Optimization of the surface properties of nanostructured Ni–W alloys on steel by a mixed silane layer

Abstract

Ni–W nanostructured coatings electrodeposited on steel by galvanostatic pulses were functionalized by tetraethoxysilane (TEOS) and octadecyltrichlorosilane (OTS) in a two-step procedure. A silica-rich layer is formed by the reaction of TEOS with the metal coating surface oxides, which allows a further reaction with OTS forming a hydrocarbon–silica outer network. This mixed silane layer provides hydrophobicity and improves the corrosion behavior of the Ni–W surface coatings without modifying their excellent mechanical properties.