Measurement of hardness of superhard films by microindentation

A critical analysis is presented of the measurement by microindentation of the hardness of superhard films with hardness, H, exceeding 50 GPa. This analysis shows that a very high hardness of the Ti–Si–N nanocomposite film reaching a value of 105 GPa, which was recently reported, is hardly a correct value and so till now, very probably, no material harder than diamond has been prepared.