The determining influence of the perimeter of graphene islands on phase equilibria in graphene–metal system containing dissolved carbon

It was found that an insignificant increase of the concentration of carbon atoms in the volume of metal ($\sim$2–3%) leads to a significant increase (by 3–4 times) of the total equilibrium relative area of the graphene islands on the metal’s surface. This effect is observed at high temperatures of 1800–1900 K at diffusive equilibrium between the volume and surface of a sample. This effect is related to the determining role of the perimeter of 2D graphene islands that determines the equilibrium interphase flows of carbon. Islands characterized by a drastically different area but similar total perimeters formed due to coalescence can be found on the surface. This factor also explains the temperature hysteresis of thermodynamic equilibrium processes observed in metal–graphene islands' processes.