PTSS:
Assuming it's not all BS I assume that they use an ultrasonic spray process (don't know how you came up with HT ovens regarding this method).
Also, considering the conductive nature of the Graphene I would not be surprised if the cone material receives a static charge in order to better/more uniformely attract the conductive Graphene mist.
Such charges are used with metal as well as ceramic plating, and I don't see why it would not apply here as well.
Otherwise, ask the manufacturer,
