In general, such deposits are obtained at pressures of <
in the temperature region
on metals such as iron, cobalt or nickel. Typical filaments consist of a duplex structure, a relatively oxidation
-resistant skin surrounding a more easily oxidizable core, with a metal particle located at the growing end of the filament. They generally range from
in diameter and up to
in length. In some systems, the metal particles are located in the middle of the filaments, and there are also examples where several filaments originate from a single particle. The filaments may be produced in different conformations, such as helical, twisted and straight.