Effect of aluminizing of Cr-containing ferritic alloys on the seal strength of a novel high-temperature solid oxide fuel cell sealing glass

Compliant alkali silicate sealing glass for solid oxide fuel cell applications: The effect of protective alumina coating on electrical stability in dual environment

“…4). Without aluminization, a dense and continuous Cr 2 O 3 layer of 1e2 mm will form after the same heat treatment, with an outer thin discrete layer of (Mn,Cr) 3 O 4 , often in the form of fine crystals as reported for Crofer22APU with very similar composition as AISI441 [9,32]. The microstructure analysis clearly indicated that the aluminization process did block the Cr diffusion from forming a dense Cr-oxide layer.…”

“…The metals were tested either in the asreceived state or coated with Al 2 O 3 . For SOFC application, the ferritic stainless steel AISI441 requires a protective coating to block the Cr diffusion, which can cause cathode poisoning and seal degradation by forming chromates with very high CTEs if sealing glass contains alkaline earths (e.g., Ba and Sr) [9,19,32]. In this study we have adopted a novel reactive air aluminizing coating process involving ultrasonic spraying of AISI441 substrates with a mixture of Al powders in a binder solution, followed by drying and oxidizing at 1000 C for 1 h in air [33].…”

Viscous Glass Sealants for SOFC Applications

“…3.4 and 3.5. [36]. Figure 3.5 shows that the alumina coating, though not highly uniform across the stainless steel surface, remains intact and does not react with the glass.…”

“…The Al-SS was designed to prevent diffusion of Cr from the stainless steel chromium-containing compounds from interacting with sealing glass and the evaporation of the volatile Cr phases [36]. After the 1000h thermal treatment in air and humidified hydrogen, the partially crystallized sealants were analyzed using XRD.…”

Evaluation of the Parabolic Rate Constant During Different Types of Oxidation Tests for Spinel Coated Fe–17%Cr Alloy

“…Numerous techniques have been developed to apply coatings to ferritic stainless steels. These include slurry coatings [6][7][8][9], anodic electrodeposition [10], cathodic electrodeposition of particular metals or alloys, followed by annealing/oxidation in air and pack cementation [11][12][13][14]. The latter method has been attracting attention, due to its low costs, its ease of fabrication, the good adhesion between the deposited coating and substrate, and its extensive application.…”