CN102534600A - Method for carrying out seawater corrosion resistant treatment on surface of Q345 steel by using silane coupling agent Si-69 - Google Patents

Abstract

The invention relates to a method for treating the surface of Q345 steel with seawater corrosion resistance by silane coupling agent Si-69, which belongs to the technical field of carbon steel surface modification, and is characterized in that it comprises the following steps: (1) Si-69 silane coupling agent, Add deionized water and absolute ethanol to the Erlenmeyer flask at a volume ratio of (3-6):10:40, place it in a water bath at 25°C for ultrasonic oscillation for 1 hour, adjust the pH value to 2-7, and place it at 25 ℃ hydrolyze in a constant temperature water bath for 4-72 hours, and set aside; (2) Pretreatment of the substrate surface: epoxy resin solidifies the non-working surface, rinses the working surface with deionized water after polishing, and removes the surface grease of the sample by ultrasonic cleaning; (3) Substrate surface impregnation - Blow-drying-dipping-drying treatment. The beneficial effects of the present invention are: the Q345 steel treated with the surface of the silane coupling agent Si-69 can effectively improve the corrosion resistance of the Q345 steel in the marine environment because the surface has a Si-69 film with a dense and uniform structure, thereby The service life is prolonged; the required medicine is cheap and easy to obtain, the preparation method is simple, and the practicability is strong.

Description

Method of Seawater Corrosion-resistant Treatment of Q345 Steel Surface Using Silane Coupling Agent Si-69

technical field

The invention relates to a method for treating the surface of Q345 steel with seawater corrosion resistance by silane coupling agent Si-69, belonging to the technical field of carbon steel surface modification.

Background technique

The surface treatment of the metal substrate plays a very important role in the performance of the coating. The quality of the surface treatment of the substrate not only determines whether the surface of the workpiece can be painted, but also greatly affects the adhesion, appearance, moisture resistance and durability of the coating. corrosive performance. In the traditional metal surface pretreatment process, the most widely used are phosphate conversion (phosphating) and chromate passivation treatment. However, due to the strong toxicity of high-valent chromium ions and phosphate is one of the culprits of eutrophication in water bodies, these two methods will cause environmental pollution and endanger human health.

At present, scientists from all over the world are looking for and developing environmentally friendly surface pretreatment technologies, among which silanization treatment and rare earth conversion coating treatment are considered to have the most potential for development. However, rare earth conversion coating technology is limited due to the complex process in practical application, and more and more attention has been paid to the silanization treatment that is environmentally friendly, simple in treatment process and good in protection effect.

The metal surface silanization film-forming methods mainly include the complete impregnation method and the electrodeposition method. Recently, some scholars have proposed a composite silane film technology. Generally speaking, the corrosion resistance of the passivation film on the metal surface is related to the thickness of the film. The thicker the film, the better the corrosion resistance, but the thicker the film, the easier it is for cracks to occur, which makes the corrosion resistance of the film reduce. In the research process of the present invention, the complete immersion method is mainly used to form silane film on the surface of Q345 steel, and its technological process is relatively simple. After a period of time, it can be used for metal surface treatment. During the treatment, the metal sheet is put into the silane solution, taken out after a few seconds, and then dried and cured. The film-forming process conditions on the metal surface have an important impact on the anti-corrosion performance of the silane film. The type, concentration, pH value, hydrolysis time and temperature, and curing temperature and time of silane are the main factors affecting the effect of silane treatment on the metal surface. At present, the silane self-assembled films constructed in the literature report have some shortcomings such as incomplete film formation, easy to form inverted adsorption phenomenon during film formation, and weak bonding between the film layer and the substrate. The purpose of the present invention is to overcome the problems encountered by predecessors in the process of studying silane film formation, to study the influence of various main factors on the corrosion resistance of Si-69 after film formation on the surface of Q345 steel, and to provide a method for polymerizing Si-69 on the surface of Q345. A new process for forming a uniform network structure Si-69 film.

Contents of the invention

The purpose of the present invention is to provide a kind of method that uses silane coupling agent Si-69 to Q345 steel surface to carry out the method for seawater corrosion-resistant treatment in order to solve above-mentioned technical problem, namely by the method of dipping-blowing-drying-dipping-drying, in A uniform and dense Si-69 film is prepared on the surface of Q345 steel to improve its corrosion resistance in the marine environment.

In order to achieve the above object, the technical solution adopted in the present invention is: use silane coupling agent Si-69 to carry out the method for seawater corrosion-resistant treatment to the surface of Q345 steel, the steps are as follows:

(1) Preparation of Si-69 solution: successively add silane coupling agent Si-69, deionized water, and absolute ethanol into the conical flask with a grinding mouth at a volume ratio of (3-6): 10:40. Put the Erlenmeyer flask in a water bath at 25°C for 1 hour of ultrasonic vibration, then adjust the pH value to 2-7 with glacial acetic acid or ammonia water, then place it in a constant temperature water bath at 25°C for 4-72 hours for hydrolysis, and set aside;

(2) Pretreatment of the substrate surface: Cut the substrate material Q345 steel into small pieces, seal the non-working surface with epoxy resin, rinse the working surface with deionized water after polishing, and then put it in acetone and use ultrasonic cleaning for 15 minutes to remove the surface of the sample Grease, then ultrasonically wash with 1mol/L NaOH for 30s to further remove the grease on the surface of the steel plate, take it out and rinse it with deionized water;

(3) Substrate surface dipping-drying-dipping-drying treatment; immerse the polished Q345 carbon steel sheet in the hydrolyzed Si-69 solution for 60s, dry it with a hair dryer, and then soak it in the Si-69 solution for 60s. Dry it with a hair dryer and put it in an oven at 100°C for 60 minutes to dry and solidify.

The beneficial effects of the present invention are: the surface of Q345 steel treated with silane coupling agent Si-69 has a Si-69 film with a dense and uniform structure on the surface, and the excellent chemical corrosion resistance of the Si-69 film is used to reduce the corrosion resistance of simulated seawater. Corrosive effect on Q345 steel. The required medicine of the present invention is cheap and easy to obtain, the preparation method is simple, no complicated process and equipment are needed, and it can be operated under simple conditions. Therefore, this modification method has the advantages of simple and easy operation, wide practicability, etc., and is beneficial to large-scale production.

Detailed ways

The present invention is described further below by embodiment, but does not limit the present invention.

The method for carrying out seawater corrosion-resistant treatment on the surface of Q345 steel with silane coupling agent Si-69, the steps are as follows:

(1) Preparation of Si-69 solution: Add the commercially available KH-550 silane coupling agent Si-69, deionized water, and absolute ethanol into the conical flask with a volume ratio of (3~6):10:40, The ground-mouth Erlenmeyer flask was placed in a 25°C water bath for 1 hour of ultrasonic oscillation, then adjusted to a pH value of 2 to 7 with glacial acetic acid or ammonia water, and then hydrolyzed in a constant temperature water bath of 25°C for 4 to 72 hours, and then used for later use;

(2) Pretreatment of the substrate surface: Cut the substrate material Q345 steel into small pieces, seal the non-working surface with epoxy resin, rinse the working surface with deionized water after polishing, and then wash it with ultrasonic waves (working frequency 40kHz) in acetone Remove the grease on the surface of the sample for 15 minutes, then ultrasonically wash with 1mol/L NaOH for 30 seconds to further remove the grease on the surface of the steel plate, take it out and rinse it with deionized water;

(3) Substrate surface dipping-drying-dipping-drying treatment; immerse the polished Q345 carbon steel sheet in the hydrolyzed Si-69 solution for 60s, dry it with a hair dryer, and then soak it in the Si-69 solution for 60s. Dry it with a hair dryer and put it in an oven at 100°C for 60 minutes to dry and solidify.

Example 1

The method for carrying out seawater corrosion-resistant treatment on the surface of Q345 steel with silane coupling agent Si-69 comprises steps as follows:

(1) Preparation of Si-69 solution: Add Si-69, deionized water, and absolute ethanol to a ground-mouth Erlenmeyer flask according to the volume ratio of Si-69: deionized water: absolute ethanol = 4ml: 10ml: 40ml In this method, the ground-mouth Erlenmeyer flask was placed in a 25°C water bath for 1 hour of ultrasonic vibration, then the pH of the solution was adjusted to 4 with glacial acetic acid or ammonia water, and the solution was hydrolyzed in a constant temperature water bath of 25°C for 48 hours for later use.

(2) Pretreatment of the matrix material: Cut the matrix material Q345 steel into small pieces of 1cm×1cm, seal the non-working surface with epoxy resin, and the area of the working surface is 1cm ² . The electrode is polished step by step with 1#, 3#, 6# metallographic sandpaper, rinsed with deionized water, then placed in acetone and ultrasonically washed for 15 minutes to remove the surface grease of the sample, and then ultrasonically cleaned with 1mol/L NaOH (working frequency 40kHz ) for 30s to further remove the grease on the surface of the steel plate, take it out and rinse it with deionized water.

(3) Substrate surface dipping-drying-dipping-drying treatment; immerse the Q345 carbon steel sheet polished step by step with 1#, 3#, 6# metallographic sandpaper into the hydrolyzed Si-69 solution for 60s Then take it out, dry it with a hair dryer, soak it in the Si-69 solution for 60s, blow it dry with a hair dryer, and put it in an oven to dry and solidify at 100°C for 60 minutes. The Q345 steel whose surface is treated with Si-69 can be obtained.

Example 2

Step (1) In the preparation of Si-69 solution, change the volume ratio of Si-69, deionized water, and absolute ethanol to 6ml: 10ml: 40ml, add it to the conical flask, and adjust the pH of the solution to 7. Stand still in a constant temperature water bath at 25°C for 30 hours for hydrolysis. Step (2) and step (3) are the same as in Example 1.

Example 3

Step (1) In the preparation of Si-69 solution, change the volume ratio of Si-69, deionized water, and absolute ethanol to 3ml: 10ml: 40ml into the conical flask, and adjust the pH of the solution to 2 , the hydrolysis time was changed to 4h, and other operations were the same as step (2) and step (3) as in Example 1.

Example 4

In step (1) of Example 1, place the mixture of Si-69, deionized water and absolute ethanol in a constant temperature water bath at 25°C, change the static hydrolysis time to 72h, and keep other operations unchanged, step (2) And step (3) is operated with embodiment 1.

Obtain the 1cm * 1cm small block Q345 steel sample that the surface is processed through Si-69 from embodiment 1～4, use the electrochemical testing method to the Q345 steel seawater corrosion resistance that silane coupling agent Si-69 surface treatment has done experimental verification, The electrolyte solution is simulated seawater (3.5% NaCl solution). The scanning speed is 1mV/s. From the scanning electron microscope photos, it can be seen that the Q345 steel surface treated by the silane coupling agent Si-69 has a layer of Si-69 film with a dense and uniform structure on the surface, making use of the excellent chemical corrosion resistance and seawater corrosion resistance of the Si-69 film. Greatly improve. The test results of electrochemical test method: in the simulated seawater, the impedance value increased sharply; and the self-corrosion potential dropped from -651.104mV of Q345 steel before modification to -620.865mV after modification, and a certain positive shift occurred; self-corrosion The current density decreased from 23.68μA/cm ² of Q345 steel before modification to 0.3610μA/cm ² of Si-69 modification, which decreased by 2 orders of magnitude. Therefore, after the surface treatment of Q345 steel by the silane coupling agent Si-69 of the present invention, the Q345 steel has good corrosion resistance in simulated seawater. The medicine required by the invention is cheap and easy to obtain, and the treatment method of substrate surface dipping-drying-dipping-drying is simple, easy to operate and strong in practicability.

Claims (1)

1. The method of using silane coupling agent Si-69 to treat the surface of Q345 steel with seawater corrosion resistance, the steps are as follows: (1) Preparation of Si-69 solution: add silane coupling agent Si-69, deionized water, and absolute ethanol into the conical flask with a volume ratio of (3-6): 10: 40, and the ground cone Place the shaped bottle in a water bath at 25°C for 1 hour of ultrasonic vibration, then adjust the pH value to 2-7 with glacial acetic acid or ammonia water, then place it in a constant temperature water bath at 25°C for 4-72 hours for hydrolysis, and set aside; (2) Pretreatment of the substrate surface: Cut the substrate material Q345 steel into small pieces, seal the non-working surface with epoxy resin, rinse the working surface with deionized water after polishing, and then put it in acetone and use ultrasonic cleaning for 15 minutes to remove the surface of the sample Grease, then ultrasonically wash with 1mol/L NaOH for 30s to further remove the grease on the surface of the steel plate, take it out and rinse it with deionized water; (3) Substrate surface dipping-drying-dipping-drying treatment; immerse the polished Q345 carbon steel sheet in the hydrolyzed Si-69 solution for 60s, dry it with a hair dryer, and then soak it in the Si-69 solution for 60s. Dry it with a hair dryer and put it in an oven at 100°C for 60 minutes to dry and solidify.