Multilayer Regulation of Atomic Boron Nitride Films to Improve Oxidation and Corrosion Resistance of Cu.

Boron nitride (BN) monolayer (1L) with high impermeability and resistivity seems to hold promise as a long-term corrosion barrier for Cu at ambient condition, which is supported by recent researches. Here we perform a complete study of the alternating temperature tests (the sample is exposed in air for 30 days and subsequently heated at 200 ? for 2 h) and electrochemical measurements on 1L and multilayers BN coated Cu foils. Results imply that the BN coated Cu foils are less oxidized than uncoated Cu foil after alternating temperature tests, regardless of the layers of BN. Particularly, the oxidation process proceeds slowly in multilayer since most of underlying defects are covered with BN layers to suppress the oxygen diffusion in the vertical direction and the oxidation mainly occurs on the wrinkles region of BN films. The electrochemical analyses reveal that the BN layers provide effective physical barrier against corrosive medium, and inhibit the electron diffusion because of its high electrical insulativity. And the corrosion resistance of the samples increases with increasing BN layers. These findings indicate that BN films with adequate layers are good candidate for oxidation and corrosion protection in atomically level, which is vital to many industrial and academic applications.