Protective Coatings for SOFC Metallic Interconnects

Corrosion of nickel and nickel–phosphorous-coated AISI 430 in dry (Ar–3%H2) and humid hydrogen (Ar–3%H2–3%H2O) atmosphere

“…2.54 cm × 2.54 cm × 0.06 cm AISI 430 coupons (MSC Industrial Supply Co. USA) were etched and cleaned. Nickel coating, 4.96 ± 0.28 μm thick, was electrochemically deposited on AISI 430 using sulfamate bath as described in another report [22,23]. Another set of cleaned AISI 430 was coated with Ni-P, 5.24 ± 0.10 μm thick, by a proprietary electroless deposition method (Advanced Technical Finishing, Huntsville, Alabama, USA) in accordance to MIL-C-26074 Class 1.…”

“…Nickel-coated (∼15 μm thick) AISI 441 corrodes in simulated dual atmosphere and forms oxide layer with porosity; metallic elements and gap between hematite and spinel layers in an air side and gap between iron oxide and nickel in a fuel side (H 2 -H 2 O) were observed [19]. Nickel coating is also reported to mitigate chromium evaporation of SOFC interconnects in the air side [20,21] and to improve oxidation resistance in humidified air [22,23]. However, the microstructure of nickel-coated SOFC interconnect, the aim of our study, has not been detailed in humidified hydrogen and/or dual environment although interfacial microstructure plays a crucial role for long-term performance.…”

Corrosion of nickel and nickel–phosphorous-coated AISI 430 in dry (Ar–3%H2) and humid hydrogen (Ar–3%H2–3%H2O) atmosphere

“…2.54 cm × 2.54 cm × 0.06 cm AISI 430 coupons (MSC Industrial Supply Co. USA) were etched and cleaned. Nickel coating, 4.96 ± 0.28 μm thick, was electrochemically deposited on AISI 430 using sulfamate bath as described in another report [22,23]. Another set of cleaned AISI 430 was coated with Ni-P, 5.24 ± 0.10 μm thick, by a proprietary electroless deposition method (Advanced Technical Finishing, Huntsville, Alabama, USA) in accordance to MIL-C-26074 Class 1.…”

“…Nickel-coated (∼15 μm thick) AISI 441 corrodes in simulated dual atmosphere and forms oxide layer with porosity; metallic elements and gap between hematite and spinel layers in an air side and gap between iron oxide and nickel in a fuel side (H 2 -H 2 O) were observed [19]. Nickel coating is also reported to mitigate chromium evaporation of SOFC interconnects in the air side [20,21] and to improve oxidation resistance in humidified air [22,23]. However, the microstructure of nickel-coated SOFC interconnect, the aim of our study, has not been detailed in humidified hydrogen and/or dual environment although interfacial microstructure plays a crucial role for long-term performance.…”

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). , …”