Oxidation Performance Coating for Future Supercritical Power Plants

Abstract

For improved efficiency and reduced emissions, the future power plants need to operate at high temperatures and pressures, which however are limited by the durability of conventional materials such as ferritic steels. Steam oxidation of a number of coatings (Al slurries, thermal spraying, chemical vapor deposition siliconizing, and nickel plating) has demonstrated the feasibility of coatings to improve oxidation resistance. Al slurry coatings combine good hightemperature oxidation resistance through the growth of an Al2O3 layer and the possibility to apply the coating on an industrial scale at moderate cost. This work aimed to test the oxidation performance of coatings and reference alloys in ultrasupercritical (USC) water. The tested materials included Al slurry coating on ferritic 9%Cr steel and nickelbased A263 substrates, and bulk P92, MARBN, and A263 alloys as reference specimens. Oxidation resistance was tested by exposure to flowing supercritical water (SCW) with 125آ ppb dissolved oxygen at 650آ°C (1202آ°F)/25  MPa (3625آ psi) up to 1000آ hr.