Bonding strength of a carbon nanofiber array to its substrate

The bonding strength of a carbon nanofiber array (CNFA) grown on a copper substrate is evaluated based on the measured shearing force-at-failure and the developed analytical stress model that enables one to determine the magnitude and the distribution of the interfacial shearing stress causing the measured (given) shearing force. The experiment is conducted using specially designed test specimens. A table version of the Instron tester is used to measure the applied force and the corresponding displacement in shear. The maximum predicted shear-off stress is about 300 psi (0.211 kgf/m²), and was determined, based on the developed stress model, as a product of the measured 5 kgf/m force at the interface failure and the computed parameter k = 0.0422 m^–1 of the interfacial shearing stress.