High Temperature Corrosion Resistance of Coextruded and Weld Overlay Coatings Under Low NOx Combustion Conditions

High Temperature Corrosion Resistance of Coextruded and Weld Overlay Coatings Under Low NOx Combustion Conditions

J.N. DuPont1, W. Van Geertruyden2, T.Caizza3, and T. Esposito3 

1. Lehigh University, Bethlehem, PA
2. EMV Technologies, Bethlehem, PA
3. Plymouth Engineered Shapes, Hopkinsville, KY
The corrosion behavior of a Alloy 600 and 622 coextruded coatings was evaluated using thermogravimetric techniques under simulated low NOx combustions conditions. The corrosion behavior of the coextruded coatings was compared to that of counterpart weld overlays and wrought material. The results demonstrate that the coextruded coating provides corrosion resistance that is comparable to the wrought alloy and significantly better than the weld overlay coating. The improved corrosion resistance is attributed to elimination of dilution and microsegregation in the coextruded coating. Additional benefits of the coextruded coating in terms of service performance are also likely, and include better control over coating thickness/surface finish and reduced residual stresses.