| TiC_xN_(1-x) coatings were deposited on high speed steel and Si substrates by PECVD with CH₄/N₂ inlet fraction of 0.3, 0.4, 0.5 and 0.6. The chemical composition, surface and fracture cross-section morphology, preferred orientation and microhardness of the coatings were analyzed. It has been found that the compostiion of TiC_xN(1-x) coatings was changed from TiC_(0.54)N_(0.46) to TiC_(0.60)N_(0.40) with an increas of CH₄/N₂ inlet fraction. When CH₄/N₂ inlet fraction was small, TiC_xN_(1-x) coating showed the columnar grains with a domed top. The faceted columnar grains, however, began to develop with the increase of CH₄/N₂ inlet fraction. The grain size increased as well. At CH₄/N₂=0.3, the coatings had (200) preferred orientation, while no preferred orientation was observed at CH₄/N₂=0.6. It is suggested that these results are caused by enhanced adatom mobility and surface diffusion with CH₄/N₂ inlet fraction. |
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