Abstract
Double-layer electroplated steel sheet composed of upper Zn-Fe alloy and lower Zn-Ni alloy is analysed quantitatively using glow discharge spectrometry (GDS).
Increase of discharge current and decrease of Ar pressure, i.e., increase of discharge energy, improves depth resolution. Excess in energy, however, makes discharge unstable and deteriorates depth resolution. As the optimum discharge condition, 30 mA and 22 mbar is adopted. For each element, integrated value of emission intensity and coating weight are linearly related. Accuracy of these calibration curves (σd) is 1.5 g/m2 for 1050 g/m2 of Zn, 0.15 g/m2 for 17 g/m2 of Ni, and 0.34 g/m2 for 214 g/m2 of Fe. In this experiment, no effect of co-exsisting elements on the emission intensity of Zn is observed. Coating weight and composition of each layer obtained by GDS agree well with those analysed by atomic absorption spectrometry.
These results show that GDS can be applied to the quantitative analysis of this product.
