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Nonlinear Acoustic Detection Method for the Dispersion of Nanocomposite Dielectrics

Nanocomposite dielectrics have attracted more and more attention in the field of insulation due to their good mechanical and electrical properties. The dispersion of nano fillers in dielectrics has a great influence on the properties of materials. However, the detection of dispersion mainly depends on scanning electron microscopy, which has a narrow detection field and damages the samples. There is no non-destructive testing method that can measure it quickly and quantitatively. Based on the principle of nonlinear acoustics, this paper theoretically analyzes the mechanical relationship between uniform dispersion and agglomeration of nanoparticles, and preliminarily reveals the nonlinear source of agglomeration. Then the test samples with different dispersion degree were prepared, and the dispersion of the samples was characterized by scanning electron microscopy. Finally, the relationship between nonlinear coefficient and nanoparticle dispersion was explored by nonlinear ultrasonic testing. The experimental results provide a new idea for the evaluation of nanoparticle dispersion by nonlinear acoustic method.