Overview
ISO 4155:2022 specifies an inductively coupled plasma optical emission spectrometric (ICP‑OES) method for the determination of nickel (Ni) in magnesium and magnesium alloys. The method covers nickel mass fractions from 0,0002 % to 0,2 % and describes sample preparation, reagents, apparatus requirements, calibration and calculation of results. It is intended for laboratories performing compositional control and quality assurance of magnesium materials.
Key Topics and Requirements
- Scope and detection range: Nickel determination in magnesium/magnesium alloys between 0.0002 % and 0.2 % (mass fraction) using ICP‑OES.
- Principle: Dissolve sample in nitric and hydrochloric acids, nebulize into an ICP, and measure nickel emission; concentrations are derived from magnesium‑based calibration curves.
- Reagents: Analytical‑grade acids and water (ISO 3696 grade 2); primary standards include pure magnesium (≥99,99 %) and pure nickel (≥99,99 %); stepwise nickel standard solutions (1 mg/ml down to 1 μg/ml) are specified.
- Apparatus: Use a properly optimized ICP‑OES instrument. All volumetric glassware must be Class A and calibrated per ISO 648 / ISO 1042.
- Wavelength selection & interferences: No single wavelength mandated; recommended sensitive lines are Ni 231.604 nm and Ni 221.647 nm. Possible interferences (Co, Fe, Cu) should be evaluated by each laboratory.
- Performance criteria: Limit of detection (see Annex A) shall be ≤ 0.001 mg/L. Calibration linearity requires a correlation coefficient > 0.999.
- Sampling and sample prep: Representative fine drillings/chips (max 1 mm thickness); remove oil/grease if present (ethanol/acetone), avoid surface oxidation, and for Si/Zr‑bearing samples add 1–2 drops HF to aid dissolution.
- Calibration & procedures: Detailed stepwise preparations for low (0.0002–0.01 %) and high (0.01–0.2 %) nickel ranges, adjustment of apparatus, measurement sequence, calculation of results and precision assessment (Annexes B & C).
Applications and Who Uses It
- Quality control and incoming inspection in magnesium producers, foundries and alloy manufacturers.
- Materials testing laboratories verifying compliance with product specifications.
- Industries where magnesium alloys are critical-automotive, aerospace, electronics, and lightweight engineering-to ensure corrosion resistance and safety.
- Procurement and certification labs requiring trace‑level nickel quantification for conformity with material standards.
Related Standards
Keywords: ISO 4155:2022, magnesium alloys, nickel determination, ICP‑OES, inductively coupled plasma optical emission spectrometry, limit of detection, calibration, sample preparation.