Influence of Thermo-Chemical Treatment on the Surface of CP Titanium

The effect of the holding time on the surface hardening of commercially pure titanium (CP-Ti) by thermo-chemical treatment (TCT) process was studied in the present paper. Surface treatments with three different times were carried out and investigated. The TCT process using nitrogen gas was carried out under vacuum atmosphere in treatment time (0.5, 1, 2 h) at 800 °C (thermo-chemical nitriding temperatures). The hardened surface was analyzed by scanning electron microscope (SEM) to observe the microstructure of cross-sections of TCT-treated specimens. In observations of the gradient-hardened inner-layer, as the holding time was increased the layer thicker and the depth of the Ti2N + TiNx layer was higher. And the specimen thickness of Ti2N and TiNx layers, measured from cross-section specimen was about 9 μm, 10 μm and 13 μm, respectively.