Indentation-Debonding Test for Adhered Thin Polymer Layers
The indentation-debonding test is basically a nondestructive test for checking the adherence of thin polymer films to hard substrates (such as epoxy film adhered to copper). A small pointed indenter is pressed to the surface in the normal direction. The tensile stresses arising in the bond outside the contact area may exceed the limiting value and debonding would then take place. Observation of this phenomenon is often facilitated by the appearance of Newton’s rings created by the diffraction of light passed through and reflected from the debonded film. Mechanical analysis of the deforming polymer film is based on the computation of displacements of a thin plate segment confined between the rim of the indentation and the edge of the debonded area. It is experimentally found that the radial bending strain in the film limits the adherence, i.e., determines the onset of “peeling”. Cases of pure interfacial debonding have been treated, and experimental data are described, for a wide variation of parameters.
KeywordsPolymer Film Cone Angle Thin Polymer Film Peel Test Knoop Hardness
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