Abstract
It is very important to clarify the mechanism of hardening of a powder layer under humid conditions in order to avoid the potential trouble caused by the layer hardening. This phenomenon is believed to be closely related to the formation of liquid bridge at the contact point of two particles which leads to an increase in adhesion force.
In this paper, the applicability of impedance of an electrical equivalent circuit for a particle-contact point system has been examined for the evaluation of adhesion force at different humidity. An electrical equivalent circuit was designed to express the condition of contacting particles in powder layer and the impedance of conductive and non-conductive particles was calculated at different humidity.
Adhesion force and impedance of a single contact point of particle with liquid bridge has been measured directly by a modified AFM. Based on the measurements, the applicability of impedance for the investigation of the change in adhesion force acting between contacting particles with liquid bridge was discussed.
