ISO 2085:2018

Overview

ISO 2085:2018 specifies a rapid, practical method to check the continuity of thin anodic oxidation (anodized) coatings on aluminium and its alloys using a copper sulfate contact test. The procedure is intended for thin anodic coatings (less than 5 µm) or mechanically deformed coatings such as those produced by coil anodizing. The test helps verify whether visible surface faults are actual local gaps that expose bare aluminium.

Key Topics and Requirements

• Scope: Applicable to anodic oxidation coatings < 5 µm or deformed coatings (including coil anodizing).
• Principle: Drops of a copper sulfate reagent are applied to a defined test area; copper deposits and gas evolution occur at sites where the anodic coating is discontinuous, producing black/dark-reddish spots or lines.
• Reagent: Copper(II) sulfate solution prepared from CuSO4·5H2O (20 g), hydrochloric acid ρ = 1.18 g/ml (20 ml), made up to 1 000 ml with distilled/deionized water.
• Test area: Standard test area is approximately 100 mm² (select a flat, horizontal region away from edges and anodizing contact areas). If a flat area is unavailable, immersion of the specimen is permitted with masking of non-test surfaces.
• Procedure:
  • Clean test area (remove dirt/stains; avoid solvents that create protective films or corrode aluminium).
  • Apply roughly four drops of reagent to the test area at room temperature.
  • Leave reagent in contact for 5 minutes, observe for instantaneous gas release, then rinse.
  • Count the number of black/dark-reddish spots or lines per 100 mm²; optionally measure average diameter/length for quantitative assessment.
• Reporting: Test report should reference ISO 2085:2018 and record product identification, numerical results, any unusual observations, and the test date.

Applications and Users

ISO 2085 is used for quality control and inspection in:

• Anodizing plants and coil anodizing operations
• Surface finishing and corrosion-protection laboratories
• Quality assurance and inspection teams for architectural, automotive, electronics, and industrial aluminium components
• Failure analysis when visible surface defects need confirmation as coating breaches

Benefits include fast on-site verification of coating continuity, simple implementation without complex equipment, and targeted evaluation of thin or mechanically stressed anodic layers.

Related Standards

• ISO 7583 - Anodizing of aluminium and its alloys: Terms and definitions (normative reference used by ISO 2085)

Keywords: anodizing of aluminium, anodic oxidation coatings, copper sulfate test, coating continuity, thin anodic coatings, coil anodizing, surface inspection, quality control.