Overview
ISO 2353:1972 specifies an internationally recognized photometric method for the determination of manganese content in magnesium alloys containing zirconium, rare earth elements, thorium, and silver. This standardized method applies to manganese concentrations ranging from 0.002 to 0.2% by mass, ensuring precise and reliable chemical analysis essential for quality control and material characterization in lightweight metal industries.
The document outlines the principle of the periodate photometric method, detailing the required reagents, apparatus, sampling techniques, procedural steps, expression of results, and test reporting protocols. Developed under ISO Technical Committee ISO/TC 79, this standard reflects global consensus and best practices for accurate manganese quantification in complex magnesium alloys.
Key Topics
- Scope of Application: Measurement of manganese between 0.002 and 0.2% (m/m) in magnesium alloys with zirconium, rare earths, thorium, and silver.
- Analytical Principle:
- Initial dissolution of the alloy sample in sulfuric acid followed by oxidation using nitric acid in the presence of fluoboric acid.
- Conversion of manganese (II) to manganese (VII) via potassium periodate oxidation in an acidic medium.
- Photometric measurement of the developed color at approximately 545 nm wavelength.
- Reagents and Apparatus:
- Potassium periodate, sulfuric acid (9N and 35.6N), nitric acid (15N), fluoboric acid (0.4%), sodium nitrite solution, and manganese standard solutions at varying concentrations.
- Spectrophotometer or electrophotometer equipped with appropriate filters.
- Sample Preparation:
- Use of powdered or chip form magnesium alloy samples of specified sizes.
- Precise sampling based on expected manganese content (from 0.5 to 2 g depending on concentration).
- Calibration and Measurement:
- Preparation of standard calibration curves using known manganese standards.
- Detailed procedure for color development via boiling with potassium periodate.
- Correction for blank and interfering substances through controlled additions of nitrite solution.
- Expression of Results: Manganese content expressed as a percentage of mass calculated from absorbance data correlated against calibration curves.
- Test Report Guidelines: Comprehensive documentation including method reference, measured results, any deviations or unusual observations during testing, and details of any optional analytical steps.
Applications
ISO 2353:1972 serves as a critical quality assurance tool within metallurgy and materials testing laboratories handling magnesium alloys. Key applications include:
- Quality control in magnesium alloy manufacturing: Ensuring manganese levels meet specified limits to achieve desired mechanical properties and corrosion resistance.
- Material certification for aerospace, automotive, and electronics: Verification of alloy composition for safety and compliance with industry standards.
- Research and development: Supporting the development of novel magnesium alloys with tailored compositions involving rare earth elements and other additives.
- Regulatory compliance: Certification of manganese content aligned with international trade and materials standards.
This standard supports industries focusing on lightweight metals where accurate elemental analysis is fundamental to performance and safety.
Related Standards
- ISO 9001: Quality management systems applicable in laboratories performing elemental analysis.
- ISO 6507 / ISO 9459: Standards related to hardness testing of magnesium and its alloys, often complementing chemical composition analysis.
- ISO 3017: Magnesium and its alloys – Chemical analysis methods for various elements.
- ISO/TC 79: Technical committee working on lightweight metals and alloys standards encompassing analysis, testing, and material specifications.
Implementing ISO 2353:1972 ensures consistency in manganese determination, supporting compliance with broader quality and safety frameworks in alloy production and materials science.