JPH07138772A - Dip stripping agent for copper and nickel - Google Patents

Abstract

PURPOSE:To obtain a non-cyan based stripping agent capable of stripping copper and nickel or the alloy without eroding the base of a material to be treated such as a neodymium based magnet by incorporating a specific ratio of an aromatic nitro compound and an alkyl amine compound. CONSTITUTION:The stripping agent for copper and nickel is composed of 10-200g/l aromatic nitro compound and 20-800g/l alkyl amine compound. Furthermore, a sulfur compound can be blended by <=100g/l with the stripping agent. The stripping agent is suitable as a dip stripping agent for a copper and nickel plated film on the neodymium based magnet because the stripping agent does not etch the base of the neodymium based magnet and does not cause degranulation. And because a cyan compound is not used, the burden on waste water treatment is relieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripping agent used for dipping and removing copper and nickel, and particularly suitable for dipping and stripping a copper and nickel plating film formed on a neodymium magnet. It relates to a release agent.

[0002]

2. Description of the Related Art Since neodymium magnets are extremely susceptible to oxidation, conventionally, neodymium magnets have been plated for the purpose of preventing rust (improving corrosion resistance).

In this case, the plating treatment is often copper plating or nickel plating, and the coating is Cu → N.
i, Ni->Cu-> Ni, Ni-> Ni, etc., and a nickel alloy film such as Ni-P may be formed as nickel.

In such a plating process, a neodymium-based magnet is expensive in a product that fails in the plating process. Therefore, it is required to remove the plating film and perform the re-plating process.

Conventionally, as the immersion release agent for the copper and nickel plating films formed on the neodymium magnet, an aromatic nitro compound is used as an oxidizing agent, and soda cyanide or potassium cyanide is used as a complexing agent. However, since this immersion remover uses a cyanide compound,
There is a ground problem of environmental destruction.

When the plating film is peeled off, it is necessary that only the plating film is peeled off and the base material is not eroded. However, the neodymium magnet has a weak chemical resistance, and a neodymium magnet is a peeling agent containing a cyanide compound. When the copper and nickel plating films on the magnet are peeled off, a phenomenon (shrinkage) occurs in which a part of the neodymium magnet sintered product falls out, depending on the type of material of the neodymium magnet. It can no longer be reused (replated). Therefore, regardless of the type of material of the neodymium magnet, it does not cause shedding etc.,
A release agent that does not corrode, erode or etch the neodymium magnet base is desired.

Further, as the stripping agent, a stripping agent capable of stripping and removing the plating film in the shortest possible time is required.

The present invention has been made in view of the above circumstances, and is a non-cyan type copper and nickel capable of exfoliating copper and nickel metals or alloys without eroding the base material of an object to be treated such as a neodymium type magnet. It is an object of the present invention to provide an immersion remover of.

[0009]

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventor used an aromatic nitro compound as an oxidizing agent and an alkylamine compound as a complexing agent. By doing so, since the cyanide compound is not used, the wastewater treatment burden is reduced, and
Even if a neodymium-based magnet was treated, which could cause grain shedding with a conventional cyanide-based stripping agent, the copper and nickel plating films can be dissolved and removed without causing grain shedding, and the stripping speed is fast. The present invention has been discovered and has led to the present invention.

The present invention will be described in more detail below. The stripping agent of the present invention is one for dissolving and stripping copper and nickel by immersion treatment, and contains an aromatic nitro compound and an alkylamine compound. .

Here, examples of the object to be treated with the release agent of the present invention include those in which a copper plating and / or a nickel plating film is formed on a metal such as steel or stainless steel or a plastic, In particular, it is preferably used for peeling the copper plating film and / or the nickel plating film on the neodymium magnet. As a neodymium magnet,
Fe-Ni-B type sintered products and the like can be mentioned. The copper and nickel plating films are Cu-P, Ni-P,
Mainly made of copper or nickel such as Ni-B (preferably 8)
Alloys are also included.

The aromatic nitro compound used in the stripping agent of the present invention acts as an oxidizing agent for oxidizing copper and nickel, and includes o-, m-, p-nitrobenzenesulfonic acid,
o-, m-, p-nitrobenzene acid, and their salts _{(Na, K, NH 4,} Li , etc.) and the like.

The amount of the aromatic nitro compound used is 10 to 10.
It is 200 g / l, preferably 40 to 100 g / l. If it is less than 10 g / l, there is almost no effect, and 20
If it is more than 0 g / l, the solubility limit will be reached, and it is difficult to recommend from the economical point of view.

On the other hand, the alkylamine compound acts as a complexing agent for dissolving the metal (copper, nickel) oxidized by the oxidizing agent, and ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and the like are exemplified. It

The amount of the alkylamine compound used is 20
~ 800 g / l, preferably 100-300 g / l
It is l. If it is less than 20 g / l, there is almost no effect,
If it exceeds 800 g / l, the solubility limit will be reached.

The stripping agent of the present invention further contains thiocyanate (N) for the purpose of further promoting stripping and suppressing roughening of the underlying metal substrate.
a, K, NH ₄ , Li salt, etc.), hydroxymercaptopyrimidine, mercaptobenzothiazole, mercaptobenzimidazole, and other sulfur compounds are preferably added. The blending amount of this sulfur compound is preferably 0 to 100 g / l, and particularly preferably 1 to 20 g / l. When it is more than 100 g / l, further remarkable effects of promoting peeling and suppressing substrate roughening are not observed, and it is difficult to recommend from the economical point of view.

The stripping agent of the present invention contains ammonia water or Na for the purpose of adjusting the pH and assisting the dissolution of the oxidizing agent.
OH, KOH, etc. may be added. In this case, the stripping agent of the present invention preferably has a pH of 10 to 13, particularly 12 to 13, and if the pH is lower than 10, the solubility of the oxidizer may be lowered and precipitate.

The stripping agent of the present invention is used by immersing an object to be treated therein, and the treatment temperature is room temperature to 90 ° C.
Is preferably in the range of 70 to 80 ° C. The treatment time cannot be specified because it depends on the thickness of copper and nickel of the object to be treated, but it is usually 2-1 at a treatment temperature of 70-80 ° C.
It has a dissolution rate of 0 μm / hr. In addition, in processing,
From the viewpoint of dissolution rate, it is recommended to stir the stripping agent or shake and rotate the object to be treated. Further, the object to be processed can be put in a basket or a barrel for processing.

[0019]

Since the stripping agent of the present invention does not use a cyanide compound, it does not require wastewater treatment for cyanide decomposition, the wastewater treatment load is reduced, and there is no danger of cyanide pollution. Further, even when applied to peeling of a copper and nickel plating film on a neodymium-based magnet, since the magnet base is not etched and the granulation does not occur, neodymium that has been granulated with a cyanide-containing release agent is used. It can also be used for system magnet materials, so the range of applicable neodymium magnets is wide. Moreover, since the substrate is not etched in this way, there is no problem even if the object to be treated is immersed in the release agent for a long time after the copper and nickel have been completely removed. Workability is good because it can be treated and it can be left immersed in the release agent at night. Further, even if the object to be treated after such a peeling treatment is subjected to the plating treatment again, the appearance and adhesion of the plating film are good. Furthermore, since the release agent of the present invention has a high release rate, the release treatment time is short and efficient treatment is achieved.

[0020]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples and Comparative Examples] A release agent having the following composition was prepared, and an object to be treated having an electroplated coating of Cu 5 μm and Ni 15 μm formed on a neodymium magnet (Fe-Nd-B) was dipped therein. Then, the Cu and Ni plating films were processed until they were completely peeled off.

The appearance of the magnet after the Cu and Ni plating films were peeled off, and the shedding of particles from the substrate was observed with a scanning electron microscope.
The degree of difference from the non-plated magnet and the presence or absence of erosion were observed. Further, the magnet after the plating film peeling treatment is electroplated again with Cu 5 μm and Ni 15 μm,
The appearance and adhesion of the plating film were evaluated. The results are shown in the table. (Example 1) Paranitrobenzoic acid 80g / l Diethylenetriamine 200g / l Treatment temperature 75 ° C (Example 2) Paranitrobenzoic acid 80g / l Ethylenediamine 200g / l Hydroxymercaptopyrimidine 2g / l Treatment temperature 75 ° C (Example 3) Paranitro Benzoic acid 80 g / l Diethylenetriamine 100 g / l Ammonium thiocyanate 10 g / l Treatment temperature 75 ° C. (Example 4) Paranitrobenzoic acid 80 g / l Ethylenediamine 200 g / l Ammonium thiocyanate 5 g / l Treatment temperature 75 ° C. (Comparative example 1) Paranitro Benzoic acid 50 g / l Sodium bromide 100 g / l Treatment temperature 60 ° C. (Comparative example 2) Sodium metanitrobenzene sulfonate 80 g / l Sodium bromide 120 g / l Treatment temperature 60 ° C. (Comparative example 3) Paranitro Benzoic acid 80g / l Sodium bromide 100g / l Processing temperature 60 ° C

[0023]

[Table 1]

[0024]

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kiyoshi Asakawa Kiyoshi Asakawa 1-5-1, Exit Hirakata, Osaka Prefecture Central Research Institute, Uemura Industrial Co., Ltd. (72) Tetsuji Hayakawa 2-19 Minami Suita, Suita City, Osaka 1 Sumitomo Special Metals Co., Ltd. Suita Works

Claims (3)

[Claims] 1. Aromatic nitro compound 10 to 200 g / l
And a dipping release agent of copper and nickel containing 20 to 800 g / l of an alkylamine compound. 2. The release agent according to claim 1, further comprising a sulfur compound at a concentration of 100 g / l or less. 3. The stripping agent according to claim 1, which is for stripping a copper and nickel plating film on a neodymium magnet.