Nitridation of a Super-Ferritic Stainless Steel for PEMFC Bipolar Plate

Journal Article · Mon Jan 01 00:00:00 EST 2007 · ECS Transactions

DOI:https://doi.org/10.1149/1.2781059· OSTI ID:939524

Wang, H; Turner, J A; Brady, M P

AL29-4C alloy nitrided in pure nitrogen resulted in a nitrogen-modified oxide surface, which is the same as AISI446 nitrided under identical conditions. When the alloy was nitrided 24h at 900 C in N2-4H2, XRD and XPS analysis indicated that the surface layer consisted of a nitride outer layer ({approx}0.20 {micro}m) and an oxide inner layer ({approx} 0.82 {micro}m). According to XPS, the nitride outer layer is composed of CrN and [Cr(N),Fe]2N1-x, with much more Cr2N than Fe2N. Mn is migrated and enriched in the oxide inner layer and combined with chromium oxide.AL29-4C alloy nitrided in N2-4H2 resulted in low ICR and excellent corrosion resistance in simulated PEMFC environments. Current was at ca. -3.0 {micro}A/cm2 in the PEMFC anode environment, and at ca. 0.3 {approx} 0.5 {micro}A/cm2 in the cathode environment. This is considered to be rather stable. After being polarized in a PEMFC environment, the ICR increased slightly compared with the as-nitrided sample, but was still rather low.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC36-99-GO10337
• OSTI ID: 939524
• Journal Information: ECS Transactions, Vol. 11, Issue 1, 2007
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALLOYS
ANODES
CATHODES
CHROMIUM
CORROSION RESISTANCE
NITRIDATION
NITRIDES
NITROGEN
OXIDES
PLATES
STAINLESS STEELS
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY
Hydrogen Technologies and Systems