JPS5896860A - Surface treatment with corrosion resistant metallic film - Google Patents

Abstract

PURPOSE:To form a corrosion resistant protective Ti film by mixing a TiCl2 soln. with a TiCl4 soln., blending the mixture with an additive and a reducing agent to prepare a surface treating soln. of a specified pH or below contg. Ti ions, and subjecting an Mg substrate to nonelectrolytic treatment in the treating soln. CONSTITUTION:A TiCl2 soln. is mixed with a TiCl4 soln., and the mixture is with an additive such as sodium silicate and a reducing agent such as sodium acetate or glycolic acid to prepare a surface treating soln. contg. Ti ions adjusted to <=3pH. An Mg substrate is immersed in the treating soln. and subjected to nonelectrolytic treatment for 10sec-10min to form a corrosion resistant protective Ti film on the surface of the substrate. The protective Ti film has superior adhesive strength, and the treating soln. causes no environmental pollution and has stability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface treatment method using a corrosion-resistant metal film, and more particularly to a plating method for plating titanium on a magnesium substrate, in which the corrosion-resistant metal film is It has been discovered that it is possible to form a protective film that has extremely good adhesion to the paint film, so it is certified as JIS-
1. We propose a non-polluting treatment method to replace the chromate method of the JIS-5 standard.

Titanium or titanium oxide has excellent corrosion resistance and heat resistance.
When this material is used as a protective film to surface-treat other metals, it is highly effective for industrial use, and many attempts have been made to use this method, but it has not yet been realized industrially. The main reasons for this are that the film is difficult to grow, the formed film is porous, etc., so the characteristics of titanium cannot be utilized as a plating technology, and titanium is difficult to dissolve in plating as a material. , etc. Recently, physical processing methods such as vapor deposition method or ion blating method have been tried. However, considering the composition, shape, and area size of the material to be plated, design problems of the equipment or auxiliary tools themselves, and the structure of specialized equipment, techniques using chemical and electrochemical solutions are not suitable. More practical.

The acid used for the purpose of dissolving titanium and manufacturing a plating bath is difficult to dissolve if it contains oxygen, so hydrofluoric acid or hydrochloric acid is used exclusively, but of these two types, Hydrogen fluoride vR reacts violently with titanium and dissolves easily, but when used as a plating bath, it is difficult to grow a film, and the material to be plated may suffer from contamination, such as contamination in the smearing film. It is not suitable for dormitory use.

Secondly, hydrochloric acid is less soluble than the former. This method compensates for these drawbacks and can produce a titanium plating stock solution by dissolving it in a short time. In addition, since increasing the dissolution surface area of titanium is proportional to shortening the dissolution time, in the following examples, sponge titanium was used and the hydrochloric acid used had a content of 35N, but the use of hydrochloric acid The titanium stock solution prepared according to the range has a pH value of 1 to 5.

Also, the larger the range of dilute acid, the more it becomes an oxidizing bath, so F
When attempting to obtain an H value of 5 or more, glacial acetic acid/glycolic acid (hydroxyacetic acid) is added as a reducing agent to prevent oxidation. As the melting material, in addition to the titanium sponge mentioned above, it is of course possible to use a metal reduction material such as titanium dioxide or titanium metal. First, the raw material titanium is the above-mentioned Kinpo titanium, sponge titanium, titanium dioxide (7't
□s) etc. However, titanium dioxide is obtained by collecting and using titanium obtained by rothermal reduction by immersing it in acetic acid with added sugars based on the oxide metal reduction method. Titanium is chemically difficult to ionize, but when conditions are applied that make it easy to elute, such as with hydrofluoric acid, titanium generates intense smoke and reacts, making it toxic and dangerous.

Next, a method for producing a titanium plating raw material and a titanium plating stock solution will be explained.

The titanium plating stock solution is made as follows.

That is, the method proposed by the present inventor is as follows.

First, prepare a container A in which titanium is immersed in a mixture of hydrochloric acid and water, and then prepare a container B that can be continuously boiled at a hot water temperature of 80''C to 100°C. A titanium plating stock solution could be produced by inserting A and continuously boiling in hot water for about 2 hours while keeping the water temperature at 8011C to 100'C to dissolve titanium in hydrochloric acid.

Experimental example t A 50f titanium sponge was put into 15066 hydrochloric acid and 500C6 water was added to the volume 6 (A), and the water temperature was 0C and the amount was 20006! When immersed in the container (B) containing the water and started heating with a 500 watt electric heater,
After about 25 minutes, the container CA) reaches 85"'C, which is the boiling point, and after another 15 minutes, it reaches 92C, and the heat source is turned off.

At this point, the temperature of the hot water in container CB> is 95°C. Since this dissolution method involves boiling in hot water and the temperature of the container (B) does not exceed 100° C., it is possible to limit deterioration of the dissolved solution and gas generation due to unnecessary heating. After the heat source is stopped,
The amount of weight lost when the solution in container CA) evaporates due to heating is
While it is in a boiling state, add water and replenish the titanium stock solution at the time when the preparation of the titanium stock solution is completed. The time to reach this state is one hour after the heat source is stopped, when the temperature of the hot water in container (B) is 78°C and the temperature of the solution in container (A) is 79°C. From the start of heating to the end of preparing the stock solution is 1 hour and 40 minutes. It is.

The heat source used in this experimental example was a 500 watt electric heat source, the container (, 4) was made of ordinary glass, and the container (B) was a cylindrical soft iron plate with a thickness of 0 and a capacity of 2000 cc of hot water. It is. In this dissolving method, the dissolution time may be increased or decreased depending on the rate of animal use, and the rate of acid use and solution conditions can be adjusted depending on the type and composition of the material to be plated. In order to industrially use the wetted solution manufactured in a short time as described above, it is practical to use hydrochloric acid as the acid in consideration of the non-toxicity of the solution and the growth rate of the plating film.

Experimental Example 2 Nitric acid is added to the titanium solution prepared in Experimental Example t and used as a titanium tetrachloride atmospheric solution. In this case, as described later, the pg value is adjusted to 6 or less to prepare a plating solution.

Experimental example 1 explained above. The titanium or titanium-based mixed bath according to Experimental Example 2 makes it possible to perform stable and dense titanium plating without the need for the pretreatment process of cyankali melting, which is used industrially in conventional plating technology. And so.

The applicant uses the titanium plating stock solution described above to
Proposed a method for forming a corrosion-resistant film (4?
No. 661321). However, this proposed example is a type of chromate treatment in that it includes a chromium-oxygen bath solution and can utilize existing equipment.

An object of the present invention is to propose a pollution-free treatment method that forms a corrosion-resistant coating that has superior adhesion to a corrosion-resistant coating than the treatment method related to conventional chromate treatment (proposed example 1). Therefore, the biggest feature is that no chromium oxygen solution is used.

Example 1 Magnesium die-casting material was mainly used as a sample, and sodium acetate, ammonium chloride, sodium citrate, and glycolic acid were mixed in 1 to 100 parts of titanium tetrachloride solution.
102 was added to keep the pH value below 2, and then sodium silicate 1
Using the 00fit solution at a concentration of 10 to 100 Cc, prepare a stock solution of the surface treatment solution in a titanium ion atmosphere. An aqueous solution is added at a ratio of 3 to 10 parts of the stock solution, and the pH value is adjusted to 5 or less.The sample is rinsed with water and placed in a solution to form a protective film with good corrosion resistance on the surface of magnesium, an active metal.The treatment is electroless. The processing time is 10 seconds to 10 minutes.

After treatment, wash with water and heat dry. After the surface treatment, heat sealing treatment may be performed.

Example 2 The sample is the same as in Example 1. Mix 5 parts of titanium chloride liquid to 1 part of titanium tetrachloride liquid, make the remaining liquid titanium tetrachloride liquid, and add 1 to 10 parts of sodium citrate to 100 parts of this liquid.
F is added, and 10 to 100 C1l+ of sodium silicate is added to the solution to prepare a stock solution of a card surface treatment solution in a titanium ion atmosphere with a pH value of 2 or less.

The subsequent liquid preparation treatment method is the same as in Example 1.

Example 6 The sample is the same as in Example 1. Tartaric acid 0.1-1F, sodium silicate 10-100C per 100% titanium tetrachloride solution
C, and create a surface treatment solution in a titanium ion atmosphere with a pH value of 2 or less. The subsequent liquid preparation method is as per 91.
It is the same as 11.

Note that an aqueous solution containing caustic soda may be used for adding water in Examples 1 to 5.

Next, test results of the present invention (by public institutions) are shown in a table. All treated materials are magnesium alloy die-cast JZ-
91 and conventional (D) are shown in comparison with JIS-1 and JIS-5 chromate treatment standards.

Test conditions, method expansion, temperature 55℃±1℃, pressure 1.0 exposure 4
A salt spray test was conducted at 8 hours of spraying, 16 hours of rest, and 5% NgaL was used as the liquid.

The occurrence of bees in the fittings described below is visually determined, and the rusting rate is expressed as a percentage (X).

4 to 1 square wheel ratio means 3 to 3. 46 expenses are p.
It is a processing method.

Next, Example 1 was prepared for magnesium AX-91 manufactured by one company.
After the treatment, a salt spray test was conducted on the painted (acrylic painted) sample using the same test and method as described above, and as a result, a test result of "no estrus" was obtained even after 120 hours had elapsed. Other synthetic resin-based coating agents, such as epoxy and melamine, have excellent adhesion to the surface film and can be expected to have great industrial applicability.

Next, we will discuss the dimensional changes due to the treatment of magnesium AZ-91. This treatment includes the treatment of the present invention and the conventional method (J
IS-1), and it can be confirmed that the present invention has extremely small dimensional changes over time.

The mark indicates that there is a measurement error, so it means that there is almost no change.

The treatment of the present invention described above is as described in Examples 1 to 3, but if a forced drying step at 100°C to 600°C using infrared rays, electric heat, etc. is included during the treatment process, the electroless treatment time will be shortened. It can be completed within 1 minute.

The addition of this forced drying step is industrially effective as an extremely good surface treatment.

The characteristics of the surface treatment according to the present invention are as follows.

1. The surface treatment liquid in a titanium ion atmosphere is non-polluting, stable, has a simple working process, is easy to manage, and is economical.

2. This treatment is superior to JIS-'I and JIS-5 standards, and is also suitable for surface treatment for painting.

5. JIS treated material is the applicant's earlier application No. 55-066.
The compatibility with 821 is poor, but the processing method of the present invention has very good compatibility.

4. Dimensional changes due to the process of the present invention are smaller than those due to the JIS standard process.

5. The liquid obtained by blending ferrous chloride and salt with the waste liquid of the processing liquid according to the present invention is suitable for the treatment of magnesium cutting powder.

Procedural amendment (spontaneous) Indication of the case Patent Application No. 195956 (1982) Name of the invention Surface treatment method using a corrosion-resistant metal film Address of the representative agent making the amendment 2-5 Minami-Nagasaki, Qyushima-ku, Tokyo No. 2 & Subject of Amendment The description of “Claims” in the specification, “Invention t”, page 1, lines 5 to 119 of the specification, the statement of the scope of claims will be deleted and amended as follows.

[A butane chloride solution and a titanium tetrachloride solution, each alone or a mixture thereof, are mixed with additives and reducing agents to create a surface treatment solution with a titanium ion atmosphere with a pH value of 3 or less, which is then applied to a magnesium substrate. A method of forming a corrosion-resistant protective film made of titanium through electrolytic treatment. ” 2. Insert the following sentence between page 8, line 18 and line 19 of the specification.

“Example 4 Example 15: Therefore, for 100C of the titanium solution prepared, i
Add 10 to 100 cc of 1#It soda and further add 2 to 2 Of of catholicum citrate and sodium acetate to prepare a stock solution of surface treatment solution in a titanium ion atmosphere with a pH value of 5 or less.

The subsequent liquid preparation method is the same as in Example 1. 5. The table from page 8, line 8 to the end of the specification is deleted and amended as follows.

[Bone means a rusting rate of 0 to 2%. This is the treatment method of Hone Dor Company. ” 4. Statement No. 10, lines 1 and 2, “Next, Company A.
...after doing so, delete the text and make the following corrections.

Claims (1)

[Claims] A titanium tetrachloride solution is mixed with a titanium chloride solution, and additives and reducing agents are added to this to create a surface treatment stock solution in a titanium ion atmosphere with a pH value of 6 or less, and then applied to a magnesium substrate by electroless treatment. A method of forming a corrosion-resistant retaining film made of titanium.