ISO 11997-3:2022

Overview

ISO 11997-3:2022 specifies a cyclic corrosion test method for assessing the corrosion protection of automotive coating systems on aluminium, steel and galvanized steel. The standard defines a laboratory cycle combining salt spray, temperature ramps and humidity ramps to reproduce realistic automotive corrosion patterns, including delamination and corrosion creep originating from artificial damage (scribes). While developed for automotive bodywork and mounted parts, the method can also be applied to other metals and alloys with caution. The standard is intended for evaluating coated substrates (test specimens, body panels and mounted parts) under accelerated, repeatable conditions.

Key technical topics and requirements

• Test principle: Repeated cycles of salt spray, controlled temperature and humidity ramps to generate realistic corrosion patterns typical for automobiles.
• Specimen scope: Coating systems on aluminium, steel and galvanized steel; includes surface, edge and flanged-area corrosion, adhesive specimens and specimens with defined artificial damage.
• Chamber and apparatus:
  • Corrosion test chamber materials must resist attack by test solutions and not influence results.
  • Chambers require heating/cooling, pressure equalization and measurement/control to meet climate tolerances (temperature ±2 °C, RH ±5 %; permitted RH deviation −8 % to +5 % during ramps).
  • Spray nozzles: compressed-air atomizing nozzles suitable for the test temperature range; no direct spray on specimens.
• Test solution: Sodium chloride solution prepared per ISO 9227 at 10 g/L NaCl (sprayed/collected concentration 10 ± 1 g/L), density and pH control (pH ~6.5–7.2).
• Spray distribution and quantity: Collection rate target 3.0 ± 1.0 ml/h per collecting device in the specimen zone; uniformity checks required (funnels/collectors per ISO 9227).
• Evaluation & reporting: Results assessed using agreed subjective criteria and referenced evaluation methods (ISO 4628 series). The standard includes requirements for specimen preparation, chamber corrosivity evaluation, precision and test reporting.

Practical applications and users

ISO 11997-3:2022 is used to:

• Validate and compare automotive paint and coating systems for corrosion resistance.
• Assess delamination/corrosion creep after simulated damage (scribes, stone chip points, gaps, flanges).
• Support material selection, coating development, supplier qualification and quality assurance.

Primary users:

• Automotive OEMs and suppliers
• Coating formulators and applicators
• Independent testing laboratories and corrosion engineers
• R&D and quality assurance teams in automotive materials and surface engineering

Related standards

Commonly used with:

• ISO 9227 - Corrosion tests in artificial atmospheres (salt spray)
• ISO 4628 series - Evaluation of degradation of coatings
• ISO 2409 - Cross-cut test
• ISO 17872 - Guidelines for scribing through coatings
• ISO 20567-1 - Stone-chip resistance testing

ISO 11997-3:2022 provides a reproducible, industry-focused cyclic corrosion procedure for realistic assessment of automotive coating systems-useful for product development, benchmarking and conformity testing.