Isothermal nitridation kinetics of TiSi2 powders

• Influence of grain size on TiSi2 powder nitridation.
• Influence of temperature on TiSi2 powder nitridation.
• Experimental measurements of the nitridation kinetics.
• An explanation of the nitridation mechanism.

The aim of the present work is to determine the kinetics of reaction between TiSi2 powder and gaseous nitrogen. Isothermal nitridation of TiSi2 powders with fine (1.4 µm) and medium (4.5 µm) particle size has been studied in pure nitrogen atmosphere from 1000 to 1200 °C for duration up to 50 h. The isothermal nitridation kinetics of TiSi2 powders were investigated by thermogravimetry. The nitridation rate strongly depends on the particle size and temperature. Smaller size particle exhibits higher nitridation rate due to its larger surface area. The conversion process is complex with nucleation and growth of TiN at the surface of the grain and Si3N4 inside the grain promoted by the Kirkendall effect with an influence of the volume increase.

Backscattered electrons image of a transverse TiSi2 grain nitrurated at 1100 °C for 50 h.Figure optionsDownload as PowerPoint slide