ISO 10289:1999

Overview

ISO 10289:1999 specifies a standardized rating system for corrosion testing of metallic and other inorganic coatings on metallic substrates. It defines how to evaluate both the coating’s ability to protect the base metal (protection rating, Rp) and the coating’s visual condition (appearance rating, RA) after exposure to natural or accelerated corrosive environments. The standard is intended for test panels and manufactured articles and supports consistent reporting of corrosion test results.

Key topics and requirements

• Two-part rating: separate Protection Rating (Rp) for substrate corrosion and Appearance Rating (RA) for coating deterioration; combined as a performance rating “Rp/RA”.
• Protection rating calculation: Rp derived from the percentage area A of substrate corrosion using the formula Rp = 3(2 − 10·log A), rounded to the nearest whole number. Rp = 10 is assigned to surfaces showing no substrate corrosion.
• Appearance rating: uses defect codes (A–J) such as staining, dulling, pitting, flaking, blistering, cracking, etc., plus qualifiers for severity (vs, s, m, x) and area assessed on the same 10-to-0 scale as Rp.
• Defect classification: Table of defect types (e.g., crater corrosion, pin-holes, blisters, corrosion products) to be recorded when reporting RA.
• Inspection method: guidance on lighting, inspecting uncleaned specimens when possible, limited cleaning if necessary, edge defect handling (within 5 mm usually excluded), and use of dot charts/graticules and photographs for localized defects (Annex A/B informative).
• Reporting requirements: test conditions, exposure period, coating system and base metal description, and any appraisal difficulties must be included in the test report.

Applications and practical value

• Standardizes evaluation and reporting for:
  • Corrosion test laboratories performing accelerated salt spray, cyclic corrosion or natural-exposure tests.
  • Quality control for coating manufacturers, OEMs and suppliers assessing protective and decorative finishes.
  • Procurement and specification authors who need objective acceptance criteria for coated components.
  • Failure analysis and comparative performance studies of coating systems.
• Supports consistent decision-making: acceptance/rejection, coating selection, lifetime estimation and improvement of surface treatments.

Who uses this standard

• Corrosion test engineers and laboratories
• Coating and metal finishing manufacturers
• Quality assurance/inspection teams in manufacturing
• Product designers, materials engineers and procurement specialists
• Certification and conformity assessment bodies

Related standards

• Prepared by ISO/TC 107/SC 7. This edition cancels and replaces earlier standards ISO 1462:1973, ISO 4540:1980 and ISO 8403:1991. Annexes A and B provide informative dot charts and color photographs to aid assessment.

Keywords: ISO 10289, corrosion testing, protection rating, appearance rating, metallic coatings, inorganic coatings, performance rating, corrosion defects, accelerated corrosion tests.