Development of FeAl Coatings by a Combined Aluminizing Process to Improve the Dry Sliding Wear Resistance of HH309 Alloy

• Published in: Journal of materials engineering and performance 2022-09, Vol.31 (9), p.7337-7352
• Main Authors: Zarei, Farhad, Nuranian, Hossein, Shirvani, Kourosh
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Materials Science; Quality Control; Reliability; Safety and Risk; Technical Article; Tribology
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-022-06744-1

In the present study, cast-aluminizing (CA) and subsequent diffusion annealing processes were exploited to develop simple and Si-modified aluminide coatings on HH309 stainless steel. The CA method involved casting of HH309 melt into a mold, and Al-alloy sheets (pure Al and Al-12wt.%Si) were already inserted at the bottom of the mold. Afterward, the CA samples were diffusion-annealed at 1050 °C for 1 h and 1000 °C for 4h during two stages of heat treatment. The morphology, composition, and phase analysis of the coating were characterized by FE-SEM, EDS, and XRD. The results indicated that a multilayer aluminide coating containing (FeCrNi) 2 Al 5 + (FeCrNi)Al 2 and (FeCrNi)Al sub-layers was formed on the samples in the first stage heat treatment, while an integrated (FeCrNi)Al layer replaced the primary multilayer coating after the second stage. Then, the wear resistance of the coatings was evaluated. It was found that the applied aluminizing technique improved the wear resistance of HH309 alloy, significantly. The wear rate values for uncoated steel, aluminide, and Si-modified aluminide coatings were about 4.48 × 10 −7 , 1.44 × 10 −7 , and 0.74 × 10 −7 mm 3 /N mm, respectively. Wear mechanisms analysis demonstrated that the type of wear for HH309 alloy was abrasive and adhesive and for aluminized steel was dominated by fatigue wear. Chemical composition analysis of the worn aluminide coatings showed that the aluminized samples also suffer oxidation wear.