Characterization of corrosion products on iron aluminide coated alloys
EMSL Project ID
9990
Abstract
Iron-rich iron aluminide coatings were deposited via enclosed vacuum evaporation at PNNL on stainless steel type 316, Al-base alloy 6061, and alloy steel AISI 4130. The coatings are intended to improve the corrosion resistance of the alloys in the presence of hot, moist exhaust gases resulting from combustion in heavy duty diesel engines. Recent environmental regulations now require exhaust gas recirculation to reduce harmful emissions from diesel combustion. Unfortunately, the exhaust system components do not currently have the necessary corrosion resistance to last the expected lifetime of the engine. A variety of coatings were produced with varying Al concentrations and thicknesses, deposited at various temperatures to produce a variety of microstructures. The samples were subjected to accelerated corrosion tests by Cummins Engine Company to simulate diesel exhaust environments. The corrosion products on the coated samples will be characterized at EMSL by scanning electron microscopy and energy dispersive x-ray spectroscopy to produce images such as line scans and elemental dot maps. The proposed effort will allow correlation between the coating characteristics and the corrosion performance. Using these data, improved coatings will be developed and tested to confirm the validity of the results. If successful, coatings of these types could ultimately be incorporated in diesel engine exhaust system components such as exhaust gas recirculator heat exchangers, inlet manifolds, or exhaust ducting to increase lifetime and reduce long-term cost.
Project Details
Project type
Exploratory Research
Start Date
2004-07-06
End Date
2006-07-18
Status
Closed
Released Data Link
Team
Principal Investigator