Application of advanced and non destructive testing in solid oxide fuel cells

Size: px

Start display at page:

Download "Application of advanced and non destructive testing in solid oxide fuel cells"

Lester Wood
5 years ago
Views:

1 Materials Science & Technology Application of advanced and non destructive testing in solid oxide fuel cells Peter Wyss, Erwin Hack Laboratory for Electronics/Metrology/Reliability Artur Braun, Lorenz Holzer, Christian Soltmann, Peter Holtappels Laboratory for High Performance Ceramics Empa, Swiss Federal Laboratories for Materials Testing and Research Überlandstr 129, CH-8600 Switzerland

2 Outline metallic components ceramic components Test items and techniques Non-destructive testing neutron tomography x-ray radiography thermography Advanced destructive testing FIB tomography Outlook Innenringdichtung Radialdichtung Empa, Peter Holtappels, FC Tools, Trondheim,

3 Solid Oxide Fuel Cell - Principles - Air: O 2 /N 2 e - N 2 SOFC features&scaling Electrocatalytic activity Nano/atomic scale Metallic IC Cr-, Ni-Cr-Steels cathode LSM, LSCF, LSF electrolyte O x YSZ O anode anode support Metallic IC Cr-, Ni-Cr-Steels Fuel: CH 4 /H 2 O 3-D structures e - Ni/YSZ Ni/YSZ CO 2 /H 2 O Ionic conductivity Nano/atomic scale Electronic conductivity Nano/atomic/micro scale (Open) porosity Microscale SEM/OM/EDX Only 2-D imaging Empa, Peter Holtappels, FC Tools, Trondheim,

4 Non-destructive Testing (NdT) component state potential problem ndt test method metallic machined part cracks, bad welds X-ray RT, CT, UT for interconn. metallic assembled in stack corrosion, contamination RT, CT X-rays, Neutrons? ceramic green machined part porosity + homogenity, shrinkage cracks RT, µct local mode, X-rays, TT ceramic assembled and fired to cell cracks + delaminations (thermal cycling) RT, µct local mode, X-rays, TT ceramic cells mounted in the stack fatigue cracks (thermal cycling) RT, CT, Neutrons + contrast fluid? Empa, Peter Holtappels, FC Tools, Trondheim,

5 1. NdT methods and test items RT system data (typical) X-ray direction Field of view source beam geometry resolution in µm field of view (FOV) in mm typ. penetrable ZrO 2 in mm Neutrons almost parallel > 200 X-ray Mini / Micro focus conical X-ray Synchrotron parallel Empa, Peter Holtappels, FC Tools, Trondheim,

6 Neutron tomography ~ 20 cm permits insight into submillimeter porosity of SOFC stack Empa, Peter Holtappels, FC Tools, Trondheim,

panorama tube head or TXD 9160 subµ tube head The RT / CT microscopy

7 2. RT and local µct to Empa YSZ pellets X-ray flat panel Hamamatsu 7942 CA-02 Sample on low runout rotation stage VISCOM TEP 9225 panorama tube head or TXD 9160 subµ tube head The RT / CT microscopy (macroscopy) system Empa, Peter Holtappels, FC Tools, Trondheim,

8 RT and local µct to Empa YSZ pellets The crack detection limit in radiography X-ray direction α c w crack detection is possible if: c > 0.01 w * sin α tube spot size * 0.5 Empa, Peter Holtappels, FC Tools, Trondheim,

9 RT and local µct to Empa YSZ pellets Visible light microscopy Radiographies of a hidden coarse grain FOV 5 x 5 mm, pixelsize 2.5 µm Empa, Peter Holtappels, FC Tools, Trondheim,

10 RT and local µct to Empa YSZ pellets Visible light microscopy Radiographies of a shrinkage crack FOV 5 x 5 mm, pixelsize 2.5 µm Empa, Peter Holtappels, FC Tools, Trondheim,

11 RT and local µct to Empa YSZ pellets Local X-ray µct of crack in pellet Ø 35 x 1 mm Field of view 5 x 5 mm, voxelsize 5 µm Slices parallel to main surface Empa, Peter Holtappels, FC Tools, Trondheim,

12 RT and local µct to Empa YSZ pellets Local X-ray µct of hidden coarse grain Field of view 5 x 5 mm, voxelsize 5 µm Slices parallel to main surface Empa, Peter Holtappels, FC Tools, Trondheim,

TT, RT and local µct to HTceramics cells Camera Cedip JADE Camera type Resolution Wavelength range Frame rate Array 240 x 320 pix 3-5 μm Full: 170 Hz ROI: 9 khz Lateral

13 TT, RT and local µct to HTceramics cells Camera Cedip JADE Camera type Resolution Wavelength range Frame rate Array 240 x 320 pix 3-5 μm Full: 170 Hz ROI: 9 khz Lateral resolution 15 x 15 μm 2 NETD 20 mk Temp. range C Lock-In frequency < 5 khz The thermography cam, heart of the TT system Empa, Peter Holtappels, FC Tools, Trondheim,

14 TT, RT and local µct to HTceramics cells Thermography testing (TT), impulse method flash hits surface bad bond spot lateral resolution 2 x depth time depth 2 diffusion wave propagates bad bond spot stops the heat diffusion wave and after some time a thermic contrast appears: positive at the impulse side, negative at the rear side Empa, Peter Holtappels, FC Tools, Trondheim,

Istantaneous after flash 20 msec later FOV 180 x 150 pixel or 28 x 25

15 TT, RT and local µct to HTceramics cells Impulse thermography images of a region containing a spot of high thermal conductivity FOV for RT +µct Istantaneous after flash 20 msec later FOV 180 x 150 pixel or 28 x 25 mm, Pixelsize 167 µm Empa, Peter Holtappels, FC Tools, Trondheim,

16 TT, RT and local µct to HTceramics cells Thesameregion(FOV 5 x 5 mm) imagedwith: Radiographies, pixel size 2.5 µm Local tomography, voxel size 5 µm Empa, Peter Holtappels, FC Tools, Trondheim,

17 Focussed Ion Beam (FIB) technique Conventional preparation procedure Advanced preparation procedure Hi2 DLR BekNi 275/3 H 2 Empa, Peter Holtappels, FC Tools, Trondheim,

18 TEM: Imaging & elemental analysis DLR BekNi 275/3 chemical map: Ni Zr Empa, Peter Holtappels, FC Tools, Trondheim,

electrode Ni-Cermet DLR BekNi 275/3 volume: 40 x 40 x

19 FIB-Nanotomography: 3-D structure of a FC Electrolyte stabilised zirconia Air electrode perovskite Fuel electrode Ni-Cermet DLR BekNi 275/3 volume: 40 x 40 x 40 m 3 Empa, Peter Holtappels, FC Tools, Trondheim,

Nanotomography: Informationsgewinn 3D Imaging

20 Nanotomography: Informationsgewinn 3D Imaging Particulate und micro structure A 6 µm Distinction Crystallite-Particulate aggregates B 6 µm Use of Information: Modeling Understanding degradation e.g. sulphur poisoning Empa, Peter Holtappels, FC Tools, Trondheim,

, Nature Materials 5 541-544, 2006 cm / mm micro meter

21 Advanced characterisation access to large scale facilities software sample preparation Source: J.R. Wilson et al., Nature Materials , 2006 cm / mm micro meter nano meter Empa, Peter Holtappels, FC Tools, Trondheim,

22 NdT methods and diagnostics strategy Visual testing (VT), including visible light microscopy will be done in any case Ultrasonic testing (UT) requires flat surfaces and low damping, 3D possibility Eddy current testing (ET) for electrical conductors only Magnetic testing (MT) for ferritic materials only Thermography (TT) best for close to surface items, 3D possibility Radiographic testing (RT, CT, XTM) No requirements to surfaces and damping, 3D possibility Quality assurance cell production stacking Life time / Durability comparison of pre and post test state by NdT possible failures affecting mechanical properties visible by NdT Combination of NdT advantageous identification of points for destructive analysis 3D imaging real structures validation of 2D analysis (e.g. SEM, OM) Empa, Peter Holtappels, FC Tools, Trondheim,

23 Acknowledgement Defne Bayraktar, EMPA Ulrich Vogt, EMPA Thomas Graule, EMPA Günter Schiller, DLR SINQ, PSI Josef Sfeir, Hexis HTceramix H Hi2 2 Empa, Peter Holtappels, FC Tools, Trondheim,

24 4. A possible NdT procedure for cells Impulse thermography overview (FOV = 80 x 80 mm) Pixel size 0.33 mm, meas. time per cell 2 min Impulse thermography close up (FOV = 8 x 8 mm) Pixel size 33 µm, meas. time per cell 10 min (automated) Radiography overview (FOV = 80 x 80 mm) Pixel size 20 µm, meas. time per cell 5 min Radiography close up (FOV = 8 x 8 mm) Pixel size 4 µm (OVHM - Movie), meas. time per item 10 min (auto) Local tomography (FOV = 8 x 8 mm), meas. time per item 60 min voxel size 4 µm or calculation of items depth by evaluating the trajectories from OVHM -Movie Empa, Peter Holtappels, FC Tools, Trondheim,

WDX Studies on Ceramic Diffusion Barrier Layers of Metal Supported SOECs

Published in "Fuel Cells (2009): doi: 10.1002/fuce.200800118" which should be cited to refer to this work. WDX Studies on Ceramic Diffusion Barrier Layers of Metal Supported SOECs D. Wiedenmann 1,2 *,