SCALING APPROACH TO SINTERING OF FRACTAL MATTER

A simple model for the sintering of materials made of connected fracta l aggregates, such as aerogels, is proposed. The densification at smal l scales is described by an increase of the lower cutoff length accomp anied by a decrease of the upper cutoff length, in order to conserve t he total mass of the system. General scaling laws are derived which re late the structural characteristics to the mean bulk density. The theo ry explains quite satisfactorily a large number of experiments on grad ually densified silica aero gels.