Corrosion Resistance of Nano¬structured TiB₂ Films in 3% NaCl Solution

Abstract

The corrosion behavior of TiB₂ amorphous films 70–250 nm thick and amorphous-crystalline films with crystals 15–90 nm in size in 3% NaCI solution is studied. It is shown that the corrosion resistance and passivation anodic potential increase with greater thickness of TiB₂ amorphous films. It is also established that TiB₂ films are oxidized through pitting corrosion. The corrosion instability of amorphous films is mainly due to their interaction with impurity (in particular, oxygen and carbon) structural inhomogeneities and of amorphous-crystalline films due to the interaction with amorphous-crystalline boundaries. The corrosion resistance of TiB₂ amorphous films is approximately 4000 times higher than that of massive powder material and 8 to 10 times higher than that of amorphous-crystalline films.