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Ti2N is trigonal omega-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Ti is bonded in a T-shaped geometry to three equivalent N atoms. There are one shorter (2.05 Å) and two longer (2.08 Å) Ti–N bond lengths. N is bonded to six equivalent Ti atoms to form a mixture of edge and corner-sharing NTi6 octahedra. The corner-sharing octahedral tilt angles are 9°.
Ti2N is Rutile structured and crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Ti is bonded in a distorted T-shaped geometry to three equivalent N atoms. All Ti–N bond lengths are 2.08 Å. N is bonded to six equivalent Ti atoms to form a mixture of edge and corner-sharing NTi6 octahedra. The corner-sharing octahedral tilt angles are 47°.
Titanium and Ti-8Al-1Mo-1V alloy were nitrided with an ion-beam source of nitrogen or argon and nitrogen at a total pressure of 2 x 10 to the minus 4th power to 10 x 10 to the minus 4th power torr. The treated surface was characterized by surface profilometry, X-ray diffractometry, Auger electron spectroscopy and microhardness measurements. The tetragonal Ti2N phase formed in pure titanium and Ti-8Al-1Mo-1V alloy with traces of AlN in the alloy. Two opposite processes competed during the ion-beam-nitriding process: (1) formation of nitrides in the surface layer and (2) sputtering of the nitrided layers by the ion beam. The highest surface hardnesses, about 500 kg/sq mm in titanium and 800 kg/sq mm in Ti-8Al-1Mo-1V, were obtained by ion nitriding with an ion beam of pure nitrogen at 4.2 x 10 to the minus 4th power torr at a beam voltage of 1000 V.