CM88Y superalloy blade metallurgical degradation in a gas turbine

Najmi, M.; Mirbagheri, S.M.H.

doi:10.1016/j.engfailanal.2023.107110

Cited by 6 publications

(1 citation statement)

References 30 publications

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“…Also, one of the most important ways to prevent the destruction of boilers is the correct use and removal of fuel impurities, fuel additives, the chemical improvement of boiler feed water, and choosing the suitable alloy and its proper coating. Austenitic steels and nickel-based superalloys are suitable candidates for increasing the efficiency of heat exchangers at temperatures higher than 700 °C [3,4]. If a suitable coating is used, austenitic steels can be a suitable alternative to nickel-based superalloys, which are expensive [5].…”

Section: Introductionmentioning

confidence: 99%

The effect of aluminide coating on the steam oxidation behavior of SS321 steel at 700 °C

Shirvani,

Taheri,

Hadadipour

et al. 2023

Phys. Scr.

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Steam oxidation is considered the main attack form involved in the destruction of a superheater tubes in the superheater of water-tube boiler. In this work, the effect of an aluminide coating on the way steam reacts with SS321 steel in a superheater was studied. Aluminide coating was done by powder cementation at 800 °C for 7 h and then heat treatment at 900 °C for 1 h. The coating was made with an Al-rich Fe2Al5 phase, with an inner (diffusion) layer of 5 µm and an outer layer of 25 µm. The grains were all the same size, and there were few holes. The samples were subjected to a constant stream of supersaturated water vapor at a temperature of 700 °C. The weight gain of uncoated and coated samples was measured as 1 mg/cm2 and 0.5 mg/cm2 after 20 h, and 2.5 mg/cm2 and 0.7 mg/cm2 after 350 h, respectively. The remarkable weight loss of the coated samples after 20 h and up to 350 h was attributed to the formation of stable Al2O3 oxides. This was although in the uncoated samples, the outer and inner layers of the coating were composed of Fe-rich oxides (magnetite) and Cr-rich oxides (Cr-Fe spinel oxides), respectively. Microstructural studies showed that with the increase in oxidation time, the inner layer (diffusion) increases from 5 µm to 25 µm, which is attributed to the diffusion of substrate particles towards the coating during oxidation.

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Section: Introductionmentioning

confidence: 99%