Improving anti-oxidation performance of 430 SS by fabricating co-contained spinel coating as solid oxide fuel cells interconnect

Abstract

Purpose The purpose of this study is to improve the performance of AISI 430 stainless steel (430 SS) in increasing its oxidation resistance, suppressing coating spalling and cracking, sustaining appropriate conductivity and blocking Cr evaporation as an interconnect material for intermediate temperature solid oxide fuel cells; a protective co-contained coating is formed onto stainless steel via the surface alloying process and followed by thermal oxidation. Design/methodology/approach In this work, oxidation behavior of coated specimen is studied during isothermal and cyclic oxidation measurements. Moreover, the conductivity is also investigated by area specific resistance (ASR) measurement. Findings Co-contained spinel layer shows an outstanding performance in preventing oxidation and improving conductivity compared with uncoated specimens. The protective spinel coating also reduces the ASR for coated specimen (0.0576O cm2) as compared to the uncoated specimen (1.87296O cm2) after isothermal oxidation. Originality/value The probable mechanism of co-contained alloy converting into spinel and the spinel transfer electron is presented.

Performance of CoMnO Spinel Coating onto 441 SS for SOEC Interconnect Application

“…This is due to the fact that the previous oxide layer produced on the interconnect can inhibit the subsequent redox reaction lowering the growth rate. For all specimens, these specific weight gains rose along the time parabolically, which meets with inferior diffusion-controlled parabolic kinetics expressed via Equation (1) [31,36].…”

“…The ASR measurement for all samples was carried by pseudo-4-probe direct current method with a constant current density of 5000 m Acm −2 in a simulated SOEC O-electrode environment (dynamic flow at 240 mL/min and air/oxygen 3:1), as shown in Figure 2. Two gold meshes as current collectors were placed between specimens and welded with high-temperature silver paste, referring to the previous work [31]. Gold meshes were used to collect current.…”

Impact of Different Atmospheres on Oxidation and Electrical Performance of a Solid Oxide Fuel Cell Interconnect with Co-Containing Protective Coating

“…As a plate-type SOFC stack, an interconnect is an intensely significant multifunctional part that associates units with the stack and supplies the fuel gas and oxidant for the anode and cathode, respectively. − Over the past few decades, the LaCrO 3 -based ceramic materials have been applied at high temperature (about 1000 °C), but the cost of preparation of the ceramic interconnect is higher than that of the metallic interconnect. , As the SOFC working temperature has been decreased from 1000 to 800 °C or even 600 °C, ceramic materials have been replaced by Cr-based metallic alloys. The Cr-based metallic interconnect has been extensively investigated as a potential candidate interconnect because of its inexpensive cost, excellent electronic conductivity, and exceptional thermal conductivity. , Unfortunately, there are still a considerable number of degradation problems in utilizing the Cr-based metal interconnect, including surface oxidation and Cr evaporation at high temperature, and the surface oxidation of the metallic interconnect obviously increases the contact resistance. , In addition, Cr species evaporating from the interconnect are electrochemically deposited to hinder the oxygen reduction reaction, hence shortening cathode behavior (i.e., chromium poisoning). , …”

“…9,10 Unfortunately, there are still a considerable number of degradation problems in utilizing the Cr-based metal interconnect, including surface oxidation and Cr evaporation at high temperature, and the surface oxidation of the metallic interconnect obviously increases the contact resistance. 11,12 In addition, Cr species evaporating from the interconnect are electrochemically deposited to hinder the oxygen reduction reaction, hence shortening cathode behavior (i.e., chromium poisoning). 13,14 To address these obstacles, various protective coatings on the ferritic stainless steel (FSS) interconnects are identified as the most efficacious solutions to slow down the rate of oxidation, enhance the adhesion of the oxide scale-to-metal interconnect, and restrain the evaporation of Cr.…”

Development of Mn-Co and Mn-Co-CeO2 Coatings on Crofer 22 APU Steel for Solid Oxide Fuel Cell Interconnects

“…This scale consists of an outer spinel layer (Mn, Cr) 3 O 4 and an inner layer of Cr 2 O 3 . However, prolonged oxidation can lead to the detrimental phenomenon of chromium evaporation in the cathodic region, causing cell contamination according to the following reaction: [9][10][11]…”