Overview
ISO 16539:2013 specifies two accelerated cyclic corrosion test methods (Methods A and B) that simulate sea-salt contaminated atmospheric environments using a synthetic ocean water salt-deposition process combined with cyclic “dry” and “wet” exposure under constant absolute humidity. The standard covers test solutions, apparatus, specimen preparation, operating conditions, evaluation of results and reporting for surface-treated metals and alloys, with and without coatings.
Key topics and technical requirements
- Scope and methods
- Method A: for metals and their alloys (including corrosion-resistant alloys).
- Method B: for metals and alloys with or without coatings (metallic, organic, conversion coatings).
- Test solution (synthetic ocean water)
- Mixed salt solution nominal concentration 36.0 g/L ± 3.6 g/L (formulation based on typical synthetic seawater).
- pH adjusted to 8.2 ± 0.1 using a 0.125 mol/L NaOH solution.
- Test dilutions: 1:1, 1:10 and 1:100 concentrations (as agreed between parties).
- Salt deposition and atomization
- Atomizer must be corrosion resistant (glass, plastic, titanium) and produce droplets ≤ 100 µm diameter.
- Salt deposition amount is controlled (spray duration, solution concentration, pressure, and atomizer movement).
- Compressed air for atomizer must be oil- and particle-free.
- Environmental control
- Temperature and humidity must be controlled so absolute humidity remains constant during dry/wet cycles (device must control humidity minute-by-minute).
- Transition of dry-bulb temperature to target values must be controllable and linear.
- Apparatus and procedures
- Exposure cabinet(s), salt deposition device, humidity/temperature control, and rinse treatment are specified.
- Rinse sequence: drinking water, then deionized water, then controlled air drying to avoid removing corrosion products.
- Two-cabinet and one-cabinet system types are described for automatic and manual operation.
- Evaluation and reporting
- Clauses detail specimen arrangement, measurement of salt deposition, duration, continuity and result evaluation. Normative references specify rating and assessment methods.
Applications and users
ISO 16539 is used by:
- Corrosion test laboratories and QA/QC labs
- Materials and coatings manufacturers (automotive, marine, coastal infrastructure)
- R&D teams developing corrosion-resistant alloys and surface treatments
- Certification bodies specifying atmospheric corrosion performance
Practical uses include comparative screening of coatings, validation of corrosion protection systems for marine/coastal service, and research into salt-contaminated atmospheric degradation mechanisms.
Related standards
- ISO 9227 (salt spray tests)
- ISO 14993 (cyclic salt mist/dry/wet tests)
- ISO 11130 (alternate immersion, synthetic seawater)
- ISO 4628 series (coating degradation evaluation)
- ISO 8407 (removal of corrosion products)
Keywords: ISO 16539:2013, accelerated cyclic corrosion tests, synthetic ocean water, salt-deposition, constant absolute humidity, corrosion testing, metals and alloys, coatings, atomizer, exposure cabinet.