ISO 7627-5:1983

Overview

ISO 7627-5:1983 defines a standardized flame atomic absorption spectrometry (AAS) method for the chemical analysis of hardmetals. The part covers determination of cobalt, iron, manganese, molybdenum, nickel, titanium and vanadium when each element is present in the range 0.5 to 2 % (m/m). General requirements for field of application, principle, interferences, apparatus, sampling and test reporting are referenced to ISO 7627-1.

The document notes that determination of these elements at high concentration by flame AAS produces a wider scatter of results than some alternative analytical methods, and highlights the importance of careful calibration and sample preparation.

Key Topics

• Scope: Elements measured (Co, Fe, Mn, Mo, Ni, Ti, V) in hardmetals at 0.5–2 % (m/m).
• Sample preparation: Typical procedure calls for weighing ~1 g (0.001 g precision), adding 10 ml water, 5 ml hydrofluoric acid (HF), then dropwise 5 ml nitric acid (HNO3), gentle heating to dissolution, followed by addition of matrix modifiers (10 ml cesium chloride solution and 10 ml ammonium fluoride solution) and transfer to a 100 ml polypropylene volumetric flask.
• Dilution options: A 10× dilution is described for high-sensitivity instruments by transferring 10 ml of the prepared solution into 100 ml and re-adding matrix modifier solutions before bringing to volume.
• Calibration and measurement:
  • Prepare at least six calibration standards matched to the sample matrix where possible.
  • Aspirate blank, standards and samples with at least two readings per solution; rinse with water between aspirates.
  • Establish calibration curves and convert sample absorbances to mg/L.
• Calculation: Result in % (m/m) is computed from the concentration (mg/L), dilution volume (mL) and sample mass (g) using the published formula: c × V / (10^4 × m).
• Performance and rounding:
  • The difference between three independent determinations must not exceed 0.1 × the percentage content (absolute).
  • Rounding: 0.5–1.0 % → round to 0.02; >1–2 % → round to 0.05.
• Instrument setup and safety: Select element-appropriate wavelengths and flame conditions, preheat the burner (~5 min) and follow the instrument manufacturer's ignition and safety instructions.

Applications

• Routine quality control and composition verification of cemented carbides and other hardmetal materials.
• Incoming material inspection and process control where elemental contents fall within the 0.5–2 % range.
• Situations requiring a standardized AAS approach and traceable reporting.

Related Standards

• ISO 7627-1: General characteristics and requirements for flame AAS analysis of hardmetals.
• Additional references noted in the part: ISO 3909, 4501, 4503 and 4883 (for comparative performance and broader analytical context).

Practical value: Using ISO 7627-5:1983 helps labs implement reproducible sample prep, calibration and reporting practices for mid-level element concentrations in hardmetals, while acknowledging the intrinsic variability of flame AAS at these higher contents.