Study on Conversion Treatment of Thin Titanium Layer Deposited onto Carbon Steel: Application of Physical and Mechanical Investigation

The present study has been conducted in order to obtain titanium carbide layer using a conversion treatment consisting of two main steps. In the first step a thin pure titanium layer was deposited onto 120C4 carbon steel by PVD. In a second step, a vacuum annealing treatment is conducted in order to diffuse the carbon atoms from the substrate toward the titanium coating. As a result, the pure titanium coating is transformed into titanium carbide. However, depending on the annealing temperature, partial or complete conversion into TiC is obtained. Due to that the hardness of the layer depends on the annealing temperature. By a systematic study of the hardness-load variation, the process of the phase transformation of the layer is then confirmed.