JPH06220692A - Method for controlling extent of codeposition in composite plating film - Google Patents

Abstract

PURPOSE:To effectively increase the amt. of insoluble particles codeposited in a metal matrix at the time of forming a composite plating film and to control the amt. of the codeposited insoluble particles in the composite plating film over a wider range. CONSTITUTION:A body to be plated is immersed in a composite plating soln. prepd. by dispersing insoluble particles in a metal plating soln. and plating is carried out to form a composite plating film contg. the insoluble particles codeposited in the metal matrix on the body to be plated. At this time, the amt. of the insoluble particles codeposited in the metal matrix is controlled by regulating the concn. of metal ions in the metal plating soln. By this method, the extent of codeposition can be easily and simply controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the co-bending amount of insoluble particles in a metal matrix when forming a composite plating film in which insoluble particles co-bend in a metal matrix on an object to be plated. .

[0002]

2. Description of the Related Art Conventionally, a composite plating solution in which a composite material composed of insoluble particles such as zirconia and alumina is dispersed in a metal plating solution such as a nickel plating solution is used to form a composite plating film on the object to be plated, that is, nickel or the like. It is known to form a plating film in which insoluble particles such as zirconia and alumina are co-distributed and dispersed in the metal matrix. Since this composite plating film has both the characteristics of the plated metal and the characteristics of the composite material particles, it is noted as a coating that can improve the hardness, wear resistance, lubricity, arc wear resistance, heat resistance, etc. of the coating. Has been done.

In this case, in order to more effectively exhibit both the characteristics of the plated metal and the characteristics of the composite material particles,
It is necessary to control the co-folding amount of the insoluble particles in the metal matrix and to make the amount of the insoluble particles dispersed in the metal matrix appropriate. Thus, it is desired to control the co-bending amount of the insoluble particles in the metal matrix according to the application, and in particular, recently, plating having a gradient function in which the co-bending amount of the insoluble particles is different inside and outside the composite plating film. A coating is required. When obtaining a composite plating film having such a gradient function, it is essential to freely control the co-bending amount of insoluble particles.

Conventionally, in composite plating, as a method for controlling the co-bending amount of insoluble particles, a method of increasing / decreasing the dispersion amount of insoluble particles in a plating solution, adjusting a stirring rate of the plating solution and a plating temperature, and In the case of electroplating, a method of adjusting plating conditions such as increasing or decreasing the current density has been proposed.

[0005]

However, the method of controlling the dispersion amount of the insoluble particles in the plating solution increases the co-folding amount as the dispersion amount increases. Can not be increased excessively, and this method has certain limitations. Further, the method of adjusting the plating conditions is not sufficient to control the co-bending amount in a wide range.

As a method for controlling the amount of co-folding of a composite plating film, Japanese Patent Application No. 3-339755 discloses a method of adjusting the specific surface area of insoluble particles dispersed in a plating solution. The amount can be controlled only in the range of 0 to 30% by volume, and it was difficult to control the co-folding amount in a wider range.

Further, in advanced technological fields such as space, aviation, and fusion reactor development, it is desired to develop a super heat resistant material having an excellent heat shielding property. However, it is not possible to develop a super heat resistant material by a conventional uniform material. Difficult and requires development with heterogeneous materials consisting of multiple materials. However, the restriction due to the difference in the physical properties such as the coefficient of thermal expansion at the interface of the heterogeneous material causes problems such as crack generation due to thermal stress, and limits the production and use of the material.

The present invention effectively increases the co-folding amount of the insoluble particles in the metal matrix when forming the composite plating film, and can control the co-folding amount of the insoluble particles of the composite plating film in a wider range. The purpose is to provide a method.

[0009]

Means for Solving the Problems By plating an object to be plated by immersing the object to be plated in a composite plating solution in which insoluble particles are dispersed in the metal plating solution, insoluble particles co-fold in the object to be plated in a metal matrix. In a composite plating method for forming a dispersed composite plating film, by controlling the metal ion concentration in the metal plating solution, it is possible to control the co-bending amount of insoluble particles in the metal matrix. The present invention relates to a method for controlling the amount of co-folding.

[0010]

The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, in composite plating, the co-bending amount of insoluble particles in the metal matrix is greatly affected by the metal ion concentration in the plating solution. It was found that the amount of co-folding was increased by decreasing the metal ion concentration in the solution.

That is, as will be apparent from the description of Examples below, when composite plating is carried out under the same plating conditions such as cathode current density with a fixed dispersion amount of insoluble particles in the plating solution, It was found that the amount of co-folding increases when the metal ion concentration of is decreased, and the amount of co-folding decreases when the concentration of metal ion is increased, and the amount of co-folding can be easily predicted from the concentration of metal ions in the plating solution. Therefore, it was found that the co-folding amount of insoluble particles in the metal matrix can be easily and reliably controlled by selecting the metal ion concentration in the plating solution during composite plating, and can be controlled over a wide range, and the present invention It was the eggplant.

The present invention will be described in more detail below.
The co-folding amount control method of the composite plating film of the present invention is
When a composite plating solution in which insoluble particles are dispersed in a metal plating solution is used to obtain a composite plating film in which the particles are co-dispersed in a metal matrix, the metal ion concentration of the plating solution is selected to obtain the desired co-folding. The amount of composite plating film is formed.

Usually, in composite plating, positively charged composite material particles are electrophoresed in the plating solution toward the cathode. It is known that this electrophoretic mobility is proportional to the potential gradient between the electrodes, and increasing the potential gradient increases the electrophoretic mobility and increases the adsorption rate to the cathode.

On the other hand, in the composite plating, according to the present invention, when the metal ion concentration in the plating solution is reduced to perform the plating, the cathode current density is kept constant and the thickness of the plating film produced is kept constant. Needs to increase the potential applied between the electrodes. As a result, the potential gradient between the electrodes increases, the electrophoretic mobility of the insoluble particles increases as described above, and the adsorption rate of the insoluble particles on the cathode increases. As a result, the co-bending amount of the insoluble particles increases even if the thickness of the plating film is constant.

Further, when the voltage applied between the electrodes is made constant, the cathode current density is reduced, so that the thickness of the plating film produced is reduced, that is, the amount of metal deposited is reduced. In this case, since the potential gradient between the electrodes is constant, the amount of insoluble particles adsorbed on the cathode does not change. Therefore, the co-bending amount of the composite material in the composite plating film increases.

According to the present invention, by adjusting the metal ion concentration in the composite plating solution, the potential gradient between electrodes or the current density can be changed according to the present invention by the above-described action. It is possible to control the co-bending amount of the insoluble particles.

The metal plating solution used in the present invention includes nickel plating solution, nickel alloy plating solution, chromium plating solution, copper plating solution, zinc plating solution, tin plating solution,
Examples include tin alloy plating solutions. As these metal plating solutions, those having a well-known bath structure can be appropriately diluted with purified water before use.

The insoluble particles dispersed in the metal plating solution as a composite material include oxides such as zirconia, alumina, silica, titania and ceria, and composite oxides composed of two or more of these, silicon carbide, titanium carbide and the like. Examples thereof include carbides, nitrides such as silicon nitride and boron nitride, fluororesin powders, nylon powders, polyethylene powders and the like.
Of course, it is not limited to these, and various other insoluble particles can be used.

The particle size range of the insoluble particles is not particularly limited, but usually the average particle size is 0.1 to 20 μm, particularly 0.2 to 10 μm.
It is preferable to set it as the range. If the particle size is too large, it becomes difficult to uniformly disperse the insoluble particles in the bath, and the effect of gravity becomes dominant during co-folding, which prevents good co-folding. The specific surface area of the insoluble particles is not particularly limited, but as disclosed in Japanese Patent Application Nos. 3-339755 and 3-339756, it is preferable that the specific surface area is as small as possible.
Particularly, it is preferable to use one having a specific surface area of 10 m ³ / g or less.

The amount of insoluble particles dispersed in the metal plating solution is appropriately selected and is not particularly limited.
It is usually 5 to 800 g / liter, and particularly 10 to 500 g / liter. Furthermore, the plating conditions such as the cathode current density are not particularly limited, and known conditions can be adopted.

Since the amount of the insoluble particles dispersed in the metal plating solution is a relatively large factor that influences the co-folding amount, when obtaining a plating film having a gradient function with different co-folding amounts, etc. It is also necessary to control the amount of insoluble particles dispersed in the metal plating solution.

The complex plating conditions are the type of plating solution,
Known conditions can be adopted depending on the plating method, but it is also possible to appropriately control each plating condition other than the metal ion concentration in the plating solution, such as stirring method, stirring speed, plating temperature, and cathode current density, and the amount of co-folding. Required from a control point of view.

According to the present invention, the co-folding amount can be changed simply by changing the metal ion concentration in the plating solution. Therefore, the desired co-folding amount of the composite plating film can be easily and reliably obtained. However, in particular, by preparing a plurality of composite plating solutions having different metal ion concentrations in the plating solution and sequentially plating the object to be plated with these composite plating solutions, the inside, middle and outside of the composite plating film can be It is possible to easily form a composite plating film having a gradient function with different co-folding amounts.

[0024]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

(Experiment 1) Composite plating was performed using the electrolytic plating apparatus schematically shown in FIG. As a metal plating solution, a normal sulfamic acid-based nickel bath (nickel sulfamate 1.4 mol / liter, nickel chloride 0.04 mol
/ L, boric acid 0.5 mol / L) were used after appropriately diluted with purified water. The tall beaker 1 was charged with 200 ml of a metal plating solution, the tall beaker 1 was placed in a constant temperature bath 3, and a predetermined amount of zirconia powder was placed in the metal plating solution.

The stirrer 6 was rotated by the stirrer 2 with a tachometer installed below the constant temperature bath 3, and the composite plating solution was stirred for at least 30 minutes to be aged. Then, electrolytic plating was performed under the experimental conditions shown in Table 1.

[0027]

[Table 1] Cathode current density: 1.0 A / dm ² Powder dispersion amount: 400 g / liter Powder average particle size: 1.5 μm Powder specific surface area: 3.2 m ² / g Bath temperature: 40 ° C Stirrer 6 rotation speed: 400 rpm

At the time of electrolytic plating, the cathode 4 is placed at the center of the tall beaker 1 and the anodes 5 are provided on the left and right of the cathode 4.
Was placed. The cathode 4 has a length of 40 mm and a width of 20 m.
A copper plate with m and a thickness of 0.2 mm was used. As the anode 5,
An electrolytic nickel plate was used. The rotation speed of the magnetic stirrer was monitored by a tachometer.

The current required for electrolysis was supplied by the stabilized DC power supply 7. The current was monitored by ammeter 8 and the voltage was monitored by voltmeter 9. Heater 10 in constant temperature bath 3
Was heated and the bath temperature was kept constant by the temperature controller 11.

The concentration of nickel ions in the composite plating solution was changed as shown in Table 2, the composite plating film was formed on the object to be plated as described above, and the insoluble particles (zirconia particles) in the composite plating film were formed. Was measured. The results are also shown in Table 2.

Here, the method of measuring the co-bending amount of insoluble particles (zirconia particles) in the composite plating film was carried out as follows. First, the coating weight is calculated from the weight increase of the cathode on which the coating is formed, the coating is calculated, then the coating is dissolved using nitric acid (1 + 1), only the particles are collected by a membrane filter, dried, and then weighed. It was determined by the gravimetric method.

[0032]

[Table 2]

The results of Table 2 are shown in the graph of FIG. 2 again. As can be seen from these results, since the nickel ion concentration in the metal plating solution decreases, the co-bending amount of zirconia particles in the composite plating film increases, and the nickel ion concentration in the plating solution changes. It is recognized that the co-folding amount of zirconia particles changes. Therefore, by adjusting the nickel ion concentration in the metal plating solution, it is possible to control the co-bending amount of zirconia particles in the metal matrix.

Next, the nickel ion concentration in the composite plating solution is 1.45 mol / liter, 0.5 mol / liter, and 0.1.
The object to be plated (nickel plate) is sequentially dipped in different composite plating solutions of 164 mol / liter, 0.056 mol / liter, 0.030 mol / liter, and 0.0192 mol / liter, and 1.
Composite plating was carried out at 0 A / dm ² for the same time, and a 96 μm thick composite plating film with a plating thickness of 16 μm for each plating solution was obtained.

In the obtained plating film, the co-folding amount of zirconia particles is about 20% by volume, about 22% by volume, about 25% by volume, about 40% by volume, about 55% by volume from the inside to the outside, respectively. It had a gradient function of about 65% by volume.

Further, since the inner side of this composite plating film has a small amount of co-folding of zirconia particles, the adhesion to the substrate as the object to be plated is good, while the outer side of this coating film has a co-folding amount of zirconia particles. Since the amount is large, the properties of the co-folded particles can be exhibited extremely effectively. Furthermore, since the composite plating film has a gradient function even when intense heat is applied, it is possible to effectively alleviate the thermal stress caused by the difference in the coefficient of thermal expansion of each material.

(Experiment 2) In Experiment 1, instead of zirconia particles as the composite material, silicon carbide powder (average particle diameter) was used.
Experiments were performed on a system using 0.98 μm and a specific surface area of 5.2 m ² / g). As the plating solution, a copper sulfate bath (copper sulfate 2 mol / liter, sulfuric acid 0.6 mol / liter) was appropriately diluted with purified water before use. The electrolyzer used, the experimental method and the experimental conditions are the same as those in Experiment 1 above. However, a chromium plate was used as the cathode (object to be plated).

The copper ion concentration in the copper plating solution was, as shown in Table 3, 2 mol / liter, 0.15 mol / liter and 0.1 mol / liter.
The objects to be plated are sequentially dipped in 4 kinds of composite plating solutions changed to 06 mol / liter and 0.02 mol / liter, and 3.0 A each
The composite plating was carried out at the same time with / dm ² to obtain a composite plating film with a thickness of 60 μm, which is 12 μm for each plating solution. The co-bending amount of insoluble particles in the composite plating film was measured, and the results are shown in Table 3.

[0039]

[Table 3]

The obtained composite plating film has a gradient function in which silicon carbide particles are co-folded from the inner side to the outer side of about 8% by volume, about 14% by volume, about 27% by volume, and about 42% by volume, respectively. Met.

Also in this case, as in Experiment 1, since the inner side of the composite plating film has a small amount of co-folding of silicon carbide particles, the adhesion to the substrate as the object to be plated is good, while the outer side of this film is Since the silicon carbide particles have a large amount of co-folding, the properties of the co-folding particles can be exhibited very effectively. Further, since the composite plating film has a gradient function even when placed in a high temperature state, it is possible to effectively relieve the thermal stress caused by the difference in the coefficient of thermal expansion of each material. .

[0042]

As described above, according to the method for controlling the co-bending amount of the composite plating film of the present invention, by adjusting the metal ion concentration in the plating solution, the metal matrix can be easily and easily formed. The co-folding amount of insoluble particles can be controlled. Therefore, even when the heterogeneous material is being cooled during production or is exposed to a high temperature environment during use, problems such as crack generation due to thermal stress do not occur, and the optimum thermal stress for the expected temperature distribution is obtained. It is possible to obtain a composite plating film having a gradient function in which the composition and structure of the material are continuously controlled at a micro level so that the distribution can be obtained and the thermal stress can be suppressed.

[Brief description of drawings]

FIG. 1 is a schematic view showing an electrolytic plating apparatus used in an example of the present invention.

FIG. 2 is a graph showing the relationship between the co-bending amount of zirconia powder in the composite plating film and the nickel ion concentration in the plating solution.

[Explanation of symbols]

 1 Beaker 2 Stirrer with tachometer 3 Constant temperature bath 4 Cathode 5 Anode 6 Stirrer 7 DC power supply 8 Ammeter 9 Voltmeter 10 Heater 11 Temperature controller

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Munejun Matsumura 1-5-1, Exit Hirakata, Osaka Uemura Industrial Co., Ltd.

Claims (1)

[Claims] 1. A composite plating film in which the insoluble particles are co-folded in a metal matrix is obtained by immersing an object to be plated in a composite plating solution in which insoluble particles are dispersed in the metal plating solution. In the composite plating method for forming on a plated product, by adjusting the metal ion concentration in the metal plating solution, the co-bending amount of the insoluble particles in the metal matrix is controlled. Folding amount control method.