ISO 7627-2:1983

Overview

ISO 7627-2:1983 specifies a chemical analysis method by flame atomic absorption spectrometry (AAS) for determining calcium, potassium, magnesium and sodium in hardmetals. The procedure covers the quantitative determination of these elements in the narrow range 0,001 to 0,02 % (m/m). General requirements for field of application, principle, interfering elements, apparatus, sampling and reporting are given in ISO 7627‑1. The standard emphasizes that low‑concentration determinations are very critical and require strict contamination control.

Key topics and technical requirements

• Sample preparation

  • Weigh approximately 1 g test portion to 0,001 g precision.
  • Dissolve with hydrofluoric acid and nitric acid, add water, then add cesium chloride and ammonium fluoride to the solution and transfer to a 100 ml polypropylene volumetric flask.
  • Use high‑purity reagents and take precautions to avoid contamination from atmosphere and reagents.

• Calibration and blanks

  • Prepare at least six calibration solutions with a matrix closely matching the sample.
  • Prepare at least two blank solutions.
  • For instruments with higher sensitivity, a 10× dilution of the main solution is permitted.

• Instrumental measurement (AAS)

  • Optimize the atomic absorption spectrometer at the wavelengths specified per element and preheat the burner (~5 minutes).
  • Aspirate blank, calibration and test solutions consecutively; aspirate water between solutions.
  • Make at least two measurements per solution; remove solids building up on burner slit.

• Analytical parameters (selected)

  • Wavelengths and recommended oxidant:
    • Ca: 422.7 nm (N2O), linear range 0,001–0,02 %
    • K: 769.9 nm (air), linear range 0,0005–0,02 %
    • Mg: 285.2 nm (N2O), linear range 0,0003–0,04 %
    • Na: 589.3 nm (air), linear range 0,0005–0,02 %
  • Report results as the arithmetic mean rounded to 0,001 % (m/m).
  • Permissible deviations: not to exceed 0,0005 % at the lower limit and 0,002 % at 0,02 %.

Applications

• Routine chemical analysis of hardmetals (cemented carbides) to quantify trace alkali and alkaline‑earth metals.
• Quality control during powder metallurgy production, raw‑material verification and failure analysis where trace levels of Ca, K, Mg or Na affect sintering, microstructure or performance.
• Situations requiring trace determination by flame AAS where matrix matching and contamination control are crucial.

Who should use this standard

• Analytical laboratories in the powder metallurgy and hardmetals industry.
• Quality assurance and materials engineers performing trace elemental analysis.
• Instrument specialists validating AAS methods for low‑concentration determinations.

Related standards

• ISO 7627‑1 – Hardmetals: General requirements for chemical analysis by flame atomic absorption spectrometry.