| Titanium alloys have exhibited a great application potential in modern industrial. However, the poor tribological behavior is a major drawback to their actual uses. To improve the wear resistance of Ti6Al4V, a plasma Mo-N alloying layer was prepared on its surface. The strengthening layer was composed of two sub-layers, Mo-N depositing layer and diffusing layer, with a total depth of 8 µm. XRD analysis shows that Mo2N, Ti2N, and TiN are the major phases of the surface-modified layers. Nano indentations tests indicate The modified specimens exhibited a bigger elastic modulus and much larger nano-hardness than that of the untreated substrate. The tribological behaviors of the modified layers are investigated by ball-on-disc sliding at room temperature, 300 °C, and 500 °C, respectively. The results indicated that the friction coefficients of the modified specimens recorded a lower friction coefficient at room temperature and 300 °C. At 500 °C Mo-N surface-modified specimen exhibited a higher friction coefficient. Under all the three temperatures the specific wear ratios of the modified specimens decreased greatly comparing to those of the bare metal. After plasma Mo-N co-diffusing the tensile strength of Ti6Al4V decreased slightly. |
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