Caratterizzazione a Ossidazione e Corrosione di Ricoprimenti Applicati per VPS

The useful operating life of superalloys components operating in gas turbines is dependent to a large extent on the ability of applied furface coatings to resist corrosive degradation. Coatings have been fine-tuned over many years of use to give satisfactory performance in airborne applications, but the recent adoption of gas turbines in the utility sector has placed renewed demand on the need to evaluate and develop existing and new coating systems. This paper describes the behaviour of a series of vacuum plasma sprayed MCrAlY (Si) and AL/Si coatings applied to the Ni-base IN738 and UD520 and Co-base FSX-414 and X45 superalloys. Test specimens have been exposed to both simple argon-O2SO2 gas mixtures and to simulated combustion gas mixtures in a low-velocity burner rig for times up to 1000 hours in the temperature range 800 to 1000 C. The results obtained in the form of microstructural changes suggestan upper temperature limit below 900 C for the application of high Al and Si-containing coatings due to interdiffusion with the base alloy and a strong influence of combustion gas composition on corrosion rate.

LANZA Franco;  BAXTER David; 

1996-05-15

JRC13108

https://publications.jrc.ec.europa.eu/repository/handle/JRC13108,