Traditional corrosion testing like ASTM B117 exposes materials to continuous salt spray. However, real-world environments are rarely constant. Components experience cycles of wetting, drying, humidity, and temperature changes.
This is where Cyclic Corrosion Testing (CCT) becomes important.
βοΈ Technical Principle
CCT simulates real atmospheric corrosion by applying repeating environmental cycles, typically including:
• Salt spray phase – NaCl solution is atomized to create a corrosive environment.
• Dry phase – Elevated temperature with low humidity accelerates electrolyte evaporation and salt crystallization.
• Humidity/condensation phase – High relative humidity promotes electrolyte formation and corrosion propagation.
These cycles generate electrochemical corrosion reactions similar to outdoor exposure conditions.
βοΈ Key Technical Parameters Controlled in CCT:
• Salt concentration (commonly ~5% NaCl)
• Chamber temperature
• Relative humidity (RH)
• Spray duration & interval
• Drying temperature and time
• Total exposure cycles
Because corrosion products form and dry repeatedly, coating defects, micro-cracks, and weak protective layers are revealed much faster compared to constant salt spray testing.
π Common CCT Standards
• ASTM G85
• ISO 11997-1
These methods are widely used in automotive, coatings, and metal protection industries to evaluate coating durability and corrosion resistance.
Understanding the cycle parameters and corrosion mechanisms is critical to ensure materials can survive real service environments.
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