EP0236823A2 - Metallic semi-finished product, process for its manufacture and uses of the semi-finished product - Google Patents
Metallic semi-finished product, process for its manufacture and uses of the semi-finished product Download PDFInfo
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- EP0236823A2 EP0236823A2 EP87102472A EP87102472A EP0236823A2 EP 0236823 A2 EP0236823 A2 EP 0236823A2 EP 87102472 A EP87102472 A EP 87102472A EP 87102472 A EP87102472 A EP 87102472A EP 0236823 A2 EP0236823 A2 EP 0236823A2
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- Prior art keywords
- semi
- finished product
- metal
- stem
- oxide
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- 239000011265 semifinished product Substances 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims description 15
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 229910052751 metal Inorganic materials 0.000 claims abstract description 28
- 239000002184 metal Substances 0.000 claims abstract description 28
- 239000013078 crystal Substances 0.000 claims abstract description 26
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 8
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims abstract description 8
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 7
- 239000011651 chromium Substances 0.000 claims abstract description 7
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 7
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910000423 chromium oxide Inorganic materials 0.000 claims abstract description 6
- 229910052742 iron Inorganic materials 0.000 claims abstract description 6
- 239000010941 cobalt Substances 0.000 claims abstract description 5
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 5
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 5
- 238000001816 cooling Methods 0.000 claims description 7
- 238000000137 annealing Methods 0.000 claims description 6
- 229910052746 lanthanum Inorganic materials 0.000 claims description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 239000003054 catalyst Substances 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 229910052772 Samarium Inorganic materials 0.000 claims description 3
- 229910052776 Thorium Inorganic materials 0.000 claims description 3
- 229910052770 Uranium Inorganic materials 0.000 claims description 3
- 239000000853 adhesive Substances 0.000 claims description 3
- 230000001070 adhesive effect Effects 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- 229910052735 hafnium Inorganic materials 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 229910052720 vanadium Inorganic materials 0.000 claims description 3
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- 238000005524 ceramic coating Methods 0.000 claims description 2
- 238000005266 casting Methods 0.000 claims 1
- 238000009749 continuous casting Methods 0.000 claims 1
- 239000011261 inert gas Substances 0.000 claims 1
- 239000000047 product Substances 0.000 abstract description 5
- 229910052761 rare earth metal Inorganic materials 0.000 abstract description 5
- 150000002910 rare earth metals Chemical class 0.000 abstract description 5
- 239000010410 layer Substances 0.000 description 17
- 229910045601 alloy Inorganic materials 0.000 description 11
- 239000000956 alloy Substances 0.000 description 11
- 239000000463 material Substances 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- -1 Y 2 O 3 Chemical class 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 229910001092 metal group alloy Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 238000007750 plasma spraying Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 238000007669 thermal treatment Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 239000000443 aerosol Substances 0.000 description 1
- 244000052616 bacterial pathogen Species 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000010724 circulating oil Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001784 detoxification Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000010285 flame spraying Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- 230000004222 uncontrolled growth Effects 0.000 description 1
- 238000010308 vacuum induction melting process Methods 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/03—Alloys based on nickel or cobalt based on nickel
- C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C19/00—Alloys based on nickel or cobalt
- C22C19/07—Alloys based on nickel or cobalt based on cobalt
Definitions
- the invention relates to semi-finished metal products in the form of wire, rods, billets, tubes, in particular sheet metal or strips, for applications in which high thermal shock resistance and a large surface area and / or chemical resistance and / or low thermal conductivity of the surface layer is required, in particular for catalyst supports, Soot filters, heating conductors, aerosol filters, linings of chemical and energy converting plants.
- the invention also includes a method for producing and using the semi-finished product.
- the alloys mentioned are known to form either layers of chromium oxide or aluminum oxide with high selectivity or layers composed of Al 2 O 3 chromium mixed crystals. At use temperatures of around 900 ° C and more, the alloys that form Al 2 O 3 layers are selected.
- a ferritic stainless steel which can be processed hot and is resistant to temperature changes, oxidation and scaling at elevated temperatures.
- the iron-chromium-aluminum alloy contains cerium, lanthanum and other rare earth metals and is suitable for forming a textured aluminum oxide film on the surface.
- the alloy is produced in the usual way by melting.
- the typical steel impurities such as oxygen, nitrogen and sulfur are reduced before the rare earth metals are added to the melt.
- Any conventional process, including arc furnaces, AOD and vacuum induction melting processes, is applicable.
- the melt is poured into blocks, bars, strips or sheets.
- the steel is then hot and / or cold rolled and subjected to the usual procedures such as descaling and annealing.
- the ferritic stainless steel is then heat treated to form an alumina surface.
- the object of the invention is to provide a semi-finished metal product which, preferably without an intermediate layer (wash coat), represents a temperature change-resistant adhesive base for a catalytically active coating.
- the task also includes the creation of a method which leads in the simplest possible way to a metallic semi-finished product with the property mentioned.
- a semi-finished metal product based on iron and / or nickel and / or cobalt with 2 to 16% aluminum, 12 to 30% chromium and up to 4% of at least one highly reactive element from the group Y, Zr, Ti , Ce, Sm, Hf, La, Th, U, V, W, Ta, Nb, Mo, Gd, Si, Mg, Ca and / or their dispersed oxides, preferably at least 0.01% of these elements or oxides, and Inevitable impurities proposed according to the invention that metallic stem crystals are formed at least in the surface area of the semifinished product, from which stem crystals consisting predominantly of aluminum oxide and / or chromium oxide have grown, the axes of both types of stem crystal being predominantly perpendicular to the geometric surface of the semifinished product.
- Normal steel contaminants are carbon, nitrogen, oxygen, phosphorus, sulfur, manganese, copper and nickel.
- the method according to the invention is characterized in that the semi-finished product is solidified from the molten state in a front that is predominantly parallel to the geometric surface with a cooling rate of 10 3 to 10 6 K / s, then first at one Temperature of 800 to 1000 ° C for a short time in an oxygen contained in bound form gas, in particular C0 2 , under the resulting reducing conditions and then in the temperature range from 800 to 1000 ° C for up to 25 h in air.
- the invention provides a semi-finished metal product in which metal stem crystallites are formed at least in the surface area by the directional solidification of the metal alloy. Due to the high cooling rate and thermal treatment, the additional elements from the aforementioned group X, which are highly reactive, i.e. are highly oxygen-affine, or their oxides, which are present in finely divided form in the surface area, as germs in the subsequent heat treatment. At the same time, as a kind of dowel, they ensure a high level of adhesive strength for the thermally grown oxidic stem crystallites. A further improved nucleation is achieved by briefly heating as the first thermal treatment stage under reducing conditions or those that occur during this treatment.
- the long-term annealing treatment under oxidizing conditions, preferably in air, in which the oxidic stem crystallites grow, which predominantly consist of aluminum oxide and / or chromium oxide, the axes of which are also predominantly perpendicular to the geometric surface of the semi-finished product. Due to this stem crystal formation, an extraordinarily large surface is created, in which a metallic and / or ceramic coating can be very well anchored.
- profiled, finely crystalline strips of approximately 20 to 200 ⁇ m can be produced in this way, with the aid of cooled copper rolls, possibly up to approximately 500 ⁇ m and more. It is preferable to produce tapes approximately 40 to 70 ⁇ m thick.
- stem crystals at least in the surface area of the auxiliary device, can alternatively be achieved by briefly melting a surface layer of the cast or rolled semifinished product with subsequent self-cooling, in addition to the above-mentioned pouring onto cooled rolls.
- a metal strip of 50 ⁇ m thickness was produced at a cooling rate of 10 5 to 10 4 K / s.
- the material composition is 20% chromium, 5% aluminum, 0.15% cerium, 0.01% lanthanum, the rest iron with small amounts of Si, Mn, C, S, P, Ni as trace elements.
- the tape was then preheated to 900 ° C dry carbon dioxide gas for one minute and then held in air at 925 ° C for 16 hours.
- a cold rolled sheet of the same material composition was also treated after recrystallization annealing.
- the stalk-shaped oxide grains of the cast strip have diameters of approximately 0.2 ⁇ m and lengths of on average approximately 4 ⁇ m and that they are arranged almost uniformly perpendicular to the surface of the metal grains, while the sample produced by rolling is scaly , partially in contact with each other grains of different orientation and length of up to about 3 microns.
- Example 1 A 10 mm thick plate made of the material described in Example 1 was bombarded with an electron beam in such a way that a spot approximately 0.5 mm in diameter was melted down to a depth of 100 ⁇ m. The plate was then treated in CO 2 gas at 900 ° C. for 1 minute. The procedure was as in Example 1.
- the sample was subjected to several temperature changes, being heated to approximately 1000 ° C. and quenched in an oil bath.
- the stem oxide grains in the area of the melting spot were not attacked by the treatment, the oxide layer on the rest of the sample surface shows individual flaking.
- Example 2 A plate was produced according to Example 2 with a similar melting spot, then an etching was carried out so that the grain boundaries were exposed to a depth of 20 pm and the procedure according to Example 1 was then continued. It was found that a radiation-like oxide-grain layer of the same quality as in Example 1 had grown on the metal grains which had been partially exposed.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Catalysts (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Continuous Casting (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
- Adornments (AREA)
- Forging (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
Die Erfindung betrifft ein metallenes Halbzeug auf der Basis Eisen und/oder Nickel und/oder Cobalt mit 2 bis 16% Aluminium, 12 bis 30 % Chrom und mindestens einem hochreaktiven Element X, insbesondere aus der Gruppe der Seltenen Erdenmetalle und/oder deren dispergierte Oxide. Kennzeichen der Erfindung ist, daß mindestens im Oberflächenbereich des Halbzeugs metallene Stengelkristalle gebildet sind, aus denen heraus überwiegend aus Aluminiumoxid und/oder Chromoxid bestehende Stengelkristalle gewachsen sind, wobei die Achsen beider Stengelkristalltypen überwiegend senkrecht zur geometrischen Oberfläche des Halbzeugs stehen. The invention relates to a semi-finished metal product based on iron and / or nickel and / or cobalt with 2 to 16% aluminum, 12 to 30% chromium and at least one highly reactive element X, in particular from the group of rare earth metals and / or their dispersed oxides . Characteristic of the invention is that metal stem crystals are formed at least in the surface area of the semi-finished product, from which stem crystals consisting predominantly of aluminum oxide and / or chromium oxide have grown, the axes of both types of stem crystal being predominantly perpendicular to the geometric surface of the semi-finished product.
Description
Die Erfindung betrifft metallenes Halbzeug in Form von Draht, Stangen, Knüppeln, Rohren, insbesondere Blechen oder Bändern für Anwendungen, bei denen eine hohe Temperaturwechselbeständigkeit und große Oberfläche und/oder chemische Beständigkeit und/oder geringe Wärmeleitfähigkeit der Oberflächenschicht benötigt wird, insbesondere für Katalysatorträger, Rußfilter, Heizleiter, Aerosolfilter, Auskleidungen von chemischen und Energie umwandelnden Anlagen. Die Erfindung umfaßt ferner ein Verfahren zur Herstellung und die Verwendung des Halbzeugs.The invention relates to semi-finished metal products in the form of wire, rods, billets, tubes, in particular sheet metal or strips, for applications in which high thermal shock resistance and a large surface area and / or chemical resistance and / or low thermal conductivity of the surface layer is required, in particular for catalyst supports, Soot filters, heating conductors, aerosol filters, linings of chemical and energy converting plants. The invention also includes a method for producing and using the semi-finished product.
Es ist bekannt (Strafford K. N., High temperature Corrosion of alloys containing rare earth of refractory elements: a review ..., High Temperature Teehnology Vol. 1 No. 6, Nov. 1983), daß metallene Legierungen des Typs MCrAIX und des Typs MCrAIZX mit M als Eisen und/oder Cobalt und/oder Nickel als Basis und X gewichtsmäßig kleinen Zusätzen hochreaktiver Elemente wie Y, Zr, Ti, Ce, Sm, Hf, La, Th, U, V, W, Ta, Nb, Mo, Gd, Si, Mg, Ca und Z als ein Element oder dessen Oxid aus der Reihe von X, aber ein anderes als das für X jeweils gewählte Element, für eine Verbesserung der oxidischen Schicht-Eigenschaften sorgen. Es wird die Haftung der Oxidschicht verbessert, die aus einzelnen Oxidkörnern besteht, und auch das Oxidations-Verhalten günstig beeinflußt.It is known (Strafford KN, High temperature Corrosion of alloys containing rare earth of refractory elements: a review ..., High Temperature Teehnology Vol. 1 No. 6, Nov. 1983) that metal alloys of the MCrAIX and MCrAIZX types with M as iron and / or cobalt and / or nickel as the base and X small additions by weight of highly reactive elements such as Y, Zr, Ti, Ce, Sm, Hf, La, Th, U, V, W, Ta, Nb, Mo, Gd, Si, Mg, Ca and Z as one element or its oxide from the series of X, but a different element than that chosen for X, provide an improvement in the oxide layer properties. The adhesion of the oxide layer, which consists of individual oxide grains, is improved and the oxidation behavior is also favorably influenced.
Es ist ferner bekannt (Ramanarayan T. A., Raghavan, M. und Petkovie-Luton, R., "The Characteristics of Alumina Scales Formed on Fe-Based Yttria-Dispersed Alloys", J. Eleetrochem. Soeiety, April 1984, Vol. 131 No. 4., 923-931), daß in einer Basislegierung besonders fein dispergierte Oxide der Seltenen Erdmetalle, wie Y2O3, einen ähnlich verbessernden Einfluß ausüben.It is also known (Ramanarayan TA, Raghavan, M. and Petkovie-Luton, R., "The Characteristics of Alumina Scales Formed on Fe-Based Yttria-Dispersed Alloys", J. Eleetrochem. Soeiety, April 1984, Vol. 131 No 4., 923-931) that in a base alloy particularly finely dispersed oxides of rare earth metals, such as Y 2 O 3 , exert a similarly improving influence.
Die angeführten Legierungen bilden bekanntlich je nach Zusammensetzung entweder überwiegend aus Chromoxid oder aus Aluminiumoxid bestehende Schichten mit hoher Selektivität oder auch aus Al2O3-Chromoxid-Mischkristallen bestehende Schichten aus. Bei Verwendungstemperaturen von etwa 900 °C und mehr werden die Legierungen gewählt, die Al2O3-Schiehten bilden.Depending on the composition, the alloys mentioned are known to form either layers of chromium oxide or aluminum oxide with high selectivity or layers composed of Al 2 O 3 chromium mixed crystals. At use temperatures of around 900 ° C and more, the alloys that form Al 2 O 3 layers are selected.
Der Nachteil, der nach den beschriebenen Verfahren hergestellten Schichten und Bauteile aus den geschilderten Legierungen, besteht im Fall der Verwendung bei besonders häufigen Temperaturwechseln mit hohen Temperaturdifferenzen darin, daß einzelne Bereiche der Oxidschicht abplatzen. Die so entstehenden Fehlstellen werden von den angegebenen Legierungen bei geeigneten Bedingungen zwar wieder ausgeheilt, das Auftreten von Abplatzungen bei hoher Temperaturwechselbeanspruchung begrenzt aber die Verwendbarkeitsdauer und läßt die heute bekannten Materialien für einige Anwendungen, z.B. als Träger für katalytisch aktive Substanzen, in Sonderheit Edelmetalle für die Entgiftung von Verbrennungsgasen, nicht geeignet erscheinen.The disadvantage of the layers and components made from the described alloys produced by the described methods, in the case of use in the case of particularly frequent temperature changes with high temperature differences, is that individual areas of the oxide layer flake off. The resulting defects are healed again by the specified alloys under suitable conditions, but the occurrence of flaking under high temperature cycling limits the service life and leaves the materials known today for some applications, e.g. do not appear to be suitable as a carrier for catalytically active substances, in particular precious metals for the detoxification of combustion gases.
Ein weiterer Nachteil ist es, daß man Legierungen mit mehr als ca. 6 % Aluminium, z.B. US-A-4 414 023, nicht als Folie durch Walzen herstellen kann bzw. deren Herstellung erhebliche Kosten verursacht. Zur Temperaturbeständigkeit über lange Zeit ist aber eine Ausheilung von Fehlern der Oxidschichten durch aus der Legierung nachzulieferndes Aluminium notwendig und mithin ein möglichst hoher Al-Gehalt sinnvoll.Another disadvantage is that alloys with more than about 6% aluminum, e.g. US-A-4 414 023, can not produce as a film by rolling or the production of which causes considerable costs. For temperature stability over a long time, however, it is necessary to heal defects in the oxide layers by means of aluminum to be supplied from the alloy, and consequently the highest possible Al content makes sense.
Aus der US-A-4 414 023 ist ein ferritischer rostfreier Stahl bekannt, der warm verarbeitbar und beständig ist gegen Temperaturwechsel, Oxidation und Verzunderung bei erhöhten Temperaturen. Die Eisen-Chrom-Aluminium-Legierung enthält Cer, Lanthan und andere Seltene Erdmetalle und ist geeignet, einen texturierten Aluminiumoxidfilm an der Oberfläche zu bilden. Die Legierung wird in üblicher Weise durch Schmelzen erzeugt. Dabei werden die typischen Stahlverunreinigungen, wie Sauerstoff, Stickstoff und Schwefel vor der Zugabe der Seltenen Erdmetalle zur Schmelze verringert. Jeder herkömmliche Prozeß, einschließlich Lichtbogenöfen, AOD- und Vakuuminduktionsschmelzverfahren ist anwendbar. Die Schmelze wird in Blöcke, Stangen, Bänder oder Bleche gegossen. Der Stahl wird anschließend warm und/oder kaltgewalzt und den üblichen Verfahren unterworfen, wie Entzundern und Glühen. Der ferritische rostfreie Stahl wird dann zur Bildung einer Aluminiumoxid-Oberfläche wärmebehandelt.From US-A-4 414 023 a ferritic stainless steel is known which can be processed hot and is resistant to temperature changes, oxidation and scaling at elevated temperatures. The iron-chromium-aluminum alloy contains cerium, lanthanum and other rare earth metals and is suitable for forming a textured aluminum oxide film on the surface. The alloy is produced in the usual way by melting. The typical steel impurities such as oxygen, nitrogen and sulfur are reduced before the rare earth metals are added to the melt. Any conventional process, including arc furnaces, AOD and vacuum induction melting processes, is applicable. The melt is poured into blocks, bars, strips or sheets. The steel is then hot and / or cold rolled and subjected to the usual procedures such as descaling and annealing. The ferritic stainless steel is then heat treated to form an alumina surface.
Aufgabe der Erfindung ist es, ein metallenes Halbzeug zu schaffen, das vorzugsweise ohne Zwischenschicht (wash coat) einen temperaturwechselbeständigen Haftgrund für einen katalytisch wirkenden Überzug darstellt. Die Aufgabe umfaßt ferner die Schaffung eines Verfahrens, welches in möglichst einfacher Weise zu einem metallischen Halbzeug mit der erwähnten Eigenschaft führt.The object of the invention is to provide a semi-finished metal product which, preferably without an intermediate layer (wash coat), represents a temperature change-resistant adhesive base for a catalytically active coating. The task also includes the creation of a method which leads in the simplest possible way to a metallic semi-finished product with the property mentioned.
Zur Lösung der gestellten Aufgabe wird für ein metallenes Halbzeug auf der Basis Eisen und/oder Nickel und/oder Cobalt mit 2 bis 16 % Aluminium, 12 bis 30 % Chrom und bis 4 % mindestens eines hochreaktiven Elementes aus der Gruppe Y, Zr, Ti, Ce, Sm, Hf, La, Th, U, V, W, Ta, Nb, Mo, Gd, Si, Mg, Ca und/oder deren dispergierte Oxide, vorzugsweise mindestens 0,01 % dieser Elemente bzw. Oxide, sowie unvermeidbare Verunreinigungen erfindungsgemäß vorgeschlagen, daß mindestens im Oberflächenbereich des Halbzeugs metallische Stengelkristalle gebildet sind, aus denen heraus überwiegend aus Aluminiumoxid und/oder Chromoxid bestehende Stengelkristalle gewachsen sind, wobei die Achsen beider Stengelkristalltypen überwiegend senkrecht zur geometrischen Oberfläche des Halbzeugs stehen.To achieve the object, a semi-finished metal product based on iron and / or nickel and / or cobalt with 2 to 16% aluminum, 12 to 30% chromium and up to 4% of at least one highly reactive element from the group Y, Zr, Ti , Ce, Sm, Hf, La, Th, U, V, W, Ta, Nb, Mo, Gd, Si, Mg, Ca and / or their dispersed oxides, preferably at least 0.01% of these elements or oxides, and Inevitable impurities proposed according to the invention that metallic stem crystals are formed at least in the surface area of the semifinished product, from which stem crystals consisting predominantly of aluminum oxide and / or chromium oxide have grown, the axes of both types of stem crystal being predominantly perpendicular to the geometric surface of the semifinished product.
Normale Stahlverunreinigungen sind Kohlenstoff, Stickstoff, Sauerstoff, Phosphor, Schwefel, Mangan, Kupfer und Nickel.Normal steel contaminants are carbon, nitrogen, oxygen, phosphorus, sulfur, manganese, copper and nickel.
Aus den beigefügten Schliffbildern ist die Oberflächenstruktur deutlich erkennbar. '
- Bild 1 zeigt eine nach herkömmlichen Verfahren erzeugte Halbzeug-Oberfläche mit unregelmäßig liegenden whiskerähnlichen oxidischen Stengelkristallen.
- Bild 2 zeigt die Halbzeug-Oberfläche, wie sie bei Ausübung des erfindungsgemäßen Verfahrens gebildet ist. Die großen Bereiche sind die metallenen Stengelkristalle, aus deren Oberfläche haarähnlich die oxidischen Stengelkristalle gewachsen sind.
- Bild 3 zeigt die oxidischen Stengelkristalle in gegenüber Bild 2 10-facher Vergrößerung. Danach liegen die Achsen der oxidischen Stengelkristalle überwiegend senkrecht zur geometrischen Oberfläche des Halbzeugs, die durch die Oberflächen der metallenen' Stengelkristalle gebildet wird.
- Figure 1 shows a semi-finished product surface produced using conventional methods with irregularly lying whisker-like oxidic stem crystals.
- Figure 2 shows the semi-finished product surface as it is formed when the method according to the invention is carried out. The large areas are the metal stem crystals, from the surface of which the oxide stem crystals have grown like hair.
- Figure 3 shows the oxide stem crystals in 10 times magnification compared to Figure 2. Thereafter, the axes of the oxide stem crystals are predominant perpendicular to the geometric surface of the semi-finished product, which is formed by the surfaces of the metal 'stem crystals.
Gehalte von 14 bis 25 % Chrom und 5 bis 9 % Aluminium in der Matrix aus Eisen und/oder Nickel und/oder Cobalt haben sich als besonders geeignet zur Ausbildung der überwiegend aus Aluminium-,und Chromoxid oder in Abhängigkeit von den Glühbedingungen praktisch ausschließlich aus Aluminiumoxid bestehenden oxidischen Stengelkristalle erwiesen. Weitere Elemente, die die Stengelkristallbildung nicht beeinträchtigen oder sie sogar begünstigen, können außer den genannten Elementen enthalten sein.Contents of 14 to 25% chromium and 5 to 9% aluminum in the matrix made of iron and / or nickel and / or cobalt have been found to be particularly suitable for the formation of predominantly aluminum oxide and chromium oxide or, depending on the annealing conditions, practically exclusively Alumina existing oxidic stem crystals proved. In addition to the elements mentioned, other elements which do not impair or even favor the formation of stem crystals can be present.
Der mittlere Korndurchmesser D der metallenen Stengelkristalle kann 5 bis 50 pm betragen. Vorzugsweise wählt man je nach Legierung und Wandstärke die Abkühlrate so, daß der mittlere Korndurchmesser D = 5 bis 30 µm beträgt. Die Länge der Körner sollte sein L = 15 µm bis zur Dicke des Bandes, vorzugsweise L = 20 bis 100 µm, mit L : D ≥3.The average grain diameter D of the metal stem crystals can be 5 to 50 pm. Depending on the alloy and wall thickness, the cooling rate is preferably chosen so that the average grain diameter is D = 5 to 30 μm. The length of the grains should be L = 15 µm to the thickness of the tape, preferably L = 20 to 100 µm, with L: D ≥3.
Es hat sich gezeigt, daß sich, durch die kristallographisch überwiegend einheitliche Ausrichtung der Körner des Gefüges bedingt, eng aneinander stehende aber separate Oxidkörner mit einem Durchmesser je nach Züchtungsbedingungen von d = 0,05 bis 3 µm, und Längen von 1 = 0,5 bis 15 pm mit 1 : d ≥ 3 bilden.It has been shown that, due to the crystallographically predominantly uniform alignment of the grains of the structure, there are closely spaced but separate oxide grains with a diameter of d = 0.05 to 3 μm, depending on the growing conditions, and lengths of 1 = 0.5 to 15 pm with 1: d ≥ 3.
Das Verfahren gemäß der Erfindung ist dadurch gekennzeichnet, daß das Halbzeug aus dem schmelzflüssigen Zustand in einer zur geometrischen Oberfläche überwiegend parallelen Front mit einer Abkühlungsgeschwindigkeit von 103 bis 106 K/s erstarrt wird, dann zunächst bei einer Temperatur von 800 bis 1000 °C kurzzeitig in einem Sauerstoff in gebundener Form enthaltenen Gas, insbesondere C02, unter sich dabei einstellenden, reduzierenden Bedingungen und anschließend im Temperaturbereich von 800 bis 1000 °C bis zu 25 h an Luft geglüht wird.The method according to the invention is characterized in that the semi-finished product is solidified from the molten state in a front that is predominantly parallel to the geometric surface with a cooling rate of 10 3 to 10 6 K / s, then first at one Temperature of 800 to 1000 ° C for a short time in an oxygen contained in bound form gas, in particular C0 2 , under the resulting reducing conditions and then in the temperature range from 800 to 1000 ° C for up to 25 h in air.
Durch die Erfindung wird ein metallenes Halbzeug geschaffen, bei dem mindestens im Oberflächenbereich durch die gerichtete Erstarrung der Metallegierung metallene Stengelkristallite gebildet werden. Durch die hohe Abkühlungsgeschwindigkeit und thermische Behandlung bedingt, fungieren die Zusatzelemente aus der vorgenannten Gruppe X, die hochreaktiv sind, d.h. hochsauerstoffaffin sind, bzw. deren Oxide, die in fein verteilter Form im Oberflächenbereich vorliegen, bei der anschließenden Wärmebehandlung als Keime. Gleichzeitig sorgen sie als eine Art Dübel für eine hohe Haftfestigkeit der im Anschluß thermisch gezüchteten oxidischen Stengelkristallite. Eine weiter verbesserte Keimbildung wird dadurch erzielt, daß man als erste thermische Behandlungsstufe kurzzeitig unter reduzierenden oder sich bei dieser Behandlung einstellenden reduzierenden Bedingungen erhitzt. Anschließend erfolgt die langzeitige Glühbehandlung unter oxidierenden Bedingungen, vorzugsweise an Luft, bei der die oxidischen Stengelkristallite wachsen, die überwiegend aus Aluminiumoxid und/oder Chromoxid bestehen, deren Achsen ebenfalls überwiegend senkrecht zur geometrischen Oberfläche des Halbzeugs stehen. Aufgrund dieser Stengelkristallbildung wird eine außerordentlich große Oberfläche geschaffen, in der sich ein metallener und/oder keramischer Überzug sehr gut verankern läßt.The invention provides a semi-finished metal product in which metal stem crystallites are formed at least in the surface area by the directional solidification of the metal alloy. Due to the high cooling rate and thermal treatment, the additional elements from the aforementioned group X, which are highly reactive, i.e. are highly oxygen-affine, or their oxides, which are present in finely divided form in the surface area, as germs in the subsequent heat treatment. At the same time, as a kind of dowel, they ensure a high level of adhesive strength for the thermally grown oxidic stem crystallites. A further improved nucleation is achieved by briefly heating as the first thermal treatment stage under reducing conditions or those that occur during this treatment. This is followed by the long-term annealing treatment under oxidizing conditions, preferably in air, in which the oxidic stem crystallites grow, which predominantly consist of aluminum oxide and / or chromium oxide, the axes of which are also predominantly perpendicular to the geometric surface of the semi-finished product. Due to this stem crystal formation, an extraordinarily large surface is created, in which a metallic and / or ceramic coating can be very well anchored.
Die Größe der Körner des Metallgefüges wird durch die Abkühlgeschwindigkeit und den Wärmeinhalt der Metallschmelze bestimmt. Zur Herstellung von Bändern mit ca. 50 um Dicke, wie sie z.B. als Träger für Abgaskatalysatoren für Kraftfahrzeuge und Kraftwerke benötigt werden, hat es sich als günstig herausgestellt, mit einer Vorrichtung zu arbeiten, bei der unter einem Tiegel, der einen langen, dünnen Spalt als Düse aufweist, wobei der Spalt ggf. mit Hilfe einer angeschrägten keramischen Stopfenstange geöffnet werden kann, eine oder zwei Rollen angeordnet sind. Die Rolle oder die Rollen können an ihrer Umfangsfläche eine vorgegebene Welligkeit aufweisen, so daß der Metallstrahl auf der einen Rolle bzw. im vorgegebenen Spalt zwischen den beiden Rollen schon in der für den Einsatzzweck notwendigen geometrischen Gestalt erstarrt. Die Anordnung hat folgende Vorteile:
- - das Metallband braucht im wesentlichen nicht mehr plastisch verformt zu werden; Bereiche plastischer Verformung führen bekanntlich zu unkontrolliertem Wachstum der Körner des Metallgefüges bei den anschließenden Behandlungsschritten bei erhöhten Temperaturen und damit zur unregelmäßigen Ausbildung der Körner der Oxidschicht;
- - die Rolle bzw. Rollen können aus einem Material wie Stahl oder Keramik mit einer geringeren Wärmeleitfähigkeit hergestellt werden, als dies mit Kupferrollen für die Herstellung amorpher Bänder notwendig ist;
- - die Rolle bzw. Rollen werden wenn nötig mit Hilfe von erwärmtem, umlaufendem öl auf eine vorgegebene Temperatur gehalten, wodurch auf diese Weise die gewünschte Kristallgröße des Metallgefüges eingestellt wird und eine besondere Wärmenachbehandlung zur Korngrößeneinstellung entfallen kann.
- - The metal strip essentially no longer needs to be plastically deformed; Areas of plastic deformation are known to lead to uncontrolled growth of the grains of the metal structure in the subsequent treatment steps at elevated temperatures and thus to the irregular formation of the grains of the oxide layer;
- - The roll or rolls can be made of a material such as steel or ceramic with a lower thermal conductivity than is necessary with copper rolls for the production of amorphous strips;
- - If necessary, the roller or rollers are kept at a predetermined temperature with the aid of heated, circulating oil, as a result of which the desired crystal size of the metal structure is set and a special heat treatment for grain size adjustment can be omitted.
Es hat sich nun herausgestellt, daß man auf diese Weise profilierte, feinkristalline Bänder von ca. 20 bis 200 µm, mit Hilfe von gekühlten Kupferrollen auch möglicherweise bis zu etwa 500 µm und mehr herstellen kann. Vorzugsweise stellt man Bänder von ca. 40 bis 70 µm Dicke her.It has now been found that profiled, finely crystalline strips of approximately 20 to 200 μm can be produced in this way, with the aid of cooled copper rolls, possibly up to approximately 500 μm and more. It is preferable to produce tapes approximately 40 to 70 µm thick.
So ist ea auf diese Weise moglich, Aluminiumoxid-Schichten zu erzeugen, die aus einzelnen voneinander getrennt aber weitgehend gleichformig gewaobsenen Oxid-Körnern mit einem Durchmesser von vorzugsweise d = 0,1 µm bis 0, 3 µm und einer Länge 1 = 4 bis 15 µm bestehen, so daß hierauf die Abscheidung ven katalytisch aktiven Substanzen vorgenommen werden kann, ehne daß eine zusätzliche Zwischenschicht (wash coat), wie z.B. bei rein exidischen Katalysator-Trägern, notwendig ist.It is thus possible in this way to produce aluminum oxide layers which are composed of individual oxide grains, which are separately but largely uniformly shaped, with a diameter of preferably d = 0.1 μm to 0.3 μm and a length 1 = 4 to 15 µm exist, so that the deposition of catalytically active substances can be carried out before an additional intermediate layer (wash coat), such as with purely exidic catalyst supports.
Die geschilderte Stengelkristallbildung mindestens im Oberflächenbereich des Helbzeugs kann alternativ zu dem vorstehend erwähnt en Gieben auf gekühlte Walzen auch durch kurzzeitiges Aufschmelzen einer Oberflächenschicht des gegossenen oder gewalzten Halbzeugs mit anschließendem Selbstabkuhlen erreicht werden.The described formation of stem crystals, at least in the surface area of the auxiliary device, can alternatively be achieved by briefly melting a surface layer of the cast or rolled semifinished product with subsequent self-cooling, in addition to the above-mentioned pouring onto cooled rolls.
Die Erfindung wird im folgenden anhand von drei Ausführungsbeispielen erlauter.The invention is explained below using three exemplary embodiments.
Es wurde mit Hilfe einer Relle aus Stahl, die durch einen Ölkreislauf auf einer konstanten Temperatur gehalten wurde, ein Metallband von 50 µm Dicke bei einer Abkühlrate von 105 bis 104 K/s hergestellt. Die Materialzusammensetzung ist 20 % Chrom, 5% Aluminium, 0,15 % Cer, 0,01 % Lanthan, Rest Eisen mit geringen Anteilen an Si, Mn, C, S, P, Ni als Spurenelemente.With the aid of a steel bar, which was kept at a constant temperature by an oil circuit, a metal strip of 50 μm thickness was produced at a cooling rate of 10 5 to 10 4 K / s. The material composition is 20% chromium, 5% aluminum, 0.15% cerium, 0.01% lanthanum, the rest iron with small amounts of Si, Mn, C, S, P, Ni as trace elements.
Das Band wurde anschließend einer Wärmevorbehandlung von 900 °C eine Minute lang trockenem Kohlendioxidgas ausgesetzt und anschließend an Luft bei 925 °C sechzehn Stunden gehalten. Eine kalt gewalzte Folie gleicher Materialzusammensetzung wurde nach einer Rekristallisationsglühung ebenso behandelt.The tape was then preheated to 900 ° C dry carbon dioxide gas for one minute and then held in air at 925 ° C for 16 hours. A cold rolled sheet of the same material composition was also treated after recrystallization annealing.
Es zeigt sich, daß die stengelförmigen Oxid-Körner des gegossenen Bandes Durchmesser von ca. 0,2 µm und Längen von im Mittel ca. 4 µm aufweisen und sie nahezu einheitlich senkrecht zur Oberfläche der Metallkörner angeordnet sind, während die durch Walzen hergestellte Probe schuppenförmige, untereinander zum Teil in Kontakt stehende Körner unterschiedlicher Ausrichtung und Länge von bis zu ca. 3 µm aufweist.It can be seen that the stalk-shaped oxide grains of the cast strip have diameters of approximately 0.2 μm and lengths of on average approximately 4 μm and that they are arranged almost uniformly perpendicular to the surface of the metal grains, while the sample produced by rolling is scaly , partially in contact with each other grains of different orientation and length of up to about 3 microns.
Es wurde eine 10 mm dicke Platte aus dem im Beispiel 1 beschriebenen Material mit einem Elektronenstrahl so beschossen, daß ein Fleck von ca. 0,5 mm Durchmesser bis zu 100 pm tief aufgeschmolzen wurde. Die Platte wurde anschließend 1 Minute in C02-Gas bei 900 °C behandelt. Im weiteren wurde wie im Beispiel 1 verfahren.A 10 mm thick plate made of the material described in Example 1 was bombarded with an electron beam in such a way that a spot approximately 0.5 mm in diameter was melted down to a depth of 100 μm. The plate was then treated in CO 2 gas at 900 ° C. for 1 minute. The procedure was as in Example 1.
Es zeigte sich, daß die erzeugten Oxid-Körner bzw. Whisker im Bereich des Schmelzfleckes eine ähnlich gute Qualität wie die der gegossenen Probe nach dem Beispiel 1 aufweisen.It was found that the oxide grains or whiskers produced in the area of the melting spot have a similar quality to that of the cast sample according to Example 1.
Die Probe wurde mehreren Temperaturwechseln ausgesetzt, wobei sie auf ca. 1000 °C erhitzt in einem Ölbad abgeschreckt wurde. Die Stengel-Oxid-Körner des Bereiches des Schmelzfleckes wurden durch die Behandlung nicht angegriffen, die Oxidschicht der übrigen Probenoberfläche zeigt einzelne Abplatzungen.The sample was subjected to several temperature changes, being heated to approximately 1000 ° C. and quenched in an oil bath. The stem oxide grains in the area of the melting spot were not attacked by the treatment, the oxide layer on the rest of the sample surface shows individual flaking.
Es wurde eine Platte nach Beispiel 2 mit einem ähnlichen Schmelzfleck hergestellt, anschließend eine Ätzung vorgenommen, so daß die Korngrenzen bis in eine Tiefe von 20 pm freigelegt wurden und anschließend wurde weiter nach Beispiel 1 verfahren. Es zeigte sich, daß auf den so teilweise freigelegten Metallkörnern eine strahlenförmige Oxid-Korn-Schicht gleicher Qualität des Beispiels 1 gewachsen ist.A plate was produced according to Example 2 with a similar melting spot, then an etching was carried out so that the grain boundaries were exposed to a depth of 20 pm and the procedure according to Example 1 was then continued. It was found that a radiation-like oxide-grain layer of the same quality as in Example 1 had grown on the metal grains which had been partially exposed.
Auf diese Weise gelingt es, eine besonders große Oberfläche zu erzeugen, so daß zur Verwendung als Katalysatorträger vorzugsweise keine bzw. nur ein sehr dünne (20 um dicke) Zwischenschicht (wash coat) mehr nötig erscheint.In this way, it is possible to produce a particularly large surface area, so that preferably no or only a very thin (20 μm thick) intermediate layer (wash coat) appears to be necessary for use as a catalyst support.
Es ist möglich, die so erzeugte Oxidschicht durch Besanden, Schlickern, Flamm- oder Plasmaspritzen oder auch durch andere bekannte Methoden noch zusätzlich mit Keramik oder Metallen zu beschichten. Durch die Abfolge der Schritte Schlickern-Trocknen-Plasmaspritzen lassen sich sogar nahezu gasdichte Oxidschichten aufbringen, die nur über die stengelförmigen Oxidkörner fest mit dem Metallkörper verbunden sind und deshalb eine hohe Temperaturwechselbeständigkeit aufweisen.It is possible to additionally coat the oxide layer produced in this way with sanding, slip, flame or plasma spraying or also by other known methods with ceramic or metals. The sequence of the steps of slip-drying-plasma spraying even allows almost gas-tight oxide layers to be applied, which are only firmly connected to the metal body via the stem-shaped oxide grains and therefore have a high resistance to temperature changes.
Claims (14)
daß mindestens im Oberflächenbereich des Halbzeugs metallene Stengelkristalle gebildet sind, aus denen heraus überwiegend aus Aluminiumoxid und/oder Chromoxid bestehende Stengelkristalle gewachsen sind, wobei die Achsen beider Stengelkristalltypen überwiegend senkrecht zur geometrischen Oberfläche des Halbzeugs stehen.1. Metal semi-finished product based on iron and / or nickel and / or cobalt with 2 to 16% aluminum, 12 to 30% chromium and up to 4% of at least one highly reactive element from the group Y, Zr, Ti, Ce, Sm, Hf , La, Th, U, V, W, Ta, Nb, Mo, Gd, Si, Mg, Ca and / or their dispersed oxides, as well as inevitable impurities,
that metal stem crystals are formed at least in the surface area of the semifinished product, from which stem crystals consisting predominantly of aluminum oxide and / or chromium oxide have grown, the axes of both types of stem crystal being predominantly perpendicular to the geometric surface of the semifinished product.
dadurch gekennzeichnet , daß es 14 bis 25 % Chrom enthält.2. semi-finished product according to claim 1,
characterized in that it contains 14 to 25% chromium.
dadurch gekennzeichnet,
daß die metallenen Stengelkristalle einen mittleren Durchmesser D = 5 bis 50 pm und eine Länge L = 15 pm bis zur Dicke des Halbzeugs haben mit L : D ≥3.4. Semi-finished product according to one of claims 1 to 3,
characterized,
that the metal stem crystals have an average diameter D = 5 to 50 pm and a length L = 15 pm up to the thickness of the semi-finished product with L: D ≥3.
dadurch gekennzeichnet ,
daß die metallenen Stengelkristalle einen mittleren Durchmesser D = 10 bis 30 µm und eine Länge L = 30 bis 100 µm haben mit L : D ≥ 3:5. semi-finished product according to claim 4,
characterized ,
that the metal stem crystals have an average diameter D = 10 to 30 µm and a length L = 30 to 100 µm with L: D ≥ 3:
dadurch gekennzeichnet,
daß die oxidischen Stengelkristalle einen mittleren Durchmesser d = 0,05 bis 3 µm und eine Länge 1 = 0,5 bis 15 pm haben mit 1 : d ≥ 3.6. Semi-finished product according to one of claims 1 to 5,
characterized,
that the oxidic stem crystals have an average diameter d = 0.05 to 3 µm and a length 1 = 0.5 to 15 pm with 1: d ≥ 3.
dadurch gekennzeichnet,
daß die oxidischen Stengelkristalle einen mittleren Durchmesser d = 0,1 bis 0,3 µm und eine Länge von 4 bis 10 µm haben mit 1 : d ≥ 3.7. semi-finished product according to claim 6,
characterized,
that the oxide stem crystals have an average diameter d = 0.1 to 0.3 µm and a length of 4 to 10 µm with 1: d ≥ 3.
dadurch gekennzeichnet , daß das Halbzeug aus dem schmelzflüssigen Zustand überwiegend parallel zur geometrischen Oberfläche mit einer Abkühlungsgeschwindigkeit von 103 bis 10 6 K/s erstarrt wird, dann zunächst bei einer Temperatur von 800 bis 1000 °C kurzzeitig in einem Sauerstoff in gebundener Form enthaltenen Gas, insbesondere C02, unter sich dabei einstellenden, reduzierenden Bedingungen und anschließend im Temperaturbereich von 800 bis 1000 °C bis zu 25 h an Luft geglüht wird.8. A process for the production of metal semifinished product according to one of claims 1 to 7,
characterized in that the semi-finished product is solidified from the molten state predominantly parallel to the geometric surface with a cooling rate of 10 3 to 10 6 K / s, then briefly at a temperature of 800 to 1000 ° C in a gas contained in oxygen in a bound form , in particular C0 2 , is set under reducing conditions and then in the temperature range from 800 to 1000 ° C for up to 25 h in air.
dadurch gekennzeichnet; daß das Halbzeug durch Bandgießen mittels mindestens einer gekühlten Rolle oder durch Stranggießen erzeugt wird.9. The method according to claim 8,
characterized; that the semi-finished product is produced by strip casting using at least one cooled roll or by continuous casting.
dadurch gekennzeichnet , daß das zuvor erzeugte Halbzeug oberflächlich kurzzeitig aufgeschmolzen und an Luft, im Vakuum oder unter Inertgas abgekühlt wird.10. The method according to claim 8,
characterized in that the semi-finished product previously produced is melted briefly on the surface and cooled in air, in a vacuum or under inert gas.
dadurch gekennzeichnet , daß das Glühen an Luft bei einer Temperatur im Bereich von 850 bis 1000 °C für 4 bis 20 h vorgenommen wird.11. The method according to any one of claims 8 to 10,
characterized in that the annealing in air is carried out at a temperature in the range of 850 to 1000 ° C for 4 to 20 h.
dadurch gekennzeichnet , daß das Glühen unter reduzierenden Bedingungen bei einer Temperatur im Bereich von 880 bis 980 °C für 0,5 bis 4 min vorgenommen wird.12. The method according to claim 8 to 11,
characterized in that the annealing is carried out under reducing conditions at a temperature in the range of 880 to 980 ° C for 0.5 to 4 minutes.
hergestellten Halbzeugs mit Merkmalen der Ansprüche 1 bis 7 als temperaturwechselbeständiger Haftgrund für einen metallenen oder keramischen Überzug.13. Use of one according to claims 8 to 12
Manufactured semi-finished product with features of claims 1 to 7 as a temperature change-resistant adhesive for a metal or ceramic coating.
hergestellten Halbzeugs mit Merkmalen der Ansprüche 1 bis 7 als Katalysatorträger.14. Use of one according to claims 8 to 13
Semi-finished product with features of claims 1 to 7 as a catalyst support.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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AT87102472T ATE65552T1 (en) | 1986-03-01 | 1987-02-21 | METAL SEMI-FINISHED PRODUCT, METHOD OF MANUFACTURE AND USE OF THE SEMI-FINISHED PRODUCT. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE19863606804 DE3606804A1 (en) | 1986-03-01 | 1986-03-01 | METALLIC SEMI-FINISHED PRODUCT AND METHOD FOR THE PRODUCTION AND USE THEREOF |
DE3606804 | 1986-03-01 |
Publications (3)
Publication Number | Publication Date |
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EP0236823A2 true EP0236823A2 (en) | 1987-09-16 |
EP0236823A3 EP0236823A3 (en) | 1988-05-25 |
EP0236823B1 EP0236823B1 (en) | 1991-07-24 |
Family
ID=6295321
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP87102472A Expired - Lifetime EP0236823B1 (en) | 1986-03-01 | 1987-02-21 | Metallic semi-finished product, process for its manufacture and uses of the semi-finished product |
Country Status (6)
Country | Link |
---|---|
US (1) | US4798631A (en) |
EP (1) | EP0236823B1 (en) |
JP (1) | JPH0660386B2 (en) |
KR (1) | KR940003503B1 (en) |
AT (1) | ATE65552T1 (en) |
DE (2) | DE3606804A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0358309A1 (en) * | 1988-09-06 | 1990-03-14 | General Motors Corporation | Accelerated whisker growth on iron-chromium-aluminium alloy foil |
EP0625585A1 (en) * | 1993-05-20 | 1994-11-23 | Kawasaki Steel Corporation | Fe-Cr-Al alloy foil having high oxidation resistance for a substrate of a catalytic converter and method of manufacturing same |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6411957A (en) * | 1987-07-04 | 1989-01-17 | Kawasaki Steel Co | Manufacture of stainless steel having high-temperature oxidation film excellent in corrosion resistance |
JP3386848B2 (en) * | 1992-06-10 | 2003-03-17 | 株式会社島津製作所 | Exhaust gas purification device and method of manufacturing the same |
JP3374173B2 (en) * | 1999-10-21 | 2003-02-04 | 独立行政法人物質・材料研究機構 | Method for producing heat-resistant intermetallic compound Ni3Al foil having ductility at room temperature and heat-resistant intermetallic compound Ni3Al foil having ductility at room temperature |
JP3611107B2 (en) * | 2000-04-12 | 2005-01-19 | セイコーエプソン株式会社 | Cooling roll |
JP3728396B2 (en) | 2000-04-12 | 2005-12-21 | セイコーエプソン株式会社 | Manufacturing method of magnet material |
JP3587140B2 (en) | 2000-07-31 | 2004-11-10 | セイコーエプソン株式会社 | Method for producing magnet powder, magnet powder and bonded magnet |
JP4554794B2 (en) * | 2000-08-23 | 2010-09-29 | 日本冶金工業株式会社 | Stainless steel with insulating layer |
EP1344907A1 (en) * | 2002-03-12 | 2003-09-17 | Capital Technology GmbH | Device for removing carbon particles from exhaust gases |
EP1935996A1 (en) * | 2002-11-04 | 2008-06-25 | Paralloy Limited | High temperature resistant alloys |
GB2394959A (en) * | 2002-11-04 | 2004-05-12 | Doncasters Ltd | Hafnium particle dispersion hardened nickel-chromium-iron alloys |
JP4614063B2 (en) * | 2004-05-20 | 2011-01-19 | 日産自動車株式会社 | Whisker forming body and method for producing whisker forming body |
JP4788878B2 (en) * | 2004-07-01 | 2011-10-05 | 日産自動車株式会社 | Whisker coating material and manufacturing method thereof |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3027252A (en) * | 1959-09-29 | 1962-03-27 | Gen Electric | Oxidation resistant iron-chromium alloy |
US3298826A (en) * | 1964-04-06 | 1967-01-17 | Carl S Wukusick | Embrittlement-resistant iron-chromium-aluminum-yttrium alloys |
EP0091526A2 (en) * | 1982-04-12 | 1983-10-19 | Allegheny Ludlum Corporation | Iron-chromium-aluminium alloy and article and method therefor |
EP0232793A1 (en) * | 1986-01-30 | 1987-08-19 | Nippon Steel Corporation | Stainless steel ribbon for use as a catalyst carrier for automobile exhaust gas and method for producing same |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4945456B1 (en) * | 1969-06-25 | 1974-12-04 | ||
US4331631A (en) * | 1979-11-28 | 1982-05-25 | General Motors Corporation | Enhanced oxide whisker growth on peeled Al-containing stainless steel foil |
GB2158746A (en) * | 1984-05-14 | 1985-11-20 | Olin Corp | Apparatus and process for rolling spin cast strip |
-
1986
- 1986-03-01 DE DE19863606804 patent/DE3606804A1/en active Granted
-
1987
- 1987-02-21 AT AT87102472T patent/ATE65552T1/en not_active IP Right Cessation
- 1987-02-21 DE DE8787102472T patent/DE3771526D1/en not_active Expired - Fee Related
- 1987-02-21 EP EP87102472A patent/EP0236823B1/en not_active Expired - Lifetime
- 1987-02-25 US US07/018,545 patent/US4798631A/en not_active Expired - Fee Related
- 1987-02-28 KR KR1019870001778A patent/KR940003503B1/en not_active IP Right Cessation
- 1987-02-28 JP JP62044144A patent/JPH0660386B2/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3027252A (en) * | 1959-09-29 | 1962-03-27 | Gen Electric | Oxidation resistant iron-chromium alloy |
US3298826A (en) * | 1964-04-06 | 1967-01-17 | Carl S Wukusick | Embrittlement-resistant iron-chromium-aluminum-yttrium alloys |
EP0091526A2 (en) * | 1982-04-12 | 1983-10-19 | Allegheny Ludlum Corporation | Iron-chromium-aluminium alloy and article and method therefor |
EP0232793A1 (en) * | 1986-01-30 | 1987-08-19 | Nippon Steel Corporation | Stainless steel ribbon for use as a catalyst carrier for automobile exhaust gas and method for producing same |
Non-Patent Citations (2)
Title |
---|
J. ELECTROCHEM. SOC., Solid-State Science and Technology, Band 131, Nr. 4, Seiten 923-931; T.A. RAMANARAYANAN et al.: "The characteristics of alumina scales formed on FE-based Yttria-dispersed alloys" * |
K.N. STRAFFORD, "High Temperature Technology, vol. 1, No. 6, Nov. 1983, p. 307-318 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0358309A1 (en) * | 1988-09-06 | 1990-03-14 | General Motors Corporation | Accelerated whisker growth on iron-chromium-aluminium alloy foil |
EP0625585A1 (en) * | 1993-05-20 | 1994-11-23 | Kawasaki Steel Corporation | Fe-Cr-Al alloy foil having high oxidation resistance for a substrate of a catalytic converter and method of manufacturing same |
Also Published As
Publication number | Publication date |
---|---|
JPH0660386B2 (en) | 1994-08-10 |
EP0236823B1 (en) | 1991-07-24 |
KR870009050A (en) | 1987-10-23 |
US4798631A (en) | 1989-01-17 |
KR940003503B1 (en) | 1994-04-23 |
ATE65552T1 (en) | 1991-08-15 |
EP0236823A3 (en) | 1988-05-25 |
JPS62290857A (en) | 1987-12-17 |
DE3606804C2 (en) | 1989-03-30 |
DE3606804A1 (en) | 1987-09-10 |
DE3771526D1 (en) | 1991-08-29 |
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