U.S. patent application number 14/776539 was filed with the patent office on 2016-02-04 for plating film, method of manufacturing plating film, and plated product.
The applicant listed for this patent is SONY CORPORATION. Invention is credited to Noriyuki SAITO.
Application Number | 20160032478 14/776539 |
Document ID | / |
Family ID | 51579918 |
Filed Date | 2016-02-04 |
United States Patent
Application |
20160032478 |
Kind Code |
A1 |
SAITO; Noriyuki |
February 4, 2016 |
PLATING FILM, METHOD OF MANUFACTURING PLATING FILM, AND PLATED
PRODUCT
Abstract
There are provided a plating film having high durability and
high reliability, a method of manufacturing the plating film, and a
plated product using the plating film. The plating film according
to the disclosure is formed with use of a solvent in which a
metallic salt is dissolved and a compound having functionality is
dissolved or colloidally dispersed, and the metal and the compound
having the functionality are homogenously dispersed and joined.
Inventors: |
SAITO; Noriyuki; (Miyagi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SONY CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
51579918 |
Appl. No.: |
14/776539 |
Filed: |
February 28, 2014 |
PCT Filed: |
February 28, 2014 |
PCT NO: |
PCT/JP2014/055062 |
371 Date: |
September 14, 2015 |
Current U.S.
Class: |
205/50 ;
205/109 |
Current CPC
Class: |
C25D 5/18 20130101; C25D
15/00 20130101 |
International
Class: |
C25D 15/00 20060101
C25D015/00; C25D 5/18 20060101 C25D005/18 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 19, 2013 |
JP |
2013-056936 |
Claims
1. A plating film including a metal and a compound having
functionality, the metal and the compound being homogenously
dispersed and joined.
2. The plating film according to claim 1, wherein the metal and the
compound having the functionality are joined at a molecular
level.
3. The plating film according to claim 1, wherein the compound
having the functionality includes one or more of water repellency,
oil repellency, and surface lubricity.
4. The plating film according to claim 1, wherein the metal and the
compound having the functionality are coprecipitated by
electrolytic plating.
5. A method of manufacturing a plating film, the method using a
solution in which a metal is dissolved and a compound having
functionality is dissolved or colloidally dispersed.
6. The method of manufacturing the plating film according to claim
5, comprising: preparing a plating solution by dissolving a
metallic salt of the metal in a solvent and then adding the
compound having the functionality in the solvent to dissolve or
colloidally disperse the compound; and immersing an object to be
plated in the plating solution to make a cathode, and applying a
voltage between the cathode and an anode.
7. The method of manufacturing the plating film according to claim
6, wherein the object to be plated is immersed in the plating
solution to make the cathode, and the voltage is applied between
the cathode and the anode to coprecipitate the metal and the
compound having the functionality, thereby forming a plating film
added with a function of the compound having the functionality.
8. The method of manufacturing the plating film according to claim
6, wherein the solvent in which the metallic salt is dissolved is
an organic solvent or mixed solution of the organic solvent and
water.
9. The method of manufacturing the plating film according to claim
8, wherein the organic solvent contains a non-polymerizable
compound, or one of a monomer and a polymer of a polymerizable
compound.
10. The method of manufacturing the plating film according to claim
8, wherein the organic solvent contains one or more kinds of
polymerizable compounds, and each of the polymerizable compounds
includes two or more kinds of compounds having respective
polymerization degrees different from one another.
11. The method of manufacturing the plating film according to claim
7, wherein the plating film is formed by electrolytic plating.
12. The method of manufacturing the plating film according to claim
11, wherein the electrolytic plating is carried out by application
of one of a DC voltage and an AC voltage.
13. A plated product comprising a plating film on a surface,
wherein the plating film includes a metal and a compound having
functionality, the metal and the compound being homogenously
dispersed and joined.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a plating film formed by
electrolytic plating, to a method of manufacturing the plating
film, and to a plated product using the plating film.
BACKGROUND ART
[0002] In a component, a mechanical component, and the like of an
electronic apparatus and a communication apparatus, metal plating
is used as surface treatment in order to improve abrasion
resistance and to reduce contact electric resistance. In recent
years, a so-called functional plating film has been developed in
which functionality such as water repellency, oil repellency, and
lubricity is provided to a plating film formed by the metal
plating.
[0003] A method of providing the above-described functionality to a
plating film has been in practical use in surface treatment for a
heating part of an electric iron, scissors for mowing. The method
is called composite plating in which microparticles (normally, each
having a particle diameter of 0.03 to 5 .mu.m) having functionality
that is to be provided to the plating film, specifically, for
example, diamond, molybdenum sulfide, a fluorine resin, a nitride,
or a metal oxide may be dissolved together with a surfactant in a
plating solution, and a plating metal and the above-described
microparticles are precipitated (coprecipitated) by electroless
plating on an object to be plated (for example, see PTLs 1 and 2).
As a result, it is possible to provide a function of hardness,
abrasion resistance, heat resistance, water repellency, lubricity,
and the like, to an object to be plated.
CITATION LIST
Patent Literature
[0004] PTL 1: Japanese Unexamined Patent Application Publication
No. 2012-92416
[0005] PTL 2: Japanese Unexamined Patent Application Publication
No. 2009-288463
SUMMARY OF INVENTION
[0006] However, in the plating film formed by any of the methods in
the PTLs 1 and 2, distribution of particles in the plating film is
easily biased due to difference in specific gravity between the
plating film and the microparticles having functionality.
Accordingly, there are issues of occurrence of film peeling and a
crack due to temperature change, and occurrence of unevenness in
expression of the functionality in the plating film.
[0007] Accordingly, it is desirable to provide a plating film
having high durability and high reliability, a method of
manufacturing the plating film, and a plated product using the
plating film.
[0008] A plating film according to an embodiment of the technology
includes a metal and a compound having functionality, and the metal
and the compound are homogeneously dispersed and joined.
[0009] A method of manufacturing a plating film according to an
embodiment of the technology uses a solution in which a metal is
dissolved and a compound having functionality is dissolved or
colloidally dispersed.
[0010] A plated product according to an embodiment of the
technology includes the above-described plating film.
[0011] In the plating film, the method of manufacturing the plating
film, and the plated product according to the respective
embodiments of the technology, the plating film is formed with use
of the solution in which the metallic salt of the metal configuring
the plating film is dissolved and the compound having the
functionality is dissolved or colloidally dispersed. Accordingly,
the metal configuring the plating film and the compound having the
functionality (functional compound) are homogenously dispersed and
joined.
[0012] According to the plating film, the method of manufacturing
the plating film, and the plated product of the respective
embodiments of the technology, the metal configuring the plating
film and the compound having the functionality (the functional
compound) are homogenously dispersed and joined. Therefore,
distribution of the compound having the functionality is
homogenized, which improves durability of the plating film. In
addition, it becomes possible to improve homogeneity and
reliability of characteristics provided to the plated product.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a schematic diagram of a sectional structure of a
plating film according to an embodiment of the disclosure.
[0014] FIG. 2 is a flowchart of steps of manufacturing the plating
film illustrated in FIG. 1.
[0015] FIG. 3A is a schematic diagram before conduction of a
plating bath in the steps of manufacturing the plating film
illustrated in FIG. 1.
[0016] FIG. 3B is a schematic diagram during the conduction of the
plating bath illustrated in FIG. 3A.
[0017] FIG. 4 is a waveform diagram of an applied voltage (AC).
[0018] FIG. 5 is a schematic diagram of a sectional structure of a
plating film in a related art.
DESCRIPTION OF EMBODIMENTS
[0019] An embodiment of the disclosure will be described in detail
below with reference to drawings. Note that description will be
given in the following order.
1. Embodiment
[0020] 1-1. Structure of plating film
[0021] 1-2. Method of manufacturing plating film
2. Application Examples
3. Examples
1. Embodiment
1-1. Structure of Plating Film
[0022] FIG. 1 schematically illustrates a sectional structure of a
plating film (a plating film 10) according to an embodiment of the
disclosure. The plating film 10 is formed of a metal (a plating
metal 11) and a compound having functionality (a functional
compound 12), and provides a function of water repellency, oil
repellency, lubricity, or the like to an object to be plated such
as a metal product and a metal component. In the present
embodiment, for example, the plating film 10 may be formed, by
non-aqueous plating, in a state where the plating metal 11 and the
functional compound 12 are homogeneously dispersed as illustrated
in FIG. 1. Here, homogeneous indicates a state in which the
functional compound 12 is uniformly distributed without deviation
in an in-plane direction and a film thickness direction of the
plating film 10, as illustrated in FIG. 1. Specifically, for
example, the homogeneous indicates a state in which the plating
metal 11 and the functional compound 12 is coprecipitated at a
molecular level at the time of forming the plating film 10 by
plating operation, and the functional compound 12 is directly
joined with the plating metal 11. Alternatively, the homogeneous
indicates a state in which one or more functional compounds are
coupled with a metal grain (metal crystal grain boundary of the
plating metal 11). Alternatively, the homogeneous indicates a state
in which the plating metal 11 and the functional compound 12 are in
a so-called solid solution state.
[0023] The plating metal 11 is not particularly limited as long as
the plating metal is dissolved in a plating solvent of non-aqueous
plating described later. Specific examples of the plating metal may
include lithium (Li), beryllium (Be), boron (B), sodium (Na),
magnesium (Mg), aluminum (Al), silicon (Si), potassium (K), calcium
(Ca), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn),
iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn),
gallium (Ga), germanium (Ge), arsenic (As), rubidium (Rb),
strontium (Sr), zirconium (Zr), niobium (Nb), molybdenum (Mo),
ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium
(Cd), tin (Sn), antimony (Sb), cesium (Cs), barium (Ba), hafnium
(Hf), tantalum (Ta), tungsten (W), iridium (Ir), platinum (Pt),
gold (Au), mercury (Hg), lead (Pb), and bismuth (Bi).
[0024] The functional compound 12 has a function of water
repellency, oil repellency, lubricity, or the like as described
above. Examples of the compound having these functions may include
fluorine-based compound, silicon-based compound, hybrid compound of
fluorine and silicon, and fatty oils. Among them, the
fluorine-based compound is most suitable for the method in the
present embodiment because the fluorine-based compound exhibits
high effect by a small amount.
[0025] In the present embodiment, the functional compound that is
dissolved in the plating solvent or maintains colloidal state in
plating is used. In addition, one or two or more kinds of the
functional compound 12 described below may be combined and
used.
[0026] Examples of the fluorine-based compound may include a
compound (fluoroalkyl compound) having a functional group in which
a part or all of hydrogen atoms of an alkyl group are substituted
with fluorine atoms. Specifically, out of fluoroalkyl compounds, a
compound having a hydroxyl group, a carboxyl group, a phosphate
group, or the like as an end group may be used singly, or may be
coupled with other compound having reactivity with these compounds
(alternatively, a compound subjected to structure modification
appropriately in order to prepare reflectivity) and used. In other
words, fluoroalkyl ether, fluoroclkyl ester, or the like may be
used. Note that the number of ether bonds or ester bonds in one
molecule is not particularly limited as long as the compound is
dissolved in a solvent or maintains the colloidal state. An amount
of the compound with respect to the plating solution may be
appropriately adjusted within a range where phase separation of the
compound does not occur in the plating solution. It is desirable to
avoid the phase separation because unevenness occurs on the plated
surface when the phase separation occurs.
[0027] Examples of the commercially-available fluorine-based
compound may include Braycoat (trademark; Castrol Limited), Fomblin
(trademark; Solvay), Krytox (trademark; Du Pont), Demnum
(trademark; Daikin Industries, Ltd.), Barrierta (trademark; NOK
Kluber Co., Ltd.), Sumitec (trademark; Sumico Lubricant Co., Ltd),
Multemp (trademark; Kyodo Yushi Co., Ltd.), and Surflon (trademark;
AGC Seimi Chemical Co., Ltd.).
[0028] As the solvent of the plating metal 11 and the functional
compound 12 (a plating solvent), a solvent dissolving the metallic
salt of the plating metal 11 that is a supply source of plating
metal and dissolving or colloidally dispersing the functional
compound 12 may be used. As the solvent dissolving the metallic
salt, a highly-polar organic solvent is suitable, and a
highly-polar organic solvent containing a heteroatom of nitrogen
(N), sulfur (S), oxygen (O), or the like in a molecule may be
preferable. The highly-polar organic solvent is mixed with a
low-polar solvent to obtain a mixed solvent with appropriate
polarity. According to combination of the metallic salt of the
plating metal 11 and the functional compound 12, for example, the
organic solvents described below may be used singly or as a mixture
of two or more solvents.
[0029] Examples of the nitrogen-containing organic solvent may
include acetonitrile, N-methylpyrrolidone, ethanolamine,
diethanolamine, triethanolamine, N-methyldiethanolamine,
N-ethyldiethanolamine, morpholine, N-ethylmorpholine,
ethylenediamine, diethylenetriamine, triethylenetetramine,
polyethyleneimine, tetramethyl propylenediamine, formamide,
N,N-dimethylformamide, N,N-dimethylacetamide, .beta.-lactam,
.gamma.-lactam, .delta.-lactam, 2-pyrrolidinone,
N-methyl-2-pyrrolidinone, N-vinyl-2-pyrrolidinone, 2-oxazolidone,
and 1,3-dimethyl-2-imidazolidinone.
[0030] Examples of the sulfur-containing organic solvent may
include sulfolane, dimethyl sulfoxide, dimethyl sulfone,
2-mercaptoethanol, 3-mercapto-1-propanol, 3-mercapto-1-propanol,
2,3-dimercapto-1-propanol, 3-mercapto-1,2-propanediol,
1,3-propanedithiol, and thiodiglycol.
[0031] Examples of the oxygen-containing organic solvent may
include propylene carbonate, dimethylcarbonate, ethylenecarbonate,
methyl acetate, ethyl acetate, .gamma.-butyrolactone,
dimethoxyethane, methanol, ethanol, propanol, isopropanol, butanol,
isobutanol, sec-butanol, t-butanol, pentanol, hexanol,
cyclohexanol, benzyl alcohol, ethylene glycol, diethylene glycol,
triethylene glycol, polyethylene glycol, propylene glycol,
dipropylene glycol, polypropylene glycol, butylene glycol,
hexanediol, pentanediol, hexanetriol, 1,3-propanediol,
2-methyl-1,3-propanediol, 1,2-propanediol, 1,4-butanediol,
2-methyl-1,4-butanediol, 1,3-butanediol, 1,2-butanediol, glycerol,
2,3-butanediol, diethylene glycol monomethyl ether, diethylene
glycol monoethyl ether, diethylene glycol monobuthyl ether,
triethylene glycol monomethyl ether, triethylene glycol monobuthyl
ether, dipropylene glycol monomethyl ether, dipropylene glycol
monoethyl ether, tripropylene glycol monomethyl ether,
diethylether, tetrahydrofuran, acetone, and methyl ethyl ketone.
Note that an acidic solvent easily isolating proton causes
generation of hydrogen on a cathode, and therefore it is desirable
to avoid the use of the acidic solvent.
[0032] Also, when the polarity of the functional compound 12 to be
coprecipitated with the plating metal 11 is small, it is possible
to enhance compatibility by using a low-polar organic solvent;
however, typically, the plating metal 11 is easily dissolved in a
highly-polar organic solvent. In such a case, as the plating
solvent, the highly-polar solvent to dissolve the metallic salt and
the low-polar solvent to dissolve the functional compound 12 may be
mixed at an appropriate ratio and the mixed solvent may be used.
Alternatively, the metallic salt is dissolved in the highly-polar
solvent, and the low-polar functional compound 12 may be
colloidally dispersed in this highly-polar solvent, and the
resultant may be used.
[0033] Examples of the low-polar organic solvent may include a
halide such as dichloromethane, dichloroethane, chloroform, and
dichlorobenzene, an aromatic compound such as benzene, toluene, and
xylene, and an aliphatic compound such as hexane, heptane, and
octane.
[0034] Also, as the plating solvent, molecular weight may be
adjusted by polymerization of polymerizable monomer having large
polarity with use of the fact that the polarity of the entire
molecule decreases as the molecular weight increases, and a plating
solvent whose polarity is controlled may be used. Note that it is
desirable to avoid a plating solvent that causes resolution and
polymerization by plating operation such as heating and voltage
application. Accordingly, examples of the preferable polymerizable
monomer may include glycols such as ethylene glycol, propylene
glycol, and butylene glycol. As described above, the plating
solvent may include one of a monomer and a polymer of a
polymerizable compound, or non-polymerizable compound.
[0035] As described above, although the organic solvent is
described as the plating solvent, the above-described organic
solvent added with water may be used depending on solubility of the
functional compound.
[0036] Moreover, the plating film 10 may control the precipitation
form of the plating metal 11 by selecting a kind of the plating
solvent. Typically, degree of ionization of the compound (for
example, the metallic salt of the plating metal 11) dissolving in
the solvent becomes higher as the polarity of the plating solvent
becomes higher. Therefore, ionic conductance of the solvent becomes
higher and precipitation rate of the plating metal 11 also
increases. At this time, whisker-like metallic crystal called
whisker easily grows depending on the kind of the metal to be
precipitated. The whisker causes short circuit between electrodes.
Moreover, even in the case of a metal difficult to cause whisker,
the metallic crystal precipitated easily increases in size, which
influences hardness, peeling strength, color, gloss, etc. of the
plating film 10. Therefore, the precipitation form of the plating
metal 11 is first observed, and a solution in which ion
conductivity is decreased to a level where a glossy metallic film
with suppressed whisker is obtained, by combining the metallic salt
to be used for plating, temperature of the plating solution, or
application voltage and the waveform thereof, based on the result
of the observation, may be preferably used as the plating solvent
in the present embodiment.
[0037] An additive such as a brightener and a supporting
electrolyte may be added to a plating solution R. Properties of the
brightener and the supporting electrolyte may be considered
similarly to those of aqueous plating typically used.
[0038] The brightener caps a projection generated on a surface of
the plating film 10 to prevent electric field concentration,
thereby planarizing the plating film 10. Examples of the brightener
may include typically an organic compound having high absorptive
property, namely, having large polarization in a molecule, for
example, an organic compound containing a functional group such as
a carboxyl group, an aldehyde group, an ester group, a hydroxy
group, a thiol group, a cyano group, a sulfonic group, an amide
group, and an imide group. Specific examples thereof may include
thiourea, coumarin, ethylene cyanohydrin, and saccharin. Note that
there is a case where a compound added as the functional compound
12 or an organic solvent as a plating solvent itself expresses a
function of the brightener.
[0039] The supporting electrolyte is to enhance the conductivity of
the electrolytic solution (the plating solution R). The supporting
electrolyte is selected from salts easily ionized at the time of
being dissolved in the plating solvent. When the plating solvent is
the organic solvent, the perchlorate of tetraalkylammonium,
tetrafluoroborate, or the like is often used. Specific examples
thereof may include ammonium perchlorate, tetramethylammonium
perchlorate, tetraethylammonium perchlorate, tetramethylammonium
tetrafluoroborate, and tetraethylammonium tetrafluoroborate. When
the plating solvent contains water, metal halide, metal nitrate, or
the like is often used. Specific examples thereof may include
sodium chloride, lithium chloride, sodium nitrate, lithium nitrate,
sodium perchlorate, and lithium perchlorate.
[0040] Hereinafter, a method of manufacturing the plating film 10
according to the present embodiment is described.
1-2. Manufacturing Method
[0041] In the method of manufacturing the plating film 10 according
to the present embodiment, non-aqueous plating is used. In the
non-aqueous plating, an organic solvent is used as a main plating
solvent.
[0042] FIG. 2 illustrates a flow of steps of manufacturing the
plating film 10 with use of electrolytic plating according to the
present embodiment. The metallic salt of the plating metal 11 is
dissolved in an appropriate solvent. The functional compound 12 is
added thereto, and dissolved or colloidally dispersed. At this
time, the solvent may be used singly or as a mixture of two or more
solvents (step S101).
[0043] Subsequently, the plating solution R is placed in a plating
bath 31 (FIG. 3A) that has an anode electrode 32 provided with a
supply source (a metal plate 32A) of the plating metal 11 and a
cathode electrode 33 provided with an object to be plated, and the
plating solution R is adjusted to predetermined temperature while
being stirred (step S102). Here, the temperature of the plating
solution R may be arbitrarily set within a range where the plating
solution R exhibits suitable fluidity and is free from deposition
and precipitation of electrolyte. Since the ion conductivity of the
plating solution R is increased as the temperature is set higher,
the precipitation rate of the plating metal on the cathode
electrode 33 also increases. In the case of the non-aqueous
plating, it is possible to set the temperature of the plating
solution R to be higher with use of a high-boiling organic solvent,
a molten salt, an ionic liquid, or the like, as the plating
solvent. Incidentally, there is a case where oxidation reduction
reaction or the like between the organic solvent and the electrode
is accelerated by high temperature, which may cause deterioration
of the electrode. In addition, there is a case where the metal used
for the electrode functions as a catalyst and accelerates
resolution and polymerization of the organic solvent. Therefore,
the organic solvent corresponding to the material of the electrode
to be used may be desirably selected, and plating operation may be
desirably carried out at appropriate temperature.
[0044] Next, a predetermined voltage is applied to the anode
electrode 32 and the cathode electrode 33 to cause coprecipitation
of the plating metal 11 and the functional compound 12 on the
object to be plated 20 that is disposed on the cathode electrode
33, as illustrated in FIG. 3B (step S103). Here, there is a case
where whisker occurs on the surface of the plating layer 11 as
described above or a diameter of crystal grain of the precipitated
metal is changed by the voltage or the temperature. For example,
these appear as fine irregularity on the surface of the plating
layer 11 or as difference in color. These changes depend on a kind
of a metal to be plated; however, controlling the waveform of the
application voltage makes it possible to homogenize the grain
diameter to some extent. Both of a DC voltage and an AC voltage may
be used as the application voltage; however, for the
above-described reason, an AC voltage including a large number of
controllable parameters may be preferably used.
[0045] It is possible to set an arbitrary voltage waveform and then
apply the AC voltage. The voltage waveform may be, for example, a
rectangular wave, a sine wave, or a triangle wave. FIG. 4
illustrates the waveform of the application voltage used in
Examples described later. It is unnecessary for the cathode
electrode 33 to be a minus (-) voltage constantly, and the voltage
of the cathode electrode 33 may be switched over to a plus (+)
voltage within a range where the precipitated metal remains. It is
possible to dissolve generated whisker and a part where electric
field concentration easily occurs such as a projection, by this
operation. It becomes possible to improve flatness (specularity and
gloss level) of the surface of the plating film 10 and to increase
the thickness of the plating film 10 by using the property.
[0046] Note that it is considered that, by the AC voltage, the
thickness of a diffusion layer of the plating solution R formed on
the surface of the plating film 10 is decreased to about one-tenth
of that by the DC voltage. Therefore, it is considered that the
plating film 10 is formed at high current density of several
hundred times or several thousand times of that by the DC voltage,
the generation rate of the crystalline nucleus often exceeds the
growth rate, and thus it is possible to form fine metallic
crystal.
[0047] In this way, the plating film 10 illustrated in FIG. 1 is
formed.
[0048] Incidentally, water is not necessarily eliminated entirely
as the plating solvent, and water may be added to the organic
solvent depending on a case. There is a case where moisture
contained in the organic solvent as the plating solvent or
crystalline water contained in the metallic salt exhibits an effect
similar to that in the case where water is added to the organic
solvent. Incidentally, in a case where a highly hydrophobic
compound is used as the functional compound 12 to be coprecipitated
with the plating metal 11 on the object to be plated 20 and the
plating operation is carried out with use of the plating solution R
in which the highly hydrophobic compound is sufficiently compatible
with the organic solvent and adjusted, an amount of moisture in the
plating solution 11 may be desirably managed. The amount of
moisture contained in the state of the plating solution R may be
preferably equal to or lower than a volume of the organic solvent.
More preferably, the amount of moisture may be equal to or lower
than 10%. In the case where the highly hydrophobic compound is
used, a solvent dehydrated by dehydration treatment is used. In
this case, the plating operation may also be preferably carried out
in a dry box in which the inner air is substituted with nitrogen or
argon.
[0049] FIG. 5 illustrates a sectional structure of a plating film
110 formed with use of a typical composite plating. A functional
plating film provides a function of, for example, water repellency,
oil repellency, or lubricity to an object to be plated, by
combining a plating metal and a material having any functionality
as described above. When the plating film 110 is formed with use of
the composite plating, functional particles 112 are often different
in specific gravity from the plating solution in which a plating
metal 111 is dissolved, and the surface thereof often have no
affinity with the plating solution. Accordingly, if both are simply
mixed and stirred, it is difficult to disperse the functional
particles 112 homogenously in the plating solution. Thus, an
attempt has been made to enhance affinity of the particle surface
to the plating solution by performing surface treatment, for
example, irradiation of an active energy ray such as an ultraviolet
ray to the functional particles 112, adding a surfactant to the
plating solution, or performing surface treatment on the functional
particles 112 with use of silane coupling agent. However, it is
difficult to sufficiently resolve the distribution issue of the
functional particles 112 in the formed plating film 110 even by
performing such operation.
[0050] In such a plating film 110, the functional particles are
dispersed inhomogeneously in the plating metal 111. Accordingly,
when the coefficient of thermal expansion of the plating metal 111
is different from that of the functional particles 112, the metal
and the particles of the functional particles 112 are peeled off in
the plating film 10, and the peeled-off metal and the peeled-off
particles are coupled, which may cause crack. Alternatively, the
particles of the functional particles 112 on the surface of the
plating film 110 may fall off, which may cause pinhole. Moreover,
when the content percentage of the functional particles 112 to the
plating film 110 is large, the plating film 110 becomes fragile.
Further, since a size of each of the functional particles 112
typically used is about 0.03 to 5 .mu.m normally, it is difficult
to use the plating film 110 for a component demanding accuracy at
nano level, such as micro electro mechanical systems (MEMS).
[0051] In contrast, in the method of manufacturing the plating film
10 according to the present embodiment, non-aqueous plating is
used. It is possible for the non-aqueous plating to coprecipitate
wide variety of metals as compared with plating using water as a
solvent (aqueous plating). This is because hydrogen gas derived
from water or proton is difficult to be generated in the
non-aqueous plating, and thus it is possible to precipitate a metal
whose oxidation-reduction potential is significantly low (for
example, an alkali metal and alkaline earth metal). Further, in the
non-aqueous plating, it is possible to precipitate a metal having
high affinity for oxygen, such as Al, Ti, Tl, Nb, and V that are
not precipitated by aqueous plating due to oxygen and dissolved
oxygen derived from water.
[0052] Moreover, in the non-aqueous plating, selecting a low protic
solvent as the plating solvent makes it possible to suppress
generation of hydrogen on the cathode electrode even when a high
voltage (for example, 10 V or higher) is applied. Therefore, it is
possible to suppress generation of pinhole on the plated surface
caused by generation of bubbles. Further, it is possible to control
the property of the plating solvent by mixing a plurality of
organic solvents. This makes it possible to widen a control range
of the characteristics of the plating film 10.
[0053] In the present embodiment, the plating metal 11 is dissolved
in the plating solvent with use of the above-described non-aqueous
plating, and the plating film 10 is formed in a state where the
functional compound 12 is dissolved or colloidally dispersed in the
plating solvent. As a result, it is possible to form the plating
film 10 in which a metal configuring the plating film and a
compound having functionality (a functional compound) are
homogeneously dispersed and joined, that is, are homogeneously
mixed at molecular level.
[0054] The plating film 10 formed in this way maintains the
functionality if the plating film 10 is worn away. In other words,
as compared with the above-described plating film 110 formed by the
composite plating, crack is difficult to occur in the plating film
10, and resistance to bending, batting, and the like is enhanced.
In addition, a factor causing a pinhole, such as falling off of the
functional particles 112 in the plating film 110 is eliminated.
Accordingly, it is possible to provide the plating film 10 that has
improved durability, functionality expressed with high uniformity,
and improved reliability, and to provide a plated product including
the plating film 10.
2. Application Examples
[0055] The plating film 10 described in the above-described
embodiment is applicable to various kinds of plated products.
Specifically, the plating film 10 may be applicable to, for
example, a metal product, a metal component, a gear, a bearing, an
edge of a skate, a ski board, a snowboard, and the like. As a
result, rust-proof function, lubricity, and the like are imparted
to the above-described products. In addition, it is possible to
impart corrosion resistance and acid resistance of metal against
corrosive gas, etc.
[0056] Further, for example, it is possible to prevent adhesion of
barnacles to seawater suction port of an electric generation plant,
ship bottom, or the like, to facilitate demolding of a resin molded
product from a mold, and to make adhered substance hard to remain
to a blade. Alternatively, it becomes possible to use the plating
film 10 in prevention of residue in a nozzle that discharges
viscous liquid such as an adhesive, in control of fluid resistance
in a pipe, in reduction of resistance of an injection needle,
etc.
[0057] Furthermore, it is possible to maintain lubricity under
ultimate condition of outer space, or the like. In the outer space,
machinery is exposed to severe conditions such as non-gravity, high
vacuum, high temperature, low temperature, and radiation exposure.
Therefore, it is desirable to maintain the operation function in
the outer space. At present, high-boiling grease is used for the
purpose. However, since optical equipment such as various kinds of
sensors and a spectroscope are vulnerable to contamination by
evaporant, a non-volatile lubricating material is strongly
demanded. The plating film according to the present technology may
fulfill such demand.
3. Examples
[0058] Hereinafter, Examples of the disclosure are specifically
described. However, the technology is not limited to these
Examples.
Example 1
[0059] For example, 100 g of tin chloride (the metallic salt of the
plating metal 11) was dissolved in 300 ml of 4-butyrolactone (the
plating solvent) to prepare the plating solution R. The plating
solution was placed in Hull cell tester (trademark; Yamamoto-MS
Co., Ltd.) that was made of glass and was attached with the anode
electrode 32 and the cathode electrode 33 as illustrated in FIG.
3A, and the plating solution was maintained at temperature of
70.degree. C. while being stirred with a rotor. Here, the plating
metal and the metal to be plated were used as is as the anode
electrode and the cathode electrode, respectively. In this state,
the AC voltage that had the AC waveform illustrated in FIG. 4 and
whose parameters were set to those in voltage condition 1 was
applied to perform the plating operation. As a result, the plating
film 10 (Example 1-1) was obtained. Besides, the plating films 10
in respective Examples 1-2, 1-3, and 1-4 were obtained with use of
similar procedure. Conditions in the respective Examples were as
follows.
Example 1-1
[0060] [Solvent] 4-butyrolactone (molecular weight 86)
[0061] [Plating Metal] tin
[0062] [Functional Compound] none
[0063] [Voltage Condition 1] Vp=15 [volt] [0064] Vb=-4 [volt]
[0065] Tp=50 [msec] [0066] Tw=4 [msec]
[0067] [Cathode] copper plate (100 m in width.times.67 mm in
length)
[0068] [Anode] tin plate (64 mm in width.times.64 mm in length)
Example 1-2
[0069] [Solvent] ethylene glycol (molecular weight 62)
[0070] [Plating Metal] tin
[0071] [Functional Compound] none
[0072] [Voltage Condition 1]
[0073] [Cathode] copper plate (100 mm in width.times.67 mm in
length)
[0074] [Anode] tin plate (64 mm in width.times.64 mm in length)
Example 1-3
[0075] [Solvent] polyethylene glycol (average molecular weight
200)
[0076] [Plating Metal] tin
[0077] [Functional Compound] none
[0078] [Voltage Condition 1]
[0079] [Cathode] copper plate (100 mm in width.times.67 mm in
length)
[0080] [Anode] tin plate (64 mm in width.times.64 mm in length)
Example 1-4
[0081] [Solvent] polyethylene glycol 400 (average molecular weight
400)
[0082] [Plating Metal] tin
[0083] [Functional Compound] none
[0084] [Voltage Condition 1]
[0085] [Cathode] copper plate (100 mm in width.times.67 mm in
length)
[0086] [Anode] tin plate (64 mm in width.times.64 mm in length)
[0087] In the Example 1-1, a contact angle of water in a glossy
part was measured by a sessile drop method. As a result, the
contact angle was 66.degree. in a tangent method. In addition,
conductivities of the plating solutions in the respective Examples
were 2.40 (mS, Example 1-1), 1.13 (mS, Example 1-2), 0.17 (mS,
Example 1-3), and 0.08 (mS, Example 1-4) at the temperature of
25.degree. C.
[0088] The conductivity in the Example 1-1 was higher than that in
the Example 1-2, and therefore, lot of whisker occurred. In the
Examples 1-2 to 1-4, polymerizable monomers varied in
polymerization degree were used as the plating solvent, and the
conductivity decreased as the molecular weight increased. When
plating was carried out until the plating film 10 had a certain
film thickness, it was confirmed that whisker occurrence amount at
the edge part of the copper plate on a side where a distance
between electrodes was short decreased in proportion to the
conductivity. This indicated that the metallic salt (tin chloride)
was dissolved in the electrolytic solution (the plating solution R)
in a state where the metallic salt was not sufficiently ionized. In
other words, it was estimated that this was because when the
metallic salt existed as ions, metallic cation was easily
precipitated on the anode electrode 32, and therefore, whisker
easily grew depending on slight irregularity on the metal plate and
difference in activation, whereas when the ionization was
insufficient and the metal was precipitated as the metal after
ionized on the surface of the electrode, whisker was difficult to
grow. An area occupied by a mirror part in the plating film 10 also
increased as the molecular weight of the plating solvent increased,
and rough surface (nonglossy plating) occurred on the side where
the distance between electrodes was short decreased.
[0089] As described above, it was possible to increase the
thickness of the plating film 10 while maintaining gloss on the
surface of the plating film 10 by mixing a monomer and a polymer
(oligomer or polymer) of polymerizable monomer as the plating
solvent or increasing the average molecular weight of the solvent
of the electrolytic solution with use of only the polymer.
Example 2
[0090] 3.0 g of pentadecafluorooctanoic acid and 0.3 g of glycerin
were dehydrated and condensed. As a result, 3.1 g of fluoroalkyl
ester serving as the functional compound 12 was obtained as an oily
matter. This was dissolved in 50 ml of propylene carbonate (plating
solvent B) (plating solution B). 100 g of tin chloride (the
metallic salt of the plating metal 11) was dissolved in 250 ml of
ethylene glycol (plating solvent A) (plating solution A). After
that, the plating solution A and the plating solution B were mixed
to prepare the plating solution R. Subsequently, the plating
solution R was placed in Hull cell tester (trademark; Yamamoto-MS
Co., Ltd.) that was made of glass and was attached with the anode
electrode 32 (the tin plate) and the cathode electrode 33 (the
copper plate) similarly to the above-described Example 1, and the
plating solution was maintained at temperature of 70.degree. C.
while being stirred with a rotor. In this state, the AC voltage
that had the AC waveform illustrated in FIG. 4 and whose parameters
were set to those in voltage condition 1 was applied to perform
plating. As a result, the plating film 10 (Example 2-1) was
obtained.
[0091] Also, plating with use of a commercially-available
fluoroalkyl compound was carried out. 100 g of tin chloride was
dissolved in 300 ml of ethylene glycol. 16 g of Surflon
(manufactured by AGC Seimi Chemical Co., Ltd.) was mixed thereto
and sufficiently stirred and dissolved to prepare the plating
solution. The plating solution was placed in Hull cell tester
(Yamamoto-MS Co., Ltd.) that was made of glass and was attached
with the anode electrode 32 (the tin plate) and the cathode
electrode 33 (the copper plate), and the plating solution was
maintained at temperature of 70.degree. C. while being sufficiently
stirred with a rotor. In this state, the AC voltage that had the AC
waveform illustrated in FIG. 4 and whose parameters were set to
those in voltage condition 1 was applied to perform plating. As a
result, the plating film 10 (Example 2-2) was obtained. The
conditions in the respective Examples were as follows.
Example 2-1
[0092] [Solvent] ethylene glycol/propylene carbonate=5/1
[0093] [Plating Metal] tin
[0094] [Functional Compound] fluoroalkyl ester
[0095] [Voltage Condition 1]
[0096] [Cathode] copper plate (100 mm in width.times.67 mm in
length)
[0097] [Anode] tin plate (64 mm in width.times.64 mm in length)
Example 2-2
[0098] [Solvent] ethylene glycol (molecular weight 62)
[0099] [Plating Metal] tin
[0100] [Functional Compound] Surflon S-242 (manufactured by AGC
Seimi Chemical Co., Ltd.)
[0101] [Voltage Condition 1]
[0102] [Cathode] copper plate (100 mm in width.times.67 mm in
length)
[0103] [Anode] tin plate (64 mm in width.times.64 mm in length)
[0104] In the Examples 2-1 and 2-2, the contact angles of water in
the glossy part of the plating film 10 were measured by the sessile
drop method. As a result, the contact angles were 134.degree. and
102.degree. in the tangent method. In addition, the contact angle
of water was measured after the plated surface was scraped by about
2 .mu.m with use of a polishing sheet (3M lapping film sheet), and
it was confirmed that water repellency was maintained.
Example 3
[0105] The plated samples of the above-described Examples 1-1 and
2-1 were immersed in pure water and left at room temperature. Note
that the plating film 10 before immersion had a silvery luster
smooth surface in both of the Examples 1-1 and 2-1. Two weeks
later, the plated samples of the Examples 1-1 and 2-1 were taken
out, and water was then sufficiently removed with air blow. The
plating film 10 in the Example 1-1 was changed in color to mat gray
and a part thereof was peeled off and detached, whereas the plating
film 10 in the Example 2-1 maintained silver gloss. The surface
roughness of the plating films 10 were measured by a surface
roughness meter (manufactured by KLA-Tencor Corporation, P-15
surface profiler). As a result, the surface roughness Ra were 0.49
.mu.m (the Example 1-1) and 3.41 pm (the Example 2-1).
Example 4
[0106] Next, the plating films 10 of Examples 4-1 and 4-2 were
obtained through the procedure similar to that in each of the
above-described Examples 1 and 2. Conditions in the respective
Examples were as follows.
Example 4-1
[0107] [Solvent] 4-butyrolactone/ethylene glycol=3/1
[0108] [Plating Metal] nickel
[0109] [Functional Compound] none
[0110] [Voltage Condition 2] Vp=0 [volt] [0111] Vb=10 [volt] [0112]
Tp=50 [msec] [0113] Tw=25 [msec]
[0114] [Cathode] copper plate (100 mm in width.times.67 mm in
length)
[0115] [Anode] nickel plate (64 mm in width.times.64 mm in
length)
Example 4-2
[0116] [Solvent] 4-butyrolactone/ethylene glycol=3/1
[0117] [Plating Metal] nickel
[0118] [Functional Compound] Surflon S-611 (manufactured by AGC
Seimi Chemical Co., Ltd.)
[0119] [Voltage Condition 2]
[0120] [Cathode] copper plate (100 mm in width.times.67 mm in
length)
[0121] [Anode] nickel plate (64 mm in width.times.64 mm in
length)
[0122] In the Examples 4-1 and 4-2, the contact angles of water in
the glossy part of the plating film 10 were measured by the sessile
drop method. As a result, the contact angles were 73.degree. and
104.degree. in the tangent method. In addition, as Example 4-3, the
contact angles of water were measured after the respective plated
surfaces were scraped by about 2 .mu.m with use of a polishing
sheet (3M lapping film sheet). As a result, it was confirmed that
water repellency was maintained.
Example 5
[0123] The plated samples of the above-described Examples 4-1 and
4-1 were immersed in pure water and left at room temperature. Note
that the plating film 10 before immersion had a silvery luster
smooth surface in both of the Examples 4-1 and 4-2. Two weeks
later, the plated samples of the Examples 4-1 and 4-2 were taken
out, and water was then sufficiently removed with air blow. The
plating film 10 in the Example 4-1 was changed in color to mat
gray, whereas the plating film 10 in the Example 4-2 maintained
silver gloss. Average values of the surface roughness of the
respective plating films 10 were measured by a surface roughness
meter (manufactured by KLA-Tencor Corporation, P-15 surface
profiler). As a result, the average values of the surface roughness
Ra were 5.25 .mu.m (the Example 4-1) and 0.52 .mu.m (the Example
4-2).
[0124] Hereinbefore, although the disclosure has been described
with referring to the embodiment and the Examples, the disclosure
is not limited to the above-described embodiment and the like, and
various modifications may be made. For example, the metal source
attached on the anode electrode does not necessarily have a plate
shape, and for example, may be a bead or a sphere housed in a
porous container, a basket, etc. Alternatively, the metal source
may not be attached to the anode electrode, and plating may be
carried out only with use of electrolyte dissolved in the plating
solution. The shape of an object to be plated attached on the
cathode electrode is also arbitrary. In addition, to homogenize the
film formation, operation of rotating or oscillating the object to
be plated, etc. may be added. Hull cell tester is used as the
plating bath in this case; however, the shape of the plating bath
is also arbitrary, and the plating operation may be desirably
carried out while keeping an appropriate distance between the anode
electrode and the cathode electrode in order to obtain the highest
homogeneity. The method of stirring the plating solution is not
limited to a rotor, and various methods such as a rotor blade, pump
circulation, and bubbling.
[0125] Further, according to the technology, alloy plating may be
carried out by using two or more kinds of plating metals. In this
case, a plurality of metallic salts is used as the metallic salt to
be dissolved in the plating solution. Accordingly, two or more
kinds of metals may be used as the metal source attached to the
anode electrode, and an alloy formed of two or more kinds of metals
may be also used. Alternatively, the metal source may not be
attached to the anode electrode, and the plating may be carried out
only with use of electrolyte dissolved in the plating solution.
Note that, in the case of the alloy plating, it is necessary to pay
attention to the fact that the ratio of metals to be precipitated
may be varied depending on the waveform of the application
voltage.
[0126] Note that the technology may be configured as follows.
[0127] (1) A plating film including a metal and a compound having
functionality, the metal and the compound being homogenously
dispersed and joined.
[0128] (2) The plating film according to (1), wherein the metal and
the compound having the functionality are joined at a molecular
level.
[0129] (3) The plating film according to (1) or (2), wherein the
compound having the functionality includes one or more of water
repellency, oil repellency, and surface lubricity.
[0130] (4) The plating film according to any one of (1) to (3),
wherein the metal and the compound having the functionality are
coprecipitated by electrolytic plating.
[0131] (5) A method of manufacturing a plating film, the method
using a solution in which a metal is dissolved and a compound
having functionality is dissolved or colloidally dispersed.
[0132] (6) The method of manufacturing the plating film according
to (5), including:
[0133] preparing a plating solution by dissolving a metallic salt
of the metal in a solvent and then adding the compound having the
functionality in the solvent to dissolve or colloidally disperse
the compound; and
[0134] immersing an object to be plated in the plating solution to
make a cathode, and applying a voltage between the cathode and an
anode.
[0135] (7) The method of manufacturing the plating film according
to (6), wherein
[0136] the object to be plated is immersed in the plating solution
to make the cathode, and the voltage is applied between the cathode
and the anode to coprecipitate the metal and the compound having
the functionality, thereby forming a plating film added with a
function of the compound having the functionality.
[0137] (8) The method of manufacturing the plating film according
to (6) or (7), wherein [0138] the solvent in which the metallic
salt is dissolved is an organic solvent or mixed solution of the
organic solvent and water.
[0139] (9) The method of manufacturing the plating film according
to (8), wherein
[0140] the organic solvent contains a non-polymerizable compound,
or one of a monomer and a polymer of a polymerizable compound.
[0141] (10) The method of manufacturing the plating film according
to (8) or (9), wherein
[0142] the organic solvent contains one or more kinds of
polymerizable compounds, and each of the polymerizable compounds
includes two or more kinds of compounds having respective
polymerization degrees different from one another.
[0143] (11) The method of manufacturing the plating film according
to any one of (7) to (10), wherein
[0144] the plating film is formed by electrolytic plating.
[0145] (12) The method of manufacturing the plating film according
to (11), wherein
[0146] the electrolytic plating is carried out by application of
one of a DC voltage and an AC voltage.
[0147] (13) A plated product including
[0148] a plating film on a surface, wherein
[0149] the plating film includes a metal and a compound having
functionality, the metal and the compound being homogenously
dispersed and joined.
[0150] This application is based upon and claims the benefit of
priority of the Japanese Patent Application No. 2013-56936 filed in
the Japan Patent Office on Mar. 19, 2013, the entire contents of
this application are incorporated herein by reference.
[0151] It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations, and
alterations may occur depending on design requirements and other
factors insofar as they are within the scope of the appended claims
or the equivalents thereof.
* * * * *