Cyclic Corrosion Testing (CCT): A Practical Guide for Engineers
Why Has CCCT Become Essential?
In advanced technical fields such as automotive, aerospace, or maritime industries, it is important to understand how materials react to corrosion under conditions that closely resemble real-life environments. The ASTM B117 testing standard, which involves the use of a salt spray apparatus, although widely used, does not accurately replicate the variations in humidity, temperature, or drying phases encountered in the field.
Cyclic Corrosion Testing (CCT) addresses this challenge by combining different environmental phases: salt spray, humidity, drying, and sometimes UV exposure. This test simulates natural exposure more realistically, providing more representative and predictive data.
For example, in the automotive industry, components such as suspension mounts or chassis parts are subjected to intense corrosion cycles due to road salts. A well-calibrated CCT test can predict the appearance of rust or blistering after just a few days, whereas an ASTM B117 test would require several weeks.
The CCT: How Does It Work?
CCT combines several environmental phases into a single cycle, typically programmed over 6 to 24 hours and repeated over several days or weeks:
- Salt Spray: 5% NaCl solution, controlled pH
- Drying: Elevated temperature with air circulation
- Humidity: Around 95% RH, 40 to 50 °C
- UV (optional): To assess the photo-degradation of coatings
This cycle reproduces typical failures observed under real-world conditions: corrosion, blistering, coating delamination, etc.
However, care must be taken to calibrate the parameters of each phase correctly. Poorly controlled humidity or overly rapid drying can skew the results. It is also common to underestimate the impact of the order of cycles on degradation mechanisms. This highlights the importance of working with an ISO/IEC 17025-accredited testing laboratory that is capable of adjusting protocols to reflect real-world conditions.
CCT vs ASTM B117: Key Differences
| Parameter | ASTM B117 | Cyclic Corrosion Testing (CCT) |
| Test environment | Constant salt spray | Alternating conditions (dry/humid/temperature) |
| Field correlation | Low | Moderate to high |
| Simulated mechanisms | Limited (mainly uniform corrosion) | More varied: rust, blistering, delamination |
| Failure detection | Slow | Faster |
When to Use CCT
CCT is particularly recommended for testing:
- Multilayer paint systems
- Galvanized or alloy substrates
- Parts exposed to varying humidity (e.g., chassis, engine compartments)
This test not only helps predict durability under extreme conditions but also verifies compliance with industry standards or supports failure analysis.
Standards Related to CCT
| Norme | Sector | Notes |
| ASTM G85 | General industry | Multiple annexes depending on application |
| SAE J2334 | Automotive | Adopted by GM, Ford, Stellantis |
| ISO 11997-1 | Paints and coatings | Frequently referenced in Europe |
| OEM Protocols | Aerospace / Electronics | Customized per client requirements |
Micom Laboratories Can Support Your Corrosion Testing
At Micom Laboratories, we offer customized CCT corrosion tests, carried out in controlled climate chambers, according to your protocol requirements.
Our Q-Fog chambers do not support most CCT cycles because humidity cannot be controlled during drying phases. That’s why we use climate chambers to ensure precise and reproducible conditions.
Our facilities allow us to simulate complex corrosion cycles, including humidity, drying, salt spray, and UV if required, in compliance with standards such as ASTM G85, SAE J2334, or ISO 11997-1.
We offer:
- ISO/IEC 17025 accredited testing
- Personalized technical support
- Fast delivery of results
Our experts collaborate with engineering teams across North America to validate various materials, meet OEM requirements, or investigate failures.
Simulate Real-World Conditions With CCT
If your materials need to withstand complex corrosion conditions, CCT is the method of choice. Reliable, adaptable, and rooted in industry standards, it helps you make sound technical decisions.
Whether you are in the material selection phase, product validation, or failure root cause investigation, CCT delivers concrete answers. At Micom, we tailor each protocol to your real-world needs — so your products hold up where it matters most.
Contact us to discuss your corrosion testing needs or request a quote for a CCT test.
