Effect of annealing on adhesion of TiB2 films deposited by pulsed magnetron sputtering

TiB2 films were deposited on silicon wafers and AISI M2 steel substrates by pulsed dc close field unbalanced magnetron sputtering. The samples were annealed in an inert argon atmosphere at 673, 873 and 1073 K for 1 h. The structural changes due to annealing were evaluated using X-ray diffractometry and scanning electron microscopy. The mechanical properties of the films were characterised by microhardness and scratch tests. The microstructure, microhardness and adhesive strength of the films varied depending on the annealing temperature. While it was observed that the hardness and adhesion strength of TiB2 films annealed at 673 K improved, these properties decreased for the films that were annealed at higher temperatures.