Lab. d'Instrum. et de Mesures, Faculte des Sci. d'Agadir, Univ. Ibnou Zohr, Agadir, Morocco
Universite du Havre, Le Havre, France
A pulse ultrasonic technique has been developed to study the quality of the liquid/solid transformation of an epoxy resin made up of two components (resin and hardener). The epoxy resin is in a tank with parallel faces. A reflection technique allows the measurement of the phase velocity, the attenuation, and the acoustical impedance. The first and second parameters give an average state of the resin hardening in the thickness. The temporal evolution of the last parameter allows an evaluation of the state of the resin at the interface resin/tank wall. These experiments have been achieved for different proportions of the hardener. The velocity and the attenuation increase at first and then stabilize after a time which is as short as the hardener concentration is high. The experiment shows that 10% of the hardener is the optimum value and that 20% of it produces a vitreous transition. The experimental results also show that the acoustical impedance stabilizes after a time longer than the one observed for the velocity and the attenuation. The velocity and the attenuation are significant parameters of the optimum value of the hardener concentration. The acoustical impedance is the significant parameter of the bond quality.