Exposing Vehicle Exterior Parts to Corrosive Conditions
SAE J2334 Laboratory Cyclic Corrosion Test, is a corrosion testing standard developed by the Society of Automotive Engineers (SAE) to evaluate the performance of coated automotive materials, substrates, processes, and designs. This test gives automotive OEMs and suppliers a standardized procedure to test the ability of their coatings to protect from corrosion caused by outdoor conditions. The test is a great tool to aid in the development and qualification of coatings as it provides better correlation to corrosive environments than typical salt spray and Prohesion test exposures.
Test Parameters
- Electrolyte (Salt) Solution:
- Sodium Chloride (NaCl) 0.5 %
- Calcium Chloride (CaCl2) 0.1%
- Sodium Bicarbonate (NaHCO3) 0.075%
Note: Calcium chloride and sodium bicarbonate must be dissolved separately, or the insoluble precipitate calcium chloride will form.
- Test Cycle
- Humid Stage: 50 °C and 100% relative humidity (RH)
- Salt Application Stage: 15 minutes, conducted at ambient conditions
- Dry Stage: 60°C and 50% RH
- Application Methods: Solution can be applied by any of three techniques: direct spray (shower), atomized fog, or sample immersion. Spray is the most widely practiced. Q-FOG CRH testers can perform either spray or fog exposures.
- Spray (shower): Salt solution is sprayed on specimens for 15 continuous minutes every 24 hours. This duration ensures specimens are sufficiently wet through the entire period. High-pressure spray should not be used, as it could remove corrosion byproducts or the protective coating.
- Air atomized fog: Solution is atomized in the chamber, similar to ASTM B117. Collections are specified at 2-4 mL/hr rather than the typical 1-2 mL/hr. Total fog duration is also 15 minutes, so the total amount of salt solution deposited on the specimens is far less than the Spray Method.
- Immersion: Specimens are immersed in the solution for 15 minutes. Market availability for chambers that perform this method automatically is limited. Most users of this method instead perform the operation manually.
- Corrosion Coupons
- SAE J2334 does require corrosion coupons to be used to monitor the test, but unfortunately does not provide an exposure schedule or target mass loss.
- Many companies that use this standard have their own target mass loss as part of their laboratory procedures.
You can find in-depth information on how to set up and program the SAE J2334 test cycle into your Q-FOG CRH corrosion test chamber by logging into your Q-Portal account.
Why Test to SAE J2334
Laboratory testing is essential for automotive manufacturers, parts suppliers, and coatings companies to ensure their coated components perform well in corrosive conditions. Cyclic corrosion standards, such as SAE J2334, provide better correlation to service environments than continuous salt fog tests. The advanced requirements of this standard require a modern corrosion test instrument with precise relative humidity control: the Q-FOG CRH model.
Pros and Cons of SAE J2334
- Accurate representation of real-world corrosion
- SAE J2334 provides a standardized method to simulate real-world salt exposure, ensuring automotive paint systems are rigorously tested for corrosion resistance.
- Industry-recognized test method
- It is widely-recognized and used across the automotive industry, ensuring consistency in testing and product quality.
- Limited Scope
- While effective for simulating salt spray exposure, the test doesn’t account for all environmental factors. Organic coatings may also degrade from UV exposure, which could affect corrosion rates.
- Wet/Dry Transition Guidance
- The exposure includes transitions from wet to dry, but does not specify the time. Evidence shows the transition rate is a critical factor for the corrosion rate of coating systems.
- Confusion on Which Salt Application Method to Use
- The three different salt application methods allow users to use whichever one would be most appropriate for their application. The results from the three methods can be vastly different, which can cause labs to question test results and which method is correct.
How Q-Lab Can Help
Q-FOG Cyclic Corrosion Test Chambers
Cyclic corrosion tests that include controlled relative humidity provide the best laboratory simulation of natural atmospheric corrosion. Q-Lab’s Q-FOG CRH models can maintain defined temperature and relative humidity values, recreating the same corrosive effects that occurs over several years outdoors.
Testing Services
Q-Lab offers a full range of ISO 17025 accredited laboratory testing services in our fully-equipped laboratories in Florida and Germany. We can perform everything from simple salt spray testing to modern automotive cyclic corrosion tests. Laboratory corrosion testing can be used for quality control, material certification, durability studies, and independent third-party verification.
Q-PANEL Standard Test Substrates
Q Lab’s CX-series mass-loss corrosion coupons ensure repeatability and reproducibility when performing laboratory corrosion testing. Q-Lab’s CXB-12 come precleaned and ready to use right of the pack to satisfy the requirements of mass-loss coupons for SAE J2334.
More SAE J2334 Resources
Standards Tool
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