THE STUDY OF DIFFUSION OF MEDIA IN THE ORGANIC COATING FILMS BY BAW ADMITTANCE ANALYSIS

The permeation of water and corrosive species in coating films is very important for the corrosion protection by organic coatings. As a new method for the study of diffusion of media in coating films, bulk. aco ustic wave (BAW) admittance analysis has been proposed in this article . Real-time information on the change of the him mass, mechanic proper ty of the layer, and the permeation process of the media can be provid ed simultaneously by the parameters of BAW admittance analysis, f(s) ( series resonant frequency), Delta L-1 (inductance variance), R-1 (resi stance), Q (quality factor), and C-s (film capacitance). The diffusion behavior of media and the corresponding film stability can be describ ed by the following parameters: D (diffusion coefficient), P (permeati on coefficient), S (the solubility of media), and SC (the swelling coe fficient of the coating layer). (C) 1998 John Wiley & Sons, Inc.