Determination of Trace Amounts of Rare-Earth Impurities in Yttrium Oxide

Abstract

This paper discusses investigations conducted to achieve optimum sensitivity for the determination of rare earths in yttrium oxide and describes a specific technique evolved for the above analysis. A dc arc burning in a controlled atmosphere of argon and oxygen is used together with a spectrograph of very high dispersion in order to provide optimum signal-to-noise ratio. Because the excitation efficiency is not uniform along the entire height of the arc column, only the most efficient portion is transmitted to the slit. Without any treatment or concentration of the sample other than dilution with graphite powder, the above method achieves sensitivities for the rare earths in yttrium oxide ranging from about 50 ppm for the least sensitive rare earths (Pr, Ce) to about 0.5 ppm for the most sensitive rare earths (Lu, Sc, Yb).