Chemical bond formed between electrodeposits and substrate at room temperature with a novel in situ electrochemical treatment

Abstract

The interfacial adhesion strength between electrodeposits and substrate is crucial in many applications, such as the thrust chamber of hydrogen-oxygen rocket engines. To achieve excellent adhesion, herein we propose a novel in situ electrochemical treatment that promotes formation of chemical bonds at the electrodeposit/substrate interface. This treatment integrates the electrochemical dissolution, substrate transport between baths and electrodeposition in a continuous homologous-acid system, thereby achieving and maintaining the activated interface. As a result of the Ni electrodeposition on the Cu substrate, Cu-Ni bonds forms between the deposits and the substrate at the nanoscale interface roughness (<200 nm), realizing the ultrahigh adhesive strength of 386 MPa. The detected diffraction peak intensities of Cu–Ni bonds, initial electrodeposition potential, and deposit–substrate adhesive strength show that the smooth interfacial micromorphology and the continuous homologous-acid environment are the keys to the formation of the Cu–Ni bonds. Qualitative models are built to further analyze and understand chemical bond formation during electrodeposition.