Salt spray testing, also known as salt fog testing or salt corrosion testing, is a commonly used method in various industries to evaluate the corrosion resistance and durability of materials and coatings. It involves exposing test samples to a controlled environment of salt-laden mist or spray, simulating the harsh conditions of coastal or marine environments. There are several reasons why salt spray testing is considered a good idea:
- Corrosion Assessment: Salt spray testing is a reliable and standardized method to assess the corrosion resistance of materials, coatings, and surface treatments. Corrosion is a major concern in many industries, such as automotive, aerospace, marine, and construction, and this testing helps identify potential vulnerabilities in materials or coatings before they are put to practical use.
- Real-World Simulation: Coastal and marine environments have high levels of salt in the air due to sea spray, which can significantly accelerate corrosion processes. By subjecting materials to salt spray testing, manufacturers can simulate real-world conditions and evaluate how their products will perform in harsh environments over time.
- Quality Control: Salt spray testing is an essential part of quality control during the production process. Manufacturers can use the results to ensure that their products meet specified corrosion resistance standards, regulatory requirements, or customer expectations.
- Comparative Analysis: The testing allows for a direct comparison between different materials, coatings, or surface treatments. Engineers and designers can select the most suitable option based on the results and choose materials that provide the best corrosion protection for the intended application.
- Cost Savings: Identifying potential corrosion issues early in the development or production process can save significant costs in the long run. Addressing corrosion vulnerabilities before the product reaches the market can prevent expensive recalls, repairs, or replacements.
- Research and Development: Salt spray testing is also valuable in the research and development of new materials and coatings. It helps researchers understand the effectiveness of new corrosion-resistant formulations and aids in the continuous improvement of existing products.
- Compliance and Certification: In some industries, compliance with specific corrosion resistance standards is mandatory. Salt spray testing provides the necessary data for certification and regulatory compliance, ensuring that products meet the required quality and safety standards.
- Customer Confidence: Providing evidence of salt spray testing and corrosion resistance can instill confidence in customers who rely on products to withstand harsh environments. Demonstrating this performance through testing can be a strong selling point for businesses.
The most widely adopted standard for salt spray testing chambers is the ASTM B117. This standard specifies test conditions such as the methods of salt water solution spray including fluid pressure and solution acidity; the pH value of the salt solution should be between 6.5 and 7.2 (also known as neutral salt spray), and the spray mist volume should be within 1.0 – 2.0 ml/80cm2/hr. Other test conditions such as a chamber temperature of 35°C are established. Other standards regarding salt spray testing are ISO9227, JIS Z 2371, Mil-Std 810H, 509.7, and ASTM G85.
Relia Test Labs uses the Nvirosolutions HST-412RJY, a salt spraying chamber with an interior volume of 412 L (14.5 cu.ft) composed of 8 mm thick PVC. The chamber uses the Neutral Salt Spray Test Method (NSS), Acetic Acid Salt Spray Test (AASS), Copper Accelerated Acetic Acid Salt Spray Test CASS , operating with a temperatures of 35°C and 50°C and spray mist volume of 1-2 ml/hr. The spray jets are made of tempered glass, featuring adjustable volume and angle position. The chamber coincides with the Mil-Std 810H, 509.5, and ASTM B117, which specify standard practices for operating and testing with salt and fog chambers.
Mil-Std 810H, 509.5 specifies criteria such as test setup and preparation, parameter configuration (temperature, air pressure, salt concentration, etc.), and more. The figure below states the required salt density per temperature:
More information on Mil-Std 810H, 509.7 can be found in the link below.
Salt spray testing is a critical test conducted on products used in the aircraft, automotive, and marine industries. Vehicles, planes, and ships exposed to the atmosphere, especially in regions near salt water, must be capable of withstanding rust corrosion. Protective coatings are tested to validate their effectiveness and lifespan; a coating that meets the minimum life as determined by the manufacturer via testing can be approved for production.
Relia Test Labs (subsidiary of Hastest Solutions Inc) is accredited with the ISO/IEC 17025 testing and calibration laboratories standard, making us an attractive solution for your testing needs in the heart of the Silicon Valley.
It is important to note that salt spray testing is just one of many corrosion testing methods available, and its results should be used in conjunction with other relevant tests to get a comprehensive understanding of a material or coating’s performance in various environments. Additionally, while salt spray testing is valuable, it cannot completely replicate all the complex environmental factors that a product may face in the real world, so the results should be interpreted with consideration for the specific application and conditions in which the product will be used.
To assess the corrosion resistance and durability of your materials and coatings, call Relia Test Labs for a quote. Test according to MIL standards, ASTM, IEC, NSS, JIS, Automotive and others.
