Metals are widely
used, from daily life to modern industry. Great
efforts have been made to protect the metals with various coatings.
However, the well-known conventional electrochemical corrosion induced
by cations and the ubiquitous nature of the coffee-ring effect make
these processes very difficult. Here, a scheme by two bridges of cations
and ethylenediamine (EDA) is proposed to overcome the coffee-ring
effect and electrochemical corrosion and experimentally achieve uniform,
anticorrosive, and antiabrasive coatings on metallic surfaces. Anticorrosive
capability reaches about 26 times higher than that without cation-controlled
coatings at 12 h in extremely acidic, high-temperature, and high-humidity
conditions and still enhances to 2.7 times over a week. Antiabrasive
capability also reaches 2.5 times. Theoretical calculations show that
the suspended materials are uniformly adsorbed on the surface mediated
by complexed cations through strong cation–metal and cation−π
interactions. Notably, the well-known conventional electrochemical
corrosion induced by cations is avoided by EDA to control cations
solubility in different coating processes. These findings provide
a new efficient, cost-effective, facile, and scalable method to fabricate
protective coatings on metallic materials and a methodology to study
metallic nanostructures in solutions, benefitting practical applications
including coatings, printing, dyeing, electrochemical protection,
and biosensors.