Effect of peak load on the determination of hardness and Youngʹs modulus of hot-pressed Si3N4 by nanoindentation

The indentation load–displacement curves of a hot-pressed silicon nitride were measured under different peak load levels. The unloading segments of these curves were analyzed using the widely adopted Oliver–Pharr method. It was found that both the hardness, H, and the Youngʹs modulus, E, exhibit significant peak-load-dependence. Empirical approaches were then proposed to determine the load-independent hardness and modulus. The hardness and modulus deduced from these empirical approaches were proven to be comparable with the literature reported data measured with conventional methods.