Preparation of super-hydrophobic micro-needle CuO surface as a barrier against marine atmospheric corrosion

A super-hydrophobic (SH) CuO surface was prepared on copper using chemical etching followed by fluorination treatment. The relationship between surface morphology and hydrophobicity was investigated. When the etching time varied from 5 to 120 min, morphology changed from sparse sharp needles to dense sharp needles, and then to a stamen-like structure with flower-like clusters. All these surfaces were SH with the dense micro-needle surface (10 min etching) the best. This SH surface made salt (NaCl) particles deliquesce and roll away. Electrochemical tests showed that it reduced corrosion in a 3.5% (w/w) NaCl solution by more than 102 times.