Fuel cell interconnect with reduced voltage degradation and manufacturing method

A method of forming an interconnect for a solid oxide fuel cell stack, the method comprising:

• filling a die cavity with an interconnect powder comprising a chromium alloy;
• compressing the interconnect powder to form an interconnect comprising ribs configured to form fuel channels on a first side of the interconnect;
• disposing iron on tips of the ribs after compressing the interconnect powder;
• and
• sintering the interconnect after disposing the iron on tips of the ribs without further compressing, such that the iron forms a contact layer on the tips of the ribs.

A method of forming an interconnect for a solid oxide fuel cell stack, the method comprising:

• contacting an interconnect powder located in a die cavity with iron, the interconnect powder comprising chromium and iron;
• compressing the interconnect powder to form an interconnect comprising ribs and fuel channels on a first side of the interconnect, such that the iron is disposed on tips of the ribs;
• and
• sintering the interconnect, such that the iron forms a contact layer on the tips of the ribs having a higher iron concentration than a remainder of the interconnect,
• wherein the contacting comprises:
• filling the die cavity with the interconnect powder;
• and
• disposing the iron on portions of the interconnect powder, and
• wherein the iron comprises iron wire having a thickness ranging from about 20 μm to about 200 μm.

A method of forming an interconnect for a solid oxide fuel cell stack, the method comprising:

• contacting an interconnect powder located in a die cavity with iron, the interconnect powder comprising chromium and iron;
• compressing the interconnect powder to form an interconnect comprising ribs and fuel channels on a first side of the interconnect, such that the iron is disposed on tips of the ribs;
• and
• sintering the interconnect, such that the iron forms a contact layer on the tips of the ribs having a higher iron concentration than a remainder of the interconnect,
• wherein the contacting comprises:
• filling the die cavity with the interconnect powder;
• and
• disposing the iron on portions of the interconnect powder, and
• wherein the disposing comprises disposing the iron wire in recesses formed between ribs of an upper punch, and then bringing the upper punch into contact with the interconnect powder.

A method of forming an interconnect for a solid oxide fuel cell stack, the method comprising:

• contacting an interconnect powder located in a die cavity with iron, the interconnect powder comprising chromium and iron;
• compressing the interconnect powder to form an interconnect comprising ribs and fuel channels on a first side of the interconnect, such that the iron is disposed on tips of the ribs;
• and
• sintering the interconnect, such that the iron forms a contact layer on the tips of the ribs having a higher iron concentration than a remainder of the interconnect,
• wherein the contacting comprises:
• filling the die cavity with the interconnect powder;
• and
• disposing the iron on portions of the interconnect powder,
• wherein the iron comprises an iron powder having an average particle size ranging from about 30 μm to about 300 μm, and
• wherein the contacting comprises disposing the iron powder in recesses formed between ribs of an upper punch, and then bringing the upper punch into contact with the interconnect powder.

A method of forming an interconnect for a solid oxide fuel cell stack, the method comprising:

• contacting an interconnect powder located in a die cavity with iron, the interconnect powder comprising chromium and iron;
• compressing the interconnect powder to form an interconnect comprising ribs and fuel channels on a first side of the interconnect, such that the iron is disposed on tips of the ribs;
• sintering the interconnect, such that the iron forms a contact layer on the tips of the ribs having a higher iron concentration than a remainder of the interconnect;
• forming a protective coating on a second side of the interconnect;
• and
• forming a cathode contact layer on the protective coating, the cathode contact layer comprising an electrically conductive metal oxide material and from about 4 wt % to about 10 wt % of a glass material, based on the total weight of the cathode contact layer.