ISO 2355:1972

Overview

ISO 2355:1972 specifies a standardized gravimetric method for the chemical analysis of magnesium and its alloys, focusing on the determination of rare earth element (REE) content. This internationally recognized standard applies to the measurement of rare earths ranging from 0.2% to 10% by mass, specifically in samples devoid of thorium. It covers the entire analytical procedure including sample preparation, reagent use, apparatus requirements, testing method, result expression, and reporting.

This method is vital for industries where precise quantification of rare earths in magnesium alloys is required for quality control, material certification, and research and development purposes.

Key Topics

• Scope and Application

  • Determination of rare earth elements content in magnesium alloys between 0.2% and 10% by weight.
  • Excludes samples containing thorium.

• Analytical Principle

  • Dissolution of magnesium alloy samples by hydrochloric acid.
  • Precipitation of zirconium hydroxide for separation purposes.
  • Separation of rare earth elements as their sebacates in an ammoniacal medium.
  • Oxalate precipitation of rare earths, followed by calcination and gravimetric quantification of the resulting oxides.

• Reagents and Solutions

  • Ammonia solutions of varying normalities.
  • Peroxide of hydrogen and a mixture of nitric acid with peroxide for oxidation.
  • Sebacic acid ammoniacal solutions for rare earth separation.
  • Oxalic acid for oxalate precipitation.
  • Indicator solutions such as bromophenol blue for pH control.

• Apparatus Requirements

  • Standard laboratory vessels and devices compliant with official standards.
  • Use of a pH meter to accurately adjust precipitation conditions.

• Sampling Guidance

  • Recommended sample sizes vary according to expected rare earth content: from 1 g to 3 g.
  • Sample form should be in chips or small particles (≤1 mm thickness).

• Test Report and Result Expression

  • Results expressed as percentage mass of rare earth oxides calculated using a conventional conversion factor.
  • Inclusion of test conditions, specifics of the method, any deviations or optional steps in test reports.

Applications

• Metallurgy and Materials Engineering
  ISO 2355:1972 is essential for ensuring the quality and composition control of magnesium alloys used in aerospace, automotive, electronics, and other high-performance applications where precise rare earth content affects material properties.

• Quality Assurance in Alloy Production
  Provides a reliable, reproducible method for manufacturers and testing laboratories to verify compliance with composition specifications.

• Research and Development
  Enables researchers to accurately measure and adjust rare earth content during the development of new magnesium-based materials with enhanced mechanical and chemical properties.

• Regulatory Compliance
  Supports conformity with international trade and material standards by providing a universally accepted analytical method.

Related Standards

• ISO/TC 79 - Light Metals and Their Alloys
  The technical committee responsible for developing standards related to light metals, including methods for chemical analysis like ISO 2355.

• Other Gravimetric and Chemical Analysis Standards for Magnesium Alloys
  Complementary methods addressing different elements or techniques for comprehensive alloy analysis.

• Standards for Sampling and Statistical Methods
  Guidelines under ISO/TC 69 that address appropriate sampling techniques and statistical evaluation consistent with ISO 2355’s analytical accuracy goals.

Keywords: ISO 2355:1972, chemical analysis, magnesium alloys, rare earths determination, gravimetric method, magnesium alloy testing, REE analysis, international standard, metallurgical analysis, quality control.