JP2008214741A - Method for manufacturing hexavalent iron ion solution, chemical conversion treating agent and chemical conversion treatment method for magnesium alloy and method for etching surface of resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemical conversion treatment method carried out using a hexavalent iron ion solution having small environmental load instead of a chemical conversion treating agent such as harmful chromic acid used to improve the corrosion resistance of a member of magnesium alloy or the like and a chemical conversion treating agent comprising the hexavalent iron ion solution. <P>SOLUTION: An electrolytic cell 1 partitioned by a cation exchange electrolytic membrane or a bipolar membrane is filled with a predetermined alkaline aqueous solution in the anode side of the cell and is filled with a predminant alkaline aqueous solution in the cathode side of the cell, an anode 5 made of iron is placed and a cathode 6 made of an arbitrary conductive cathode is placed, and predetermined electric power is supplied from a DC power supply 7 to dissolve the anode 5 made of iron as a hexavalent ion into the aqueous solution to obtain a stable hexavalent iron ion solution. By applying chemical conversion treatment to the magnesium alloy using a liquid agent containing the stable hexavalent iron ion, the chemical conversion member 11 having excellent corrosion resistance equivalent to that in the chromic acid chemical conversion treatment is obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a hexavalent iron ion solution production method, a magnesium alloy chemical conversion treatment agent and a treatment method, and a resin surface etching method that do not use a heavy metal such as chromic acid, which has been conventionally used, and has a low environmental load. It is extremely useful as a chemical conversion treatment method for imparting corrosion resistance when an alloy is formed by thixomolding, die casting, press working or the like and used as an exterior product.

The hexavalent iron ion (ferrate) solution has a strong oxidizing action, and thus is extremely useful as an oxidative decomposition treatment agent for organic substances. However, there have been several studies on ferrate that have been used so far for disinfection using higher oxidizing power than ferrate potassium vortex manganate and sterilization of viruses. The application is not recognized very much. For example, a method for producing an alkali ferrate such as patent literature has been proposed. In the present invention, the use of ferrate for chemical conversion treatment of a magnesium alloy was newly examined and earnest research was repeated.
Japanese Patent Publication No.57-19054

The present invention has been made as a result of further earnest research based on these findings. Based on the research so far, a stable and strong oxidizing hexavalent iron ion elution method, a method for producing the hexavalent iron ion solution, and an oxidative decomposition treatment agent for organic materials produced by the method for producing the hexavalent iron ion have been developed. The inventor has filed a patent application (Japanese Patent Application No. 2006-116137).

  The present invention was made as a result of further earnest research on the application of these ferrates. According to the present invention, the ferrous ion solution was produced by the method for producing the hexavalent iron ion solution and the method for producing the hexavalent iron ion. The purpose of this invention is to propose a chemical conversion treatment technique for magnesium alloys using a farate solution.

  In order to solve the above problems, the present invention provides an electrolytic water tank, an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide adjusted to 1 to 18 mol / l, and alkali corrosion resistance such as platinum on the cathode side of the electrode. An electrode made of pure iron on the anode side of the electrode, and applying electrolysis by applying a voltage of 0.1 V to 50 V to the electrode. It is characterized by elution in a state.

  Moreover, in the electrolysis water tank, an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide adjusted to 1 to 18 mol / l, an electrode having high alkali corrosion resistance such as platinum on the cathode side of the electrode, and the anode side of the electrode A liquid agent containing hexavalent iron ions is produced by installing an electrode made of pure iron and applying electrolysis by applying a voltage of 0.1 V to 50 V to the electrode to generate hexavalent iron ions. It is characterized by doing.

Also, in an electrolytic water tank partitioned by a cation exchange membrane or a bipolar membrane, an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide adjusted to 1 to 18 mol / l, and platinum or the like on the cathode side of the ion exchange membrane An electrode with high alkali corrosion resistance,
When an electrode made of pure iron is installed on the anode side of an electrolytic diaphragm such as a cation exchange membrane or a bipolar membrane, electrolysis is performed by applying a voltage of 0.1 V to 50 V to the electrode to generate hexavalent iron ions. Thus, a liquid preparation containing hexavalent iron ions is produced.

  Further, the present invention is characterized in that a magnesium alloy or the like is subjected to a chemical conversion treatment using a chemical conversion treatment agent such as a magnesium alloy which is a liquid agent containing the above stable hexavalent iron ions.

  An electrolytic water tank is filled with an aqueous alkali solution such as sodium hydroxide aqueous solution or potassium hydroxide adjusted to 1 to 18 mol / l, and an alkali corrosion resistance such as platinum is formed on the cathode side of an electrolytic membrane made of a cation exchange membrane or a bipolar membrane. A high-performance electrode and an electrode made of pure iron are installed on the anode side of the cation exchange membrane, and electrolysis is started by applying a voltage of 0.1 V to 50 V from the DC power source between the anode and cathode. Then, the pure iron of the anode is eluted as hexavalent iron ions in the aqueous solution to generate an aqueous solution of hexavalent iron ions.

  According to the present invention, when electrolysis is started in the electrolytic cell, pure iron at the anode becomes hexavalent positive ions, and iron can be eluted in the alkaline aqueous solution in the state of hexavalent ions.

  Further, according to the present invention, by performing electrolysis in the electrolytic cell, the elution reaction of hexavalent iron ions proceeds on the anode side, and at the same time, the electrolysis reaction of water proceeds on the cathode surface. By these reactions, a hexavalent iron ion solution can be obtained in the anode chamber.

  In addition, according to the present invention, by performing electrolysis in the electrolytic cell, elution of hexavalent iron ions on the anode side and at the same time a magnesium alloy made of a liquid agent containing hexavalent iron ions in the electrolytic water bath A chemical conversion treatment agent can be obtained.

  Furthermore, according to the present invention, by performing electrolysis in the electrolytic cell, an aqueous solution containing hexavalent iron ions is generated in the electrolytic water tank simultaneously with elution of hexavalent iron ions. By using the aqueous solution, it is possible to obtain a chemical conversion treatment solvent such as magnesium alloy which is excellent in rust prevention ability such as magnesium alloy and does not contain heavy metals such as chromium.

  Furthermore, a magnesium alloy member excellent in corrosion resistance can be obtained by chemical conversion treatment of a magnesium alloy or the like using a chemical conversion treatment solvent such as a magnesium alloy obtained in the present invention.

  Hereinafter, a hexavalent iron ion elution method, a hexavalent iron ion production method, a chemical conversion treatment agent such as a magnesium alloy, and a chemical conversion treatment method to which the present invention is applied will be described with reference to the drawings.

  FIG. 1 is an explanatory view showing an example of a hexavalent iron ion elution method, a hexavalent iron ion production method, an oxidation treatment liquid composition, and a surface chemical treatment solvent production apparatus such as a magnesium alloy to which the present invention is applied. The electrolysis water tank 1 is an electrolysis tank for performing electrolysis work by providing various facilities necessary for the production of hexavalent iron ion aqueous solution by electrolysis, and includes an electrolytic diaphragm 2, an anode 3, a cathode 4, a direct current stabilizing power source 5, The facilities necessary for the production of the electrolytic solution, such as the alkaline aqueous solution 6 as the cathode electrolytic solution, the alkaline aqueous solution 7 as the anodic electrolytic solution, the aqueous solution circulation pump 8, and the voltmeter 9, are configured.

  As the anode 3 of the electrode, an electrode made of iron and steel wool are used. As the iron, an electrolytic iron plate having a low impurity element and a steel wool having a large surface area are used, but a general iron plate, a metal mesh, or iron powder may be used. good. On the other hand, platinum is used as the cathode 4 of the electrode, but another electrode having high alkali corrosion resistance may be used.

  As the alkaline aqueous solution 6 as the cathode electrolytic solution, a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution is used, but another alkaline aqueous solution may be used. As the alkaline aqueous solution 7 as the anodic electrolytic solution, a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution is used, but another alkaline aqueous solution may be used.

  For the electrode of the anode 3, a pure iron plate having a thickness of 1 mm is cut into 25 mm × 40 mm, pickled, and then fixed by inserting steel wool between the electrolytic diaphragm. Next, anodization is performed using a platinum electrode having high alkali corrosion resistance as the electrode of the cathode 4.

  The electrolysis water tank 1 is filled with an aqueous sodium hydroxide solution as the cathodic alkaline aqueous solution 6 adjusted to 1 to 18 mol / l. Next, a sodium hydroxide aqueous solution is filled as the cathode alkaline aqueous solution 6 adjusted to 1 to 18 mol / l. In this state, when electrolysis is started by applying a voltage of 0.1 V to 50 V from the DC power source 5 between the anode 3 and the cathode 4, the iron at the anode is eluted as hexavalent iron ions (ferrate) in the sodium hydroxide aqueous solution. Is done.

  At the same time as the elution of hexavalent iron ions (ferrate) from the anode 3, hydrogen electrolysis proceeds on the surface of the cathode 4 and hydrogen gas is generated. By continuing this reaction, the concentration of hexavalent iron ions in the anodic solution increases, and a hexavalent iron ion aqueous solution (ferrate solution) is obtained. The magnesium alloy chemical conversion treatment agent comprises a solution containing hexavalent iron ions (ferrate). Can be obtained.

  The hexavalent iron ion aqueous solution (ferrate solution) may be a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution. Similarly, a stable hexavalent iron ion aqueous solution (ferrate solution) can be obtained.

  2 (a) and 2 (b), a chemical conversion treatment is performed on a member such as a magnesium alloy using a chemical conversion treatment agent such as a magnesium alloy made of a liquid agent containing hexavalent iron ions (ferrate) manufactured according to the present invention. The schematic of the chemical conversion treatment member after giving is shown. 2A is a schematic diagram of the magnesium alloy member 10, and FIG. 2B is a schematic diagram of the magnesium alloy member 11 after chemical conversion treatment and its chemical conversion treatment layer.

Using a chemical conversion treatment agent such as magnesium alloy composed of a liquid agent containing the above stable hexavalent iron ion (ferrate), when chemical conversion treatment is performed on a member such as magnesium alloy, it reacts with magnesium to form a chemical conversion treatment film. Can exhibit an excellent anti-rust ability.
As chemical conversion treatment conditions, for example,
(I) Caustic soda concentration is in the range of 1-18 mol / l,
(Ii) Hexavalent iron ion (ferrate) concentration is in the range of 0.1 to 10 g / l,
(Iii) The chemical conversion treatment temperature is in the range of room temperature to 100 ° C.,
(Iv) A chemical conversion treatment agent and a chemical conversion treatment method, such as a magnesium alloy whose main component is iron having a low environmental load, by performing chemical conversion treatment within a recommended range of chemical conversion treatment time in the range of 1 second to 100 minutes. Can provide.

It is the schematic of a hexavalent iron ion aqueous solution manufacturing apparatus. (A) is the schematic of the magnesium alloy member 10, (b) is the schematic of the magnesium alloy member 11 after a chemical conversion treatment, and its chemical conversion treatment layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolysis tank 2 Electrolytic diaphragm 3 Anode chamber alkaline aqueous solution 4 Cathode chamber alkaline aqueous solution 5 Anode 6 Cathode 7 DC power supply 8 Voltmeter 9 Circulation pump 10 Magnesium alloy member 11 Magnesium alloy member 12 Chemical conversion treatment layer of magnesium alloy member

Claims (5)

In an electrolytic water tank partitioned by an electrolytic membrane made of a cation exchange membrane or a bipolar membrane, an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide adjusted to 1 to 18 mol / l;
An electrode with high alkali corrosion resistance such as platinum on the cathode side of the electrolytic cell;
An electrode made of iron is installed on the anode side of the electrolytic cell,
By performing electrolysis by applying a voltage of 0.1 V to 50 V to the electrode,
A method for producing a hexavalent iron ion solution, wherein iron is eluted in the form of hexavalent ions. In claim 1,
A chemical conversion treatment agent for a magnesium alloy member, characterized by subjecting a member such as a magnesium alloy to chemical conversion treatment using a solution containing the hexavalent iron ion composition. In claim 2,
A chemical conversion treatment method for a magnesium alloy member, characterized by subjecting a member such as a magnesium alloy to chemical conversion treatment using a solution containing the hexavalent iron ion composition. In claim 3,
A magnesium alloy member chemical conversion treatment method for chemical conversion treatment of a member such as a magnesium alloy using a solution containing the hexavalent iron ion composition,
(I) Caustic soda concentration is in the range of 1-18 mol / l,
(Ii) Hexavalent iron ion (ferrate) concentration is in the range of 0.1 to 10 g / l,
(Iii) The chemical conversion treatment temperature is in the range of room temperature to 100 ° C.,
(Iv) The chemical conversion treatment method for a magnesium alloy member, wherein the chemical conversion treatment time is in the range of 1 second to 100 minutes. In the method of performing a chemical conversion treatment on the magnesium surface using the chemical conversion treatment agent and the chemical conversion treatment method according to claim 1,
The magnesium alloy member is selected from the group consisting of pure magnesium, alloys such as AZ31B and AZ91D, which contain aluminum and zinc, and alloys such as AM60 and AM50, which contain aluminum and manganese. A chemical conversion treatment method for magnesium alloy.

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