Analysis of nitrogen implantation profiles in titanium and Ti-Nb alloys by glow discharge optical emission spectroscopy: nitrogen calibration

Abstract

In the analysis of nitrogen in Ti-based matrices by glow discharge emission spetroscopy (GDOES), emission yield of the N I 149.262 nm line was found to depend on the sample composition, in particular, on the N/Ti ratio of the sample surface being sputtered. This was attributed to differences in the transport and redeposition of nitrogen in the GDOES discharge cell: if the surfaces surrounding the plasma consist largely of elemental Ti, the sticking coefficient of nitrogen on them is high and the number density of nitrogen in the volume of the plasma is reduced by adsorption more strongly than if these surfaces are partly or completely saturated with nitrogen. This leads to a decrease of emission yields of nitrogen lines and needs to be reflected in the analytical methodology. Analogous mechanism might be at play in the analysis of other gaseous elements also.