EPMA of spinodal-like decomposition patterns in (TixNb1-x)N

Although TiN and NbN are known to form a complete quasibinary solid solution, it was found that upon nitridation of Ti/Nb or annealing of (Ti,Nb)N alloys the formation of large lamellae occurs, which could be optically distinguished by their golden yellow (Ti-rich) and light yellow (Ti-poor) colour. Such structures at much smaller scales are known to result from spinodal decomposition. In order to characterize the decomposition process, the samples were investigated by wavelength-dispersive electron probe microanalysis. The measurement conditions were adjusted in order to account for the Ti Ll and N K? overlap, as well as to take an appropriate mass absorption coefficient for N in Nb into consideration. Different acceleration voltage for electron probe microanalysis were applied, which showed that the problem can be overcome by tuning the measurement conditions.