Research On Micro-structure And Properties Of Ti-Mo-N Nanostructure Composite Coatings

MoN single-layer films and TiMoN composite films were prepared by reactive magnetron sputtering technique. And reaserched on their microstructure and properties influenced by Mo target power. The main conclusions in this work are summarized as follows.The studies on the MoN single-layer films indicated that, The MoN single-layer films mainly presented the cubicγ-Mo₂N structure, and growed in columnate structure. The oxidized temperature occurred between 500℃to 600℃, while at 600℃oxidized seriously, and produced the acicular oxide. In the dry wear, when the power at 240W, its hardness was low, but the friction coefficient was small, and the wear-resistance was well,the reason is lubrication of Mo。The studies on the low content of TiMoN composite films indicated that with Mo target power's increased, (1) the Mo atom's content elevated gradually, and the crystal grain had TiN(111) preferential growth trend in the TiMoN composite films. (2)TiMoN composite films'hardness improved comparing to TiN', its greatest hardness value was 24.76GPa. (3)TiMoN composite films oxidation-resistance temperature were at about 500 to 600℃. (4)At the room temperature, the TiMoN composite films friction coefficient is small, and the wear rate was low, the wear-resistance was well, the smallest average friction coefficient was 0.3583. The wear mechanism was mainly the abrasive wear, the major factors possibly stemed from the bonding strength beteen the films and substrate and hardness difference. At 700℃, the friction coefficient firstly increased and then reduced, the smallest average friction coefficient was 0.3882, Magnéli phase_the Mo oxide was the primary factor, and the wear mechanism was oxidative wear.The studies on the high content of TiMoN composite films indicated that with Mo target power's increased, (1)TiMoN composite films assumed cubic Mo₂N structure, TiMoN composite films'diffraction peak of (111)reduced and (200) increased gradually. (2)TiMoN composite films'microhardness increased gradually, the maximum value was 36.32GPa, which owned to the factors of melting strengthening and grain size fining. (3)TiMoN composite films'oxidation resistance performance was well, about 600℃, the reason was Mo'alloying impedimented oxygen element permeating to inside. (4)At room temperature, the friction coefficients of TiMoN composite films'dropped gradually, the minimum value was 0.3917, the main factor was hardness. At 700℃, TiMoN composite films' friction coefficient increased first and then reduced, the minimum value was 0.3817, the main factors were the degree of lubricating oxides and adhesive wear.The crystal chemistry theory of MoO₃ and the TiO₂'ion potential difference explained the TiMoN composite films'well wear-resistance. With 73.15at.% Mo content, TiMoN composite film'overall performance was the most superior, the microhardness was 36.32GPa, the oxidation resistance temperature was about 600℃, at room temperature friction coefficient was 0.3917, at 700℃was 0.3817.