ASTM G69-20 PDF

Full title and description

ASTM G69-20 — Standard Test Method for Measurement of Corrosion Potentials of Aluminum Alloys. This test method specifies a laboratory procedure to measure the open-circuit (corrosion) potential of aluminium alloys in an aqueous sodium chloride solution with added hydrogen peroxide to provide a cathodic reactant; results are used to characterize metallurgical condition and alloying-in-solution effects.

Abstract

Provides a reproducible procedure to measure the corrosion (open-circuit) potential of aluminum alloys in a NaCl electrolyte with hydrogen peroxide. The measured potential is sensitive to alloying elements (notably copper and zinc) in solid solution and is useful for assessing solution heat treatment, aging, welding effects, and cladding diffusion. The method is brief (procedure and test details fit in a short test method) and references ASTM terminology G193 for corrosion-related terms.

General information

• Status: Active standard (current edition).
• Publication date: May 1, 2020 (designated G69-20).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 77.120.10 — Aluminium and aluminium alloys (Non‑ferrous metals).
• Edition / version: G69-20 (2020 edition).
• Number of pages: 5 pages (short test method document).

Key bibliographic/product identifiers commonly shown for this document include designation G69-20 and DOI reference used in ASTM listings (document sold through ASTM and standards resellers).

Scope

This test method covers measurement of the corrosion potential (open-circuit potential) of aluminium alloys in an aqueous sodium chloride solution to which hydrogen peroxide is added to supply a cathodic reactant. It is intended for laboratory characterization of metallurgical condition (e.g., effectiveness of solution heat treatment, extent of precipitation during aging or welding, and diffusion from cladding) and reporting of potentials relative to a reference electrode. SI units are used and safety precautions appropriate to corrosive electrolytes and peroxide are required.

Key topics and requirements

• Test specimen preparation and surface condition requirements (cleaning, geometry and electrical isolation).
• Electrolyte composition: sodium chloride solution with sufficient hydrogen peroxide as cathodic reactant.
• Reference electrode selection and measurement of open-circuit/rest potential (OCP) procedures.
• Conditions for equilibration and recording of stable potential values.
• Interpretation: potentials indicate relative nobility/activity linked to alloying elements in solid solution (notably Cu and Zn) and treatment history.
• Reporting requirements: specimen identification, test solution, reference electrode, measured potentials (with units and sign convention), and test temperature/conditions.

Typical use and users

Used by metallurgists, corrosion and materials engineers, laboratory technicians, and quality/control personnel in aerospace, automotive, marine, and manufacturing sectors where aluminium alloy condition and susceptibility to corrosion must be assessed. Common applications include verification of solution heat treatment, monitoring of aging/welding effects, evaluation of cladding diffusion, and comparative alloy characterization.

Related standards

Commonly referenced documents include ASTM G193 (Terminology and acronyms relating to corrosion) for definitions of corrosion potential/OCP and other ASTM corrosion practices and guides addressing specimen preparation and electrochemical measurements. Users often consider complementary ASTM test practices for specimen cleaning and polarization methods when performing broader electrochemical evaluations.

Keywords

aluminum, aluminium alloy, corrosion potential, open-circuit potential (OCP), sodium chloride electrolyte, hydrogen peroxide, electrochemical measurement, metallurgy, heat treatment assessment.

FAQ

Q: What is this standard?

A: ASTM G69-20 is a short ASTM test method that defines a laboratory procedure to measure the corrosion (open-circuit) potentials of aluminum alloys in a NaCl solution with added hydrogen peroxide.

Q: What does it cover?

A: It covers specimen preparation considerations, electrolyte composition (NaCl + H2O2), reference electrode use, equilibration and measurement of the rest potential, and reporting of results for comparative and metallurgical assessment.

Q: Who typically uses it?

A: Metallurgists, corrosion engineers, QA/QC labs, and researchers working with aluminium alloys—especially in industries where alloy condition (solution treatment, aging, welding, cladding) affects performance.

Q: Is it current or superseded?

A: The G69-20 edition published in May 2020 is listed as the active/current edition in major standards catalogues and the ASTM store; there is no indication of a later revision or superseding edition as of the current document listings. Users should check the official ASTM catalog for any updates after February 22, 2026 if they require absolute current-status confirmation.

Q: Is it part of a series?

A: G69 is a single test method within ASTM Committee G01 (Corrosion of Metals) publications and cross-references other corrosion terminology and electrochemical practice standards (for example, Terminology G193 and related G-series electrochemical practices). It is often used alongside other G‑series methods for broader corrosion testing programs.

Q: What are the key keywords?

A: aluminium, corrosion potential, open-circuit potential, NaCl, hydrogen peroxide, electrochemical, alloying elements, solution heat treatment.