Fracture behavior of TiN coating under nanoindentation and nanoscratch test

Abstract

A TiN coating with (111) and (222) preferred orientations was deposited on a Si(111) substrate by using reactive magnetron sputtering a Ti target. The deformation mechanism and fracture behavior of the coating are determined by nanoindentation and nanocratch experiments. The morphologies of the indentations and nanoscratch marks are revealed by scanning electron microscopy, in situ atomic force microscopy and optical microscopy. Local cracks of TiN appear around the indentation marks when the peak indentation displacement is below the critical value of 1000 nm. As the peak displacement exceeds 1000 nm, an interfacial fracture between the TiN coating and the Si(111) substrate is observed. Nonoscratch tests show that interfacial fractures are also induced by nanoscratch experiments under peak loads of 100 and 200 mN. The critical loads for interfacial fractures under 100 and 200 mN peak loads are equal to those under nanoindentation tests.