JPH0689480B2 - Basket type anode chamber - Google Patents

Description

TECHNICAL FIELD The present invention relates to a basket-type anode chamber for electroplating, which is suitable for chloride-based molten salt electroplating and which stores a granular or pellet-shaped metal body to be used as an anode. Regarding

(Prior Art) Conventionally, a method of plating using an aqueous plating bath using a basket type anode chamber and using metal pellets or the like as an anode is known. The surface of the casing forming the anode chamber facing the cathode is porous and has a flow path for the electrolytic solution and a flow path for the current. In an aqueous plating bath,
In many cases, a metal is used to form the housing, which is easily passivated. In this case, the enclosure is galvanically protected as long as the pellet is soluble.

FIG. 1 is a schematic explanatory view showing an example of the structure of a plating tank using a conventional basket type anode chamber, and FIG. 2 is a partial explanatory view of the structure of the basket type anode chamber.

A steel material 10 to be plated (hereinafter represented by "steel plate") is continuously charged into a plating tank 14 containing an aqueous solution plating bath or a molten salt plating bath 12, while a basket type anode chamber 16
Are arranged to face the surface of the steel sheet. In the illustrated example, a total of two pairs of basket type anode chambers 16 are provided for plating both sides of a steel plate. Steel plate 10 is a conductor roll
It is connected via 18 to the cathode of a power supply 20. On the other hand, the pellet metal body 22 stored in the basket type anode chamber 16 is connected to the anode.

In the illustrated example, the pellet metal body 22 is stored in a housing 24 and immersed in the plating bath 12, or the electrolytic solution is filled between the housing 24 and the steel plate 10 constituting the cathode. . In any case, the cathode facing surface of the casing 24 forming the anode chamber is constituted by the porous panel 26. This is for forming the flow path of the electrolytic solution and the flow path of the electric current.

The porous panel 26 is composed of a structural material having a strength capable of withstanding the pressure generated by the weight of the pellet metal body 22 or the like, but at the same time, it is composed of a metal that is passivated because it is electrochemically positively polarized. . Many metals that are passivated in an aqueous solution are known, such as Ti. Pellet metal body
Since the diameter of 22 is reduced by melting, it is held by a screen 28 attached inside in order to prevent leakage and drop from the porous panel on the outside surface. See FIG. Instead of the porous panel 26, it is possible to use a punching metal in which a small number of small holes are formed in a thin metal plate which is easily passivated in an aqueous solution.

However, conventionally, there is a structural example in which a porous panel on the outer surface is made of a metal such as Ti and a screen is made of a metal such as Ti, which is the same as that of a plating apparatus using an aqueous solution plating bath, but in a molten salt electrolytic plating bath. Such a structure cannot be used because Ti is anodically dissolved.

Japanese Unexamined Patent Publication (Kokai) No. 57-161085 discloses an example of a structure of an anode chamber in which a surface facing a cathode is made of a mesh material as a single-sided plating device. However, there is no suggestion as to the material, rather, the device disclosed in this publication uses a vertical type instead of a horizontal type in the past to make the distance between the electrodes vertical, and the flow of the aqueous electrolytic solution is uniform. Is intended to be.

(Problems to be Solved by the Invention) Here, one object of the present invention is to provide a basket type anode chamber for molten salt electroplating of a chloride system that can withstand continuous operation for a long period of time. is there.

Another object of the present invention is to provide a basket type anode chamber suitable for chloride-based molten salt electroplating.

(Means for Solving Problems) The inventors of the present invention tried to apply the above-mentioned conventional method to electroplating using a molten salt bath, particularly Al-based plating of steel using a molten chloride bath. The passivation of Ti was insufficient in chloride, and the casing material dissolved in a short period of time. Therefore, as a result of detailed investigation of the anode behavior of various metal materials and alloy materials in the chloride molten salt bath, Al
There was no material that could fully withstand 0V-10V noble potential range. However, the metals that are relatively inactively soluble are molybdenum and tungsten, which are stable in the 0 V to 2 V noble potential range with Al as a reference, and thus can be partially used.

By the way, in order to prevent the leakage and dropping of the pellet dissolution residue, it is desirable to install a screen inside the panel as in the conventional method, but the size of the hole of the screen is
0.1-2 mm is preferable. This is because when the thickness is smaller than 0.1 mm, the aperture ratio becomes small and the electric resistance increases, and when it is larger than 2 mm, the leakage of the residue cannot be sufficiently prevented. On the other hand, in the case of this screen, as compared with the above-mentioned panel material, almost no strength is required, so a thickness of 1 mm or less is sufficient. For this reason, the increase in the potential with energization is 2 V or less, and the aforementioned molybdenum and tungsten can be used.

Although it is conceivable that the screen is made of a material other than a metal material, the flexibility of glass or the like is poor, and a resin-based material deteriorates and collapses in a molten salt in a short time. In addition, if it is made of a metal material, the potential on the front surface of the anode chamber can be made uniform through the screen, so that the current distribution can be made more uniform.

In general, the porous panel on the front surface, which is the basic structural material of the housing, needs to have a strength capable of withstanding the pressure such as the weight of the metal pellet, and a thickness of 5 mm or more is required. Therefore, at the time of energization, this forefront has a noble potential of several V to several tens of V due to the electric resistance of the chloride molten salt bath, and this porous panel is made of a heat-resistant insulator such as ceramic or a heat-resistant insulator. It has been found that the above-mentioned object is achieved only by using a coated metal material.

In addition, it is not always easy to form the entire porous panel that is required to have sufficient mechanical strength and precise shape with an insulating material such as ceramics. Therefore, after forming the whole with a metal material, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , C
It has been found that it is also possible to spray ceramics such as r ₂ O ₃ and more preferably to seal the sprayed material and use it as an insulating material.

Here, the gist of the present invention is that it is composed of a housing for accommodating a granular or pellet-shaped metal body used as an anode, the surface of the housing facing the cathode is made of a porous panel and In a basket-type anode chamber for chloride-based molten salt electroplating provided with a screen member, the screen member is made of a material selected from tungsten, molybdenum, and a composite material thereof, and at least the cathode of the casing is opposed to the cathode. A basket-type anode chamber for chloride-based molten salt electroplating, characterized in that the porous panel is made of a heat-resistant insulator or a metal material coated with the heat-resistant insulator.

Further, the insulating material constituting the porous panel is preferably a ceramic, and even if it is used alone or, for example, a metal material is a ceramic such as Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Cr ₂ O ₃ or the like. It may be used as a coating material for coating by thermal spraying.

In the present invention, the shape and size of each member are not particularly limited and may be appropriately selected and used as necessary, but in the case of the screen member, preferably, the length of one side of the mesh is in the range of 0.1 to 2 mm. Good to have.

(Operation) Next, the present invention will be described in more detail with reference to the drawings.
FIG. 3 is a schematic explanatory view of a basket type anode chamber according to the present invention, and FIG. 4 is a schematic front view thereof. The same members as those in FIGS. 1 and 2 are designated by the same reference numerals.

In the figure, a pellet-shaped metal body 22 that is an anode metal is housed in a housing 24 and faces the steel plate 10 that constitutes the cathode. The outermost surface of the housing 24 that constitutes the facing surface is appropriately made of metal,
Porous panels made of eg mild steel or Ni or Ni-based alloys
It is composed of 26 and is covered by an insulator or lining 30. The coating may be provided by so-called ceramic spraying. A screen 28 is provided on the opposite side of the porous panel 26. The screen member 28 is made of a material selected from tungsten, molybdenum, and a composite material thereof. The other surface of the housing 24 may be formed and surrounded by an insulating material or an insulating lining 32. The outermost porous panel 26 forms an opening 34 to form a flow path for an electric current or the like. Only some openings are shown in FIG.

In order to continuously operate molten salt electrolytic plating using the basket type anode chamber according to the present invention, the metal particles settle as they are dissolved, and along with that, through the charging port from the upper portion of the housing 24 as appropriate, in the form of pellets. The metal body 22 may be added and added.

According to the present invention, it is preferable that at least the outermost porous panel of each component of the casing constituting the basket type anode facing the cathode is made of a metal material and covered with an insulating material. In this case, the other structural materials of the housing 24 are also covered with the insulating material. The screen member 23 is provided inside the porous panel.

Since the degree of corrosion changes depending on the composition, temperature, etc. of the molten salt plating bath, the type and thickness of the coated insulating material may be appropriately selected according to the purpose.

The following is an example of a combination of materials for the porous panel and the screen member when used in a specific molten salt plating bath.

Molten salt plating bath composition: AlCl ₃ -NaCl-KCl Porous panel: Ni-based alloy + SiC ceramic coating Screen member: W mesh material (mesh length 1.0 mm) Therefore, according to the present invention, the use of expensive materials can be minimized. It is possible to construct a basket type anode chamber that is sufficiently anticorrosive to the molten salt plating bath, and not only its economic effect, but also excellent advantages such as enabling long-term continuous operation of molten salt electroplating. To be

[Brief description of drawings]

1 and 2 are schematic explanatory views showing an example of a conventional basket type anode chamber; and FIGS. 3 and 4 are schematic explanatory diagrams showing the structure of the basket type anode chamber according to the present invention. . 10: Steel material, 12: Molten salt plating bath 14: Plating tank, 16: Basket type anode chamber 22: Pellet metal body, 24: Housing 26: Porous panel

Front page continuation (72) Inventor Toshio Nakamori 1-3, Nishi-Nagasumoto-dori, Amagasaki-shi, Hyogo Sumitomo Metal Industries, Ltd. Research Institute (72) Hirohisa Seto 1-chome, Nishi-Nagasumoto-dori, Amagasaki-shi, Hyogo 3 Sumitomo Metal Industries, Ltd., Research Institute of Technology (72) Inventor Gen Shimazaki, 4-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd., Hiroshima Laboratory (72) Inventor Katsushi Hidaka, Hiroshima Prefecture 4-6-22 Kannon-Shinmachi, Nishi-ku, Japan Mitsubishi Heavy Industries Ltd. Hiroshima Works (56) References: 60-6089277 (JP, U): 60-89278 (JP, U): 60-105662 (JP, U)

Claims (3)

[Claims] 1. A chloride comprising a housing for accommodating a granular or pellet-shaped metal body used as an anode, the surface of the housing facing the cathode being made of a porous panel and having a screen member on the inner surface. In a basket type anode chamber for molten salt electroplating, the screen member is made of a material selected from tungsten, molybdenum, and a composite material thereof, and the porous panel facing at least the cathode of the casing is heat-resistant insulated. Characterized by comprising a metal material coated with an object or a heat-resistant insulator,
Basket type anode chamber for chloride-based molten salt electroplating. 2. The basket type anode chamber for molten salt electroplating according to claim 1, wherein the insulator is ceramics. 3. The basket type anode chamber for molten salt electroplating according to claim 1 or 2, wherein the length of one side of the mesh of the screen member is in the range of 0.1 to 2 mm.