Low-Temperature Slurry Aluminizing: Investigating the Influence of Aluminizing Time on the Corrosion Performance of Aluminide Coating on 304 SS
No Thumbnail Available
Date
2024-12-26
Journal Title
Journal ISSN
Volume Title
Publisher
Published by IOP Science UK,
Abstract
The surface of austenitic stainless steel (304 SS) was modified with aluminium and alumina powders using a slurry aluminizing
route to enhance its lifespan at high temperatures. The substrate was subjected to low heat treatment temperature (680°C) at various
aluminizing times (4, 6, 8, and 10 hours). The corrosion resistance of the aluminide coating was evaluated by exposing them to a
mixture of molten solar salt containing 60 wt.% NaNO3 and 40 wt.% KNO3 at 600°C for 100 hours. The coatings were characterized
using FESEM, EDX, and XRD. Coating thickness, hardness, multi-layered phases, and corrosion products were determined before
and after corrosion. The results indicated that a dense and continuous inner layer made up of FeAl-based intermetallic improved
the corrosion resistance of 304SS. Coating thickness increased with increasing aluminizing time, with a maximum thickness of
75.12 μm observed for samples with 10 hours of aluminizing. The highest coating hardness of 1060 HV was observed on Fe2Al5
of aluminide layer heat treated at 10 hours. The corrosion product found on the aluminide layer was NaAlO2 and the sample heat
treated for 6 hours exhibited the lowest corrosion rate of 0.21 mm/year.
Description
Keywords
Slurry aluminizing, corrosion rate, FeAl-based intermetallic, molten nitrate salt, high-temperature application
Citation
Ambali, I. O., Anasyida, A. S., & Abdullah, T. K.