Alman, D. E.

Jablonski, P. D.

UNT Digital Library

National Energy Technology LaboratorySOFC Interconnect Work at NETLPaul Jablonski and David E. AlmanNational Energy Technology LaboratoryOffice of Fossil EnergyRE Surface Treatment Results• Oxidation resistance of Crofer improved by 3x (800C/3% water/4,000h)− Appears to minimize internal silica layer formation• Improved ASR (800C/500h)− Button cell tests underway• Oxidation resistance of type 430 vastly improved− Eliminated spall (800C/3% water/4,000h)• Effectively makes 12 Cr alloys perform as 22 CrImproving Oxidation Resistance with Rare Earths• Well established that small amounts RE improve oxidation resistance (RE:  Ce, La, Y)• Melt addition+Elements added during ingot production (single manufacturing step)−Difficulty in melting (react with crucibles)−Surface concentration limited by solubility and diffusivity• Surface treatments+Rare Earth concentrated where needed (at surface and have most benefit)− “Extra” manufacturing step.? Long term effectiveness (as with any coating or surface treatment)Research Goal• Investigate rare earth surface treatment for improving oxidation resistance of alloys for SOFC applications.• Two different surface treatments investigated−Developed at NETL• Similar to pack cementation: coated with a powder mixture containing CeO2 or CeN and halide activator followed by heating in a controlled atmosphere (900oC-12 hrs), after which residual “pack” coating is washed off the surface. • Patent application filed with USPTO in September, 2005.• Applied to over 50 alloys of interest to FE.−Described in a paper by P.Y. Hou and J. Stringer (H/S)• J. Electrochem Soc., Vol 134, No. 7, July 1987, pp. 1836-1849• Coupons heated to 200oC were coated with a cerium-nitrate slurry (10w/o nitrate adjusted with HNO3 to pH=2), followed heating in air at 400oC to decompose to CeO2Surface Treatments to Improve Oxidation• As part of NETL-Albany’s SOFC research effort, we have utilized surface treatments to incorporate reactive elements (Ce, La, Pr) into the surface of metallic alloys for  development of metallic interconnects.Crofer 22APU: 800oC-Air+3%H2OTime (hrs)0 1000 2000 3000 4000 5000Specific Mass Change (g/cm2)0.00000.00020.00040.00060.00080.00100.00120.0014Crofer22APU - As received Crofer 22APU + ARC RE AdditionCrofer 22APU + RE Addition via method described                          by Hou and Stringer (1987)800oC-Air+3%H2O-500hrsBinding Energy (eV)01002003004005006007008009001000Relative Intensity02000400060008000Mn 3pCrofer 22APUCrofer 22APU+Ce (ARC process)Crofer 22 PU+Ce (Hou and String r process)Cr 3sSi  2sCe 4p3Si 2p / Ce 4dC 1sTi 2pO 1sTi 2sCr 2pMn 2pCe 3d5Ce 3d3Mn 2sCr 2SFe 2pThermal Treatment (TC) Only is IneffectiveRepeatable Behavior800oC-Air+3%H2OTime (hrs)0 1000 2000 3000 4000 5000Specific Mass Change (g/cm2)0.00000.00050.00100.0015#1, Nov 04#2, Nov 04#3, Nov 04#4, Mar 05#5, Nov 05#6, Nov 05#1, Nov 04#2, Nov 04#3, Nov 04 #4, Mar 05 #5, Nov 05 #6, Nov 05 Crofer 22APU+Ce Crofer 22APUCrofer 22APUCrofer 22APU+CeEffect of Ce Treatment: Fe-Ce-0.5Mn-1Ti800oC-Air+3%H2OTime (hrs)0 200 400 600 800 1000 1200 1400 1600 1800Specific Mass Change (g/cm2)0.0000.0010.0020.003F9 (12Cr)F10  (18Cr)F11 (22Cr)F9+Ce (12Cr)F10+Ce (18Cr)F11+Ce (22Cr)Fe-Cr-0.5Mn-1.0Ti baseFe-12Cr + Ce alloy superior performance to an Fe-22Cr alloyIn Melt Additions of REFe-22Cr-0.5Mn-0.1Ti800oC Air+3% H2OTime (hrs)0 500 1000 1500 2000Specific Mass Change (g/cm2)0.00000.00020.00040.00060.00080.00100.00120.00140.0016F1 (0 mischmetal)F2 (0.05 mischmetal)F3 (0.1 mischmetal) F4 (1.0  mischmetal) Crofer 22APU (0.1 La)In Melt + Surface Treatment800oC Moist Air (Fe-22Cr-0.5Mn-0.1Ti)Time (hrs)0 500 1000 1500 2000Specific Mass Change (g/cm2)0.00000.00020.00040.00060.00080.00100.0012F3+Ce F3 Crofer Crofer+Ce Minor Element Effect800oC-Air+3%H2OTime (hrs)0 400 800 1200 1600 2000 2400Specific Mass Change (g/cm2)0.00000.00020.00040.00060.00080.00100.00120.0014Crofer-JCrofer-10Crofer-20 Crofer 22APUHaynes 230differencedue to Al,Si and OcontentCe Surface Treatment on Crofer 22APU800oC-Air+3%H2OTime (hrs)0 400 800 1200 1600 2000 2400Specific Mass Change (g/cm2)0.00000.00020.00040.00060.00080.00100.00120.0014Crofer-JCrofer-10Crofer-20 Crofer 22APU+ CeCrofer 22APUHaynes 230Ce surfacetreatmentreduced weight gain~ 3 timesCROFER-10CROFER-10+CeTYPE-430spallingSurface: Type-430800oC-4000hrs-Air+3%H2O430 430+Ce (ARC) 430+Ce (H/S)Surface: Type-430800oC-4000hrs-Air+3%H2OType 430 Type 430 + CeO(NETL)Type 430 + CeO(H/S)Stainless Steel Alloys430-A 430-B 430-C 430-D 430-std Crofer22APUFe Bal Bal Bal Bal Bal16.6<0.0010.0160.370.420.06BalCr 16.85 17.03 17.13 17.11 22.42Ti <0.001 <0.001 <0.001 0.080 0.092Al <0.001 <0.001 <0.001 <0.001 0.13Si <0.01 <0.01 <0.01 <0.01 0.12Mn 0.44 0.47 0.49 0.52 0.45C 0.005 0.05 0.1 0.01 0.02Alloys 430A-D were melted and fabricated at NETLLow Si 430 Alloys800oC-Air+3%H2OTime (hrs)0 100 200 300 400Specific Mass Change (mg/cm2)0.00.10.20.30.4Crofer 22APU (Fe-22Cr-0.45Mn-0.09Ti-0.12Si)430-commercial (Fe-16.7Cr-0.41Mn-0.37Si) 430-A (Fe-16.9Cr-0.44Mn-0.01Si)430-B (Fe-17.0Cr-0.47Mn-0.01Si)430-C (Fe-17.1Cr-0.49Mn-0.01Si)430-D (Fe-17.1Cr-0.52Mn-0.08Ti-0.01Si)Surface Treated Low Si 430 Alloys800oC-Air+3%H2OTime (hrs)0 100 200 300 400Specific Mass Change (mg/cm2)0.000.100.200.300.40430 (commercial) 430-A 430-B 430-C 430-D closed symbols Ce surface treatedSummary• Oxidation results of a simple surface treatment have been presented.• The Cerium surface treatment improves the oxidation performance of type 430.• The Cerium surface treatment improves the oxidation performance of RE containing alloys such as Crofer 22 APU.• Improved ASR results have been achieved with RE treated Crofer 22 APU.Acknowledgements• Gordon Xia and Z. Gary Yang from PNNL for performing the ASR measurements.• Chris Johnson from NETL-Morgantown for assistance with initial SOFC button cell testing.• W.J. Quadakkers from Forschungszentrum Jülich for supplying the “Crofer J” material. • Ed Argetsinger, Marisa Arnold, Richard Chinn, Keith Collins, Paul Danielson, Dan Davis, Neal Duttlinger, Mike Hayes, Al Hunt, Steve Matthes, and Dave Smith from NETL-Albany for assistance with experiments.• Margaret Zoimek-Moroz, Tom Adler, Omer Dogan, Gordon Holcomb, Karol Schrems, Rick Wilson, John Dunning and Paul King from NETL-Albany for contributions to the SOFC effort at Albany.Experimental Alloys and RE Surface Treated Materials Available For Evaluation by SECA ParticipantsContact: Paul D. Jablonski: 541.967.5982 orDavid E. Alman: 541.967.5885

SOFC Interconnect Work at NETL

https://digital.library.unt.edu/ark:/67531/metadc894509/m2/1/high_res_d/926170.pdf

SOFC Interconnect Work at NETL

Abstract

Similar works

Full text

Available Versions

UNT Digital Library