COMPOSITE COATINGS FOR ELEVATED TEMPERATURE EROSION-CORROSION PROTECTION IN FOSSIL-FUELED BOILERS

摘要

Fluidized bed combustors components suffer severe erosion, frequently accomplished by corrosive gases attack at elevated temperatures. The tubes damage rate depends on the boiler design, bed constituents and combustion parameters, however an accelerated metal wastage is usually found in the same specific areas of different boilers. New HVOF sprayed coatings are developed for the tubing erosion-corrosion protection, based on Cr_3C_2/ Ni-Cr, Cr-Ti-C/ Ni-Cr-Mo, and Al_2O_3/NiAl composite materials. The Combustion arc Fe-Cr-C coatings were found as an economical solution for relatively low erosion rate zones. The coatings properties and behavior under simulated elevated temperature erosion conditions and in the operating boilers are discussed.