Overview
ISO 8407:2021 - Corrosion of metals and alloys - Removal of corrosion products from corrosion test specimens - defines standardized procedures for removing corrosion products formed on metallic test specimens so that accurate mass loss determination and corrosion-rate calculations can be made. The standard covers pure metals and alloys and, in some cases, metal coatings (when substrate effects are accounted for). It emphasizes removing corrosion products with minimal loss of base metal and documents chemical, electrolytic and mechanical cleaning approaches, plus controls and reporting requirements.
Key topics and requirements
- Scope and objective: Procedures are intended to remove all corrosion products while avoiding significant base-metal removal to enable accurate mass-loss measurements.
- Cleaning hierarchy: Start with light mechanical cleaning (soft brush under running water). If insufficient, proceed to:
- Chemical procedures (see Annex A, Table A.1)
- Electrolytic procedures (see Annex A, Table A.2)
- Mechanical procedures (e.g., bristle scrubbing, grit or water-jet blasting) - used only when others fail.
- Control specimens: Use uncorroded controls of similar composition/geometry and weigh before/after cleaning to estimate metal loss caused by the cleaning procedure.
- Repetitive cleaning cycles: Repeat cleaning and plot mass vs. cleaning cycles/time to distinguish removal of corrosion products from substrate loss and to extrapolate the true metal mass.
- Good laboratory practice: Use distilled/deionized water and reagent-grade chemicals; ultrasonic baths are recommended to facilitate removal; rinse sequence (tap → deionized → ethanol) and drying in air/desiccator before weighing are specified.
- Safety: Handling of potentially hazardous solutions (e.g., cyanide, chromium trioxide) requires skilled personnel and appropriate precautions.
- Test reporting: Reports must reference ISO 8407:2021 and record the chosen procedure, solution composition/temperature/times (or table designation), electrolytic parameters, mechanical methods, control-test results, calculated mass loss and any unusual observations.
Practical applications
- Ensures consistent, reproducible mass-loss measurements in laboratory corrosion testing.
- Supports corrosion rate determination, materials selection, quality control, coatings evaluation and failure analysis.
- Useful for research labs, independent testing bodies, manufacturers of metals and coatings, and certification organizations that require standardized post-test cleaning and documentation.
Who uses this standard
- Corrosion test laboratories and metallurgical labs
- Materials and corrosion engineers
- Coatings and surface-treatment specialists
- Product qualification and QA teams
- Standards and conformity assessment bodies
Related standards (if applicable)
ISO 8407:2021 was developed by ISO/TC 156 (Corrosion of metals and alloys). Users commonly consult complementary ISO corrosion and materials testing standards and local testing protocols when designing test programs and reporting results.
Keywords: ISO 8407:2021, corrosion products removal, corrosion test specimens, mass loss determination, chemical cleaning, electrolytic cleaning, mechanical cleaning, corrosion testing.
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