination in the structural characteristics indicates that the device
Polished, using a 20 × stereo microscope, and
Observe the appearance using a 20 × stereo microscope
And judged. [Embodiment 4] (I) Production of molybdenum-coated aluminum oxide powder Molybdenum solution instead of palladium solution (molybdenum
50 g of metal dissolved in 2 l of aqua regia) 2 l
Aluminum oxide (average grain) instead of barium titanate powder
The same method as in Example 3 except that 6 g was used.
To produce molybdenum-coated aluminum oxide powder
Was. The yield was 98 g (theoretical yield 100 g), and the acid in the powder was
Aluminum / molybdenum weight ratio was 50/50.
Was. According to observation with a scanning electron microscope, this molybdenum
Molybdenum
Only from ceramic powder
No non-uniformity due to outflow was observed. (II) Multilayer Wiring Substrate in Substrate Molybdenum-coated aluminum oxide obtained by the above (I)
A mixture was prepared having the following composition, including the lithium powder. Molybdenum (Mo) coating Aluminum oxide powder 45 g 3.8 g of ethyl cellulose 3.8 g of dibutyl phthalate 42.5 g of butyl carbitol This mixture is further mixed well using a three-roll kneader.
After kneading, a conductive paint for an electrode was obtained. The obtained conductive paint and aluminum oxide
Multi-layer wiring by simultaneous baking method using system element (substrate)
Production of substrate [30 layers, dielectric layer thickness 16 μm (after firing)]
Built. The electrical characteristics and structural characteristics of this multilayer wiring board
Table 4 shows the results of measuring the characteristics. Also for comparison
Instead of molybdenum (Mo) coated powder, Mo coated powder
Using the same amount of molybdenum (Mo) simple powder as the powder,
The same measurement was performed on the Mo electrode manufactured by firing.
Was. Table 4 also shows the results. [0055]                                   Table 4                  Characteristics Mo coated powder electrode Mo electrode              Electrical characteristics           C 181.4 pF 181.0 pF           εs 8.8 8.8           Rsq 16mΩ / sq 16mΩ / sq       Structural properties       Delamination 0/50 50/50        The capacitance (εs) and the wiring resistance (Rsq) are
At 25 ° C, YHP Digital LCR Meter Model 42
Using 74A, the measurement voltage and measurement frequency,
1.0 Vrms, 100 KHz and 1.0 Vrms, 10
The measurement was performed under the condition of 0 Hz. Delamination implemented
Observation was made in the same manner as in Example 3 and judged. [Embodiment 5] (I) Production of palladium-coated titanium oxide powder (0.3μ)
Construction Palladium solution (50 g of palladium metal in aqua regia 700 m
1) ammonium chloride 12 in 700 ml
0 g (1.2 equivalent times based on palladium) was added.
An orange gel solution was obtained. Add ammonia water to this solution
(25% aqueous solution)
Becomes a pink gel-like solution, and the pH of the solution becomes about 7.
Was. To this solution was added titanium oxide powder (average particle size:
0.3μ) 50 g, and hydrogenating
1000 m of sodium iodide aqueous solution (0.75% by weight)
l When added, the gel state disappears and a black powder is formed
did. The liquid phase is removed by decantation and
10 times each with water and hot water by canting operation
After washing, dry at 85 ° C.
Indium coated titanium oxide powder was produced. Yield 99g
(Theoretical yield 100 g), titanium oxide / palladium in powder
Weight ratio was 50/50. Scanning electron microscope
According to the observation of this palladium-coated titanium oxide powder
The surface coating layer is made of palladium only.
Non-uniformity due to mixing powder, exposure, etc.
I couldn't. (II) Internal electrode of multilayer capacitor Palladium-coated titanium oxide obtained by the above (I)
A mixture having the following composition including powder was prepared. Palladium (Pd) coating Titanium oxide powder 45 g 3.8 g of ethyl cellulose 3.8 g of dibutyl phthalate 42.5 g of butyl carbitol This mixture is further mixed well using a three-roll kneader.
After kneading, a conductive paint for an electrode was obtained. The obtained conductive paint and barium titanate
Using the element (substrate) and the simultaneous condensation method
[35 layers, electrode spacing 16 μm (after firing)]
Was. Electrical characteristics and structure of this multilayer capacitor
Table 5 shows the results of measurement of the dynamic characteristics. Also for comparison
Instead of palladium (Pd) -coated powder, Pd-coated powder
Using the same amount of palladium (Pd) simple powder as the powder,
The same measurement was performed on the fired Pd electrode.
Was. Table 5 also shows the results. [0061]                                   Table 5                  Characteristics Pd coated powder electrode Pd electrode              Electrical characteristics           C 236 nF 235 nF           εs 9650 9600       tan δ (%) 0.52 0.51           IR 3.5X10^TenΩ 3.5X10^TenΩ           V_B                 635V 645V       Temperature characteristics (ΔC / C)         MAX (%) 12.1 18.0         MIN (%) -72.0 -73.0         Tc (° C) 20 20       Structural properties       Delamination 0/50 50/50       Cracked, chipped 0 out of 50 2 out of 50        Each characteristic value is the same as in the third embodiment.
Measured. The obtained multilayer capacitor is made of epoxy resin
Hardened and cut, and the electrode part is 10,000 times with a scanning electron microscope
Observed in, palladium forms a continuous layer and
The so-called ultra-fine titanium oxide particles are uniformly dispersed inside,
Sea (Pd) -Island (TiO_Two ) Form a matrix of structures
It was confirmed that. Comparative Example 1 Palladium solution (palladium
50 g of metal dissolved in 700 ml of aqua regia) 700 m
50g of titanium oxide powder (average particle size 0.3μ)
Add 50 ml of hydrazine hydrate with stirring
Then, it foamed instantaneously and produced black aggregates as a whole.
Done. Obtained by drying at 65 ° C. after washing
The powder weighed 52 g (theoretical yield 100 g). Analysis results
Less than 50 g of fruit is Pd, and the remaining 2 g is titanium oxide and hydroxylated
It was titanium. From the above results, it can be seen that ordinary palladium solution
Because titanium oxide is largely dissolved, this method requires
And titanium oxide coprecipitated powder cannot be obtained.
became. Comparative Example 2 (1) Production of palladium-coated titanium oxide powder Palladium solution (50 g of palladium metal in aqua regia 700 m
1) ammonium chloride 12 in 700 ml
0 g (1.0 equivalent times with respect to palladium) was added.
An orange gel solution was obtained. Heat this solution to 60 ° C
While adding 450m of aqueous ammonia (25% aqueous solution)
and stirred at 80 ° C for 1 hour.
It became a yellow solution and the pH of the solution was about 7. This solution
50 g of titanium oxide powder (average particle size: 0.3 μ)
Then, with sufficient stirring, add 50 ml of hydrazine hydrate
When added, it reacts instantly, producing a gray-black powder.
Was. The liquid phase is removed by decantation and
10 times each using water and hot water
After washing, drying at 85 ° C allows
A radium / titanium oxide coprecipitated powder was produced. Yield 99
g (theoretical yield: 100 g) of titanium oxide / para
The weight ratio of indium was 50/50. Scanning electron microscope
According to observations at this site, this palladium-titanium oxide coprecipitated powder
The powder is in the form of agglomerated palladium particles and titanium oxide particles.
In the state, the surface is exposed palladium and titanium oxide exposed
Part and was formed from. (II) Internal electrode of multilayer capacitor Palladium-coated titanium oxide obtained by the above (I)
A mixture having the following composition including powder was prepared. Palladium (Pd) coating Titanium oxide powder 45 g 3.8 g of ethyl cellulose 3.8 g of dibutyl phthalate 42.5 g of butyl carbitol This mixture is further mixed well using a three-roll kneader.
After kneading, a conductive paint for an electrode was obtained. The obtained conductive paint and barium titanate-based
Using the element (substrate) and the simultaneous condensation method
[35 layers, electrode spacing 16 μm (after firing)]
Was. Electrical characteristics and structure of this multilayer capacitor
Table 6 shows the results of measuring the characteristic characteristics. Also for comparison
Instead of palladium titanium oxide coprecipitated powder,
Manufactured by sintering similarly using radium (Pd) simple substance powder
The same measurement was performed for the Pd electrode thus obtained. The result
The results are shown in Table 6. [0068]                                   Table 6                  Characteristics Pd titanium oxide coprecipitated powder electrode Pd electrode              Electrical characteristics           C 10 nF 235 nF           εs 0.365 9600       tan δ (%) 3.6 0.51           IR 3.5X10^TenΩ 3.5X10^TenΩ           V_B                 620V 650V       Temperature characteristics (ΔC / C)         MAX (%)-18.0         MIN (%)--73.0         Tc (° C) -20       Structural properties       Delamination 25/50 50/50       Cracked, chipped 5 out of 50 2 out of 50        Each characteristic value is set in the same manner as in the third embodiment.
Measured. The obtained multilayer capacitor is made of epoxy resin
Hardened and cut, and the electrode part is 10,000 times with a scanning electron microscope
Observation showed that fine particles in the continuous phase of titanium oxide
Pd phase ranging from a coarse to a coarse one is discontinuous and dispersed
It was confirmed that. Comparative Example 3 (I) Production of chemically plated silver-coated barium titanate powder The same barium titanate powder as used in Example 1 (flat
46.2 g of hydrochloric acid 1: water 9
After immersing in the above solution for 3 minutes,
To 77g silver nitrate Potassium hydroxide 40g Glucose 70 90g of ammonia water 1 liter of water For 30 minutes in a plating solution consisting of
became. The obtained silver-coated barium titanate powder is filtered.
It was removed by filtration, washing and drying. Profit
The resulting powder is incompletely coated with silver and the surface of the powder is
A portion where barium titanate was exposed was observed.
The yield of the above powder was 94.14 g, and the yield was 99%.
It is. (II) Ceramic capacitor electrode Silver-coated barium titanate powder obtained by the above (I)
The same procedure as in Example 1 was carried out except that the powder was used.
A water-soluble paint was obtained. Use the resulting conductive paint for screen printing
Thus, the same barium titanate cell as used in Example 1 was used.
Printed on the surface of the element (substrate) for lamic capacitors,
The firing was performed at 800 ° C. The fired product (chemically-plated silver-coated powder electrode)
Electrical properties, mechanical properties and solder resistance
Table 7 shows the measured results. However, the above fired product
Since no solder adhered, the electrical characteristics were
With the electrode surface of the product sandwiched between clips,
It measured similarly. About mechanical strength and solder resistance
Can not be measured because the solder did not adhere
Was. Table 7 shows the measurement results of Example 1 for comparison.
(Table 1) is shown again. [0073]                                 Table 7                  Characteristics Silver coating Silver electrode Chemically plated silver                         Powder electrode Coated powder electrode              Electrical characteristics         εs 6500 6420 10         tan δ (%) 1.5 1.6 40       Lead wire tension         Strength (kg) 2.5 1.8 Unmeasurable       Solder erosion No erosion Peripheral erosion Unmeasurable       Solderability Wet on the entire surface Same as left Unmeasurable        From the above results, it has been conventionally used.
Silver-coated powder manufactured using the chemical plating method
Internal core material such as ceramics is exposed on the surface
Therefore, it can be used as an alternative to silver paste for electrode production.
You can see that you can not.

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Claims (1)

(57) [Claims] Fine- grained ceramic powder with an average particle size of 1.5 microns or less covered with a coating layer made of only a conductive metal material that does not contain or expose ceramic components (however, the weight of the ceramic part is (In the range of 90 to 10% by weight of the whole powder). 2. The conductive metal-coated ceramic powder according to claim 1, wherein the conductive metal material is a noble metal. 3. From a dispersion of an aqueous solution of a conductive metal material in a dissolved state and a dispersion of a ceramic powder dispersed in the solution, the conductive metal material is deposited on the surface of the ceramic powder in a gelled state, and is obtained by coating. The conductive metal-coated ceramic powder according to claim 1.