Thermally Sprayed Coatings For Supercritical Steam Power Plants: High Temperature And Fireside Corrosion Behavior

During the last years several improvements have been implemented to increase the efficiency of steam power plants. Nowadays, the new “oxy-fuel combustion” concept, for the reduction of the CO₂emission and for achieving even higher efficiency, is under investigation.

The materials normally employed in steam power plants are no more capable to withstand those new severe atmospheres, made more critical by the higher process temperatures. As a consequence, the development of materials and coatings suitable for oxy-fuel conditions became one of the most important challenges.

In the present work, carried out under the EC funded project POEMA, Al₂O₃, ZrO₂ and M-CrAlY coatings have been deposited by High-Velocity-Oxygen-Fuel and Air-Plasma-Spray onto P92 and HR3C steel substrates. Different deposition conditions have been investigated. The high-temperature behavior of those systems was evaluated by means of isothermal and cyclic-oxidation tests, whereas the fireside corrosion resistance was determined under new defined steam and oxy-combustion conditions.