Abstract :
In this work a novel method for synthesising TiN coatings is reported. A high-power diode laser at different powers and traverse speeds was
applied to a mild steel substrate, coated with a slurry of titania sol–gel, urea and graphite. The reaction chemical thermodynamics was investigated
to estimate the compositions, temperature range, and the required reaction enthalpy for producing TiN. A one-dimensional heat transfer model was
used to optimise the processing parameters. Surface morphology and microstructure of the deposited coatings and substrate surface layers were
examined using optical microscopy, scanning electron microscope, and field emission gun scanning electron microscope which reveals deposition
of very thin layer about 0.3 mm of pure TiN and the presence of sub-micron crystalline structure of TiN forming a metal matrix composite interlayer
with the substrate below the film which suggest a good metallurgically bonding with the substrate. Chemical composition was determined by
energy dispersive X-ray analysis. The phases were identified by X-ray diffraction which confirms the synthesis of TiN film for all the samples.
Results of nano-hardness measurements revealed a hardness value of the order of 22–27 GPa
