V.A. Yolshina, L.A. Yolshina.
ABSTRACT
The solubility of boron carbide powder in chloride melt was studied at temperatures 793–903 К. It was shown that no carbon films were formed even at prolonged exposure of boron carbide in molten salt, the boron ions В3+ determined by quantity of oxygen adsorbed on the surface of carbide powder.
The formation of carbon as coarse deposits consisting from multilayered grapnene and graphite proceeds on the surface of titanium in currentless regime in the B4C containing melt.
Defect free two-layered graphene films of large area- about 1000 µm2 – obtained by electrochemical synthesis in molten alkali chlorides. Raman spectroscopy used for analysis of purity of carbon phase. The characteristic peaks identified in the obtained spectra make it possible to attribute the studied structure to allotropic modification of carbon in the sp2-hybridized state. The numerical characteristics of well-defined and symmetrical scattering lines of the first and second order make it possible to identify carbon films formed on the surface of a titanium anode as two-layer graphene with a small number of defects.
The morphology of the resulting graphene film can be carefully controlled using the parameters of the deposition process: synthesis temperature, boron carbide additive concentration and applied anode current density. The process is well reproducible, has a rather low synthesis temperature – up to 973 K, does not require the use of expensive reagents, proceeds in one stage.
KEY WORDS:
graphene, molten salts, anodic polarization, boron carbide, titanium.
DOI: 10.31857/S0235010620060043