Recent Development of SOFC Metallic Interconnect

Highly Dense Mn-Co Spinel Coating for Protection of Metallic Interconnect of Solid Oxide Fuel Cells

“…However, the ASR value for the sample with the porous coating increased at a substantially higher rate during operations, and reached 0.0081 Ohm cm 2 after 500 hours while the ASR value for the sample with the dense coating was 0.0037 Ohm cm 2 after the same duration of time under the same conditions. In general, the metallic SOFC interconnects with the state-of-the-art protective coating show the ASR values of 5∼10 mOhm cm 2 after 500∼1000 hours of operation, 9,18 and the ASR results in Figure 6 indicate that the spinel coating presented in this paper is promising. The spikes of the ASR values, which occurred in the uncoated sample after ∼120 hours of operation, were not observed for both samples up to 500 hours, indicating that the interfaces remained stable and free of structural damage.…”

“…The ASR value of the uncoated sample was initially 0.0016 Ohm cm 2 and reached 0.017 Ohm cm 2 after 500 hours. During the SOFC operation, growth of the chromia inner scale on Crofer 22 APU, whose thickness could reach several micrometers on the cathode side, is mainly responsible for the increase of ohmic ASR of the stack, 9 and the rapid increase of ASR in the uncoated sample in Figure 6 corresponds to the fast degradation of stack performance. In addition, the formation of interfacial defects, such as voids, cavities and spallation, is also an important factor that influences the stability of the SOFC stacks.…”

“…4,8,9 These metallic interconnect materials offer many advantages over their ceramic counterparts, such as high electric and thermal conductivities, low cost, ease of manufacturing and good workability. 10 Among various candidate materials, chromia-forming ferritic alloys are considered to be promising because the chromia scale on the surface exhibits relatively high electrical conductivity and low growth rate.…”

“…9,[14][15][16] To overcome the inherent weaknesses of the chromia-forming ferritic alloys upon exposure to high temperatures, significant research efforts have been devoted to developing the protective coating techniques. 9,17,18 The key requirements for a protective coating include dense structure, high electronic conductivity, thermal, mechanical and chemical compatibility with the adjacent components and low diffusion coefficients of Cr and O.…”

“…9,[14][15][16] To overcome the inherent weaknesses of the chromia-forming ferritic alloys upon exposure to high temperatures, significant research efforts have been devoted to developing the protective coating techniques. 9,17,18 The key requirements for a protective coating include dense structure, high electronic conductivity, thermal, mechanical and chemical compatibility with the adjacent components and low diffusion coefficients of Cr and O. Among coating mate-rials, such as reactive element oxides, 11,[19][20][21][22][23][24] 72,73 Although the feasibility of these techniques has been substantiated, individual processes exhibit their characteristic drawbacks along with their advantages.…”