On the Determination of Carbon, Phosphorus, Sulfur and Silicon in Grey Cast Irons Using Glow Discharge Optical Emission Spectrometry

Abstract

Glow discharge optical emission spectrometry is used to determine C, P, S and Si in grey cast irons. White cast irons are used as calibrants, and data are acquired while sputtering is non-stoichiometric. Type standardization is employed to correct the resulting matrix effect. For comparison, analytical mass fractions of P, S and Si are also calculated from the data while omitting the matrix effect correction. A statistical evaluation of the data shows that while all except one of the experimental mass fractions, computed with or without type standardization, are in agreement with corresponding certified values at theP=0.05 level of significance, the use of the type standard is indispensible for the unbiased determination of C and S and may be helpful in the case of P. In contrast, the data indicate that type standardization may in some cases introduce analytical bias into the determination of Si.