JPS6224520B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an alloy plating method and an apparatus for carrying out the method. Immersing an object on which a plating film is to be formed in a plating bath containing two or more metal components as ions,
The method of forming an alloy plating layer by electrolytic plating has already been widely put into practical use. For example, in the case of alloy plating consisting of two metal components x and y, the main ingredient is an electrolyte containing x ions and y ions, and further includes brighteners, accelerators, inhibitors, complexing agents, etc.
Electrolysis is carried out using the object to be plated as a cathode in an alloy plating bath containing known additives such as a buffer, thereby forming an alloy plating layer consisting of x and y on the object to be plated. In addition to general requirements such as adhesion to the plated object and uniformity of plating thickness, such an alloy plating layer requires homogeneity of the alloy composition consisting of x and y. In the unlikely event that the alloy composition differs in different locations, or if the alloy composition differs depending on the depth of plating in the same location, the function or performance required for alloy plating will not be fully exhibited. As is well known, in order to form the desired plating layer, the plating conditions (PH, liquid temperature, current density, degree of stirring), physical properties of the plating liquid (surface tension, viscosity), etc. must be maintained within a certain range. However, these management methods have already been established and there are no particular problems. Therefore, the most important issue in alloy plating baths is how to maintain the ion concentration and ratio of each metal in the plating solution within an acceptable range and obtain a homogeneous alloy composition. Exists. However, it is extremely difficult to maintain the ion concentration of each metal and the ratio of each ion within a certain range. For example, there is a method in which an alloy plating bath is analyzed at short time intervals and an amount of metal in the form of a salt is replenished to compensate for the reduction in metal ions. However, this method requires a lot of labor for analysis, cannot adequately replenish the metal ions that decrease from moment to moment during the plating operation, and accumulates anions derived from metal salts (for example, from the Ni source). When NiCl ₂ 6H ₂ O is used as Cl ^{- and} when NiSO ₄ is used as SO ^{- -} ₄ ), the PH and conductivity of the solution change greatly, shortening the life of the plating solution. There are drawbacks such as: Alternatively, a method is also known in which an anode made of the metal is used as a supply liquid for metal ions. For example, when forming a Ni-Fe alloy plating layer, Ni
A method has also been put into practical use in which a composite material with a fixed surface area of Fe and Fe is used as an anode, and Ni ions and Fe ions are eluted and replenished into the plating solution as electrolysis progresses. However, even in this method, the elution ratio of Ni ions and Fe ions is usually different from the surface area ratio of both metals, and the concentration of both metal ions and the ratio of both metal ions in the plating solution are Analyzes and measurements are carried out as needed, and missing metal ions are replenished in the form of metal salts. Therefore,
Although this method has been reduced compared to the above-mentioned methods, the drawbacks of labor-intensive analysis and accumulation of anions remain. Furthermore, attempts have been made to use two or more metals as independent positive electrodes to control and replenish the amount of metal ions generated. For example, Ni
- When forming a Fe alloy plating layer, Ni and Fe
The material is used as a positive electrode connected to a separate power source, and the eluted Ni and Fe ions are used to form a Ni-Fe alloy plated layer of a specific composition on the cathode plated body. However, even in this case, the electrolytic elution amount of Ni and Fe and the electrolytic elution ratio of both should be maintained within a predetermined range, and the Ni-Fe alloy plating layer formed on the plated body should have a predetermined composition. Therefore, the surface area of each pole, the distance between each pole,
It is virtually impossible to appropriately control all conditions such as voltage and current density. The inventor of the present invention, while conducting various researches in view of the problems of the conventional technology of replenishing metal ions in an alloy plating tank, discovered that the ions of each metal to be formed into an alloy are supplied separately from the alloy plating tank. The idea was to replenish each tank independently. As a result of further research based on this idea, we have finally completed the present invention. That is, the present invention
An alloy plating method using an insoluble electrode as an anode, in which a part of the alloy plating solution containing two or more metal components is applied to two or more metals provided outside the alloy plating tank during the alloy plating operation. Guide each component to the component supply tank,
An alloy plating method characterized by separately replenishing metal components corresponding to the amount reduced by forming an alloy plating layer and then refluxing them into an alloy plating tank, and an alloy plating tank using an insoluble electrode as an anode. At least one metal component replenishment tank is provided for each metal component in the alloy plating solution, an alloy plating solution outflow path from the alloy plating tank to each metal component replenishment tank, and an alloy plating solution flow path from each alloy component replenishment tank to the alloy plating tank. The present invention relates to an alloy plating apparatus characterized by being equipped with an alloy plating liquid return path leading to a plating tank. Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the drawings. In FIG. 1, an alloy plating layer 1 contains a plating solution containing two types of metal components, x ions and y ions, and the plating solution contains an object 3 to be plated as a cathode. An insoluble anode 5 made of platinum-coated titanium, ferrite, or the like is placed in a dipping manner. As the plating operation progresses, a plating layer made of an x-y alloy is formed on the object 3 to be plated, and the concentrations of x ions and y ions in the plating solution gradually decrease. . Therefore, a part of the plating liquid is extracted from the alloy plating layer 1 via lines 7 and 9, and is sent to the metal component supply tanks 11 and 13, where it is detected in the alloy plating tank 1. x ions and y ions are replenished in proportion to the amount consumed by plating formation. That is, in the metal component supply tank 11, an insoluble cathode 15 made of graphite or the like and x
Electrolysis is performed between the consumable positive electrode 17 made of metal, and a necessary amount of x ions are eluted. In order to prevent the x metal from precipitating on the surface of the insoluble cathode 15, a hollow cylindrical body 19 such as an unglazed cylindrical body that allows current to pass through but does not allow x ions to pass through.
to surround the cathode 15. Hollow cylindrical body 19
A catholyte, such as an ammonium sulfate solution, is contained within. Also in the second metal component replenishment tank 13 that replenishes y ions, the hollow cylindrical body 23
Electrolysis is performed between the insoluble cathode 21 surrounded by the y-metal and the consumable anode 25 made of y metal, and a required amount of y ions are eluted into the plating solution. Supply tank 1
1: Replenishment liquid and replenishment tank 1 with x ions supplied
The plating solution supplemented with y ions in step 3 is returned to the alloy plating tank 1 via lines 27 and 29, respectively. Note that the lines 27 and 29 are provided with pumps (not shown) and, if necessary, can be further provided with a filter (not shown). The present invention is also applicable to multi-component alloy plating of eight or more components. In this case, at least one metal component replenishment tank is provided for each metal component. Furthermore, two or more replenishment tanks may be provided for each metal component. Examples of alloy plating compositions covered by the present invention are as follows. Binary system…Cu−Zn, Cu−Sn, Cu−Pb, Cu−
Ni, Cu−Cd, Cu−Sb, Cu−Bi, Cu−Au,
Cu−In; Pb−Sn, Pb−In, Pb−Ta; Sn−
Zn, Sn-Ni, Sn-Co, Sn-Sb, Sn-Bi, Sn
−Cd; Zn−Cd, Zn−Ni, Zn−Co, Zn−In,
Zn−Fe; Ni−Co, Ni−Fe, Ni−Ti, Ni−
Cd, Ni-W, Ni-Re, Ni-Cr, Ni-Pd; Ti-
Fe, Ti−Co; Co−Pd, Co−Re; Fe−Cr, Fe
−Re; Cr−Mo; Zn−Mn, etc. Ternary system…Fe−Ni−Cr, Cd−Ni−Co, Zn−Co
−Mo, Zr−Co−Cr, Sn−Ni−Cu, Zr−Ni−
Co, Cu−Zn−Sn, Pb−Sn−Zn, Pb−Sn−
Cu, Pb-Sn-Sb, etc. Instead of the traditional idea of controlling all parameters within a single alloy plating bath, the present invention
This system was developed based on the concept of controlling the concentrations of two or more metal components, which are the most difficult to control, and their relative proportions in separate metal component replenishment tanks, making it easy to form homogeneous alloy plating. This is an extremely useful invention. As an application example of the present invention, it is also possible to measure parameters other than the concentration of metal components, such as the pH of the plating solution, the temperature of the plating solution, and the concentration of various additives, in a tank independent from the alloy plating tank. It is. Examples will be shown below to clarify the features of the present invention. It goes without saying that the present invention can be applied to all alloy plating, and therefore the present invention is not limited in any way by the following examples. Example 1 The present invention was carried out using an alloy plating apparatus of the type shown in FIG. Nickel sulfate (as nickel) 21.7g/, copper sulfate (as copper) 2.3g/and glycine 20g/
A copper plate with a surface area of 1 dm ² was immersed as a cathode 3 in an alloy plating tank 1 containing an alloy plating solution 2 containing . Performed plating operation. PH of plating solution 4.5±0.2 Cathode current density 3A/dm ² Solution temperature 40±2℃ Cathode current efficiency 72% During plating operation, alloy plating solution 3/hour is led from line 7 to nickel ion supply tank 11. A current of 0.68 A was applied continuously during the plating operation between the graphite plate as the cathode 15 and the nickel anode 17 immersed in an ammonium sulfate solution (concentration 150 g/2) contained in the unglazed hollow cylindrical body 19. was allowed to elute an amount of nickel ions commensurate with the amount consumed, and then refluxed into the alloy plating tank 1. In the same way, the alloy plating solution 7/hour was led from the line 9 to the copper ion supply tank 13, and the cathode 21 was immersed in the ammonium sulfate solution (concentration 150 g/hour) 2 housed in the unglazed hollow cylinder 23. During the plating operation, a current of 1.47 A was continuously passed between the graphite plate and the copper anode 25 to elute copper ions. Thus, the surface of the cathode copper plate 3 contains approximately 60% Ni.
An alloy plating layer consisting of approximately 40% Cu was formed. There was no variation in the alloy composition at different locations on the copper plate 3, and no variation in the composition was observed in the depth direction at the same location on the alloy plating layer. In alloy plating tank 1, it was only necessary to replenish glycine and add dilute sulfuric acid for pH adjustment, and the concentrations of Ni and Cu were maintained at predetermined values. Examples 2 to 4 Same as Example 1 except that the cathode current density in the alloy plating tank 1, the current value in the Ni ion replenishment tank 11, and the current value in the Cu ion replenishment tank 13 were changed as shown in Table 1. Then, an alloy plating layer was formed.

[Table] Example 5 The present invention was carried out using an alloy plating apparatus of the type shown in FIG. A copper plate with a surface area of 1 dm 2 was immersed as a cathode 3 in an alloy plating tank 1 containing an alloy plating solution ² having the composition shown in Table 2 below, and a graphite (anode bag was used)
Using as anode 5, plating operation was carried out for 1 hour under the conditions of plating solution pH 5.0, cathode current density 4 A/dm ² and solution temperature 50°C. Table 2 Ferrous sulfate 150g / Nickel sulfate 125g / Sodium citrate 140g / Formaldehyde 12.5cc / Satucharin 2g / During plating operation, alloy plating solution 3 / hour is led from line 7 to ferrous ion replenishment tank 11 During the plating operation, a current of 0.78 was continuously passed between the graphite plate cathode 15 and the iron anode 17, which were immersed in ammonium sulfate solution (concentration 150 g/2) contained in the unglazed hollow cylindrical body 19. After eluting ferrous ions corresponding to the consumption amount, the alloy plating solution was refluxed to the alloy plating tank 1. In the same manner, the alloy plating solution 3/hour was led from the line 9 to the nickel ion replenishment tank 13, and the graphite cathode 21 was immersed in the ammonium sulfate solution (concentration 150 g/hour) 2 housed in the unglazed hollow cylindrical body 23. A current of 0.82 A was continuously passed between the anode 25 and the nickel anode 25 during the plating operation to elute the nickel ions, and then the alloy plating solution was returned to the alloy plating tank 1. Thus, an alloy plating layer consisting of 86% Fe and 14% Ni was formed on the surface of the cathode copper plate 3.
The alloy composition is also different at different locations on the copper plate 3.
The alloy plating layer was also uniform in the depth direction at the same location. In alloy plating tank 1, it is only necessary to replenish sodium citrate, formaldehyde, saccharin, and a trace amount of dilute sulfuric acid for pH adjustment.
The concentration of Ni was maintained at a predetermined value. Examples 6 to 8 Same as Example 5 except that the cathode current density in the alloy plating tank 1, the current value in the Fe ion replenishment tank 11, and the current value in the Ni ion replenishment tank 13 were changed as shown in Table 3. Then, an alloy plating layer was formed. The plating solution was stable during the plating operation, and the operation was performed very well.

【table】 [Brief explanation of the drawing]

FIG. 1 is a drawing showing an example of an alloy plating apparatus used to carry out the method of the present invention. 1...Alloy plating layer, 3...Plated object, 5
...Insoluble anode, 7,9...Alloy plating liquid outflow line, 11,13...Metal component supply tank, 15,2
1... Insoluble cathode, 17, 25... Consumable anode,
19, 23...Hollow cylindrical body, 27, 29...Alloy plating liquid reflux line.

Claims (1)

[Claims] 1. An alloy plating method using an insoluble electrode as an anode, in which a part of the alloy plating solution containing two or more metal components is provided outside the alloy plating tank during the alloy plating operation. Alloy plating characterized by introducing the metal components into two or more metal component replenishment tanks, separately replenishing each metal component corresponding to the amount reduced by forming the alloy plating layer, and then allowing the metal components to flow back to the alloy plating tank. Method. 2. Alloy plating tank with an insoluble electrode as the anode, at least 1 for each metal component in the alloy plating solution.
Equipped with metal component replenishment tanks provided separately, an alloy plating liquid outflow path from the alloy plating tank to each metal component replenishment tank, and an alloy plating liquid return path from each alloy component replenishment tank to the alloy plating tank. An alloy plating device characterized by: