New oxidation-resistant coatings for steam power plants at 650 °C

Abstract

The increase of live steam temperature and pressure in new steam power plants is certainly the most effective measure to realize the stipulated CO 2 reduction targets for the conventional power industry. The development of new materials becomes a key challenge on the way forward to a more efficient and sustainable power generation. There are two approaches being followed in materials technology in order to facilitate higher steam temperatures and pressures in the water steam cycle: 1.) The development of new materials. 2.) The use of oxidation resistant coatings on currently available materials with higher creep strength but inferior steam oxidation resistance. Both approaches are currently being followed in several R&D projects worldwide. The development and qualification of coatings is complementary to the development of new materials.The object of the EC funded R&D project SUPERCOAT is the development of new coatings according to the second approach. Eight partners from five European countries participate in the work. SUPERCOAT is the first R&D project of its kind in Europe. This presentation covers the project targets, the efforts carried out while exploring the suitability of coatings for steam turbine components and the actual state of the work. As far as possible, an excerpt from the main results of coating development and lab testing will be presented. Additionally the applied deposition techniques, chosen according to practical criteria will be presented and applicability to certain components will be discussed.

Effect of Total Pressure and Furnace Tube Material on the Oxidation of T22 in Humidified Air

“…Other studies at elevated pressure have been performed on SiC [29,30]. In some of the mentioned work, an increase in oxide scale growth at elevated pressure was found [17,24,27,28], while other studies found similar or enhanced oxide scale growth at atmospheric pressure [23,25,26]. A possible explanation for enhanced scale growth at elevated pressure is an increase of diffusion rates in the oxide and alloy [24,28,31].…”

“…Studies at elevated pressure showed changes in the high temperature corrosion behavior, as reported e.g., for dry air [16], supercritical CO 2 [17][18][19][20][21] or carburizing atmospheres [14,22]. Corrosion issues in steam turbines have initiated research on water vapor-induced oxidation at elevated pressure in static or flowing pure steam [17,[23][24][25][26][27][28]. In these studies, Fe-and Ni-base alloys were tested.…”

Identification of degradation mechanisms in coatings for supercritical steam applications

“…Details of the standard procedure are given in Table 3. This paper concentrates on the results of steam oxidation testing for 1000 h; results for longer testing times have been presented elsewhere 9–13.…”

Requirement for and Use of Coated P92 Steel for Enhanced Structural Integrity at High Temperature

“…Therefore oxidation resistant coatings [7], which form a stable and slow growing oxide as a barrier to oxidation [8], are now being considered when applied to P92. Aluminide diusion coatings have traditionally been the focus of coated P92 research.…”