Overview
ISO 11130:2017 - "Corrosion of metals and alloys - Alternate immersion test in salt solution" specifies a laboratory method to assess corrosion resistance by repeatedly immersing metal specimens in a salt solution and then drying them. The test can be run with or without applied tensile stress and is intended for quality control, alloy development and comparative assessment where the chosen test solution simulates service environments such as marine splash zones, de‑icing fluids or acid‑salt conditions.
Key topics and technical requirements
- Test principle: repeated cycles of immersion in a defined salt solution followed by a drying period; this alternate immersion can be more severe than continuous immersion.
- Test solutions: a neutral NaCl solution (35 g/l ± 1 g/l) is defined; Annex A gives additional solutions to simulate de‑icing, acid salt and ocean water environments. Use analytical-grade reagents and low‑conductivity water.
- Temperature and cycle:
- Typical immersion/dry cycle: 10 min immersion followed by 50 min drying (unless otherwise specified).
- Solution temperature normally 25 °C ± 2 °C (other temperatures by agreement).
- Drying conditions: 70 °C ± 2 °C and RH ≤ 50 % (revised in this edition).
- Specimens and preparation:
- Recommended specimen (if not otherwise agreed): 90 mm × 120 mm × 1 mm; minimum three specimens.
- Remove greases by ultrasonic or solvent cleaning; protect cut/plated edges with suitable coating.
- Apparatus and set‑up:
- Automatic system for continuous alternate immersion/withdrawal; full immersion/withdrawal should take ≤ 2 min.
- Materials in contact with solution must not contaminate it; holders must electrically insulate specimens and avoid retaining solution pools.
- Air circulation should allow drying within ~40 min; avoid stagnant air and direct forced blasts.
- Assessment and reporting: extent of attack is evaluated after test duration (often 20–90 days for aluminium and ferrous metals); report test conditions, solution, temperatures, and any deviations.
Applications
- Quality control during manufacture of metals, aluminium alloys and ferrous materials.
- Alloy and coating development to compare relative corrosion resistance.
- Performance simulation for marine splash zones, de‑icing environments and acid salt exposures when appropriate test solutions are used.
- Testing of coatings: applicable to certain anodic/cathodic metallic coatings, conversion coatings, anodic oxides and organic coatings on metals.
Who uses this standard
- Corrosion engineers and testing laboratories
- Metal and alloy manufacturers
- Coatings and surface‑treatment suppliers
- R&D teams in automotive, marine, aerospace and infrastructure sectors
- Procurement and quality assurance professionals specifying corrosion tests
Related standards
- ISO 7539‑1 (stress application in corrosion testing)
- ISO 9227 (harmonized salt‑fog testing references)
- ISO 8044 (corrosion terminology)
Keywords: ISO 11130:2017, alternate immersion test, corrosion testing, salt solution, corrosion resistance, aluminium alloys, ferrous materials, marine splash, de‑icing fluids, quality control.
