Corrosion protection by plasma-polymerized coatings

A large volume microwave plasma generator was used for producing thin plasma-polymerized (PP) films as corrosion protection on metal substrates. Through the control of plasma polymerization variables (“monomer” vapour, pressure, power density and substrate temperature), strongly adhering, pinhole-free and highly cross-linked coatings can be deposited on metal surfaces. Numerous monomer-metal combinations were tested and PP films were found to outperform “conventional” polymeric coatings in various corrosive media. Organosilicone films appear to hold particular promise as they have excellent mechanical properties and are stable up to high (>800°C) temperatures. Carbon steel substrates with coatings 2 μ thick were found to withstand a simulated marine environment for periods of several weeks with no trace of corrosion.