The critical influence of surface topography on nanoindentation measurements of a-SiC:H films

Further Progress in Functional Interlayers with Controlled Mechanical Properties Designed for Glass Fiber/Polyester Composites

“…However, the determined values of Young's modulus are not realistic for the range of moduli from the polymer matrix to the reinforcement, and they are strongly affected by the surface topography of the composite sample. It was found that surface formations (grains), with a radius similar or larger than that of the AFM tip or diamond indenter, have a critical influence on probe (AFM or nanoindentation) measurements used to characterize mechanical properties based on the geometry of contact between the tip and the sample [22].…”

Elastic Modulus and Hardness of Plasma‐Polymerized Organosilicones Evaluated by Nanoindentation Techniques

“…Using conventional and cyclic nanoindentation, the mechanical properties of the a‐SiC:H films measured on a flat surface progressively increased as the power increased. However, the elastic modulus and hardness of the grains were lower compared to the flat surface values . The difference is remarkable for films deposited at powers of 50–70 W. The elastic modulus and hardness determined for the grain were approximately half those of the flat surface for the film deposited at 70 W. The results were consistent with CSM measurements and explain the high‐error margin (50 W) for the elastic modulus in Figure .…”

“…The depth profiles of the experimental and simulated data are compared for the elastic modulus and the hardness. Good agreement between the experimental and simulated data was observed for the film with the flat surface . The trend of the depth profile predicted by the FEA simulation for nanoindentation at the grain is followed by the experimental data.…”

“…The shape of the modulus profile for the top of the grain reveals that the magnitude of the storage modulus at the top of the grain is approximately 80 GPa, which is similar to that outside the grain, whereas the value of the modulus at the side of the grain is approximately 40 GPa. The difference between the mechanical properties evaluated outside and at the side of the grain appears to be similar to that observed between the flat surface and the grain evaluated using conventional and cyclic nanoindentation for the same a‐SiC:H film . Nevertheless, the difference in the storage modulus (Figure ) has a quite different origin.…”

“…A simulation of the film with a surface topography indicated that nanoindentation measurements may result in mechanical properties that are under‐ or overestimated by more than 50%. Our experimental and simulation study revealed that the surface topography of the specimen has a critical influence on nanoindentation measurements; therefore, nanoindentation and scanning probe measurements must be performed on completely flat surfaces. This conclusion applies not only to Modulus Mapping but also to AFM measurements in contact and semi‐contact mode that are used to characterize mechanical properties based on the geometry of the contact.…”