Overview
ISO 18768-2:2022: Organic coatings on aluminium and its alloys - Part 2: Liquid coatings defines methods for specifying decorative and protective organic liquid coatings applied to aluminium and its alloys. The standard describes characteristic properties of liquid coating systems, required testing methods, and minimum performance requirements referenced to the intended application and the aggressiveness of the service environment. It applies to aluminium products finished by liquid coating processes such as electrostatic liquid spraying, air spraying, and airless spraying, and explicitly excludes coil coatings.
Key Topics
ISO 18768-2 covers technical topics and test methods used to specify and verify liquid organic coatings on aluminium:
- Information exchange: data the customer must supply to the surface processor (substrate, environment, appearance requirements).
- Metal preparation and pretreatment: substrate types, degreasing, anodic oxidation, chemical conversion coatings and alternative pretreatments.
- Coating categories: classification by use and performance expectations.
- Measurement and performance tests, including:
- Appearance, colour, gloss and distinctness of image
- Coating thickness and hardness (pencil)
- Adhesion (dry, wet, pull-off, scratch/circular roll)
- Impact, multi-impact (stone chipping) and abrasion resistance (falling sand, rubber-wheel)
- Flexibility (T-bend, mandrel), cupping and processing resistance
- Chemical and solvent resistance (acids, alkalis, detergents, oils)
- Corrosion resistance and cyclic corrosion tests (neutral and acid salt spray variants, filiform corrosion, humidity and wet heat tests)
- Water resistance and thermocycling
- Minimum performance requirements tied to service environment aggressiveness.
Applications
ISO 18768-2 is practical for specifying and verifying liquid-coated aluminium used in a wide range of general applications where decorative appearance and/or corrosion protection are required. Typical application areas include:
- Architectural aluminium (cladding, windows, curtain walls)
- Exterior equipment enclosures and building components
- Transport and fabricated aluminium parts requiring painted finishes
The standard helps purchasers, specifiers and surface processors select coating systems and acceptance criteria that match environmental exposure and functional needs.
Who should use this standard
- Coating manufacturers and formulators
- Aluminium fabricators and finishing shops (surface processors)
- Specifiers, architects and OEMs issuing coating requirements
- Test laboratories and quality inspectors validating coating performance
Related standards
For a complete specification suite, consult other ISO standards on organic coatings, surface preparation and corrosion testing and other parts of the ISO 18768 series (check the ISO catalogue for related parts and cross-references).