JPH0241598B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention applies uniform plating to the surface of a cylindrical or polygonal rod-like object (hereinafter simply referred to as a carbon rod) made of carbon sintered body or graphite body, which is the base material of products such as carbon electrode rods or ground rods. The present invention relates to an electroplating method and an apparatus thereof, and a carbon electrode rod obtained by these methods and apparatus. Conventionally, the method and apparatus for plating the surface of a carbon electrode rod are as follows. The electrode rod is usually of a mass-produced type,
Since the plating time ranges from two to several hours, the plating method and apparatus inevitably adopt a method of plating a large number of carbon electrode rods at the same time. In the conventional method, for example, 10 to 30 carbon rods 10 are set in a plating frame 19 as shown in FIG. 1A, and a large number of plating frames 19 are immersed in a large plating bath 20 as shown in FIG. This is a method of fixing with the bus bar 23 and plating. Therefore, within the plating frame, each of the carbon rods was energized in parallel from the conductive portion 23, and each of the plating frames was also energized in parallel from the bus bar 23. As a result, the amount of metal plating deposited on the carbon electrode rod 10 is determined at the contact points between the conductive part 19' and the carbon rod 10 in one plating frame, and between the conductive bus bar 23 and the plating frame 19 in the plating bath 20. Since the electrical resistance of the contacts 22 is not uniform, the amount of plating varies greatly, with some being extremely unplated or having two to three times as much plating as the average plating amount. Conventionally, various measures have been taken to reduce the variation in the amount of plating, but the electrical resistance of these contacts varies due to dirt due to adhesion of the plating liquid, oxide film, and differences in contact pressure. When the temperature rises due to the Joule heat caused by the electrical resistance, contact corrosion due to plating fluid and the like is added and accelerated, so to this day there has been no fundamental measure to make this electrical resistance uniform. This is a common problem when the object to be plated is not limited to carbon electrode rods, but is a mass-produced plated product, and is a major problem in quality control of the plated method. Furthermore, in a connected carbon electrode rod having a convex portion at one end and a recessed portion at the other end, the thickness of the plating film varies due to the above-mentioned variation in the amount of plating. This variation in thickness reaches about ±0.2 mm, so even if you try to fit the uneven parts together when using this connectable carbon electrode rod, you will not be able to get a perfect fit. For this reason, the present inventors first proposed the
As proposed in the issue, the problem was solved by providing a ``long groove in the concave part of the connected carbon electrode rod'' to absorb the thickness error of the plating. However, although the electrode rod according to the above invention has been well received in the industry for a long time, its disadvantages include that the connection part expands when mated and the strength is reduced due to the groove. . In response to these conventional solutions, methods have also been proposed in which the thickness error is eliminated by processing after plating, and methods that do not involve grooves.
However, these conventional methods have not yet been perfected. The drawbacks of these conventional methods are all due to variations in the amount of plating caused by parallel energization. In view of this, the present invention proposes a plating method and apparatus using series energization in place of the conventional plating method using parallel energization, and by these, a carbon electrode rod with less variation in plating can be obtained. In fact, the reason why this series energization method was not invented was that it was impossible to energize in series using the conventional method of simultaneous plating in a large plating bath in the mass production method. . In order to solve these shortcomings, the present inventors
Instead of a large plating bath, we decided to install a large number of plating units in parallel, each consisting of a sealed container with an anode and a carbon rod as a cathode, and came up with a method of electrically connecting these plating units in series. . Based on this idea of the present invention, the variation in the plating amount between the carbon rods is reduced to less than 1/10 of the conventional value, and it has become possible to keep the error in the plating thickness of the carbon rods within ±0.05 mm. Furthermore, the unit is made into a closed type, and the distance between the anode of this unit and the carbon rod of the object to be plated, which is the cathode, is set to 1.
If the range is ~10 mm and the electrolyte is moved at high speed by providing an inlet for the electrolyte at one end and an outlet at the other end, it will be possible to break the boundary film that forms on the electrode surface and supply metal ions at high speed. We have newly discovered that the current density can be increased. This increases the current density from 0.5 A/dm ² up to 450 A/dm ²
We have newly discovered that the plating time can be significantly shortened depending on the current density. Therefore, the present inventors reduced the variation in the mutual plating amount of the electrode rods by series energization, and made the shape of the anode similar to the outer diameter of the carbon rod of the object to be plated, which is the cathode. The distance between
By maintaining equal intervals of ~10 mm, the plating film can be applied so that the plating thickness error is within ±0.05 mm, and the plating film can be applied uniformly on the surface of the carbon electrode rod body with high precision. Now I can do it. It was newly discovered that a plating film with little error can be applied to the uneven portions of a connected carbon electrode rod, and that a connected carbon electrode rod that can be perfectly fitted can be provided. In addition, the current density is 0.5 to 450 A/ ^dm2 , and the flow rate is 1 cm/30 m/sec, preferably 30 to 450 A/dm2.
dm ² and a flow rate of 60 cm to 30 m/sec, the current density is approximately 10 to 150 times that of the conventional method, and the plating time is approximately 1/10 to 1/10 of the conventional method, such as 20 to 1 minute.
An extremely efficient electroplating method and device that can shorten the time to 1/150 and significantly reduce the plating equipment and cost required for plating, as well as its device, and a connected carbon electrode rod with extremely low plating errors. This is what we provide. The present invention provides a plating unit in which a plating solution is filled and circulated between at least a container serving as an anode and an object to be plated as a cathode made of carbon rods inserted at a fixed interval in the container. A plurality of plating units are mechanically connected in series or parallel, and electrically connected in series to at least one power source, and a current is passed in series to each of the plating units to increase the current density.
0.5 to 450 A/dm ² , and the flow rate of the plating liquid to 1 cm or more.
This invention relates to a method for plating a carbon electrode rod, which is characterized by forming a plating film on the surface of a carbon rod inserted into a plating unit by circulating the current at a speed of 30 m/sec and controlling the current according to the flow rate of the plating solution. be. Another object of the present invention is that one end is convex and the other end is concave, and the concave part of one carbon electrode rod is fitted with the convex part of another carbon electrode rod of the same shape. In a connectable carbon electrode rod that can be connected together, a body to be plated made of a carbon rod is placed in a cylindrical container having at least an anode, and the distance between the anode and the body to be plated as a cathode is 1 to 10 mm. The plating liquid is maintained at approximately equal intervals within a range of 1 to 10 mm, and the plating liquid is made to flow between the plating liquid inlet provided on one side of the container and the plating liquid discharge port provided on the other side, and the protrusion of the electrode rod A plurality of plating units which plugged the inside of the concave portion in the middle of the shaped portion and on the other side are mechanically connected in series or in parallel so that the plating liquid is circulated in series or in parallel, and the plating units are connected electrically. connected in series to a power source, with a current density of 0.5 to 450 A/dm ² , circulating the plating solution at a flow rate of 1 cm to 30 m/sec, and controlling the current according to the flow rate of the plating solution.
The carbon rod charged into the plating unit is partially plated, leaving only the tip of the convex part and the inner part of the concave part, and the root part of the convex part of the carbon rod and the peripheral edge of the concave part are plated. The object of the present invention is to provide a method for partial electroplating of a carbon electrode rod, in which the plating film applied to the portion has a slight taper from the base to the tip or inward. A further object of the present invention is to provide a container having an anode having a shape substantially similar to that of a carbon rod,
This container has at least an opening through which the carbon rod to be plated is taken in and taken out, an inlet for the plating liquid at one end, and an outlet for the plating liquid at the other end. They are mechanically connected in series or parallel, and the plating liquid is configured to circulate in series or in parallel at a predetermined rate in the range of 1 cm to 30 m/sec, and the carbon rods that are the objects to be plated are electrically connected to the power source. connected in series with the current density of 0.5~
An object of the present invention is to provide a carbon electrode plating device characterized in that it is configured to provide a plating power of 450 A/dm ² . Still another object of the present invention is to provide a carbon electrode rod that is plated with high precision and the thickness error of the plated film is within the range of ±0.05 mm. A further object of the present invention is to form a convex portion at one end and a concave portion at the other end, such that one carbon electrode rod has a concave portion and another carbon electrode rod of the same shape has a convex portion. In the connectable carbon electrode rod that can be fitted and connected, the root portion of the outer surface of the convex portion and the peripheral edge of the inner surface of the concave portion are tapered continuously with the outer peripheral surface of the electrode rod main body. A metal plating film is formed, and the thickness of the plating film on the outer peripheral surface of the main body of the electrode rod and the thickness of the base of the tapered plating film between the root portion of the convex portion and the peripheral end portion of the concave portion are ±. The object of the present invention is to provide a connected carbon electrode rod which is coated with a highly accurate plating film within an error range of 0.05 mm. The principle of the plating method of the present invention will be explained below. When the plating method of the present invention is applied in series with electricity, the amount of plating deposited on each plated object is the same on all the objects to be plated, and variations are significantly reduced. The reason is as follows. 3 and 4 are diagrams showing a state in which each plating unit is mechanically connected in parallel and in series, and the electrodes of each unit are electrically connected in series. The plating unit shown in FIG. 3 is an open type, and the plating unit shown in FIG. 4 is a closed type. In FIGS. 3 and 4, the electrical resistance of each plating unit is R ₁ , R ₂ , ..., _Ro , and the resistances R ₁ , R ₂ , ...
..., the combined resistance when R _o are connected in series is R,
If the voltage across the series connection is V, and the current flowing between the anode and cathode is I, then according to Ohm's law, I-
It becomes V/R. However, the current flowing through each body to be plated is the same when connected in series unless there is leakage in the middle. That is, even if the electrical resistance of each plating unit is different, if the voltage at each terminal of the plating unit is V ₁ , V ₂ , V ₃ , ..., then V=V ₁ +V ₂
+V ₃ ... +V _o =IR ₁ +IR ₂ +IR ₃ ...IR _o = I (R ₁
+R ₂ +R ₃ ... R _o ) = IR. That is, the voltages at the respective terminals of the plating unit have different values in proportion to their respective electrical resistances, but since the current I flowing through the object to be plated is constant, the amount of plating deposited on the object to be plated is also equal. To explain the conventional parallel energization method using the schematic diagram in Fig. 5, the electrical resistance of the plating unit is expressed as R ₁ ,
When R ₂ , R ₃ , ..., _Ro are connected in parallel as shown in Fig. 5, the currents flowing through R ₁ , R ₂ , ..., _Ro are I ₁ , I ₂ , ..., respectively. ... _Io , and the voltage between the anode and cathode terminals is V. In parallel connection, the voltage at the terminal of the plating unit and the voltage at both ends are common, so V=R ₁ I ₁ = R ₂ I ₂ ＝R ₃ I ₃ ＝……＝R _o I _o . The resistance that combines R ₁ , R ₂ , ... R _o is R,
Assuming that the current flowing through R is I, it is as follows. I−I ₁ +I ₂ +I ₃ ...I _o , V=RI ∴I=V/R=I ₁ +I ₂ +I ₃ ...+I _o = (1/R ₁ +1/R ₂
+1/R ₃ +...1/R _o )V In other words, I is the setting current, and I ₁ , I ₂ ,..., I _o
Since is the current flowing through the body to be plated (carbon rod), the set current is the sum of the currents flowing through the body to be plated. The current flowing through the plated body of each unit is I ₁ =
V/R ₁ , I ₂ =V/R ₂ , ..., I _o =V/R _o . Therefore, since the amount of plating deposited on each object to be plated is proportional to this current, the amount of plating deposited on each object to be plated varies depending on the electrical resistance of each plating unit. Therefore, for the reasons mentioned above, in order to reduce the variation in the amount of plating deposited on each object to be plated, it is necessary to electrically connect the electrodes of a plurality of plating units in series,
It is necessary to keep the plating current constant for each unit. However, the mechanical connection between the plating units, that is, the plating liquid circulation piping, may be either series or parallel.
The circulation amount and flow rate of the plating liquid, the liquid delivery pressure of the plating liquid, etc. may be selected from those that are economical. In the anode, the carbon electrode to be plated may have a shape other than a round rod, a polygon, a semicircle, etc. If the shape is similar to the outer shape of the carbon rod, a plating film with a uniform thickness can be obtained. Furthermore, it is important that the distance between the container, which has at least a portion that will serve as an anode, and the body to be plated, which serves as a cathode, made of a carbon rod, is maintained at approximately equal intervals.
It is best to set this interval to about 1 to 10 mm. As will be described later, the distance from the cathode is determined comprehensively from the viewpoint of electrical efficiency and economy, based on the voltage efficiency, the flow rate and flow rate of the plating solution depending on the current density, and the difficulty of moving in and out of the object to be plated. In order to keep the thickness error of the plating film within ±0.05 mm, the plating units are electrically connected in series so that the amount of plating deposited on the objects to be plated is almost equal with little variation. The anode has a similar shape to the object to be plated, and the spacing between the cathodes is approximately equal, 1 to 10 mm, so that the metal deposited on the object to be plated is constant and the entire object to be plated is plated uniformly. A film can be formed. When plating is performed by circulating the plating solution at a current density of 0.5 to 450 A/dm ² and a flow rate of 1 cm to 30 m/sec, the higher the current density, the shorter the plating time and high-speed plating can be achieved. . In order to achieve high-speed plating, the plating solution must be circulated as quickly as possible to supply the metal ions necessary for plating. FIG. 6 shows the relationship between the flow rate of the plating solution and the current density. The flow rate of the plating liquid and the current density at which good plating can be obtained are completely directly proportional to each other, regardless of the type of plating bath. It is necessary for the plating liquid to flow at a high speed corresponding to the current density, and for this purpose, pressurized forced flow is required. The relationship between the current density, the flow rate of the plating solution, and the plating time required for carrying out the method of the present invention is as follows.

【table】

[Table] As is clear from the above table, in order to perform high-speed plating, the current density should be 30 to 450 A/dm ² , and the flow rate of the plating solution should be 60 to 3000 cm/sec, corresponding to this.
High-speed electroplating becomes possible by making the electrode spacing relatively narrow, preferably about 2 to 5 mm, and increasing the flow rate of the plating solution in accordance with the current density. In the present invention, one end has a convex portion and the other end has a concave portion, and the concave portion of one carbon electrode rod is fitted and connected to the convex portion of another carbon electrode rod of the same shape. In the electroplating method for connecting carbon electrode rods that are used in conjunction with the electrodes, the fitting and connection will be impossible or extremely difficult unless high-precision electroplating is performed so that the thickness error of the electroplated film is ±0.05 mm. Therefore, it is necessary to equalize the distance between the container that serves as an anode and the body to be plated that serves as a cathode. For this reason, when the carbon electrode rod has a circular cross section, the part of the container that becomes the anode is cylindrical, and the anode and cathode are spaced at equal intervals, so that highly accurate electroplating can be performed. When the object to be plated is simply a rod-shaped object with a circular cross section, a plating film having a uniform thickness can be applied over the entire outer peripheral surface of the rod-shaped object. However, when manufacturing a connected carbon electrode rod, which is one of the other objects of the present invention, a portion is formed between the base of the convex portion on one side of the carbon electrode rod and the peripheral end of the concave portion on the other side. The plating film applied on the base of the convex part has a thickness error of ±0.05 mm at the base of the peripheral edge of the concave part, and the thickness error is ±0.05 mm in the direction of the tip of the convex part and towards the inner end of the concave part. Therefore, the film thickness becomes thinner and has a tapered shape, so that the connecting electrode rod has a tapered convex portion and a tapered concave portion, making it easier for both to fit together, and once fitted, it is difficult to come off. Become. This is because when a carbon electrode rod is inserted into a container, the plating liquid flows through the base of the convex part and the peripheral edge of the concave part, and the plating liquid flows into the tip of the convex part and inside the concave part. This is achieved by sealing with an embolus to prevent the plating solution from flowing, and a tapered plating film is formed at the root of the convex part and the peripheral edge of the concave part of the carbon electrode rod. In this case, as will be described later, the plating film deposited on the base of the convex part and the peripheral edge of the concave part of the carbon electrode rod will gradually increase as it goes toward the tip of the convex part and inward of the concave part. As it becomes thinner and tapered, it becomes easier for the convex and concave portions to fit together, and it is difficult for them to come off.This is mainly due to the distance between the electrodes. It is not preferable to apply a plating film to the entire outer surface of the convex portion and the inner surface of the concave portion of the connected carbon electrode rod, which is the object of the present invention. Furthermore, the plating film must be formed only on the base of the convex portion and the peripheral edge of the concave portion of the electrode rod. The reason for this is that if a plating film forms on the entire outer surface and inner surface of the concave part of the electrode rod, as the electrode rod wears out, the concave and convex connection parts will be exposed to high temperatures and the plating will melt. This is undesirable since it creates a gap between the projections and projections, which causes the fitting force to be lost and the connector to come off easily. On the other hand, if there is no plating film on the outer surface of the convex part and the inner surface of the concave part, and they are fitted only with carbonaceous material, the fitting force will be maintained even if it wears down to the vicinity of the connection part. However, even if they are tightly fitted, the carbonaceous material has a high specific resistance, so it becomes red hot and oxidized, making it unusable. It is necessary for the connection of the carbon electrode rod to satisfy both conditions at the same time, so a plating film is partially provided at the base of the convex part and the peripheral edge of the concave part,
In addition, if the tip of the convex part and the inner part of the concave part are left unplated and made of carbon, when the convex part and the concave part are connected, At the same time as the plating film is fitted, the carbonaceous portions of the convex and concave portions are also fitted. The fitting of the plating film applied to the base of the above-mentioned uneven part mainly has the function of passing a large amount of current between the old and new electrode rods, and the fitting of the plating film applied to the base of the above-mentioned uneven part mainly has the function of passing a large amount of current between the old and new electrode rods. Fitting is necessary to maintain the fitting force to the end. If the plating unit used in the present invention is an open type, the plating liquid cannot be passed through at high speed due to forced flow under pressure, so the current density is 0.5 to 10 A/ ^dm2 , and the flow rate of the plating liquid is set to 1 cm to 10 cm/sec. It is necessary to slow down the process and widen the electrode gap to 5 to 10 mm, and the plating time also takes 1 to 18 hours, so high-speed plating cannot be expected. Therefore, unless the plating unit holds the carbon rod to be plated in a closed container and forces the plating solution to flow between the anode and the cathode at high speed, high-speed, short-time plating cannot be expected. The closed plating method will be described below with reference to the drawings, with specific examples of the method and apparatus of the present invention, the structure of the obtained carbon electrode rod, and the state of adhesion of the plating film. First, FIG. 7 is a plan view schematically showing the main parts of an apparatus directly used in the method of plating carbon electrode rods of the present invention. In the above drawings, reference numeral 1 denotes a hollow cylindrical container which serves as the anode of the plating unit, and the inside of this container has a hollow cylindrical shape that is almost similar to the carbon rod that is the object to be plated. That is, when the above-mentioned carbon rod is a cylindrical round rod, the above-mentioned container 1 is cylindrical with an inner diameter slightly larger than the round rod, and has a conductive material that serves as an anode insoluble in the plating solution. Any container with metal parts may be used. Further, when the carbon rod is made of a polygonal column such as a quadrangle or an octagon, the container 1 may have a similar shape with at least a slightly larger inner diameter than the carbon rod. If the cylindrical object is, for example, a cylindrical electrode rod made of carbonaceous material with a diameter of 19 mm, the container 1
The inner diameter of the electrode rod is at least 2 mm larger than the diameter of the above electrode rod, which is 19 mm.
~20 mm is large, and if the size of the container is designed so that if the electrode rod is located at the center of the container 1, the gap distance between the inner wall of the container and the surface of the electrode rod is usually about 1 to 10 mm. good. It should be noted that if the electrode gap is less than 1 mm, the flow resistance of the plating liquid will increase, and the pressure of the liquid feeding pump will increase, which is not preferable. Therefore, the desired plating flow rate cannot be obtained unless the capacity of the feed pump is also increased. As the feed pump capacity increases, energy consumption increases, which is industrially uneconomical. Therefore, the above-mentioned dimensions are determined within a range in which voltage efficiency and boundary film are not generated on the surface of the object to be plated, and in which the flow resistance of the plating liquid flowing through this gap does not become extremely high. That is, the plating voltage, which influences voltage efficiency, is expressed as the sum of the electrical resistance of the liquid, which is proportional to the distance of the gap, and the interfacial resistance between the negative and anode electrodes. Therefore, the smaller the gap, the smaller the voltage drop due to the electrical resistance of the liquid and the better the voltage efficiency. Furthermore, the interfacial resistance has a property that is inversely proportional to the velocity gradient of the high-speed plating liquid flowing between the stationary state layer on the surface of the cathode or anode that is the object to be plated and the center of the gap. If the above-mentioned electrode gap is large, the liquid flow will be laminar on the surface of each pole, and the boundary film formed on the surface of each pole will become thicker.
When the thickness of this boundary film increases, the movement speed of ions decreases within the boundary film or laminar flow, and the supply of new ions becomes insufficient, making it impossible to perform good plating. Conventionally, in order to increase the plating speed, air was blown into the plating liquid or the object to be plated was rotated and rocked to break the boundary film, but with this method, the speed could be increased by at most two to three times. It was at its limit. On the other hand, the present invention increases the velocity gradient between the surface of both electrodes and the liquid flow by moving the plating liquid between the two electrodes at a flow rate of 1 cm to 30 m/sec, preferably 60 cm to 30 m/sec. By making the laminar region generated on the surface very thin and creating a turbulent flow with an abundant supply of ions, plating can be done at high speed. On the other hand, as the flow rate of the liquid increases, the turbulent region increases and the laminar region decreases, so the boundary film becomes smaller.
The plating voltage will be reduced, but on the other hand, in order to obtain a high-speed liquid flow, the flow resistance of the liquid will increase, so a high pressure will be required in inverse proportion to the cross-sectional area, increasing power costs and requiring an airtight structure. It is also becoming difficult to maintain. For this reason, the above-mentioned gap is about 1 to 10 mm and 30 mm.
The conditions under which the best results can be obtained for high-speed plating are when the flow rate is at an appropriate flow rate of cm - 60 cm/sec or more and 30 m/sec or less. In other words, in the present invention, the shapes of the object to be plated and the inner wall of the container are substantially similar, the gap distance between the object to be plated and the inner wall of the container is as small as possible, and the object to be plated and the inner wall of the container are in contact with each other. Moreover, if the space (electrode spacing) in which the plating solution flows continuously through these gaps is kept sufficiently large, plating can be performed efficiently in a short time. Therefore, the container 1 needs to be designed in consideration of the shape and dimensions such as length and diameter of the electrode rod which is the body to be plated. Next, at least two containers, preferably about 5 to 20 containers whose shape and size have been determined in this way are arranged in parallel as shown in FIG. Then, an inlet 2 for the plating solution is provided at the tip of one container 1 arranged in the order of precedence among the plurality of containers 1 arranged in parallel, and the plating solution is continuously flowed through the plurality of containers 1 arranged in parallel. A group of containers 1 are arranged in which each container 1 is connected in series or in parallel at an appropriate predetermined position by a connecting pipe 3 so that the containers 1 can flow in series. Preferably, the appropriate predetermined positions for providing this connecting pipe are at both ends of the container 1, and in an embodiment in which one or both of these ends are removably engaged with the container body, each The optimum position is for the container engaging bodies 4 and 5 to engage at both ends. The reason for this is that in the plating method of the present invention, the electrodes are connected in series, the spacing between the electrodes is constant, and the carbon rod and the anode are similar in shape. Since the metal can be made to flow uniformly in any part of any container at a flow rate of 1, any part of the surface of the object to be plated can be metal-plated uniformly with high precision. Therefore, it is desirable that the inlet 2 for the plating solution be provided at one end of the engaging body 4 or 5 of the container 1 as much as possible. Then, the container engaging bodies 4 and 5 are connected to the container main body 1.
It is desirable that protruding supports 6 and 7 be provided at approximately the center of the side surfaces that engage with the container 1 so that the carbon rod to be plated is located approximately at the center of the container 1. Moreover, the supports 6 and 7 are assumed to have a current path necessary for electroplating. Further, each of the plurality of containers 1 arranged in parallel can be connected in series with a power source 11 so that a current flows in series at the positions at almost both ends thereof, as shown in FIGS. 8 and 8A. This is an important condition in the device of the present invention. In this way, the current flowing through the objects to be plated that are electrically connected in series can be made constant regardless of variations in the resistance between each electrode, and therefore uniform plating can be applied to each object to be plated. You will be able to do this. This is because when multiple carbon rods are electrically connected in parallel as in the conventional plating method, it is impossible for the contact resistance of each contact to be exactly the same. ) This is because the currents flowing individually are different. As a result, variations occur in the amount of metal transferred to the body to be plated (carbon rod) (hereinafter referred to as the amount of plating). On the other hand, in the present invention, the plating time can be reduced to 1/25 to 150,
This makes it possible to connect them in series in terms of equipment capacity, and it is possible to reduce variations in the amount of plating. On the other hand, an outflow port 8 for the plating solution is provided at a part of the container 1 arranged in the other order of the parallel group, for example, at the position of the side surface of either the engaging body 4 or 5 of this container. It is necessary to provide In the device of the present invention configured in this way, the opening 1 at either one end or both ends of the container 1
From A, a carbon rod to be plated is placed into the inner wall of the container 1 so that the object to be plated 10 (carbon rod) does not come into contact with it. At this time, approximately at the center of the container, preferably at any part of the surface of the object to be plated 10 and the inner wall surface of the container 1, at a position where the gap distance between these parts is equal, for example, within a range of 1 to 10 mm. It is preferable that the body to be plated is placed at. In addition, when inserting the bodies to be plated into the containers, as shown in FIG. 7A, the carbon rods that are the bodies to be plated 10 are arranged in parallel in advance so as to correspond to the spacing between the respective containers. The conveyor plate 12 held by the conveyor plate 12 can be mechanically advanced and retracted to automatically feed the conveyor plate. For this purpose, at least one end or both ends of the container 1 are open, and one end of the carbon rod is supported on the transport plate 12 in the gap between the opening 1A and the engaging body 4 or 5 in the direction C or D. It is necessary to carry out parallel transport from This can also be done by moving either the engaging body 4 or 5, which supports one end of the carbon rod 10, which is the body to be plated, back and forth in the direction of the container. The plating solution, which is a mixed aqueous solution of copper sulfate and sulfuric acid, that is, the plating solution that is the cheapest and is compatible with the present invention, is applied to the surface of the object to be plated inserted into the container at a speed of 1 cm to 3 m/sec. The plating solution is moved continuously while ensuring reliable contact with the surface of the object to be plated, and is caused to flow from the inlet 2 to the outlet 8 of the plating solution so that a large amount of the plating metal ions are supplied to the surface of the object to be plated. It is. As a result, the current density was 0.5 to 450 A/ ^dm2 , and the liquid flow rate was 1 cm to 30 m/dm.
sec, current density when high-speed plating is used daily
It is preferable to set the flow rate to 30 to 450 A/dm ² and the liquid flow rate to 60 cm to 30 m/sec. Therefore, according to the present invention, the surface of the carbon rod to be plated can be plated at an extremely high speed of approximately 25 to 150 times the plating speed of a low-speed plating method, and therefore the time required for plating is approximately 25 to 150 times that of the conventional method.
Since the time required for plating can be reduced to one-fold, the cost of plating equipment can be correspondingly reduced significantly. Figures 9A and 9B and Figures 9C and 9D
The figure shows a cross section of both ends of a connected carbon electrode rod obtained using the plating method and apparatus of the present invention. A root portion 10B of the convex portion 10A formed at one end thereof in FIG. 9A;
A plating film 14A such as copper plating is formed on the peripheral inner end 10D of the concave portion 10C formed on the other side end.
and 14B are shown with a slight taper. In the case shown in FIG. 9B, the inner end 10D of the periphery of the concave portion 10C provided on one side of the carbon electrode rod 10 is cylindrical, and a slight stepped portion 10E is provided at the tapered portion of the concave portion 10C. This is an example. In the case shown in FIG. 9C, the convex portion 10A has the same slope up to the root portion 10B, and the concave portion 10C has a cylindrical peripheral end 10D, and has a slight step with respect to the tapered portion 10C of the concave portion. The case where 10E is provided is shown. As shown in FIG. 9D, the convex portion 10A has the same slope up to the root portion 10B, the concave portion 10C has a cutout extending outwardly from the peripheral end 10D, and the tapered portion of the concave portion 10C has the same slope as the base portion 10B. This shows the case where it is connected to the cut part. According to experiments, the step shown in FIGS. 9B and 9C has a step 10E.
It was found that it was easier to fit in than the ones shown in FIGS. 9A and 9D, which are not provided with a hole, and that it was difficult to come off. In addition, the following distance exists between the outer diameter D ₁ of the plating film 14A applied to the base portion 10B of the convex portion 10A and the inner diameter D ₂ of the plating film 14B applied to the peripheral inner end 10D of the concave portion 10C. The range that satisfies the relationship is the most preferable fitted state. If ΔD=D ₁ −D ₂ , then 0≦ΔD＜0.10mm In other words, the outer diameter D ₁ of the base of the convex part and the inner diameter D ₂ of the peripheral end of the concave part are equal to or 0.10
It is desirable that D ₁ is larger than D ₂ within mm. The reason for this is that when the convex portion 10A and the concave portion 10C are fitted together, the fit of the carbonaceous portion and the fit of the plating film portion must both be satisfied at the same time, as described above. When the unplated portion (carbonaceous portion) of the convex portion 10A and the unplated portion of the concave portion 10C fit together, the mechanical connection of the carbon electrode rod becomes complete and easy. On the other hand, when fitting the plating film 14A on the root portion 10B of the convex portion 10A and the plating film 14B on the inner peripheral edge portion 10D of the concave portion 10C, the above condition is satisfied if there is a large variation in the thickness of the plating films on both sides. It becomes impossible to satisfy this condition and fitting becomes difficult. If the difference ΔD between the outer diameter D ₁ and the inner diameter D ₂ is smaller than zero, the plating film at the base of the convex part and the concave part will not come into contact with each other, and the convex shape will move into the concave part where ΔD is greater than 0.10 mm. This is because it becomes difficult to fit down to the root of the part. Therefore, by controlling the thickness of the plating film within the above conditions, the plating films on both sides are pressed and deformed by the malleability of the copper at the same time as they are pressed together with a slight pushing force, maintaining just the right fitting force and allowing a large amount of current to flow. This makes it possible to conduct electricity from the new electrode to the old electrode without generating heat. An apparatus for manufacturing such a connected carbon electrode rod is shown in FIG. In Figure 10,
Reference numeral 1 denotes a container having a cylindrical portion serving as an anode.A container engaging member 4 is applied from one opening 1A of the container 1, and is sealed and connected with a packing 16. The container engaging body 4 is provided with a rod-shaped body support body 6 that protrudes from the open end 1A of the plating unit 1 into its internal cavity. The carbon electrode is fitted into and supported by the concave portion 10C formed on one side of the connectable carbon electrode rod 10, and the support base 12 of the container engaging body 4 is supported by the cylinder 15 (see FIG. 7A). The rod 10 is inserted into the internal cavity 1C of the container 1 of the plating unit. Another container engaging body 5 is sealed and connected to the opening 1B on the other side of the container 1 by a packing 16, and this other container engaging body 5 has a plated object support 7 that projects inward. A conical recessed hole 7A is formed inside the plated body support 7, and when a convex portion 10A formed at one end of the connectable carbon electrode rod 10 is inserted, a seal ring 18 is formed.
The convex portion 10A located ahead of the seal ring 18 is configured to block the flow of plating liquid to prevent plating. Reference numeral 7B denotes a stopper provided as necessary to support the tip of the convex portion 10A of the electrode. Container 1 of 1
The container engaging body 4 that closes the opening 1A on one side is provided with a plating liquid outlet 8, and the container engaging body 5 on the other side is provided with a plating liquid inlet 2. A large number of plating units 1 are arranged in parallel as shown in FIG. 8A, and each plating unit is connected in series through a connecting pipe 3. In this way, the plating liquid enters the plating unit 1-, which has the highest priority, and sequentially enters the plating unit 1-, 1-, 1-, and so on.
-,...1-N and circulate in series. An electrode 6A protruding from the outer center of the plated body support 6 is connected to the negative terminal of a power source 11, and the plated body support 6, which is a conductor, is connected to the power source 11 by a conductive wire 13. As shown in FIG. 10, the distance between the conductor portion which becomes the anode of the container of the plating unit 1 and the carbon rod 10 which is the object to be plated is maintained at equal intervals, and the tip portion 6C of the electrode 6A is connected to the object to be plated. Plating occurs when the plating liquid flows between the anode container and the cathode to be plated. Furthermore, the plating film 14A on the base portion 10B of the convex portion 10A of the carbon electrode rod 10 and the plating film 14B on the inner peripheral edge portion 10D of the concave portion 10C are also plated at the same time, and the thickness of the base portion is within ±0.05 mm. can be controlled within. In this case, this plating film 14
A and 14B each become thinner and tapered toward the tip and inner end. In the case shown in FIG. 10, since the embolus 17 is fitted into the concave portion 10C of the electrode rod 10, the plating liquid is prevented from flowing through the concave portion 10C inward from the step portion 10E shown in the figure. , it will not be plated. The convex portion 10A on the other side is a seal ring 18.
Since the tip of the sealing point is not plated, the convex portion and concave portion of the connected carbon electrode rod of the same shape can be firmly fitted. Next, examples of the present invention will be described. Example 1 A carbon rod with a diameter of 16 mm and a length of 400 mm was inserted into the apparatus of the present invention shown in FIG. Plating was carried out for 3 hours at a current density of 3 A/dm ² while supplying this at a flow rate of 3 cm/sec. In addition, when the electrodes are arranged in parallel and connected in parallel to the power supply in the conventional open plating bath shown in Figure 2, the average current density is 3A/d, which is the same as above.
I did plating for 3 hours at ^m2 . 100 samples were used and the results are shown in Figure 11 and Tables 2 and 3. FIG. 11 is a distribution diagram of the amount of plating deposited on the electrode rods when plating was performed using the series energization method in the closed bathtub of the present invention and when plating was performed using the parallel energization method in the conventional open bathtub. The distribution diagram a in FIG. 11 shows the distribution of the amount of plating deposited on the rod when series energization is carried out in the closed bathtub of the present invention, and b is the distribution of the amount of plating deposited on the electrode rod when parallel energization is carried out in the open bathtub of the conventional method. This is the distribution of the amount of plating deposited. In parallel energization, various electrical resistances such as the contact resistance of the contacts of the carbon rods that are the objects to be plated cause the current flowing through each carbon rod that is the object to be plated to vary, resulting in variations in the amount of plating and a wide range. distribution. In the series energization of the present invention, since the current flowing to each carbon rod to be plated is constant, there is almost no variation, and almost the same amount of plating was obtained. Table 2 shows the variation in copper plating amount using deviation values. Table 3 shows the carbon electrode rod divided into three equal parts: head, center,
The differences in film thickness (maximum and minimum values) were investigated to determine the variation in film thickness of each copper plating on the rear part.

【table】

[Table] The average weight in Table 2 does not change whether series or parallel energization is applied, but when looking at the variation in plating amount in terms of deviation value, it is less than one-tenth of parallel energization. Table 3 shows that the thickness of the plating film is uniform on all parts of the carbon electrode rod when energized in series, with little variation in thickness, and the difference in film thickness is small, but when energized in parallel, a thick layer is deposited on the head and rear part of the electrode rod. The error (maximum value - minimum value) of each film thickness is large. Example 2 A carbon rod with a diameter of 19 mm and a length of 400 mm was inserted into the apparatus of the present invention shown in FIG.
A mixed aqueous solution of is used as the plating liquid, and the current density is 2A/
^dm2 , 30A/ ^dm2 , 60A/ ^dm2 , 200A/ ^dm2 ,
Variations in plating amount and plating film thickness were investigated at 300 A/dm ² and 450 A/dm ² . The number of samples was 30. The flow velocity is proportional to the current density.
0.02m/sec, 0.7m/sec, 1.6m/sec, 10m/
sec, 20 m/sec, 30 m/sec, and the plating time was set to 6 hours, 24 minutes, 12 minutes, 3.6 minutes, 2.4 minutes, and 1.6 minutes. Tables 4 and 5 show the results of experiments. Table 4 shows the variation in the amount of copper plating at each current density expressed as a deviation value (δ/×100). Table 5 shows the error (maximum value - minimum value) of the copper plating film thickness at each current density.

【table】

[Table] From Table 4, the amount of plating and its deviation value hardly changed at both low and high current densities, and no influence of current density was observed on this. Also in Table 5, there was no effect of current density on the thickness of the plating film. Judging from the above experimental results, it can be concluded that, as in the present invention, the plating bath is of a closed type, the electrodes of each unit are electrically connected in series, and each unit is connected mechanically in series so that the plating liquid flows through the units in sequence. It was confirmed that when connected and plated, the error in film thickness was ±0.05 mm or less and the amount of plating remained constant, regardless of conditions such as current density, flow rate of plating liquid corresponding to it, and plating time. Example 3 Connectable carbon electrode rods shown in Fig. 9B with a diameter of 19 mm and a length of 430 mm were inserted into a closed plating bath of the same type as the plating unit shown in Fig. 10, wired in series with a spacing of 2 mm, and 250 g of copper sulfate was added. /, sulfuric acid 35g/
A mixed aqueous solution of is used as the plating liquid, and the current density is 100A/
^Plating was performed at a flow rate of 5 m/sec, a plating time of 7.2 minutes, and a flow rate of 5 m/sec. In addition, using the plating frame for the connected carbon electrode rod shown in Fig. 1B in the open type plating bath shown in Fig. 2 using the conventional method, the carbon rod to be plated is immersed up to the base of the convex part, and the current density is A. I spent 4 hours plating on / ^dm2 . The Metsuki liquid was the same as that in the closed bathtub. The number of samples (carbon rods) was 50 each. The results are shown below. Table 6 shows the thickness of the plating film 14A at the base of the convex part of the electrode rod in Fig. 9B and the thickness of the plating film 14B at the inner end of the periphery of the concave part as t ₁ and t ₂ respectively. It is shown as a film thickness error (maximum value - minimum value). Table 7 shows a practical test in which the convex and concave parts of a connectable carbon electrode are actually fitted together, the fitted carbon electrode is attached to a torch, and an arc is struck on a steel material with a current of 1600A. This is a repeated result. (A) The plating film on one of the uneven parts is too thick and it is difficult to fit. (B) The plating film is not sufficiently fitted or there is no contact, causing the connection part to generate heat during use or wear out due to oxidation. The test results for each of the 50 samples were classified into three categories: (C) those with good fit and no problems during use.

【table】

[Table] From Table 6, the average thickness of the plating film at t ₁ and t ₂ is almost the same for both series and parallel energization.
The film thickness error is significantly smaller with series energization, ±0.05mm.
The diameter difference ΔD can be controlled as follows, and the diameter difference ΔD is 0
It was found that the value was well within the range of ≦ΔD<0.10 mm. From the results shown in Table 7, all of the connected electrode rods of the present invention had good fitting conditions and good conditions during use. However, in conventional methods, the plating film may be too thick or too thin,
These causes accounted for 16% and 18%, respectively, and 66% were in good fit and condition during use. Therefore, according to the connected carbon electrode rod of the present invention,
It was confirmed that they fit completely and easily, are difficult to come off, and do not fall off even during high-temperature abrasion, and are 100% usable.

[Brief explanation of drawings]

Figures 1A and 1B are cross-sectional views illustrating the structure of the plating frame used in the experiment, Figure 2 is a diagram of a conventional plating device, and Figure 3 shows open plating baths installed in parallel and plating liquid flowing in parallel. Figure 4 is an explanatory cross-sectional view showing a plating device in which the electrodes are connected in series to the power supply. Figure 4 shows a system in which sealed plating baths are arranged in series, the electrodes are connected in series to the power supply, and the plating liquid is circulated in series. FIG. 5 is an explanatory cross-sectional view showing the plating device of the present invention, in which both negative and negative electrodes are arranged in parallel in an open plating bath, and the two electrodes are connected in parallel to the power source. A schematic diagram, Fig. 6 is a characteristic diagram showing the relationship between the flow rate and current density of the plating liquid tested according to Fig. 3 (open plating bath, parallel energization) and Fig. 4 (closed plating bath, series energization), and Fig. 7
7A is a plan view showing an example of the apparatus for high-speed electroplating of carbon rods of the present invention, and FIGS. 8 and 8A are diagrams illustrating currents flowing in series in the apparatus for high-speed electroplating of carbon rods of the present invention. Explanatory diagram showing the state, No. 9A
9B, 9C, and 9D are partial sectional views showing embodiments of the connected carbon electrode rod of the present invention, and FIG. 10 shows details of the plating device for the connected carbon electrode rod of the present invention. The cross-sectional view shown in FIG. 11 is a plating amount distribution diagram comparing the plating method of the present invention and the conventional plating method. 1... Plating container (plating unit) serving as an anode, 2... Plating liquid inlet, 3... Connecting pipe, 4
... Container engaging body, 5... Other container engaging body, 6...
Plated object support, 6A... Recessed hole of plated object support, 7... Other plated object support, 8... Plating liquid outlet, 9... Opening, 10... Carbon rod,
11...Power source, 12A, 12B...Support stand for container engaging body, 12C...Support stand for plating unit, 1
3... Electric wire, 14... Plating film, 10A... Convex portion of electrode rod, 10B... Root portion of convex portion of electrode rod, 10C... Concave portion of electrode rod, 10D... Concave electrode rod Inner peripheral edge of the shaped portion, 10E...Step provided inward of the inner edge of the periphery of the concave electrode rod, 14A...Plating layer at the base of the convex electrode rod, 14B...Concave electrode rod plating layer at the inner end of the periphery, 15... hydraulic cylinder, 16... packing, 17... embolization, 18... seal ring, 19... plating frame,
20... Plated bathtub, 21... Carbon rod restraint part, 22... Contact part, 23... Conductive part, 24...
Plating liquid, 25... plating liquid inlet, 26... plating liquid outlet, 27... anode.

Claims (1)

[Scope of Claims] 1. A plating solution is filled and circulated between at least a container serving as an anode and a body to be plated consisting of a carbon rod serving as a cathode inserted at a predetermined distance into the container. A plurality of plating units are connected mechanically in series or in parallel, and electrically connected to at least one power source by series wiring, and a current is passed through each of the plating units to maintain a current density of 0.5 to 0.5.
450A/ ^dm2 , and the flow rate of plating liquid is 1cm~
A method for plating a carbon electrode rod, which is characterized by forming a plating film on the surface of a carbon rod inserted into a plating unit by circulating the plating solution at a rate of 30 m/sec and controlling the current according to the flow rate of the plating solution. 2. The plating method according to claim 1, wherein a plating solution is filled in a container having an anode having a shape substantially similar to the outer shape of the carbon rod. 3. The plating method according to claim 1, wherein the container is of a closed type or an open type. 4. The plating method according to claim 1, wherein the plating bath is a closed container, and the anode mounted therein is at least an insoluble electrode. 5. The plating method according to claim 1, wherein the current density is 30 to 450 A/ ^dm2 . 6. The plating method according to claim 1, wherein the plating solution is circulated at a flow rate of 60 cm to 30 m/sec. 7. The plating method according to claim 1, wherein the distance between the anode and the carbon rod serving as the cathode as the body to be plated is within the range of 1 to 10 mm in each portion and is spaced at approximately equal distances. . 8 Claim 2, characterized in that the plating solution is a mixed aqueous solution of at least copper sulfate and sulfuric acid.
Plating method described in section. 9 When forming a plating film on part or all of a carbon rod, it is necessary to connect the carbon rod to be plated in series with a power source to keep the plating current constant, and to keep the interval between the anode and the carbon rod constant. 2. The method of plating a carbon electrode rod according to claim 1, wherein the error in the plating film thickness is controlled within the range of ±0.05 mm by keeping the flow rate of the plating liquid constant. 10 A connection type carbon having a convex shape at one end and a concave shape at the other end, which allows the concave portion of one carbon electrode rod to be fitted and connected to the convex portion of another carbon electrode rod of the same shape. In the electrode rod plating method, a carbon rod to be plated is placed in a cylindrical container having at least a portion that will serve as an anode, and the distance between the anode and the cathode to be plated is in the range of 1 to 10 mm. The electrode rods are held at approximately equal intervals and configured to circulate the plating liquid between a plating liquid inlet provided on one side of the container and a plating liquid drain port provided on the other side, and one of the electrode rods A plurality of plating units in which the middle of the convex portion on one side and the inside of the concave portion on the other side are plugged are mechanically connected in series or in parallel so that the plating liquid is circulated in series or in parallel, and the plating units are is electrically connected in series with the power supply, with a current density of 0.5
〜450A/ ^dm2 , and the flow rate of plating liquid is 1cm〜
The carbon rod was circulated at a rate of 30 m/sec, and the current was controlled in accordance with the flow rate of the plating liquid, leaving only the tip of the convex part of the carbon rod inserted in the plating unit and the inner part of the concave part. The plating film applied to the root part of the convex part and the peripheral edge part of the concave part of the carbon rod is plated so that a slight taper is formed from the base toward the tip or inward. A method for partially electroplating a connected carbon electrode rod. 11 Circulating the current density at 30 to 450 A/dm ² and the plating solution flow rate at 60 cm to 30 m/sec,
The electricity according to claim 10, wherein the current density and the flow rate of the plating solution are set in correspondence so that the plating time is 25 to 3 minutes, and the thickness error of the plating film is controlled within the range of ±0.05 mm. Metsuki method. 12 The thickness of the plating film on the outer peripheral surface of the carbon rod body and the thickness error of the base of the tapered plating film on the root part of the convex part and the peripheral edge part of the concave part are controlled to be within the range of ±0.05 mm. The electroplating method according to claim 10, wherein a plating film is applied. 13 A container having an anode with a shape almost similar to that of a carbon rod, and this container has at least an opening for taking in and out the carbon rod which is the object to be plated, an inlet for the plating liquid at one end, and an inlet for the plating liquid at the other end. A plurality of containers are connected in series or in parallel, and the plating solution is connected in series or in parallel at a predetermined rate in the range of 1 cm to 30 m/sec. The carbon rod, which is the object to be plated, is electrically connected in series to a power source so that the current density is 0.5 to 450 A/ ^dm2 . Electric rod plating device. 14 Set the current density to 30 to 450 A/dm ² , and configure the plating liquid to circulate at a flow rate of 60 cm to 30 m/sec. Set the plating liquid flow rate and current density as high as possible to reduce the thickness error of the plating film. Range is ±
The plating device according to claim 13, wherein the plating device is configured to be within a range of 0.05 mm. 15. A patent claim characterized in that the distance between the container, which is at least an anode, and the carbon rod, which is a cathode and which is an object to be plated, is maintained at approximately equal distances within a range of 1 to 10 mm in each part. The plating device according to item 13.