JPH021864B2 - - Google Patents

Description

[Detailed description of the invention]

Technical Field The present invention relates to a surface treatment method for forming a corrosion-resistant protective film by dipping, coating, or the like. Conventional technology Conventionally, methods for forming corrosion-resistant films on metals such as iron and copper include: 1. Hot-dip plating method for coating zinc (Sierra Dizing), 2. Method using phosphate film (Parkerizing), 3. Electroplating method, 4. Thermal spray method (vapor deposition)
However, among these methods, methods 1 and 2 have poor salt spray test characteristics, and methods 3 and 4 have the disadvantage of being dependent on shape. In addition, there are also problems with pollution, particularly in the widely used chrome plating method. Purpose of the Invention The present invention forms a new protective film on the surface coating of metal materials such as iron materials that have already been hot-dipped with zinc, iron that has undergone electroless treatment, aluminum, zinc, magnesium materials, etc. The purpose is to create a protective film on aluminum and zinc materials after no treatment, and corrosion protection is particularly important in civil engineering, electric power communications, architecture, ships, fisheries, railway transportation, agriculture, horticulture, etc. The purpose of this invention is to provide a simple, non-polluting surface treatment method suitable for the era of resource saving and energy saving, which is extremely effective for the use of a wide range of structural materials where maintenance and management are a problem. Structure of the Invention The present invention is a surface treatment method in which a surface is treated by dipping or coating with a treatment solution in which a potassium carbonate solution is mixed with a silicic acid or silicate solution and the pH value is adjusted to 10 or more. Although the method of the present invention is extremely effective alone, it is widely useful as a pre- or post-treatment method for other surface treatments, and is an extremely effective industrial treatment (non-polluting, electroless plating) method. becomes. Hereinafter, in order to explain the present invention more specifically,
An example of a processing liquid used in the present invention (hereinafter referred to as processing liquid A) and a process using the same will be shown. Mix alum (aluminum sulfate, potassium) and potassium carbonate solution with sodium silicate solution.
Surface treatment is performed using a treatment liquid (treatment liquid A) whose pH value is adjusted to 10 or higher. Using this treatment liquid A,
Metal materials such as zinc hot-dip plated iron materials, zinc electroplated materials, iron materials, aluminum materials, zinc, magnesium materials, etc. are dipped and coated, and then heat dried to form a corrosion-resistant and heat-resistant protective film that can replace chromate treatment. Form. Further, as necessary, a treatment using various other treatment liquids (referred to as treatment liquid B) is performed as a pretreatment. In the present invention, if necessary,
A heat drying process is applied to produce a safe compound protective film with excellent corrosion resistance and heat resistance. The present invention, which is completely different from the conventional methods, enables electroless and pollution-free surface treatment regardless of shape, and also enables surface treatment of multiple types of dissimilar metals with the same surface treatment solution. Further, according to the treatment according to the present invention, the contact surface with a different metal can be made into an insulating protective film, so that the surface can be treated to prevent electrolytic corrosion. EXAMPLES OF THE INVENTION Example 1 First, an example of the surface treatment liquid (treatment liquid A) in the present invention will be shown. A solution of 10g to 700g of sodium silicate (commercially available) with a concentration of 28% to 38% dissolved in 1 part water,
Mix a solution of alum in 1 part water from 0.1 g to 10 g to a saturated solution. The mixing ratio (mixing at a ratio of 1 to 10 and 10 to 1, respectively) varies depending on the metal to be treated. At that time, adjust the pH value to 10 or higher. The pH value may also be adjusted with potassium carbonate. There are two types of processing methods: [I] Dipping method Surface treatment is possible regardless of the shape of the material to be treated. The liquid temperature may be raised higher than room temperature, but in that case the liquid temperature is 90°C or less. [II] Coating (spraying) method This method is effective when treating cut parts of treated materials, or when there are connecting parts that cannot be soaked. The figure shows a state in which the above-mentioned treatment solution A is used for surface treatment of a steel material subjected to zinc hot-dip plating using method [I] or [II]. 1 is the steel material, 2 is the zinc hot-dip plating part, and 3 is the newly formed protective layer. Example 2 Commercially available Uniqlo Bolt “M-16 (φ16mm) L-65
(l65mm)'' was mixed at a ratio of 150g of sodium silicate/5 parts of the dissolved aqueous solution and 1 part of the dissolved aqueous solution and 3 g of alum/1 part of the dissolved aqueous solution, and the mixture was adjusted to pH = 12.
The treatment was carried out at a liquid temperature of 80°C and a treatment time of 90 seconds, and was dried by hot air drying. The salt spray test results of the above M-16L-65 Uniro Volt are as follows.

[Table] The salt spray tests in each example below were conducted under the same conditions and method. Example 3 Commercially available Uniqlo Volt "4 Min-L-125" was mixed at a ratio of 230 g of sodium silicate/10 parts of dissolved aqueous solution to 10 g of alum/1 part of dissolved aqueous solution,
After treatment time of 90 seconds at pH=11 and liquid temperature of 80°C, it was heat-dried. The salt water spray test results of the above-mentioned "4-minute L-125 Uniqlo" are shown.

[Table] Example 4 Zinc melt-treated flexible band made of sodium silicate
140g/2g of alum/2g of dissolved aqueous solution/
Mix dissolved aqueous solution at a ratio of 1 part, pH = 11.8, liquid temperature
After treatment at 75°C for 60 seconds, it was heat dried.

[Table] Zinc molten materials are sensitive to high temperatures and change color over a day and night at 70-80°C, but those treated with the present invention do not change color even at 200°C and have excellent corrosion resistance and heat resistance. Example 5 Commercially available chromate bolt "M-10, L-45" was mixed with 700 g of sodium silicate/1 g of dissolved aqueous solution to 3 parts of alum/aqueous solution, adjusted to pH=13, and the liquid temperature was 73°C. and processing time
120 seconds and then heat-dried.

[Table] Example 6 A Commercially available Uniqlovolt "M-16L-65" was mixed with 500 g of sodium silicate/1 part of dissolved aqueous solution and 6 parts of alum/aqueous solution, and the pH was adjusted to 10.5. The liquid temperature was set to 70°C, the processing time was set to 90 seconds, and then heat-dried. B Sodium silicate 200g/dissolved aqueous solution 1
Add 30cc of Ti solution and adjust the pH to 10.
The liquid temperature was 60°C and the treatment time was 120 seconds, followed by heat drying.

[Table] Example 7 If a coating film is formed on Fe, Al, Mg, etc. in advance and then surface treated with treatment liquid A,
The surface is hardened and corrosion resistance is further improved. This is because a silicon-containing film is plated on the surface, and this film can bend the base material after treatment and does not affect the corrosion resistance. Salt spray test results of a sample of baked-coated iron plate treated with treatment solution B

[Table] It is also effective when painting by mixing treatment liquid B with water-based rust prevention paint, and treatment liquid B is also mixed with two-component paints that mix epoxy resin and hardening agent polyamide amine. This has a corrosion-resistant effect. (Other Examples and Test Results) Next, the above-mentioned treatment liquid B other than the above-mentioned examples and many working process examples using each of them will be summarized. This solution B has a sodium silicate concentration of 28% to 38%.
Prepare a mixed treatment solution by adding potassium aluminum sulfate dissolved in 3 to 15 g of alum to 1 of a sodium silicate solution in which 50 to 700 g of alum is dissolved, and keep the solution temperature between room temperature and 50°C or higher for 5 minutes of immersion. Electroless treatment was performed within After treatment
Heat dried at 200°C or higher. It is preferable for this heat drying to be carried out at a high temperature, but a temperature of around 100°C may be sufficient in some cases. In addition, aluminum sulfate and potassium carbonate may be mixed in order to adjust the pH value of the solution to 10 or more. This treatment solution A is extremely effective for surface treatment of zinc-plated iron materials, titanium alloy-plated iron materials, electroless-treated magnesium AZ-91, electroless-treated aluminum ADC-12, etc. It turned out to be true. This is shown below as a surface.

【table】

[Table] The percentage in the table indicates the rusting rate. In the above table, titanium alloy plating iron, aluminum ADC-12, etc. mean those processed by the titanium and/or titanium alloy plating method already proposed by the inventors and applicants of the present invention (Japanese Patent Application No. 54
−80965, Patent Application No. 1983-80966, Patent Application No. 1983-
No. 93981, Patent Application No. 1983-66821, Patent Application No. 1983-193936
(See Japanese Patent Application No. 57-120358). Although the present invention has been described in detail above, the present invention is not limited to the above-mentioned embodiments, and instead of sodium silicate, silicic acid or other silicate solution may be used, and in addition to alum, potassium carbonate may be used. Solution can be used. Further, as shown in some examples, even better processing effects can be obtained by adding aluminum Al, titanium Ti, or nickel Ni to the processing solution. The solution preferably has a pH of 10 or higher, particularly 12 to 13, which improves corrosion resistance and heat resistance. Effects of the Invention As described above, the present invention is a metal surface treatment method that is extremely effective as an individual surface treatment or a post-treatment process of other substrate surface treatment processes, and is also effective in salt spray tests for 2 to 4 cycles (48 hours). ~96 hours), it has become possible to perform treatment with almost no rusting rate. Furthermore, since the pretreatment can be carried out in an extremely short period of time (within 1 minute), it has been found that it is most suitable for processing iron materials, wire materials, etc. during assembly line operations. In addition, in the various treatments of the present invention, the film formed on the surface is an extremely thin corrosion-resistant compound, less than 10μ, usually 2~
Although it is about 3μ, it seals any minute defects on the surface and improves corrosion resistance. Furthermore, since the treatment causes almost no shape change, it can be applied to nuts and bolts without changing their engagement.

[Brief explanation of the drawing]

The figure is a diagram showing a state after processing according to the present invention. 1... Steel material, 2... Zinc hot-dip plating part, 3... Newly formed protective layer.

Claims (1)

[Scope of Claims] 1. Surface treatment with a corrosion-resistant film, characterized in that the surface of metal is treated with a treatment solution in which a potassium carbonate solution is mixed with silicic acid or a silicate solution and the pH value is adjusted to 10 or more. Method. 2. The surface treatment method using a corrosion-resistant film according to claim 1, wherein the surface treatment is a post-treatment of another surface treatment.