Modification of the ultrasonic properties of elastomers loaded with magnetic particles by applying magnetic fields during curing

Particle loaded polymers and elastomers have been largely used in different ultrasonic applications like backing materials and matching layers because composite properties (velocity, attenuation, density and impedance) can be easily engineered by changing the filler concentration. Recently, the use of magnetic particles has been theoretically proposed as a means to produce active matching layers whose response can be modified upon the application of magnetic fields. In this paper, we propose to introduce modifications of the composite properties by using magnetic particles and applying magnetic fields during curing to establish well defined patterns in the spatial distribution of the particles within the elastomer that induce material anisotropy that effectively modify ultrasonic properties.