Copper accelerated acetate salt spray test（Copper-Accelerated Acetic Acid Salt Spray Test， CASS testing, commonly known as the "Cas" test, is an accelerated corrosion testing method used to evaluate the corrosion resistance of metal materials, especially electroplating and coatings. It is an upgraded version of salt spray testing (such as neutral salt spray testing NSS and acetate salt spray testing AASS), which accelerates the corrosion process by adding copper salts and acetic acid, thus simulating the corrosion of materials in harsh environments more quicklyphenomenon.

The main steps of CASS testing

1. Solution preparation:

-Use a 5% solution of sodium chloride (NaCl).

-Add 0.26g/L of copper chloride (CuCl)₂·2H₂O）。

-Using acetic acid (CH)₃Adjust the pH value to 3.1-3.3 using COOH.

2. Testing equipment:

-recommenduseCCT600orCCT1100 salt spray test chamber, ensure that the temperature inside the chamber is maintained at 50 ± 2 ℃.

-The spray system shall evenly spray the prepared solution.

3. Sample preparation:

-The surface of the sample needs to be cleaned thoroughly to avoid oil stains or impurities affecting the test results.

-The sample is usually placed at an angle of 15 ° -30 ° to ensure uniform coverage of spray.

4. Testing time:

-According to the materials and application scenarios, the testing time is usually 24 hours, 48 hours, 96 hours or longer.

5. Result evaluation:

-After the test is completed, observe the corrosion on the surface of the sample, such as rust spots, bubbles, peeling, etc.

-Rated according to relevant standards such as ISO 9227, ASTM B368, etc.

CASS testingmethodThe mainkey points

1. Accuracy of solution preparation

-Difficulty: The pH value and copper salt concentration of the solution have a significant impact on the test results, and deviations are prone to occur during the preparation process.

-Solution: Use a high-precision pH meter and electronic balance to strictly prepare the solution according to the standard.

2. spray uniformity

-Difficulties: uneven spray will lead to inconsistent corrosion degree on the sample surface, affecting the reliability of the test results.

-Solution: Regularly calibrate the spray equipment to ensure that the nozzle is not blocked and the spray pressure is stable.

3. Temperature control

-Difficulty: Temperature fluctuations inside the testing chamber can affect the corrosion rate, resulting in non reproducible test results.

-Solution: Use a high-precision temperature control system and regularly check the operating status of the equipment.

4. Sample placement angle

-Difficulty: Improper placement angle of the sample may lead to uneven local corrosion.

-Solution: Place the samples strictly according to the standard requirements and use fixed brackets to ensure accurate angles.

5. Removal and evaluation of corrosion products

-Difficulty: The corrosion products on the surface of the sample after testing may mask the true corrosion situation and affect the accuracy of the evaluation.

-Solution: Use appropriate cleaning methods (such as ultrasonic cleaning) to remove corrosion products, but avoid damaging the surface of the sample.

6. Repeatability of test results

-Difficulty: Due to environmental factors (such as temperature and humidity) and equipment status, test results may fluctuate.

-Solution: Conduct multiple tests under the same conditions and take the average as the final result.

7. Selection and implementation of standards

-Difficulty: Different standards (such as ISO, ASTM) may have slight differences in specific requirements for CASS testing, resulting in inconsistent test results.

-Solution: Choose appropriate standards based on actual needs and strictly implement them.

The most difficult part of running this test is to simultaneously meet the collection requirements and quality loss requirements. In most test chambers, high temperature conditions can cause significant evaporation of the solution. The result is that the collected solution is usually small in volume and high in concentration. Increasing the amount of solution in order to increase the collection volume will result in excessive corrosion of the sample due to quality loss. Therefore, many corrosion chambers can meet the requirements of collection or quality loss, but cannot simultaneously meet both.

The Q-FOG CCT cyclic corrosion testing machine has a unique function that can heat up the test chamber whilerunSteam generator.like thiscan be increasedInside the boxReduce the humidity and mitigate the effects of evaporation without affecting the corrosion rate of the samples in the test chamber. With this feature,The Q-FOG CCT testing machine can meet both quality loss and collection requirements, making it compliant with CASS testing requirements. In addition, due to CASSThe experimental methodThe solution has high corrosiveness,Q-Lab needs to useharshUse an environmental heater to perform this test.thatThe test chamber heater uses highly corrosion-resistant metal alloys to resistCorrosion of CASS solution.

CASS testing is an efficient corrosion testing method that can quickly evaluate the corrosion resistance of materials. However, in the test process, factors such as solution preparation, spray uniformity and temperature control may affect the accuracy and repeatability of the test results. By strictly following standards and precisely controlling testing conditions, these difficulties can be effectively overcome to ensure the reliability of test results.

AboutCASSExperimental methods andQ-LFor more information on the AB salt spray box equipment solution, please contactQ-Lab China first level authorized agent, Shanghai Yunding Company.