Influence of B content on microstructure, phase composition and mechanical properties of CVD Ti(B,N) coatings

Within this work the effect of B content on microstructure, phase composition and mechanical properties CVD Ti(B,N) coatings is investigated. with contents from 0 (fcc-TiN) to ∼5, ∼15, ∼30, ∼45 66 (h-TiB2) at.% have been deposited by CVD. The elemental was confirmed ERDA their microstructure investigated using XRD SEM. With increasing content, a transition fcc h-dominated structure via dual-phase fcc/h-Ti(B,N) observed, which accompanied decreasing grain size µm nm range. Combinatorial use Raman spectroscopy, XPS APT measurements indicated B-rich boundary segregations formation amounts h-Ti(B,N)2 clusters embedded within an fcc-Ti(B,N) matrix up ∼30 at.%, while for predominantly composed h-Ti(B,N)2. Complementary ab initio calculations predicting interpretation experimental results. In terms properties, nanoindentation micromechanical testing revealed rise in hardness ∼18 ∼41 GPa fracture stress toughness ∼7 ∼13 ∼4.6 ∼5.5 MPam1/2, respectively, at.%. contrast, significant drop hardness, observed at B. Thus it can be concluded, that both h-TiB2 maximized yield superior over TiN consequently improved performance.