Measuring nanomechanical properties of a dynamic contact using an indenterprobe and quartz crystal microbalance

A study of the contact mechanics of a probe tip interacting with a quartz c rystal microbalance (QCM) has been performed, involving simultaneous measur ements of normal load, displacement, and contact stiffness with changes in QCM resonant frequency. For metal-metal and glass-metal contacts in air, th e QCM frequency shifts were observed to be positive, and directly proportio nal to the contact area as inferred from the contact stiffness. Interfacial characteristics of the probe-tip contact (elasticity, contact size, and an estimate of the number of contacting asperities) were deduced by extending a prior model of single asperity contact to the case of multiple contacts. The extended model clarifies a number of seemingly disparate experimental results that have been reported in the literature. (C) 2001 American Instit ute of Physics.