X-ray analysis of heat-treated titanium nitride films

Titanium nitride films deposited onto steel substrates maintained at 423 K were heat treated in the temperature interval 773–1173 K. Samples were studied by electron probe microanalysis and X-ray diffraction. The high values of the microhardness observed for the as-deposited films decreased after annealing for 3 h at 973 K to nearly bulk values. This decrease is mainly due to the improvement in the microstructure of the films. It is accompanied by strong decreases in strain, stress and the lattice parameter of δ-TiN_x. Growth of the ε-Ti₂N phase at the expense of the δ-TiN_x phase was observed in a film with 34 at .% N when it was annealed for 3 h at 973 K. The lattice parameter and strain in the substrate increased after film deposition, most probably due to a dissolution of nitrogen or titanium atoms in the lattice of -Fe.