Overview
ISO 2354:1976 - "Magnesium alloys - Determination of insoluble zirconium - Alizarin sulphonate photometric method" defines a validated photometric analytical procedure for measuring insoluble zirconium in zirconium‑containing magnesium alloys. The method is applicable to alloys with insoluble zirconium levels between 0.02% and 0.3% (m/m). It specifies principle, reagents, apparatus, sampling, calibration, result expression and reporting requirements.
Key topics and requirements
- Analytical principle: Chemical attack and isolation of insoluble residue followed by formation of a zirconium–alizarin sulphonate complex measured photometrically at about 525 nm.
- Applicable range: 0.02–0.30 % insoluble zirconium (m/m).
- Interferences: Rare earths, thorium and silver do not interfere; hafnium (when present) is determined together with zirconium.
- Reagents: Includes concentrated hydrochloric, hydrofluoric and perchloric acids, sodium alizarin sulphonate reagent, magnesium chloride solution and prepared zirconium standard solutions with procedures for standardization (gravimetric or p‑bromomandelic/mandelic acid methods).
- Apparatus: Ordinary laboratory glassware and a spectrophotometer or photoelectric absorptiometer with a 1 cm optical path.
- Sampling and test portion: Guidance on chip sampling and recommended test portion masses (examples in standard: 6 g or 4 g depending on soluble zirconium content).
- Calibration and measurement: Preparation of standard matching solutions, construction of a calibration curve, blank determination and measurement of sample absorbance within one hour of color development.
- Reporting: Results expressed as % (m/m) zirconium with method reference, any deviations or unusual observations documented.
Applications and users
ISO 2354:1976 is used where accurate quantification of insoluble zirconium in magnesium alloys is required for material control and specification compliance. Typical users include:
- Quality control and analytical laboratories in magnesium foundries and alloy producers
- Metallurgical and materials testing labs serving aerospace, automotive and electronics industries
- R&D and failure‑analysis teams assessing alloy composition or process effects
- Standards bodies and inspection authorities requiring traceable test methods
The method supports product qualification, process control, and materials research where zirconium content affects microstructure, mechanical properties or corrosion resistance.
Related standards
- ISO 1178 - Magnesium alloys - Determination of soluble zirconium - Alizarin sulphonate photometric method (referenced in ISO 2354 for related sample handling and residues)
- ISO/TC 79 - Technical committee responsible for light metals and their alloys
Keywords: ISO 2354:1976, magnesium alloys, insoluble zirconium, alizarin sulphonate photometric method, zirconium determination, spectrophotometry, calibration curve, analytical method.