ISO 1554:1976

Overview

ISO 1554:1976 specifies an electrolytic method for determination of copper content in wrought and cast copper alloys. The standard defines the principle, reagents, apparatus, sampling, step‑by‑step procedure, expression of results, repeatability requirements and the information required in the test report. It applies to common copper alloys (for example copper‑aluminium, copper‑zinc, copper‑nickel‑zinc) and refers high‑purity copper analysis to ISO 1553.

Keywords: ISO 1554, electrolytic method, copper content, copper alloys, copper assay, chemical analysis.

Key topics and technical requirements

• Principle: electrolytic deposition of metallic copper from a sample solution prepared by dissolution in a nitro‑fluoroboric mixture and acids, followed by electrolysis and weighing of the deposited copper.
• Reagents (analytical grade): boric acid solution (40 g/L), hydrofluoric acid (38–40% or optionally 48% m/m), nitric acid (diluted 1+1), ammonium hydroxide, distilled/deionized water.
• Apparatus: laboratory glassware and an electrolytic cell; recommended 6 V accumulator or rectifier with buffer battery; Winkler-type platinum cathode (mesh cloth, specified mesh and dimensions), spiral platinum anode (specified turns and dimensions); drying oven adjustable to 110 °C.
• Sampling: follow ISO/R 1811 sampling procedures for raw shapes and refinery forms.
• Procedure highlights:
  • Weigh 2.5 g test portion (±0.0001 g) and dissolve in 400 mL beaker with specified volumes of boric, hydrofluoric and nitric acids.
  • Heat to ~90 °C to expel nitrogen oxides, dilute, neutralize with ammonium hydroxide to precipitate, then re‑acidify and dilute to 300 mL with excess nitric acid.
  • Electrolyse without agitation at ~0.6 A/dm², reduce to ~0.3 A/dm² when solution becomes colorless, continue until copper deposition is complete.
  • Rinse cathode in ethanol/methanol, dry at 110 °C (3–5 min), cool and weigh deposited copper.
• Result expression: percent copper = (mass of deposited copper / mass of test portion) × 100.
• Repeatability: perform two determinations; difference must not exceed 0.07% (m/m) copper.
• Test report: must include method reference, numerical result with expression form, any special conditions or deviations and all non‑standard operations.

Applications and users

ISO 1554 is used for:

• Quality control and certification of wrought and cast copper alloys
• Metallurgical laboratories performing chemical analysis and alloy verification
• Manufacturers, refiners and inspection bodies requiring accurate copper assays
• Research and failure analysis where precise copper content is needed

Typical users include materials testing laboratories, foundries, metal producers, product inspectors and standards compliance teams.

Related standards

• ISO 1553 - Dosage of copper by electrolytic method (high‑purity copper)
• ISO/R 1811 - Sampling of refinery shapes and crude forms

ISO 1554 remains a practical, reproducible standard for electrolytic copper determination, offering defined reagents, apparatus dimensions and repeatability criteria for consistent alloy analysis.