Nickel oxide scale microstructure and accelerated growth in combustion flue gas: Effect of ash particles

Model Ni-25Cr and Ni-25Cr-2Mn-1Si (wt%) alloys coated with an industrial fly ash were exposed to a wet CO2 gas at 750 °C. It was found that the outer thermally-grown NiO scale encapsulated ash particles at an accelerated rate. TEM combined with TKD analysis revealed that nano structured NiO grains on the ash surface contributed to the observed NiO encapsulating effect.