Depth analysis of metal coatings by glow discharge spectrometry with an argon—helium gas mixture

Abstract

Abstract Depth profiles of Cu/Ni, Zn/Fe and Ni/Fe metal coatings obtained with a Grimm glow discharge lamp using an argon—helium gas mixture and pure argon gas were compared. Copper and zinc showed a large increase in intensity for the argon‐helium gas mixture, but Ni showed a small decrease. The sputter time for all three coating metals almost doubled, indicating a smaller sputtering rate for the argon—helium gas mixture. A broadened interface due to the different manner in which the surface was eroded was also observed for the argon—helium sputtered profiles. Intensity enhancement in Cu and Zn was explained by the higher excitation and ionization potential of helium and the simple energy levels (simple spectra) of these elements. On the other hand, the dense energy levels of the Ni atom (complex spectra) does not lead to intensity enhancement.