Overview
ISO 16962:2017 specifies a glow-discharge optical-emission spectrometric (GD-OES) method for the surface chemical analysis of zinc- and/or aluminium-based metallic coatings. The standard covers determination of coating thickness, mass per unit area (areic mass) and chemical composition, including quantitative depth profiling by sputtering and optical-emission measurement. It applies to a wide range of compositions and supports both direct-current (DC) and radio-frequency (RF) glow-discharge sources.
Key topics and requirements
- Scope of analysis: Applicable to Zn (0.01–100 mass %), Al (0.01–100 mass %), Ni/Fe/Mg (0.01–20 mass %), Si (0.01–15 mass %), Pb/Sb (0.005–2 mass %). Note: Pb and Sb are included for legacy products but are avoided in modern applications for health/environmental reasons.
- Principle: Cathodic sputtering of the coating in a glow discharge, excitation of atoms/ions in the plasma, and spectrometric recording of emission intensity vs. time to produce depth profiles that are converted to mass fraction vs. depth by calibration.
- Apparatus: Grimm-type or similar GD source coupled to a simultaneous optical-emission spectrometer; selection of spectral lines and source type (DC or RF) is addressed.
- Instrument settings: Procedures for adjusting discharge parameters, DC vs RF operation modes, and recommended data acquisition practices.
- Calibration & validation: Use of calibration samples and measurement of sputtering rate, calculation of calibration equations, and validation using reference materials (bulk and surface-layer RMs).
- Analysis output: Quantitative depth profiles, total coating mass per unit area, average mass fractions; guidance on test reporting and precision.
- Supporting material: Annexes provide calculation methods, suggested spectral lines and procedures to determine coating areic mass.
Applications and users
Practical applications of ISO 16962:2017 include:
- Quality control of galvanizing and aluminium-based coating processes (hot-dip, electroplating)
- Failure analysis and corrosion studies requiring composition vs depth
- Specification compliance and production inspection for coated steel components
- Development and validation of coating processes and new alloyed coatings
Typical users:
- Surface-chemical analysis laboratories and GD-OES operators
- Coating manufacturers and metallurgical engineers
- Automotive, construction and appliance industry quality teams
- Third-party testing and certification bodies
Related standards
- ISO 14284 - Sampling and preparation of steel and iron for chemical composition determination
- ISO 17925 - Determination of coating mass per unit area and composition (gravimetry, ICP-AES, FAAS)
ISO 16962:2017 is essential for laboratories and manufacturers using GD-OES to deliver reliable, calibrated depth profiles and mass-per-area measurements for zinc- and aluminium-based coatings. Keywords: ISO 16962:2017, GD-OES, glow-discharge optical-emission spectrometry, surface chemical analysis, zinc coatings, aluminium coatings, depth profiling, coating thickness, areic mass, calibration.