Corrosion resistant barrier layer for a solid oxide fuel cell stack and method of making thereof
View Patent ↗A method of forming diffusion barrier layer includes providing an interconnect for a fuel cell stack, forming a glass barrier precursor layer over a Mn and/or Co containing electrically conductive contact layer on the interconnect, and heating the barrier precursor layer to precipitate crystals in the barrier precursor layer to convert the barrier precursor layer to a glass ceramic barrier layer.
1. An interconnect for a fuel cell stack, comprising
an interconnect body having an air surface having air flow channels and ribs and a fuel surface having fuel flow channels and ribs;
an electrically conductive contact layer located on the air surface of the interconnect, the electrically conductive contact layer containing at least one of Co and Mn; and
a first layer located over the electrically conductive contact layer, the first layer comprising:
45-55 wt. % silica (SiO 2 );
5-10 wt. % potassium oxide (K 2 O);
2-5 wt. % calcium oxide (CaO);
2-5 wt. % barium oxide (BaO);
0-1 wt. % boron trioxide (B 2 O 3 );
15-25 wt. % alumina (Al 2 O 3 ); and
20-30 wt. % zirconia (ZrO 2 ) on an oxide weight basis.
2. The interconnect of claim 1 , wherein the first layer comprises a glass barrier precursor layer.
3. The interconnect of claim 1 , wherein the first layer comprises a glass ceramic barrier layer.
4. The interconnect of claim 3 , further comprising a glass or glass ceramic seal located over the first layer.
5. The interconnect of claim 4 , wherein:
the glass ceramic barrier layer comprises zirconium silicate (ZrSiO4) crystals, barium aluminum silicate (BaAlSiO4) crystals and potassium feldspar (KAlSi3O8) crystals located in a glassy matrix;
the glass or glass ceramic seal comprises a ring seal located over the glass ceramic barrier layer in at least one fuel riser region around a fuel riser opening through the interconnect;
the electrically conductive contact layer comprises lanthanum strontium manganite (LSM), manganese cobalt oxide spinel (MCO) or a mixture thereof; the interconnect comprises a chromium-iron alloy interconnect; and the glass ceramic barrier layer prevents or reduces at least one of Mn and Co diffusion from the electrically conductive contact layer to the seal.