Effect of Hydrogen Addition to the Discharge Gas in Radio-Frequency Argon Glow-Discharge Mass Spectrometry for Nonconducting Samples

摘要

The addition of a small amount of H2 into Ar considerably decreased the signal intensity for a sintered zirconium oxide (ZrO2) sample when the discharge was operated at an rf power less than 100W, while it increased the ion intensity of the analyte for a brass sample. Although the sputtering rate of the ZrO2 sample varied with the concentration of added H2, no apparent correlation between the sputtering rate and the ion intensity was observed. When the discharge was operated at 200W, the addition of H2 significantly increased the ion intensity for the ZrO2 sample. For a sintered silicon carbide (SiC) sample, a similar behavior of the ion signals was observed, though they changed from suppression to enhancement at an rf power lower than that for a ZrO2 sample. This was probably due to the higher electric conductivity of SiC compared to that of ZrO2. When He was added into Ar, the analyte-ion intensity varied similarly to the case of H2. An increase in the ion intensity was also observed when N2 or O2 was added at a concentration range of 10-20wt% in Ar, although the behavior was observed for a discharge operated at a relatively high rf power of 200W.