Wettability of TiN by Liquid Iron and Steel

The wettability of liquid iron and steel in contact with TiN substrates was studied. Initially, Spark Plasma Sintering (SPS) was used to prepare the samples using different operational conditions. It was found that a relative density of 96% and surface roughness values smaller than 250 nm could be obtained by using the following settings: a 1873 K temperature, a 89.2 MPa pressure and a 5 min sintering time. Thereafter, the wettability of the liquid iron and steel in contact with the TiN substrates was measured based on video recordings, at the moment when the metals started to melt. The results show that the contact angle value for a TiN/pure Fe system (130 to 87.9 degrees for 900 s) is larger than the value for a TiN/steel system (110 to 50 degrees for 981 s). Therefore, it is concluded that TiN has good resistance to the corrosion of the liquid iron and steel. In the liquid iron case, its wetting behaviour occurs mainly due to the oxygen increase in liquid iron after a full melting. However, in the liquid steel case the contact angle decreases sharply due to both the effects of an oxygen increase in liquid steel and a precipitation of Ti(N,C,O) at the interface.