Abstract: Cr-doped diamond-like amorphous carbon, possessing good electrical conductivity and corrosion resistance, are especially important for bipolar plates coating for fuel cells. The present work addresses its amorphous structure using the cluster-plus-glue-atom model, where a good glass forming materials described by a structural unit covering a characteristic nearest-neighbor cluster plus a few next-shell glue atoms. According to the literature, the prevailing cluster in Cr-doped diamond-like amorphous carbon is Cr-centered and C-shelled [Cr-C4] tetrahedral cluster. Then, this cluster is matched with appropriate glue atoms to satisfy the electron orbital saturation principle. Two composition formulas are thus proposed, [Cr-C4]CrC3(22.2at.%Cr) and [Cr-C4]Cr3C2(40 at.%Cr) that show good amorphous structural stabilities. It is pointed out that the coatings of the proposed chemical compositions show simultaneously low electrical resistivity (down to 10-4 Ω×cm) and superior corrosion resistance (corrosion current density ~10-2 μA/cm2). The synergetic electrical and corrosion behavior is discussed within the framework of sp2 bond content and of the percolation theory. This work verifies the feasibility of the cluster-plus- glue-atom model in composition design of coatings with high corrosion resistance and electrical conductivity.    

DOI：10.16490/j.cnki.issn.1001-3660.2020.05.001