[Technical Field]
[0001] The present invention relates to a nickel fine particle, a mixture of nickel fine
particles, a conductive paste and a method for producing a nickel fine particle.
[Background Art]
[0002] Conventionally, a metal fine particle is used as a conductive filler contained in
a conductive paste, and a nickel fine particle is known as such a metal fine particle.
The nickel fine particle has characteristics that although the nickel fine particle
has high intrinsic electric resistance compared to a silver fine particle and a copper
fine particle, the nickel fine particle does not cause the migration, resists the
oxidation relatively strongly and suffers minimally from a change in conductivity
over time.
[0003] Various shapes have been considered as a shape of the above-mentioned metal fine
particle. For example, although a spherical shape is popular as a shape of the metal
fine particle, from a viewpoint of forming a conductive paste into a thin film or
the like, it is preferable that the metal fine particle have a thin flaky shape rather
than a spherical shape.
[0004] Accordingly, recently, a nickel fine particle having a flaky shape has been developed.
For example, patent document 1 discloses a technique where a flaky nickel fine particle
is manufactured by reducing a flaky nickel hydroxide particle which is formed by a
reaction. Further, patent document 2 discloses a technique where a flaky nickel fine
particle is manufactured by plastically deforming a spherical nickel particle mechanically
into a flattened shape using a ball mill or the like.
[0005] Patent document 3 describes a preparation method of globular hollow nickel powder
by a spark errosion process making use of a mixture of deionized water and silica
flour as a working solution and a tool electrode and work piece made by metallic nickel.
[0006] Patent document 4 describes a production of metal powder such as nickel powder for
laminated ceramic capacitor electrodes. In the production method, a gaseous mixture
of metallic chloride and a carrier gas is brought into contact with water vapor to
hydrolyze a part of the metallic chloride and to produce grains of metallic oxides.
The metallic oxide grains are transferred to a gaseous hydrogen reaction part together
with the unreacted metallic chloride vapor, where they are brought into contact with
hydrogen gas for a reduction reaction. The produced metal powder has a grain size
of about 1 to 10 µm.
[Prior art document]
[Patent document]
[Summary of the Invention]
[Task to be solved by the Invention]
[0008] However, the flaky nickel fine particle has the plate-shaped structure having a surface
with a certain amount of area and hence, when the nickel fine particles are contained
in a conductive paste together with binder resins as conductive fillers, the nickel
fine particle exhibits inferior contact performance with the binder resin. Accordingly,
in the conductive paste containing the flaky nickel fine particles, the nickel fine
particles are liable to coagulate with each other or the binder resins are liable
to coagulate with each other thus giving rise to a possibility that a conductive path
is obstructed.
[0009] Accordingly, it is an object of the present invention to provide a nickel fine particle
which can easily form a conductive path when the nickel fine particle is contained
in a conductive paste.
[Means for solving the problem]
[0010] The inventors of the present invention have made extensive studies for overcoming
the above-mentioned drawbacks and, as a result, have found that by forming a nickel
fine particle into a ring body, affinity between the nickel fine particle and a binder
resin is improved so that a conductive path is easily formed, and have completed the
present invention based on such finding.
[0011] That is, the present invention provides the following (1) to (11).
- (1) A nickel fine particle as defined by claim 1.
- (2) The nickel fine particle described in the above-mentioned (1), wherein the ring
body has a center hole portion and a peripheral portion which surrounds the periphery
of the hole portion.
- (3) The nickel fine particle described in the above-mentioned (2), wherein the ring
body has a thin plate shape.
- (4) The nickel fine particle described in the above-mentioned (2) or (3), wherein
the ring body has, as a part of the peripheral portion, a breaking portion where the
peripheral portion is broken.
- (5) The nickel fine particle described in the above-mentioned (4), wherein the breaking
portion occupies 1/2 or less of a volume of the peripheral portion.
- (6) The nickel fine particle described in any one of the above-mentioned (1) to (5),
wherein an outer diameter of the ring body is 0.05 to 100 µm.
- (7) A mixture of nickel fine particles as defined by claim 7.
- (8) A conductive paste as defined by claim 8.
- (9) A method of manufacturing a nickel fine particle as defined by claim 9.
- (10) The method described in the above-mentioned (9), wherein the cooling comprises
cooling by an endothermic reaction caused by the oxidation of a solid nickel chloride.
- (11) The method described in the above-mentioned (10), wherein the nickel chloride
fine particle having a thin plate shape is a nickel chloride fine particle having
a hexagonal thin plate shape.
[Advantage of the Invention]
[0012] According to the present invention, it is possible to provide a nickel fine particle
which is thin and can make the adhesion between the fine particles difficult.
[Brief Description of the Drawings]
[0013]
Fig. 1 is a schematic view showing a formation mechanism of a nickel fine particle
according to the present invention.
Fig. 2 is a cross-sectional view schematically showing a reaction device 101.
Fig. 3 is an SEM photograph obtained by photographing a nickel fine particle.
Fig. 4 is an SEM photograph obtained by photographing a nickel fine particle.
Fig. 5 is an SEM photograph obtained by photographing a nickel fine particle.
Fig. 6 is an SEM photograph obtained by photographing a nickel oxide fine particle.
[Mode for Carrying out the Invention]
[0014] A nickel fine particle according to the present invention is a nickel fine particle
formed of a ring body having a ring shape.
[0015] The nickel fine particle according to the present invention, in summary, is formed
by oxidizing a nickel chloride (NiCl
2) fine particle and, thereafter, by reducing the fine particle.
[0016] Hereinafter, a mechanism that the nickel fine particle according to the present invention
is formed is explained in conjunction with Fig. 1. Fig. 1 is a schematic view showing
the formation mechanism of the nickel fine particle according to the present invention.
[0017] Firstly, the nickel chloride fine particle is explained. As shown in Fig. 1(A), the
nickel chloride fine particle is a crystal having a hexagonal thin plate shape. This
is because the crystal is liable to grow in the longitudinal direction of the plate.
[0018] Although a nickel chloride fine particle may be obtained by directly charging a raw
material into a reaction system, it is preferable to obtain the nickel chloride fine
particle by changing a nickel chloride phase into a solid phase from a gas phase by
cooling a nickel chloride gas in a reaction system. In this case, a size of the obtained
fine particle can be controlled based on conditions at the time of changing the phase
of the nickel chloride into a solid phase from a gas phase.
[0019] As a method of obtaining a nickel chloride gas, for example, a method which sublimates
solid nickel chloride, a method which blows a chlorine gas into heated metal nickel
or the like is named. However, in view of a fact that a chlorine gas corrodes metal
thus making handling of the chlorine gas difficult, it is preferable to adopt the
method which obtains the nickel chloride gas by sublimating solid nickel chloride.
[0020] Although a temperature at which solid nickel chloride is sublimated may preferably
be set to a high temperature for increasing an amount of sublimation, there is an
upper limit with respect to a temperature at which an inexpensive exothermic body
can be used and hence, it is preferable to set the temperature to 900 to 1200°C.
[0021] Next, a nickel oxide fine particle is obtained by oxidizing the nickel chloride fine
particle. Here, the more unstable a surface of the nickel chloride fine particle becomes,
the more crystals are liable to grow on the surface so that a reaction is liable to
be caused on a longitudinal surface of the plate. Therefore, the oxidization of the
nickel chloride fine particle having a hexagonal shape progresses toward the center
from an edge as shown in Fig. 1(B).
[0022] Here, the oxidization is finished before the nickel chloride fine particle is completely
oxidized and hence, as shown in Fig. 1(B), a state where only an outer peripheral
portion of the nickel chloride fine particle is oxidized is brought about. Thereafter,
by sublimating a nickel chloride portion remaining in the center portion, as shown
in Fig. 1 (C), a ring-shaped nickel oxide (NiO) fine particle is obtained.
[0023] As an oxidizing agent used in oxidizing the nickel chloride fine particle, for example,
water vapor, oxygen, sulfur dioxide or the like is named. In view of easy handling
with no toxicity, water vapor is preferable.
[0024] When nickel chloride is oxidized by reacting with water vapor, a reaction expressed
by the following formula (I) progresses.
NiCl
2 + H
2O→ NiO + 2HCl (I)
[0025] Next, as shown in Fig. 1 (D), by reducing the nickel oxide fine particle having a
ring shape, the nickel fine particle according to the present invention is obtained
in a state where a ring shape of the nickel oxide fine particle is maintained as it
is. That is, the nickel fine particle according to the present invention is formed
of a ring body having a ring shape.
[0026] Here, in view of the formation of the fine line structure, it is preferable to set
an outer diameter of the ring body as small as possible. However, when the outer diameter
of the ring body is excessively small, the coagulation between the nickel fine particles
is strengthened. Accordingly, it is preferable to set the outer diameter of the ring
body to 0.05 to 100 µm, and it is more preferable to set the outer diameter of the
ring body to 0.5 to 10 µm. It is preferable to set a plate thickness of the ring body
to 0.01 to 10 µm.
Control of outer diameter of ring:
[0027] A size of the ring depends on a size of a planar particle of nickel chloride formed
by sublimation. Accordingly, along with the increase in a size of the nickel chloride
particle brought about by the prolongation of the time the nickel chloride stays in
a sublimation portion, the ring having a larger outer diameter is formed.
Control of inner diameter of ring:
[0028] An outer peripheral portion of the planar nickel chloride is constituted of a surface
having high interfacial surface energy and hence, a reaction is liable to occur on
the outer peripheral portion. Accordingly, when the nickel chloride particle is oxidized,
the oxidization occurs from the outer peripheral portion. The longer a time for oxidizing
the formed nickel chloride particle, the more the oxidization progresses so that a
size of an inner hole is decreased. Further, a reaction speed also influences the
control of an inner diameter of the ring, and it is possible to make the reaction
progress faster corresponding to the elevation of temperature within a temperature
range where nickel chloride is not sublimated. Still further, the higher the oxygen
concentration, the faster the reaction progresses. By making the reaction progress
faster, it is possible to acquire an advantageous effect substantially equal to an
advantageous effect which is acquired by prolonging a reaction time.
[0029] As a reducing agent used in reducing the nickel oxide fine particle, for example,
hydrogen, magnesium or the like is named. However, in view of a reason that magnesium
is liable to form an alloy thereof, hydrogen is preferably used. In reducing nickel
oxide using hydrogen, a reaction expressed by the following formula (II) progresses.
NiO+H
2→Ni+H
2O (II)
[0030] When the oxidization of the ring-shaped nickel oxide fine particle is insufficient
so that the nickel chloride partially remains in the nickel oxide fine particle, a
volume of the fine particle is largely decreased when nickel chloride is reduced to
nickel and hence, the ring body is broken into pieces at the time of reduction and
thereby string-shaped nickel fine particles are formed.
[0031] Although the mechanism that the nickel fine particle according to the present invention
is formed has been explained heretofore, in the present invention, it is preferable
to reduce a reduction product using hydrogen after a nickel chloride gas is made to
react with water vapor.
[0032] Here, firstly, due to a reaction between the nickel chloride gas and water vapor,
solid nickel oxide is formed. Since this reaction is an exothermic reaction, the remaining
nickel chloride gas not used in the reaction is cooled so that a nickel chloride phase
is changed into a solid phase from a gas phase and thereby a nickel chloride fine
particle having a hexagonal thin plate shape is formed.
[0033] With respect to the nickel chloride fine particle having a hexagonal thin plate shape
formed in this manner, due to a reaction between the nickel chloride fine particle
and water vapor which is not used in the above-mentioned reaction, only an outer peripheral
portion of the fine particle is oxidized and a center portion of the fine particle
is sublimated and thereby a ring-shaped nickel oxide fine particle according to the
present invention is obtained. Thereafter, the ring-shaped nickel oxide fine particle
according to the present invention is reduced using hydrogen so that the nickel fine
particle according to the present invention is formed.
[0034] Nickel chloride sublimated from the center portion of the nickel chloride fine particle
having a hexagonal thin plate shape also reacts with water vapor not used in the above-mentioned
reaction so that nickel oxide which differs from the ring-shaped nickel oxide fine
particle according to the present invention is formed. This reaction is also an exothermic
reaction, and also due to this exothermic reaction, a nickel chloride gas is cooled
so that a nickel chloride phase is changed into a solid phase from a gas phase and
thereby a nickel chloride fine particle having a hexagonal thin plate shape is formed.
[0035] As described above, in reducing a reaction product using hydrogen after making a
nickel chloride gas react with water vapor, it is preferable to supply 1 to 10 mol
of water vapor with respect to 1 mol of nickel chloride gas, and it is more preferable
to supply 2 to 7 mol of water vapor with respect to 1 mol of nickel chloride gas.
Further, it is preferable to supply 1 to 5 mol of hydrogen with respect to 1 mol of
nickel chloride gas, and it is more preferable to supply 2 to 4 mol of hydrogen with
respect to 1 mol of nickel chloride gas.
[0036] By setting a supply amount of water vapor and a supply amount of hydrogen within
the above-mentioned ranges, not only a flaky and string-shaped nickel fine particle
but also a ring-shaped nickel fine particle are formed.
[0037] The nickel fine particle according to the present invention is formed of the ring
body as described above, and the ring body has a center hole portion and a peripheral
portion which surrounds the periphery of the hole portion.
[0038] Fig. 3 is an SEM photograph obtained by photographing a nickel fine particle. Examples
which clearly show a ring-body shape of the nickel fine particle according to the
present invention are ring bodies indicated by A to D in the SEM photograph shown
in Fig. 3. Although all ring bodies A through D are included in the category of the
nickel fine particle according to the present invention, the present invention is
not limited to such ring bodies.
[0039] The ring body A is a typical example where a shape of the nickel chloride fine particle
which is a hexagonal thin plate shape is held. That is, the ring body A is formed
into a thin plate shape and includes a hexagonal peripheral portion and a circular
hole portion.
[0040] The ring body B is also an example where the ring body B is formed into a thin plate
shape in the same manner as the ring body A, and includes a hexagonal peripheral portion
and a circular hole portion. However, a diameter of the hole portion of the ring body
B is set smaller than a diameter of the hole portion of the ring body A.
[0041] The ring body C has a thin plate shape and, also includes a hexagonal peripheral
portion and a circular hole portion. However, a part of the peripheral portion is
broken. That is, the ring body C includes a breaking portion where the peripheral
portion is broken, and the breaking portion forms a part of the peripheral portion
in the present invention.
[0042] In the ring body C, the breaking portion occupies approximately 1/6 of a volume of
the peripheral portion. Further, in the ring body D, a breaking portion occupies an
amount slightly smaller than 1/2 of a volume of a peripheral portion. It is considered
that this breaking portion is formed in the course of the manufacture of a nickel
fine particle.
[0043] The ring body such as the above-mentioned ring body A, for example, has a minimum
outer diameter and a maximum outer diameter in the plate surface direction. When the
ring body holds a hexagonal shape, a ratio between the minimum outer diameter and
the maximum outer diameter (minimum outer diameter/ maximum outer diameter) theoretically
becomes √3/2 (8.66/10). Even when a hexagonal shape is held insufficiently, it is
preferable to set the ratio to 1/10 or more, and it is more preferable to set the
ratio to 2/10 or more.
[0044] It is also preferable to set a ratio between a plate thickness and a maximum outer
diameter (plate thickness/ maximum outer diameter) to 1/100 to 10/100.
[0045] Further, in viewing the ring body such as the ring body A described above, for example,
in the direction perpendicular to a plate surface, it is preferable to set an area
ratio between the peripheral portion and the hole portion (peripheral portion/ hole
portion) to 1/1 to 1/1000.
[0046] Provided that a shape and a size of the nickel fine particle according to the present
invention fall within the above-mentioned ranges, the nickel fine particle exhibits
excellent affinity with a binder resin.
[0047] Fig. 4 and Fig. 5 show SEM photographs obtained by photographing nickel fine particles.
However, Fig. 4 and Fig. 5 show the SEM photographs obtained by photographing the
nickel fine particles which are formed by methods different from the above-mentioned
method.
[0048] The nickel fine particle which the SEM photograph shown in Fig. 4 indicates is a
nickel fine particle which was manufactured by excessively oxidizing a nickel chloride
fine particle having a hexagonal thin plate shape. In this case, as shown in Fig.
4, although a flaky nickel fine particle was confirmed, a ring body was not confirmed.
The nickel fine particle which the SEM photograph shown in Fig. 5 indicates is a nickel
fine particle which was manufactured by insufficiently oxidizing a nickel chloride
fine particle having a hexagonal thin plate shape. In this case, as shown in Fig.
5, a ring body was not confirmed, and string-shaped nickel was confirmed.
[0049] Next, a mixture of nickel fine particles according to the present invention is explained.
The mixture of nickel fine particles according to the present invention is a mixture
of nickel fine particles which contains a nickel fine particle according to the present
invention and other nickel fine particles.
[0050] In the SEM photograph shown in Fig. 3, other nickel fine particles are also included
besides the nickel fine particle according to the present invention and hence, it
is safe to say that the SEM photograph shown in Fig. 3 indicates the mixture of nickel
fine particles according to the present invention.
[0051] In the mixture of nickel fine particles according to the present invention, it is
preferable that a mass ratio between the nickel fine particle according to the present
invention and other nickel fine particles (nickel fine particle according to the present
invention/other nickel fine particles) is above 1/1. By setting the mass ratio to
such a value, the mixture of nickel fine particles exhibits excellent affinity with
a binder resin so that a conductive path can be easily formed.
[0052] Next, a conductive paste according to the present invention is explained. The conductive
paste according to the present invention is a metal paste which contains at least
a nickel fine particle according to the present invention and a binder resin. The
conductive paste according to the present invention contains the nickel fine particle
according to the present invention and hence, a conductive path can be easily formed
and thereby the conductive paste exhibits excellent conductivity.
[0053] The conductive paste according to the present invention may contain a solvent, various
additives and the like when necessary.
[0054] A method of manufacturing the conductive paste according to the present invention
is not particularly limited and, for example, a method which mixes nickel powder according
to the present invention, a binder resin, a solvent, various additives and the like
together using a kneader, a roll or the like is named.
[Examples]
[0055] Hereinafter, the present invention is specifically explained by listing examples.
However, the present invention is not limited to these examples.
[0056] In examples and reference examples explained hereinafter, a reaction device 101 shown
in Fig. 2 was used. Fig. 2 is a cross-sectional view schematically showing the reaction
device 101. A nickel fine particle was manufactured by causing a reaction in the inside
of a quartz tube 103 having an inner diameter of 46 mmφ which the reaction device
101 includes.
[0057] A horizontal furnace 102 which covers the quartz tube 103 (and a portion of the quartz
tube 103 which the horizontal furnace 102 covers) is divided into three zones (a zone
1, a zone 2 and a zone 3), and predetermined temperatures in the respective zones
were made different from each other depending on cases.
[0058] A nitrogen (N
2) gas which is a carrier gas was supplied to the quartz tube 103 at a rate of 6.5Nl/min.
Further, a quartz-made nozzle 104 was arranged in the inside of the quartz tube 103,
and a hydrogen (H
2) gas was supplied to the zone 3 in the inside of the quartz tube 103 at a rate of
3Nl/min. A nickel-made crucible 111 in which water is stored was arranged in the zone
1 in the inside of the quartz tube 103, and the water was vaporized. A crucible made
of nickel 112 in which solid nickel chloride (purity: 99.9%, made by Wako Pure Chemical
Industries, Ltd.) is stored was arranged in the zone 2 in the quartz tube 103, and
the solid nickel chloride was sublimated. A collector (not shown in the drawing) was
arranged at a terminal end of the quartz tube 103. A glass fiber filter (made by Advantec
Co., Ltd.) was used as the collector. A nitrogen (N
2) gas for cooling is supplied to an area in the vicinity of the terminal end in the
inside of the quartz tube 103.
[0059] In the zone 2 in the inside of the quartz tube 103, due to cooling generated by a
reaction between sublimated nickel chloride and water vapor which is vaporized water
(exothermic reaction), a nickel chloride fine particle having a hexagonal thin plate
shape was formed from the sublimated nickel chloride, and a nickel oxide fine particle
was formed by causing a reaction between the nickel chloride fine particle and water
vapor. Then, in the zone 3, the nickel oxide fine particle was reduced by causing
a reaction between the nickel oxide fine particle and hydrogen thus forming a nickel
fine particle.
<Example 1>
[0060] The predetermined temperature in the horizontal furnace 102 was set such that the
temperature in the zone 1 was 1000°C, the temperature in the zone 2 was 1000°C and
the temperature in the zone 3 was 980°C. The crucible 111 storing 10g of water and
the crucible 112 storing 40g of solid nickel chloride were arranged in the lateral
furnace 102. A carrier gas and a hydrogen gas were supplied to the horizontal furnace
102 under the above-mentioned conditions, and a reaction time was set to 10 minutes.
[0061] In the example 1, 3 mol of water vapor and 3 mol of hydrogen were supplied with
respect to 1 mol of sublimed nickel chloride. An amount of sublimation of nickel chloride
was determined by detecting a hydrogen chloride gas which was generated due to a reaction
of nickel chloride with hydrogen, and an amount of vaporization was calculated based
on a vaporization time with respect to water vapor (the substantially same steps being
taken in the following example).
[0062] A nickel fine particle which is a reaction product was collected by a collector,
and the nickel fine particle was observed using a scanning electron microscope (SEM)
(S-4300 made by Hitachi High Technologies Corporation., the substantially same step
being taken in the following example) . Here, the above-mentioned Fig. 3 shows the
SEM photograph obtained by photographing the nickel fine particle which is the reaction
product in the example 1. As shown in Fig. 3, in the example 1, a nickel fine particle
which is a ring body was confirmed.
<Reference example 1>
[0063] The substantially same steps as the example 1 were carried out except for that a
hydrogen gas was not supplied to the inside of the quartz tube 103 from the nozzle
104.
[0064] In the reference example 1, when a reaction product was observed using the SEM, a
ring body was confirmed also in the reference example 1.
[0065] Then, when an analysis using an EDX (energy-dispersion-type X-ray analyzer) attached
to the SEM was done with respect to the same portion in the SEM photograph shown in
Fig. 6, nickel was 56 mol% and O was 44 mol% (Ni:O ≈ 1: 1) . From this result, it
is understood that a ring-shaped nickel oxide fine particle was collected as a reaction
product in the reference example 1. That is, Fig. 6 shows an SEM photograph obtained
by photographing a nickel oxide fine particle.
[0066] From the reference example 1, it is understood that a ring body was already formed
before the hydrogen reduction was performed in the zone 3 in the inside of the quartz
tube 103 according to the above-mentioned example 1.
[Description of Reference Numerals and Signs]
[0067]
- 101:
- reaction device
- 102:
- horizontal furnace
- 103:
- quartz tube
- 104:
- nozzle
- 111:
- crucible
- 112:
- crucible
1. A nickel fine particle which is a ring body having a ring shape.
2. The nickel fine particle according to claim 1, wherein the ring body has a center
hole portion and a peripheral portion which surrounds the periphery of the hole portion.
3. The nickel fine particle according to claim 2, wherein the ring body has a thin plate
shape.
4. The nickel fine particle according to claim 2 or 3, wherein the ring body has, as
a part of the peripheral portion, a breaking portion where the peripheral portion
is broken.
5. The nickel fine particle according to claim 4, wherein the breaking portion occupies
1/2 or less of a volume of the peripheral portion.
6. The nickel fine particle according to any one of claims 1 to 5, wherein an outer diameter
of the ring body is 0.05 to 100 µm.
7. A mixture of nickel fine particles which contains the nickel fine particle described
in any one of the claims 1 to 6 and other nickel fine particles.
8. A conductive paste which contains at least the nickel fine particle described in any
one of claims 1 to 6 and a binder resin.
9. A method of manufacturing a nickel fine particle according to any one of claims 1
to 6, comprising:
changing a nickel chloride phase into a solid phase from a gas phase by cooling a
nickel chloride gas, to obtain a nickel chloride fine particle having a thin plate
shape;
oxidizing the nickel chloride fine particle to obtain a nickel oxide fine particle,
wherein the oxidization is finished before the nickel chloride fine particle is completely
oxidized; and
reducing the nickel oxide fine particle, thus manufacturing the nickel fine particle.
10. The method according to claim 9, wherein the cooling comprises cooling by an endothermic
reaction caused by the oxidation of a solid nickel chloride.
11. The method according to claim 10, wherein the nickel chloride fine particle having
a thin plate shape is a nickel chloride fine particle having a hexagonal thin plate
shape.
1. Nickelfeinpartikel, das ein Ringkörper ist, der eine Ringform aufweist.
2. Nickelfeinpartikel gemäß Anspruch 1, wobei der Ringkörper einen Mittellochabschnitt
und einen Randabschnitt, der den Rand des Lochabschnitts umgibt, aufweist.
3. Nickelfeinpartikel gemäß Anspruch 2, wobei der Ringkörper eine Dünnplättchenform aufweist.
4. Nickelfeinpartikel gemäß Anspruch 2 oder 3, wobei der Ringkörper, als ein Teil des
Randabschnitts, einen Unterbrechungsabschnitt aufweist, wo der Randabschnitt unterbrochen
ist.
5. Nickelfeinpartikel gemäß Anspruch 4, wobei der Unterbrechungsabschnitt 1/2 oder weniger
eines Volumens des Randabschnitts einnimmt.
6. Nickelfeinpartikel gemäß einem der Ansprüche 1 bis 5, wobei ein Außendurchmesser des
Ringkörpers 0,05 bis 100 µm beträgt.
7. Mischung von Nickelfeinpartikeln, die das in einem der Ansprüche 1 bis 6 beschriebene
Nickelfeinpartikel und weitere Nickelfeinpartikel enthält.
8. Leitpaste, die zumindest das in einem der Ansprüche 1 bis 6 beschriebene Nickelfeinpartikel
und ein Harzbindemittel enthält.
9. Verfahren zur Herstellung eines Nickelfeinpartikels gemäß einem der Ansprüche 1 bis
6, umfassend:
Umwandeln einer Nickelchloridphase von einer Gasphase in eine Feststoffphase durch
Kühlen eines Nickelchloridgases zum Erhalten eines Nickelchloridfeinpartikels, das
eine Dünnplättchenform aufweist;
Oxidieren des Nickelchloridfeinpartikels zum Erhalten eines Nickeloxidfeinpartikels,
wobei die Oxidation beendet wird bevor das Nickelchloridfeinpartikels vollständig
oxidiert ist; und
Reduzieren des Nickeloxidfeinpartikels, dadurch Herstellen des Nickelfeinpartikels.
10. Verfahren gemäß Anspruch 9, wobei das Kühlen Kühlen durch eine endothermische Reaktion,
die durch die Oxidation eines festen Nickelchlorids verursacht wird, umfasst.
11. Verfahren gemäß Anspruch 10, wobei das eine Dünnplättchenform aufweisende Nickelchloridfeinpartikel
ein Nickelchloridfeinpartikel ist, das eine hexagonale Dünnplättchenform aufweist.
1. Fine particule de nickel qui est un corps annulaire ayant une forme d'anneau.
2. Fine particule de nickel selon la revendication 1, dans laquelle le corps annulaire
a une portion formant trou central et une portion périphérique qui entoure la périphérie
de la portion formant trou.
3. Fine particule de nickel selon la revendication 2, dans laquelle le corps annulaire
a une forme plate mince.
4. Fine particule de nickel selon la revendication 2 ou 3, dans laquelle le corps annulaire
a, en tant que partie de la portion périphérique, une portion de rupture où la portion
périphérique est rompue.
5. Fine particule de nickel selon la revendication 4, dans laquelle la portion de rupture
occupe 1/2 ou moins d'un volume de la portion périphérique.
6. Fine particule de nickel selon l'une quelconque des revendications 1 à 5, dans laquelle
un diamètre extérieur du corps annulaire est de 0,05 à 100 µm.
7. Mélange de fines particules de nickel qui contient au moins la fine particule de nickel
décrite selon l'une quelconque des revendications 1 à 6 et d'autres fines particules
de nickel.
8. Pâte conductrice qui contient au moins la fine particule de nickel décrite selon l'une
quelconque des revendications 1 à 6 et une résine de liant.
9. Procédé de fabrication d'une fine particule de nickel selon l'une quelconque des revendications
1 à 6, comprenant :
le changement d'une phase de chlorure de nickel en une phase solide à partir d'une
phase gazeuse en refroidissant un gaz de chlorure de nickel, pour obtenir une fine
particule de chlorure de nickel ayant une forme plate mince ;
l'oxydation de la fine particule de chlorure de nickel pour obtenir une fine particule
d'oxyde de nickel, dans lequel l'oxydation est finie avant que la fine particule de
chlorure de nickel soit complètement oxydée ; et
la réduction de la fine particule d'oxyde de nickel, en fabriquant ainsi la fine particule
de nickel.
10. Procédé selon la revendication 9, dans lequel le refroidissement comprend un refroidissement
par une réaction endothermique provoquée par l'oxydation d'un chlorure de nickel solide.
11. Procédé selon la revendication 10, dans lequel la fine particule de chlorure de nickel
ayant une forme plate mince est une fine particule de chlorure de nickel ayant une
forme plate mince hexagonale.