Colour is not a coating specification
Visual appearance alone does not establish coating chemistry, thickness, adhesion or corrosion performance. Specify the coating system and the standard used to verify it.
Coatings, finishes and corrosion expectations
A buyer-oriented framework for describing zinc plating, hot-dip galvanizing, passivation and other finishes without treating colour as performance.
START WITH THREE QUESTIONS
What a careful reader should establish.
- Which coating system and thickness are required?
- Which corrosion test and acceptance criterion applies?
- Does the process create hydrogen-embrittlement risk?
- Coating type and thickness
- Passivation, sealer or topcoat
- Appearance and handling criteria
Testing must match the intended claim
Salt-spray hours are often quoted without the exact test method or failure criterion. Record the test method, specimen preparation, acceptance threshold and responsible laboratory.
- Test method and duration
- Definition of red or white corrosion
- Sampling plan and report format
Check the original source.
These links are starting points, not proof that a particular product or supplier complies.
ISO standards catalogue↗ASTM standards and publications↗