ISO 8251:2018

Overview

ISO 8251:2018 - "Anodizing of aluminium and its alloys - Measurement of abrasion resistance of anodic oxidation coatings" defines standardized laboratory methods to measure the abrasion (wear) resistance of anodic oxide coatings on aluminium and its alloys. The standard covers three complementary test methods-abrasive-wheel-wear, abrasive jet, and falling sand abrasion-and specifies the required apparatus, specimen preparation, test procedure, calibration, and expression of results.

Key topics and requirements

• Three test methods
  • Abrasive‑wheel‑wear test: measures abrasion resistance using an abrasive wheel on flat specimens. Includes apparatus specifications (abrasive strip, eddy‑current meter, balance) and result expressions such as wear resistance, mass loss, wear index.
  • Abrasive jet test: compares abrasion resistance by directing a jet of abrasive particles onto coated specimens. Covers apparatus design, jet nozzle calibration, abrasive media, and outcome metrics like abrasive jet factor and mean specific abrasion resistance.
  • Falling sand abrasion test: assesses thin anodic coatings using falling sand. Contains two measurement options (electrical conductivity and spot diameter methods) and guidance on test environment and reporting.
• Specimen preparation and calibration: the standard requires defined standard and test specimens, preparation steps, and calibration procedures for repeatability and comparability.
• Expression of results and reporting: prescribes how to report wear data (mass loss, wear indices, relative resistances) and includes Annexes with alternative result expressions and detailed apparatus designs.
• Normative and informative annexes: include specimen preparation (Annex A), alternative result expressions (Annex B), depth surveys, and apparatus designs (Annexes D–F).

Applications and users

ISO 8251:2018 is used for:

• Quality control and acceptance testing of anodized components in industries such as automotive, aerospace, architectural, electronics, and consumer goods.
• Process development and optimization by anodizing plants to evaluate effects of alloy, coating thickness, anodizing and sealing conditions on wear resistance.
• Material selection and specification by engineers and procurement teams who need comparative abrasion data for anodic oxidation coatings.
• Independent testing laboratories and research for reproducible wear testing and failure/forensics analysis.

Primary users include anodizing service providers, surface-engineering labs, materials engineers, coating specifiers, and standards/compliance professionals.

Related standards

• ISO 10074 - referenced for the use of abrasive‑wheel and abrasive jet tests on hard‑anodized coatings.
• ISO 8251:2011 - earlier edition; the 2018 edition adds specimen preparation, mass‑loss reporting, and a PMMA standard specimen option.

Keywords: ISO 8251:2018, anodizing abrasion resistance, anodic oxidation coatings, abrasive‑wheel‑wear, abrasive jet test, falling sand abrasion, aluminium alloys, wear resistance measurement, anodizing quality control.