Effect of Si addition to improve the performance of type II and type I hot corrosion resistance of aluminide coating. (March 2023)

• Record Type: Journal Article
• Authors: Yu, Haojun; Fan, Qixiang; Li, Jiayingnan; Ma, Dezheng; Gong, Jun; Sun, Chao
• Is Part Of: Corrosion science. Volume 212(2023)
• Publication Date: 2023-03
• Subjects: Superalloy -- Si-modified aluminide coating -- Microstructure -- Hot corrosion; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110937
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: Microstructure and hot corrosion resistance of four aluminide coatings with different Si contents ranging from 0 at % to 30 at% are studied. Si primarily exists as CrSi2 and (Cr, Ti)5 Si3 in the upper zone of Si-modified aluminide coatings; CrSi2 transforms into Cr3 Si phase during corrosion process. These silicides hinder the inward diffusion of the corrosive elements, resulting in enhanced corrosion resistance of Si-modified aluminide coatings at 700 °C. Mechanisms of severe corrosion in coatings with Si at 900 °C was disclosed; high content of Si leads to insufficient Al to renovate Al2 O3 scale, as well as high temperature causes fast depletion of Al. Highlights: Si modified aluminide coatings with various Si contents were prepared. Lamellar CrSi2 and (Cr, Ti)5 Si3 phases are formed in the upper zone of the coatings. Addition of Si increases corrosion resistance of the aluminide coating at 700 °C. For the lamellar silicide hinder the inward diffusion of corrosive elements. Si decreases corrosion resistance at 900 °C for lowering Al content in the coating.