SPUTTER-INDUCED EFFECTS ON QUANTITATIVE GD-OES DEPTH PROFILES FROM HOT-DIP ZINC-COATED STEEL

Depth profiling using glow discharge optical emission spectroscopy (GD -OES) is sometimes used by the steel industry to determine the composi tion of the zinc coating of hot-dip galvanized steel. It has been obse rved that the shape of the aluminium profile from an intermetallic pha se between the zinc coating and the steel varies from sample to sample , and that the phase is much wider than expected. We have used scannin g Auger microscopy (SAM) to study the surface composition and topograp hy of GD-OES sputtering craters. A surface roughness is introduced dur ing sputtering that considerably deteriorates the depth resolution. Th e shape of the GD-OES depth profile in the intermetallic region is rel ated to the microstructure of the zinc coating.