Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/0688—Cermets, e.g. mixtures of metal and one or more of carbides, nitrides, oxides or borides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/08—Oxides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
  • C23C14/08—Oxides
  • C23C14/088—Oxides of the type ABO3 with A representing alkali, alkaline earth metal or Pb and B representing a refractory or rare earth metal
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
  • C23C14/34—Sputtering
  • C23C14/3485—Sputtering using pulsed power to the target
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
  • H01M4/90—Selection of catalytic material
  • H01M4/9016—Oxides, hydroxides or oxygenated metallic salts
  • H01M4/9025—Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
  • H01M4/9033—Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249967—Inorganic matrix in void-containing component
  • Y10T428/24997—Of metal-containing material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
  • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
  • Y10T428/264—Up to 3 mils
  • Y10T428/265—1 mil or less

Definitions

• the invention relates to a method for producing an electrically conductive layer having a perovskite structure.
• Protective layers having a perovskite structure are used, for example, in high-temperature fuel cells (SOFC). These are operated at temperatures of about 650 to 900 0 C, because only at these temperatures, the thermodynamic conditions for efficient energy production are given.
• SOFC high-temperature fuel cells
• planar SOFC systems individual electrochemical cells, which are composed of a cathode, a solid electrolyte and an anode, are stacked into a so-called stack and connected by metallic components, so-called interconnectors.
• the interconnector also separates the anode and cathode gas spaces.
• a dense interconnector is just as important for a high efficiency fuel cell as a dense electrolyte layer. Suitable materials for interconnectors must also have sufficient conductivity and resistance to the oxidizing conditions on the air side and reducing conditions on the fuel gas side. These requirements are currently best met by lanthanum chromite, chromium-iron alloys doped with yttria, and chromium-rich ferrites.
• a conductive layer with perovskite structure is deposited on the interconnector.
• Perovskite which today for the production of cathodes in the SOFC
• Perovskites are thermodynamically stable even at high partial pressures of oxygen and are also applied to the side of the interconnector facing the cathode for improving the contacting.
• methods such as APS (Atmospheric Plasma Spraying), VPS (Vacuum Plasma Spraying), Dip Coating or Wet Powder Spraying for the coating of interconnectors have been evaluated or used semi-industrially. These spraying methods are also used to produce electrochemically active cell layers in the high temperature fuel cell.
• VPS and APS are spraying processes that are carried out either in a vacuum or under atmospheric conditions. It is thereby melted in the plasma jet powder, wherein the powder grains solidify when hit on the substrate surface immediately like a flat with a few microns thickness. A certain proportion of residual porosity can not be prevented with this technique.
• thick layers with layer thicknesses of about 30 to 50 microns are deposited. Thus, large amounts of ceramic material are applied to the substrate surfaces, resulting in correspondingly high costs.
• a reduction of the electron passage reduces the electronic conductivity.
• CVD processes starting from chloridischen compounds and reaction with water vapor at deposition temperatures of 1100 to 1300 0 C, were tested. With this process, layers with thicknesses of 20 to 50 ⁇ m were produced. This process is also expensive. In addition, the high deposition temperatures are disadvantageous.
• Anode-side MSC concepts provide high power densities and are a cost-effective alternative.
• anodes of NiO-YSZ nickel oxide-yttrium stabilized zirconia
• these carrier substrates usually consist of an Fe-based alloy with high Cr contents, at temperatures of use of 650 to 900 ° C., diffusion of Ni from the anode into the carrier substrate or of Fe and Cr from the carrier substrate into the NiO YSZ anode.
• This phenomenon of interdiffusion results in the formation of a Fe-Cr-Ni diffusion zone in the contact area. This diffusion zone has a significantly higher thermal expansion coefficient compared to the carrier substrate.
• the interdiffusion can be prevented by perovskite diffusion barrier layers.
• porous layers are deposited, otherwise the gas permeability of the carrier substrate is no longer present.
• Plasma-sprayed diffusion barrier layers are also applied on the cathode side to interconnectors. Here it is disadvantageous that due to the intrinsically high porosity very thick and therefore expensive layers are used.
• the object of the invention is therefore to provide a method which on the one hand enables a cost-effective production of thin, dense and electrically conductive ceramic layers.
• Another object of the invention is to provide a conductive ceramic diffusion barrier layer applied to a porous support substrate which does not substantially affect the gas permeability of the support substrate.
• an electrically conductive ceramic layer preferably with a perovskite structure, is deposited by a pulsed sputtering process.
• a pulsed sputtering process With the method according to the invention, it is possible to apply thin, dense and functional ceramic layers uniformly on the surface of dense, but also porous substrate materials. The mass transport through the applied layer is limited to defect mechanisms.
• the diffusivity of, for example, chromium in the layer according to the invention is even at temperatures above 600 0 C very low. It is thus possible to use very thin layers with a thickness of preferably 0.1 to 5 ⁇ m as the diffusion barrier layer. Below 0.1 ⁇ m, the barrier effect is insufficient. Above 5 ⁇ m, the layer tends to flake off.
• the use of thin layers increases the electron passage of the system metallic interconnector / layer.
• the porous support substrate preferably has a density of 40 to 70% of the theoretical density and preferably consists of sintered together grains of Fe-based alloy with 15 to 35 wt.% Cr, 0.01 to 2 wt.% Of one or more elements of Group Ti, Zr, Hf, Mn, Y, Sc, rare earth metals, 0 to 10 wt.% Mo and / or Al, 0 to 5 wt.% Of one or more metals of the group Ni, W, Nb, Ta and 0.1 to 1 wt% O, with the remainder Fe and impurities.
• PVD processes are not used for coating interconnects with ceramic materials, since it has been assumed to date that reactive PVD processes are not suitable for the deposition of conductive ceramic layers, in particular dielectric layers with perovskite structure, because of their difficult process control. since a stoichiometric deposition of the complex layer material and the required layer properties, such as high density and good electrical conductivity, can not be achieved.
• the layer is built up by electrically neutral particles, which differ due to the process
• the coating material is located opposite the substrate as a so-called target.
• the target is bombarded with positive ions.
• a voltage is applied between the substrate (holder) and the target so that positive ions are accelerated towards the target. There They eject atoms or molecules, which then settle on the substrate as neutral particles, unaffected by the external field, and form the thin functional layer.
• the principle of an independent glow discharge In order to generate the positive ions required for the sputtering process, one makes use of the principle of an independent glow discharge.
• the space between anode and cathode is evacuated and then filled with the process gas. A voltage is applied between anode and cathode.
• cathode dark space a quasi-neutral transition zone and the positive column.
• the processes between cathode and anode can therefore be summarized in the following processes: ionization of gas atoms by electron impact, ion-induced electron emission at the cathode, electron-induced secondary emission at the anode and sputtering by ion impact.
• the use of pulsed sputtering plasmas allows the use of much higher target and arc currents. Due to the higher current intensities, significantly higher coating rates can be achieved.
• oxide ceramic sputtering targets By using oxide ceramic sputtering targets, it is possible to perform the process non-reactive, whereby a high process stability is achieved and the technical complexity is reduced. Because of the higher
• Plasma excitation the proportion of multiply charged particles and the kinetic energy of the particles can be increased, which makes possible a coating without substrate bias. This leads to improved layer properties, e.g. a higher layer density, improved adhesion, higher electrical conductivity and improved chemical resistance.
• the concentration of the elements in the sputtering target differs by a maximum of 5% from the concentration of the respective element in the layer.
• the inventive method thus allows the stoichiometric deposition of ceramic, preferably perovskite layers and this also on unheated substrates.
• the layer surfaces produced are smooth and chemically stable.
• the layer is deposited at a frequency of the pulsed voltage of 1 to 1000 kHz. Below 1 kHz or in DC operation, stable deposition processes can not be used in the deposition of dielectric materials, but electrical flashovers and arcing occur.
• the technical complexity for the power supply and the necessary adjustment units for controlling the process impedance for an economical coating are too large.
• the method becomes particularly economical if a frequency of 10 to 500 kHz, preferably 100 to 350 kHz, is selected.
• the voltage rms value is +100 to -1000 V, preferably +100 to -500 V.
• the effective voltage value of an AC voltage is understood to mean the DC voltage value which corresponds to the same thermal effect.
• the ratio of peak to effective value is called the crest factor, and for sinusoids, for example, it is 1.41. Below the specified limit are the
• Particle energies too low for the desired sputtering process undesirable effects may occur due to the high particle energies, e.g. Sputtering of the vapor deposition layer, electrical flashovers due to high field strengths, implantation in the substrate, unwanted temperature increase, etc., which prevent deposition of layers with perovskite structure.
• the process gas is an inert gas, preferably argon, at a pressure of 1x10 "4 to 9x10 -2 mbar used.
• 1x10" 4 mbar the sputtering process can not be ignited.
• 9x10 "2 mbar the free path lengths of the sputtered layer particles become too small due to too many impact processes Kinetic energy of the split layer particles is thereby reduced, whereby the desired layer properties can not be achieved.
• the ceramic layer preferably has a perovskite structure with the structural formula ABO 3 .
• the crystal structure is cubic, orthorhombic or tetragonal.
• A comprises one or more elements from the group La, Ba, Sr, Ca.
• the B comprises one or more elements from the group Cr, Mg, Al, Mn, Fe, Co, Ni, Cu and Zn.
• the layers preferably have a density> 99% of the theoretical density and an impurity content ⁇ 0.5% by weight, preferably ⁇ 0.1% by weight.
• FIG. 1 shows schematically the arrangement of a perovskite layer on a porous substrate.
• Figure 2 shows EPMA measurements of a porous substrate having deposited thereon LSC layer and Ni layer after 1000 h aging at 85O 0 C
• Example 1 A porous support substrate having a composition of 26% by weight of Cr, 0.5% by weight of Y 2 O 3 , 2% by weight of Mo, 0.3% by weight of Ti and 0.03% by weight of Al, balance Fe coated by pulsed, non-reactive DC process.
• an Edwards sputter coater was used, in which an LSM target (La 0 , 8 Sr 0 , 2 Mn oxide) with a diameter of 72 mm was installed.
• a sputtering power of 400 W, a voltage of 149 V 1, a current of 2.01 A, a frequency of 350 kHz (at a pulse duration of 1, 1 ⁇ s) and a process pressure of 5 * 10 "3 mbar were set
• LSM layers with a thickness of 3 ⁇ m were produced with a composition Lao, 8 Sro, 2 Mn oxide (LSM)
• Figure 1 shows schematically the arrangement of the deposited layers on the porous carrier substrate.
• Porous and dense carrier substrates having a composition 26 wt.% Cr, 0.5 wt.% Y 2 O 3 , 2 wt.% Mo, 0.3 wt.% Ti and 0.03 wt.% Al, balance Fe was pulsed, non-reactive DC process coated. This was done using an Edwards sputter coater with an LSC target
• the LSC layers were then coated with a 50 ⁇ m thick APS nickel layer.
• This structure iron chromium alloy (porous and non-porous) - LSC layer (3 microns) - APS nickel layer (50 microns) was used to investigate the diffusion barrier effect of the thin LSC layer against nickel in iron or iron in nickel.
• the structure was thereby stored at 850 ° C to 1000 ° C in air for 100 h.
• the diffusion properties were documented by means of EPMA measurements (FIG. 2).
• the LSC layer prevents diffusion of nickel into iron or iron into nickel under the given test conditions.
• the deposited LSC layers have a high electrical conductivity (corresponding to the target used), a high density of> 99.9%, a homogeneous layer structure and a smooth surface with an average roughness value equal to the substrate mean roughness value. Due to the process, no incorporation of foreign atoms by means of EPMA and EDX can be measured.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
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• Life Sciences & Earth Sciences (AREA)
• Sustainable Energy (AREA)
• Sustainable Development (AREA)
• Manufacturing & Machinery (AREA)
• Physical Vapour Deposition (AREA)
• Compositions Of Oxide Ceramics (AREA)
• Non-Insulated Conductors (AREA)
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• 2006
  • 2006-07-07 AT AT0053406U patent/AT9543U1/de not_active IP Right Cessation
• 2007
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  • 2007-07-05 EP EP07763737A patent/EP2038450B1/de not_active Not-in-force
  • 2007-07-05 JP JP2009516817A patent/JP5421101B2/ja not_active Expired - Fee Related
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