A long-term corrosion barrier with an insulating boron nitride monolayer

Abstract

Insulating hexagonal boron nitride suppresses the electrochemical corrosion and provides a more effective long-term corrosion barrier than graphene.

Real-time oxide evolution of copper protected by graphene and boron nitride barriers

“…3, bottom panel. The hBN-coated sample showed a detectable increase for the Cu(OH) 2 signal after 40 hours; however, the intensity was insignificant in comparison with the other samples, which is strong evidence that hBN is a superior oxygen barrier compared with graphene on the timescale of several hours11. In agreement with the Raman data, the combination of XPS and XAES results after the isothermal experiments revealed the Cu 2 O as main oxide component at the surface for both bare and graphene-coated copper.…”

“…S9 Supplementary Information), a sudden increase in the oxide formation is not observed. We ascribe this phenomenon to the absence of a galvanic corrosion component in the case of the electrically insulating hBN911, although also other factors may contribute.…”

“…Figure 1 shows the time evolution of the intensities of the Raman signal for CuO (at 500 cm −1  311) and Cu 2 O (at 640 cm −1  3112425), Cu(OH) 2 (at 800 cm −1  324). In the case of the bare copper sample, both Cu 2 O and, to a smaller extent, Cu(OH) 2 start forming at around 100 °C (that is, after 10 minutes from the beginning of the experiment; Fig.…”

“…It is well known for graphene that grain boundaries, wrinkles and rips have enhanced reactivity and therefore are the points where corrosion and oxidation starts2430; we therefore propose to extend this notion to hBN31. Therefore, since the activation barrier for oxygen diffusion through hBN and graphene is similar11, it is reasonable to assume that the larger density of defects for the hBN coating will induce a faster oxidation of the copper underneath. This is a typical scenario: it is currently much easier to grow high quality graphene than high quality hBN by CVD on copper, as demonstrated by the synthesis of single-crystal graphene of millimetre- or centimetre-size32333435, whereas single-crystal hBN size is still limited to tens of micrometres1819.…”

“…Hexagonal boron nitride (hBN) has recently been proposed as an alternative91011. In addition to having mechanical and impermeable properties comparable to graphene1213, hBN is an insulator14 and does not induce galvanic corrosion when in contact with metals911.…”