Emission Spectrographic Method For Quantitative Analysis Of Corrosion Products^★

Corrosion studies of metals, piping systems, steam generators, etc., often require knowledge 'of chemical nature of corrosion products formed. As amounts of such products are sometimes very small, wet chemical analysis may be difficult. Therefore, a direct arc emission spectrographic method has been developed for quantitatively determining 13 elements, many of which are known to be present in water systems as the result of corrosion, scaling or fouling. Using high purity graphite as diluent, germanium dioxide as buffer, and barium carbonate as internal standard, it was found that an element concentration of 0.3 percent provided the spectral line densities suitable for quantitative analysis. The 13 elements yielding satisfactory results were aluminum, calcium, chromium, cobalt, iron, lead, magnesium, manganese, nickel, silicon, tin, titanium and vanadium. Method was applied to carbonates, oxides and silicates of these elements with results indicating accuracy of ±15 percent and precision of approximately 12 percent. Corrosion deposits, scales, slags and oxides can be analyzed routinely by this method.