Acid resistant coating is a common coating material used in industrial applications to prevent corrosion damage of metal structures in acidic environments. In order to ensure the quality and performance of the acid-resistant coating, it is necessary to carry out the relevant testing and evaluation. This article will describe the projects, methods, requirements, and criteria so that the reader has a comprehensive understanding of the test.

I. Test items:

It mainly includes the following items:

1. Thickness test: By measuring the thickness of the anti-corrosion layer to evaluate its coating quality and coating form. Measurements are usually made using non-destructive testing methods such as magnetic induction or ultrasonic thickness gauges.

2. Bond strength test: used to evaluate the bond between the anti-corrosion layer and the metal matrix. Common test methods include shear test and transverse tensile test. The interface bonding between the coating and the substrate and the bonding inside the coating need to be taken into account when testing.

3. Acid resistance test: Through exposure to acidic solution, evaluate the corrosion resistance of the acid-resistant anticorrosive layer. Commonly used tests for acidic liquids include hydrochloric acid, sulfuric acid, etc. The corrosion of the surface of the coating, the corrosion of the surface under the coating and the corrosion of the coating material itself need to be taken into account when testing.

Ⅱ. Test method:

1. Thickness test method: magnetic induction method or ultrasonic thickness gauge is used for measurement. Before testing, the instrument needs to be calibrated to ensure the accuracy of the test results. During the measurement process, it is necessary to ensure good contact between the probe and the surface to be tested to avoid interference from the air layer.

2. Bond strength test method: shear test can be carried out by shear machinery or tensile testing machine, and attention should be paid to the preparation and clamping of the sample when testing. In order to ensure the accuracy of the test results, the sample can be pre-treated according to the standard requirements, such as grinding, cleaning, etc.

3. Acid resistance test method: After the tested sample is exposed to a predetermined concentration of acid solution for a certain time, the morphological changes, color changes and corrosion of the coating are observed. After the test, the coating can be observed and analyzed using a microscope or scanning electron microscope.

Ⅲ. Test requirements:

When proceeding, the following requirements need to be noted:

1. Sample preparation: Ensure that the surface of the sample is clean and smooth, and processed in strict accordance with the standard requirements. The quantity and size of the sample should meet the test requirements and minimize the influence of human operation on the test results.

2. Environmental conditions: The test should be carried out under appropriate temperature and humidity conditions to ensure the accuracy of the test results. At the same time, attention should be paid to preventing the interference of the external environment on the test results, such as dust, moisture, etc.

3. Test time: Determine the test time according to the standard requirements and record it. The selection of the test time should take into account the degree of corrosion of the acid-resistant anticorrosive layer under actual conditions of use.

Ⅳ. Testing standards:

It should be selected and implemented according to relevant industry standards at home and abroad. Common criteria are as follows:

1. GB/T 23257-2009 Quality assessment of metal and other inorganic coatings Classification of anti-corrosion coatings and coating series

2. ISO 4624:2016 Paints and varnishes - Pull-off test for adhesion

3. ASTM D130-04 Standard Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test

The above are only common test standards, and the specific selection should be determined according to the material, use and industry requirements of the acid-resistant anticorrosive layer.

Conclusion: The test of acid-resistant anticorrosive coating is an important means to ensure its quality and performance. Through the introduction of test items, test methods, test requirements and test standards, readers have a more comprehensive understanding. In practical applications, further testing and analysis are required according to the specific situation to ensure the reliability and stability of the acid-resistant anticorrosive layer.