Material specific nanoscratch ploughing friction coefficient

In nanoscratch testing it is observed that the normal and tangential forces do not increase linearly. This behavior results in ploughing friction coefficients that vary with nanoindenter penetration depth. Lafaye and Troyon conducted research on ductile materials that concluded this is due to the nanoindenter not having an ideally sharp tip, but rather a blunt spherical one. The friction coefficient model, applied to brittle materials in this research, uses a previously published analytical friction coefficient model as its foundation, and extends it to include material-specific characteristics that effect friction coefficient behavior. Through the comparison between experiment and modeling, material characteristics such as pileup and nanoindenter contact area were found to aid in properly describing the friction coefficient of brittle materials.