In this study, the influence of precursor ratios on the microstructural and tribological properties of TiBN coatings was examined. TiN, TiB2, and three variations of TiBN coatings with adjusted BBr3/TiCl4 ratios were applied on H13 hot work tool steel using the plasma-assisted chemical vapor deposition (PACVD) technique. The coatings were characterized using XRD, FESEM, TEM, AFM, nanoindentation, and nanoscratch methods to analyze their microstructural properties, surface morphology, and mechanical behavior. The findings revealed that the TiBN coatings exhibited a nanocomposite structure consisting of TiN crystals embedded within an amorphous BN matrix. When the BBr3/TiCl4 ratio was raised from 0 to 1/3, a hardness increase from 13 GPa to 25 GPa was observed. However, the further increase in the ratio from 1/3 to 3/3 resulted in a decrease in hardness to 14.4 GPa because cracks were formed in the deposited coating. In comparison, the TiB2 coating exhibited a higher hardness of 19 GPa due to strong Ti-B bonds within the coating. The TiBN coating, applied with a BBr3/TiCl4 ratio of 1/3, demonstrated the lowest wear volume of 0.10×10-18 m3, attributed to its higher hardness and smoother surface texture.
