A review of nanoindentation continuous stiffness measurement technique and its applications

Nanoindentation is now commonly used for the study of mechanical properties of materials on the nanoscale. One of the significant improvements in nanoindentation testing is the continuous stiffness measurement (CSM) technique. It offers a direct measure of dynamic contact stiffness during the loading portion of an indentation test and, being somewhat insensitive to thermal drift, allows an accurate observation of small volume deformation. Nanoscale damage caused by fatigue is of critical importance to the reliability of ultrathin protective overcoats and micro/nanostructures. The cyclic loading used in the CSM makes the technique useful for the evaluation of nanofatigue. Methodologies of the CSM technique used for the characterization of layered materials and nonhomogeneous composites are reviewed and discussed. Applications of the CSM technique to the measurement of contact stiffness, elastic modulus, hardness, creep resistance, and fatigue properties of the materials used in magnetic storage devices are presented. The nanoindentation CSM technique, in conjunction with nanoscratch and friction and wear tests, can be satisfactorily used for the materials characterization of magnetic storage and microelectromechanical systems (MEMS) devices and should find more application.