EP0341456A2 - Process for electrolytically depositing a metal layer resisting corrosion by hot gases - Google Patents
Process for electrolytically depositing a metal layer resisting corrosion by hot gases Download PDFInfo
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- EP0341456A2 EP0341456A2 EP89106922A EP89106922A EP0341456A2 EP 0341456 A2 EP0341456 A2 EP 0341456A2 EP 89106922 A EP89106922 A EP 89106922A EP 89106922 A EP89106922 A EP 89106922A EP 0341456 A2 EP0341456 A2 EP 0341456A2
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- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000005260 corrosion Methods 0.000 title claims abstract description 9
- 230000007797 corrosion Effects 0.000 title claims abstract description 9
- 229910052751 metal Inorganic materials 0.000 title claims description 7
- 239000002184 metal Substances 0.000 title claims description 7
- 238000000151 deposition Methods 0.000 title abstract description 3
- 239000007789 gas Substances 0.000 title abstract 2
- 239000000843 powder Substances 0.000 claims abstract description 21
- 229910001092 metal group alloy Inorganic materials 0.000 claims abstract 5
- 239000000725 suspension Substances 0.000 claims description 16
- 239000002245 particle Substances 0.000 claims description 12
- 229910045601 alloy Inorganic materials 0.000 claims description 10
- 239000000956 alloy Substances 0.000 claims description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 239000003792 electrolyte Substances 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- 239000011651 chromium Substances 0.000 claims description 5
- 239000011159 matrix material Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 229910017052 cobalt Inorganic materials 0.000 claims description 3
- 239000010941 cobalt Substances 0.000 claims description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 238000000889 atomisation Methods 0.000 claims description 2
- 230000008021 deposition Effects 0.000 claims description 2
- 238000005086 pumping Methods 0.000 claims description 2
- 238000003756 stirring Methods 0.000 claims description 2
- 238000007664 blowing Methods 0.000 claims 1
- 239000010410 layer Substances 0.000 description 23
- 238000000576 coating method Methods 0.000 description 12
- 238000009434 installation Methods 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 6
- 239000006185 dispersion Substances 0.000 description 6
- 238000005240 physical vapour deposition Methods 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 230000001788 irregular Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 208000000260 Warts Diseases 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000007750 plasma spraying Methods 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 201000010153 skin papilloma Diseases 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000007751 thermal spraying Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
- C25D5/50—After-treatment of electroplated surfaces by heat-treatment
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
- C25D15/02—Combined electrolytic and electrophoretic processes with charged materials
Definitions
- the invention relates to a method for producing galvanically deposited hot gas corrosion layers according to the preamble of patent claim 1.
- Metal layers consisting of a MCrAlY alloy have proven particularly suitable for this.
- M stands for either nickel, cobalt or an alloy of the two. In special cases, iron can also be used.
- the coated surface protective effect is based on the fact that CrAl forms oxides at high temperatures (Cr2O3, Al2O3), which serve as protective films against further oxidation.
- the alloys usually consist of approx. 15 - 25% Cr, 10 - 15% Al, 0.2 - 0.5 Y, balance M (each weight percent).
- the share of Aluminum and chrome should be as high as possible so that the protective effect due to the oxide formation works properly.
- Thermal spraying or the PVD process physical vapor deposition
- the disadvantage of these application processes is above all the high process costs. Attempts have therefore been made to apply the protective layers by means of dispersion coating, since this would result in a considerably more economical procedure.
- the layers produced according to the invention are distinguished by an installation rate of up to 45% by volume, which means that the same layer quality can be achieved as with the known coating processes.
- the production costs of the layers according to the invention are advantageously considerably lower. For example, compared to thermal spray coatings by a factor of 10.
- the coating process is then followed by a heat treatment under vacuum for diffusion annealing, as a result of which alloying begins and a layer quality identical to the known spraying processes can be achieved.
- the low suspension concentration of less than 100 g / l advantageously allows the use of uncomplicated, conventional dispersion separation techniques, which means that the effort, in particular with regard to series production, is considerably less than, for example, for drum technology with bath concentrations of at least 600 g / l is working. In order to achieve acceptable installation rates, however, concentrations of approximately 5000 g / l are required in this known method, as comparative experiments have shown.
- a suspension concentration of 40-60 g / l proved to be particularly advantageous for achieving a high installation rate.
- the shape and other properties of the suspension powder are considered to be immaterial.
- powder particles of spherical shape and passivated surface allow considerably higher installation rates than conventional, in particular ground, powders. This allows the suspension concentration to be significantly reduced while at the same time increasing the layer quality.
- a uniform layer structure is possible, in particular, by passivating the particle surface. This is due to the fact that a particle deposited on the substrate is non-conductive and therefore does not cause a negative change in the surrounding field line course. This advantageously enables undisturbed embedding and over-coating of the particle by means of matrix material. In a preferred development of the invention, this suspension concentration is between 40 and 60 g / l. This results in a particularly uniform layer structure.
- CrAlY is preferably used as the metal powder, since the layer that can be achieved in this way is known to have good corrosion protection properties.
- one or more of the following alloys can alternatively be used as powder: CrAlHf, CrAlYHf, CrAlTa, CrAlYTa, CrNiAl, CrCoAl, CrAlSi, CrAl, MoCrSi.
- a particularly simple and cost-saving production of the suspension powder results if it is produced by spraying in a further development of the invention.
- This allows favorable values for the particle diameter and the extent of the surface passivation to be set by setting the atomization parameters or the ambient gas atmosphere.
- a particle size between 1 and 15 ⁇ m is usually selected.
- the suspension is preferably kept distributed in the electrolyte by introduction of air, pumping around and / or stirring devices. In this way, compared to a drum arrangement, the method can be simplified with good mixing at the same time.
- a co-electrolyte with 480 g / l CoSO4, 35 g / l H3BO3 and 20 g / l NaCl is given, with a pH between 4.5 and 4.7 is set.
- a CrAlY suspension with spherical, passivated powder particles with a particle size of ⁇ 10 ⁇ m was added until a concentration of 100 g / l of the suspension resulted.
- the turbine blades to be coated were then connected to the cathode and immersed in the bath.
- a direct current of current density 2 A / dm 2 was set until a layer thickness of approximately 100 ⁇ m was achieved.
- the turbine blades were then removed and a cross-section of one of them was made (FIG. 1).
- An installation rate of about 45 vol.% Was found with a very even layer structure.
- the turbine blades are then subjected to a temperature of 1050 ° C. in vacuo for 50 h. This results in an alloy formation, by means of which a known method (PVD, thermal Spray) identical layer is produced.
- PVD thermal Spray
- 2a shows an element distribution image of chromium of a Co-CrAlY-coated sample immediately after the deposition.
- 2b shows the chrome element distribution image after the heat treatment.
- a CrAlY powder with a particle size ⁇ 10 .mu.m in a concentration of 300 g / l was added to the same electrolyte, the powder having been prepared by grinding under organic liquid.
- a micrograph (cross-section) of the layer obtained here is shown in FIG. 3, an installation rate of vol.% Being achievable.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Engineering & Computer Science (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Coating By Spraying Or Casting (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (AREA)
- Hydrogen, Water And Hydrids (AREA)
- Gas Separation By Absorption (AREA)
- Filtering Materials (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Erzeugung galvanisch abgeschiedener Heißgaskorrosionsschichten gemäß Oberbegriff des Patentanspruchs 1.The invention relates to a method for producing galvanically deposited hot gas corrosion layers according to the preamble of patent claim 1.
Im Gasturbinenbau gehen die Bestrebungen dahin, das Verhalten thermisch hochbelasteter Bauteile, insbesondere der Turbinenschaufeln der ersten Turbinenstufe durch Aufbringung hochwertiger Korrosionsschutzschichten weiter zu verbessern. Hierzu erwiesen sich Metall schichten als besonders geeignet, die aus einer MCrAlY-Legierung bestehen. Dabei steht M entweder für Nickel, Kobalt oder eine Legierung der beiden. In besonderen Fällen kann auch Eisen zur Anwendung gelangen.In gas turbine construction, efforts are being made to further improve the behavior of thermally highly stressed components, in particular the turbine blades of the first turbine stage, by applying high-quality corrosion protection layers. Metal layers consisting of a MCrAlY alloy have proven particularly suitable for this. M stands for either nickel, cobalt or an alloy of the two. In special cases, iron can also be used.
Der die beschichtete Fläche schützende Effekt beruht auf dem Umstand, daß CrAl bei den hohen vorkommenden Temperaturen Oxide bildet (Cr₂O₃, Al₂O₃), die als Schutzfilme vor weiterer Oxidation dienen.The coated surface protective effect is based on the fact that CrAl forms oxides at high temperatures (Cr₂O₃, Al₂O₃), which serve as protective films against further oxidation.
Die Legierungen bestehen üblicherweise aus ca. 15 - 25 % Cr, 10 - 15 % Al, 0,2 - 0,5 Y, Rest M (jeweils Gewichtsprozent). Der Anteil von Aluminium und Chrom sollte dabei so hoch wie möglich liegen, damit der Schutzeffekt durch die Oxidbildung ausreichend funktioniert. Als Aufbringverfahren eignen sich das thermische Spritzen oder das PVD-Verfahren (physical vapour deposition), da hierdurch der erforderliche hohe Anteil von CrAlY in der Schicht erzielbar ist. Nachteilig bei diesen Aufbringverfahren wirken sich vor allem die hohen Verfahrenskosten aus. Es wurden deshalb Versuche unternommen, mittels Dispersionsbeschichtung die Schutzschichten aufzubringen, da hierdurch eine erheblich wirtschaftlichere Verfahrensweise erzielbar wäre. Dabei ergaben sich jedoch eine Reihe von Nachteilen. So ließen sich mit herkömmlichen Dispersionsbeschichtungsverfahren nur geringe Einbauraten des Suspensionspulvers in der Metallmatrix erzielen. Diese liegen im Bereich von 20 Vol. %, wodurch der erforderliche hohe Cr und Al-Anteil nicht erzielbar ist und somit die Schichtqualität unzureichend bleibt. Wünschenswert wären Anteile von über 40 Vol. %, um die gleiche Schichtqualität wie bei PVD oder Plasmaspritzverfahren zu erzielen.The alloys usually consist of approx. 15 - 25% Cr, 10 - 15% Al, 0.2 - 0.5 Y, balance M (each weight percent). The share of Aluminum and chrome should be as high as possible so that the protective effect due to the oxide formation works properly. Thermal spraying or the PVD process (physical vapor deposition) are suitable as the application process, since this enables the required high proportion of CrAlY in the layer to be achieved. The disadvantage of these application processes is above all the high process costs. Attempts have therefore been made to apply the protective layers by means of dispersion coating, since this would result in a considerably more economical procedure. However, there were a number of disadvantages. With conventional dispersion coating processes, only low installation rates of the suspension powder in the metal matrix could be achieved. These are in the range of 20 vol.%, Which means that the required high Cr and Al content cannot be achieved and the layer quality thus remains inadequate. Shares of over 40% by volume would be desirable in order to achieve the same layer quality as with PVD or plasma spraying.
In der Zeitschrift "Plating and Surface Finishing" vom Oktober 1986 ist auf Seite 42 ein Verfahren beschrieben, das diese Nachteile beseitigen soll. Bei diesem Verfahren rotiert eine suspensionsgefüllte Trommel mit teilweise porösen Wandungen und innen angebrachten Substraten in einem Elektrolytbad. Wenngleich hierbei relativ hohe Einbauraten erzielbar sind, zeigt sich jedoch der Nachteil, daß die Schicht sehr unregelmäßig ist. Insbesondere zeigen sich erhebliche warzige Abscheidungen, und bei Beschichtung von Turbinenschaufeln eine unregelmäßige Beschichtung, d. h., an den Schaufelkanten ist die Schicht dicker als in der Blattmitte. Diese nachteilige Wirkung ließe sich theoretisch durch die Montage von Blenden verhindern, da dies jedoch zu einem Kurzschluß führen würde, muß diese Maßnahme ausscheiden. Schließlich ist das Beschichtungsverfahren sehr zeitraubend und eignet sich daher wirtschaftlich nicht für den Serienbetrieb.In the magazine "Plating and Surface Finishing" from October 1986, page 42 describes a process which is intended to eliminate these disadvantages. In this process, a suspension-filled drum with partially porous walls and internally attached substrates rotates in an electrolyte bath. Although relatively high installation rates can be achieved here, there is, however, the disadvantage that the layer is very irregular. In particular, there are considerable warty deposits, and when coating turbine blades, an irregular coating, ie the layer at the blade edges is thicker than in the middle of the blade. Theoretically, this disadvantageous effect could be prevented by installing panels, but since this would lead to a short circuit, this measure must be eliminated. After all, the coating process is very time-consuming and is therefore not economically suitable for series production.
Ein weiterer wesentlicher Nachteil herkömmlicher Dispersionsbeschichtungen ist es, daß häufig ein sehr poröser Schichtaufbau und rauhe, mit Dendriten besetzte Oberflächen anzutreffen sind.Another major disadvantage of conventional dispersion coatings is that a very porous layer structure and rough surfaces covered with dendrites are often encountered.
Aufgabe der Erfindung ist es daher, diese Nachteile zu vermeiden und ein Dispersionsbeschichtungsverfahren der gattungsgemäßen Art anzugeben, bei dem unter geringem Verfahrensaufwand eine gleichmäßige, qualitativ hochwertige Heißgaskorrosionsschicht erzielbar ist, die eine Einbaurate von über 40 Vol. % des Suspensionspulvers in der Metallmatrix aufweist.It is therefore an object of the invention to avoid these disadvantages and to provide a dispersion coating process of the generic type in which a uniform, high-quality hot gas corrosion layer can be achieved with little outlay on the process and which has an installation rate of over 40% by volume of the suspension powder in the metal matrix.
Erfindungsgemäß wird die Aufgabe mit den Merkmalen des Patentanspruchs 1 gelöst. Vorteilhafte Weiterbildung der Erfindung ergeben sich aus den Unteransprüchen.According to the invention the object is achieved with the features of claim 1. Advantageous further developments of the invention result from the subclaims.
Die erfindungsgemäß hergestellten Schichten zeichnen sich durch eine Einbaurate von bis zu 45 Vol. % aus, wodurch sich die gleiche Schichtgüte, wie mit den bekannten Beschichtungsverfahren erzielen laßt. Hingegen sind die Herstellungskosten der erfindungsgemäßen Schichten vorteilhafterweise erheblich geringer. Beispielsweise gegenüber thermischen Spritzschichten um den Faktor 10.The layers produced according to the invention are distinguished by an installation rate of up to 45% by volume, which means that the same layer quality can be achieved as with the known coating processes. In contrast, the production costs of the layers according to the invention are advantageously considerably lower. For example, compared to thermal spray coatings by a factor of 10.
Dem Beschichtungsverfahren folgt anschließend eine Wärmebehandlung unter Vakuum zum Diffusionsglühen, wodurch eine Legierungsbildung einsetzt, und eine zu den bekannten Spritzverfahren identische Schichtqualität erzielbar ist.The coating process is then followed by a heat treatment under vacuum for diffusion annealing, as a result of which alloying begins and a layer quality identical to the known spraying processes can be achieved.
Die niedrige Suspensionskonzentration von unter 100 g/l erlaubt vorteilhafterweise den Einsatz unkomplizierter, konventioneller Dispersionsabscheidetechniken, wodurch der Aufwand, insbesondere im Hinblick auf die Serienfertigung erheblich geringer ist als beispielsweise bei der Trommeltechnik, die mit Badkonzentrationen von mindestens 600 g/l arbeitet. Um annehmbare Einbauraten zu erzielen, sind bei diesem bekannten Verfahren jedoch Konzentrationen von ca. 5000 g/l erforderlich, wie Vergleichsversuche gezeigt haben.The low suspension concentration of less than 100 g / l advantageously allows the use of uncomplicated, conventional dispersion separation techniques, which means that the effort, in particular with regard to series production, is considerably less than, for example, for drum technology with bath concentrations of at least 600 g / l is working. In order to achieve acceptable installation rates, however, concentrations of approximately 5000 g / l are required in this known method, as comparative experiments have shown.
Besonders vorteilhaft erwies sich eine Suspensionskonzentration von 40 - 60 g/l zur Erzielung einer hohen Einbaurate.A suspension concentration of 40-60 g / l proved to be particularly advantageous for achieving a high installation rate.
Im Stand der Technik wird die Form und sonstige Beschaffenheit des Suspensionspulvers als unwesentlich angesehen. Demgegenüber wurde überraschenderweise herausgefunden, daß Pulverpartikel kugeliger Gestalt und passivierter Oberfläche erheblich höhere Einbauraten zulassen als herkömmliche, insbesondere gemahlene Pulver. Hierdurch laßt sich die Suspensionskonzentration bei gleichzeitiger Steigerung der Schichtqualität erheblich senken.In the prior art, the shape and other properties of the suspension powder are considered to be immaterial. In contrast, it has surprisingly been found that powder particles of spherical shape and passivated surface allow considerably higher installation rates than conventional, in particular ground, powders. This allows the suspension concentration to be significantly reduced while at the same time increasing the layer quality.
Insbesondere durch die Passivierung der Partikeloberfläche ist ein gleichmäßiger Schichtaufbau möglich. Dies ist darauf zurückzuführen, daß ein auf dem Substrat angelagerter Partikel nichtleitend ist und daher keine negative Veränderung des umgebenden Feldlinienverlaufs bewirkt. Hierdurch ist vorteilhafterweise eine ungestörte Einbettung und Überbeschichtung des Partikels durch Matrix-Material möglich. In bevorzugter Weiterbildung der Erfindung liegt diese Suspensionskonzentration zwischen 40 und 60 g/l vor. Hierbei ergibt sich ein besonders gleichmäßiger Schichtaufbau.A uniform layer structure is possible, in particular, by passivating the particle surface. This is due to the fact that a particle deposited on the substrate is non-conductive and therefore does not cause a negative change in the surrounding field line course. This advantageously enables undisturbed embedding and over-coating of the particle by means of matrix material. In a preferred development of the invention, this suspension concentration is between 40 and 60 g / l. This results in a particularly uniform layer structure.
Vorzugsweise wird als Metallpulver CrAlY verwendet, da die hierdurch erzielbare Schicht bekannt gute Korrosionsschutzeigenschaft aufweist. Im Falle anderer Anforderungen an die Schichteigenschaften, insbesondere hinsichtlich Haftfestigkeit oder Beständigkeit gegenüber besonderen Gaszusammensetzungen (Schwefelkorrosion, Vanadiumkorrosion) sind jedoch alternativ eine oder mehrere der folgenden Legierungen als Pulver einsetzbar: CrAlHf, CrAlYHf, CrAlTa, CrAlYTa, CrNiAl, CrCoAl, CrAlSi, CrAl, MoCrSi.CrAlY is preferably used as the metal powder, since the layer that can be achieved in this way is known to have good corrosion protection properties. In the case of other requirements for the layer properties, especially with regard to adhesive strength or resistance to special gas compositions (sulfur corrosion, vanadium corrosion), one or more of the following alloys can alternatively be used as powder: CrAlHf, CrAlYHf, CrAlTa, CrAlYTa, CrNiAl, CrCoAl, CrAlSi, CrAl, MoCrSi.
Eine besonders einfache und kostensparende Herstellung des Suspensionspulvers ergibt sich, wenn dieses in Weiterbildung der Erfindung mittels Verdüsung hergestellt ist. Hierdurch lassen sich durch Einstellung der Verdüsungsparameter bzw. der Umgebungsgasatmosphäre günstige Werte für den Partikeldurchmesser und den Umfang der Oberflächenpassivierung einstellen. Üblicherweise wird eine Partikelgröße zwischen 1 und 15 um gewählt.A particularly simple and cost-saving production of the suspension powder results if it is produced by spraying in a further development of the invention. This allows favorable values for the particle diameter and the extent of the surface passivation to be set by setting the atomization parameters or the ambient gas atmosphere. A particle size between 1 and 15 μm is usually selected.
Vorzugsweise wird die Suspension durch Lufteinleitung, Umpumpen und/oder Rührvorrichtungen im Elektrolyten verteilt gehalten. Hierdurch laßt sich gegenüber einer Trommelanordnung eine Vereinfachung des Verfahrens bei gleichzeitig guter Durchmischung erzielen.The suspension is preferably kept distributed in the electrolyte by introduction of air, pumping around and / or stirring devices. In this way, compared to a drum arrangement, the method can be simplified with good mixing at the same time.
In einer Dispersionsbeschichtungsanlage wird ein Co-Elektrolyt mit 480 g/l CoSO₄, 35 g/l H₃BO₃ und 20 g/l NaCl gegeben, wobei ein pH-Wert zwischen 4,5 und 4,7 eingestellt wird. Eine CrAlY-Suspension mit kugelförmigen, passivierten Pulverpartikeln einer Partikelgröße < 10 um wurde dazugegeben, bis sich eine Konzentration von 100 g/l der Suspension ergab. Anschließend wurden die zu beschichtenden Turbinenschaufeln mit der Kathode verbunden und in das Bad eingetaucht. Ein elektrischer Gleichstrom der Stromdichte 2 A/dm² wurde eingestellt, bis eine Schichtdicke von etwa 100 um erzielt war. Anschließend wurden die Turbinenschaufeln entnommen und bei einer von ihnen ein Querschliffbild angefertigt (Fig. 1). Dabei ließ sich eine Einbaurate von etwa 45 Vol. % bei sehr gleichmäßigem Schichtaufbau feststellen.In a dispersion coating system, a co-electrolyte with 480 g / l CoSO₄, 35 g / l H₃BO₃ and 20 g / l NaCl is given, with a pH between 4.5 and 4.7 is set. A CrAlY suspension with spherical, passivated powder particles with a particle size of <10 μm was added until a concentration of 100 g / l of the suspension resulted. The turbine blades to be coated were then connected to the cathode and immersed in the bath. A direct current of current density 2 A / dm 2 was set until a layer thickness of approximately 100 μm was achieved. The turbine blades were then removed and a cross-section of one of them was made (FIG. 1). An installation rate of about 45 vol.% Was found with a very even layer structure.
Anschließend werden die Turbinenschaufeln für 50 h einer Temperatur von 1050 °C im Vakuum unterzogen. Hierdurch wird eine Legierungsbildung bewirkt, durch die eine zu bekannten Verfahren (PVD, thermisches Spritzen) identische Schicht hergestellt wird. Fig. 2a zeigt ein Elementverteilungsbild von Chrom einer Co-CrAlY-beschichteten Probe unmittelbar nach dem Abscheiden. Fig. 2b zeigt das Chrom Elementverteilungsbild nach der Wärmebehandlung.The turbine blades are then subjected to a temperature of 1050 ° C. in vacuo for 50 h. This results in an alloy formation, by means of which a known method (PVD, thermal Spray) identical layer is produced. 2a shows an element distribution image of chromium of a Co-CrAlY-coated sample immediately after the deposition. 2b shows the chrome element distribution image after the heat treatment.
Zu Vergleichszwecken wurde in dem gleichen Elektrolyten ein CrAlY-Pulver einer Partikelgröße < 10 um in einer Konzentration von 300 g/l gegeben, wobei das Pulver mittels Mahlen unter organischer Flüssigkeit hergestellt worden war. Ein Schliffbild (Querschliff) der hierbei erzielten Schicht ist in Fig. 3 gezeigt, wobei eine Einbaurate von Vol. % erzielbar war.For comparison purposes, a CrAlY powder with a particle size <10 .mu.m in a concentration of 300 g / l was added to the same electrolyte, the powder having been prepared by grinding under organic liquid. A micrograph (cross-section) of the layer obtained here is shown in FIG. 3, an installation rate of vol.% Being achievable.
In ein Co-Elektrolytbad gleicher Zusammensetzungen (Zusammensetzung wie in den Beispielen 1 und 2) wurde eine Rotationstrommel gemäß der im Artikel "Plating in surface finishing" Oktober 76, Seite 42 offenbarten Ausführungen gebracht und mit CrAlY-Pulver kugeliger Form in einer Konzentration von 5700 g/l gegeben. Das Pulver wies eine Partikelgröße < 10 um auf. In Fig. 4 ist dargestellt, daß zwar eine hohe Einbaurate von 35 Vol. % erzielbar war, jedoch eine sehr unregelmäßige Abscheidung mit warzenhaften Auswüchsen erfolgt war. Weiterhin war die Beschichtungsdicke an den Kanten erheblich größer als im Mittel bereich der Schaufel.In a co-electrolyte bath of the same compositions (composition as in Examples 1 and 2), a rotary drum was placed in accordance with the statements disclosed in the article "Plating in surface finishing" October 76, page 42 and with CrAlY powder spherical in a concentration of 5700 g / l given. The powder had a particle size <10 µm. 4 shows that although a high installation rate of 35% by volume could be achieved, a very irregular separation with wart-like outgrowths had taken place. Furthermore, the coating thickness at the edges was considerably greater than in the middle area of the blade.
Claims (7)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3815976 | 1988-05-10 | ||
DE3815976A DE3815976A1 (en) | 1988-05-10 | 1988-05-10 | METHOD FOR PRODUCING GALVANICALLY SEPARATED HOT GAS CORROSION LAYERS |
DE3935957A DE3935957C1 (en) | 1988-05-10 | 1989-10-27 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0341456A2 true EP0341456A2 (en) | 1989-11-15 |
EP0341456A3 EP0341456A3 (en) | 1990-05-30 |
EP0341456B1 EP0341456B1 (en) | 1994-11-30 |
Family
ID=39427740
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89106922A Expired - Lifetime EP0341456B1 (en) | 1988-05-10 | 1989-04-18 | Process for electrolytically depositing a metal layer resisting corrosion by hot gases |
EP90120273A Expired - Lifetime EP0424863B1 (en) | 1988-05-10 | 1990-10-23 | Process for electrolytically depositing a metal layer resisting corrosion by hot gases |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
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EP90120273A Expired - Lifetime EP0424863B1 (en) | 1988-05-10 | 1990-10-23 | Process for electrolytically depositing a metal layer resisting corrosion by hot gases |
Country Status (5)
Country | Link |
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US (2) | US4895625A (en) |
EP (2) | EP0341456B1 (en) |
JP (2) | JP2713458B2 (en) |
DE (2) | DE3815976A1 (en) |
ES (1) | ES2086348T3 (en) |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3815976A1 (en) * | 1988-05-10 | 1989-11-23 | Mtu Muenchen Gmbh | METHOD FOR PRODUCING GALVANICALLY SEPARATED HOT GAS CORROSION LAYERS |
GB2254338B (en) * | 1988-07-29 | 1993-02-03 | Baj Ltd | Improvements relating to the production of coatings |
JP2949605B2 (en) * | 1991-09-20 | 1999-09-20 | 株式会社日立製作所 | Alloy-coated gas turbine blade and method of manufacturing the same |
GB9414859D0 (en) * | 1994-07-22 | 1994-09-14 | Baj Coatings Ltd | Protective coating |
US5613705A (en) * | 1995-03-24 | 1997-03-25 | Morton International, Inc. | Airbag inflator having a housing protected from high-temperature reactive generated gases |
DE10251902B4 (en) * | 2002-11-07 | 2009-05-07 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for coating a substrate and coated article |
DE60231084D1 (en) * | 2002-12-06 | 2009-03-19 | Alstom Technology Ltd | Method for the selective deposition of an MCrAlY coating |
DE10259361A1 (en) * | 2002-12-18 | 2004-07-08 | Siemens Ag | Method and device for filling material separations on a surface |
WO2004092450A1 (en) * | 2003-04-11 | 2004-10-28 | Lynntech, Inc. | Compositions and coatings including quasicrystals |
EP1533398B1 (en) * | 2003-10-24 | 2011-08-31 | Siemens Aktiengesellschaft | Process for producing an electrolyte ready for use out of waste products containing metal ions |
WO2006017327A2 (en) * | 2004-07-13 | 2006-02-16 | University Of New Hampshire | Electrocodeposition of lead free tin alloys |
EP2119805A1 (en) * | 2008-05-15 | 2009-11-18 | Siemens Aktiengesellschaft | Method for manufacturing an optimized adhesive layer through partial evaporation of the adhesive layer |
DE102011100100A1 (en) * | 2011-04-29 | 2012-10-31 | Air Liquide Deutschland Gmbh | Method for treating a line component |
DE102013218687A1 (en) | 2013-09-18 | 2015-04-02 | MTU Aero Engines AG | Galvanized wear protection coating and method therefor |
CN105598655A (en) * | 2016-03-02 | 2016-05-25 | 华北水利水电大学 | Method for strengthening surface of metal turbine runner blade through combination of electric spark deposition and welding |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2571386A1 (en) * | 1984-10-05 | 1986-04-11 | Baj Ltd | PROTECTIVE METAL COATINGS |
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GB2014189B (en) * | 1977-12-21 | 1982-06-09 | Bristol Aerojet Ltd | Processes for the electrodeposition of composite coatings |
GB2182055B (en) * | 1985-10-28 | 1989-10-18 | Baj Ltd | Improvements relating to electrodeposited coatings |
DE3815976A1 (en) * | 1988-05-10 | 1989-11-23 | Mtu Muenchen Gmbh | METHOD FOR PRODUCING GALVANICALLY SEPARATED HOT GAS CORROSION LAYERS |
GB8818069D0 (en) * | 1988-07-29 | 1988-09-28 | Baj Ltd | Improvements relating to electrodeposited coatings |
-
1988
- 1988-05-10 DE DE3815976A patent/DE3815976A1/en active Granted
-
1989
- 1989-04-18 EP EP89106922A patent/EP0341456B1/en not_active Expired - Lifetime
- 1989-04-28 JP JP1111949A patent/JP2713458B2/en not_active Expired - Fee Related
- 1989-05-09 US US07/349,211 patent/US4895625A/en not_active Expired - Lifetime
- 1989-10-27 DE DE3935957A patent/DE3935957C1/de not_active Expired - Lifetime
-
1990
- 1990-10-23 EP EP90120273A patent/EP0424863B1/en not_active Expired - Lifetime
- 1990-10-23 ES ES90120273T patent/ES2086348T3/en not_active Expired - Lifetime
- 1990-10-25 JP JP02290555A patent/JP3027600B2/en not_active Expired - Fee Related
- 1990-10-26 US US07/604,825 patent/US5064510A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2571386A1 (en) * | 1984-10-05 | 1986-04-11 | Baj Ltd | PROTECTIVE METAL COATINGS |
Non-Patent Citations (4)
Title |
---|
Plating and Surface Finishing, Oktober 1986, Seiten 42-46, J. Honey et al. "Electrodeposits for High-Temperature Corrosion Resistance" * |
R.S. Sajfullin "Betriebspraxis Dispersionsschichten", Berlin 1978, Seite 25, Bild 8 * |
Schriftenreihe Praxis-Forum 20/89, G. Lausmann "Neue Anwendungen von Nickel- Dispersions- und Chromschichten im Motorenbau" * |
TRANSACTIONS OF THE INSTITUTE OF METAL FINISHING, Band 63, Nr. 3-4, 1985, Seiten 115-119; FOSTER: "The production of multicomponent alloy coatings by particle codeposition" * |
Also Published As
Publication number | Publication date |
---|---|
JP2713458B2 (en) | 1998-02-16 |
EP0341456A3 (en) | 1990-05-30 |
EP0424863B1 (en) | 1996-04-17 |
US5064510A (en) | 1991-11-12 |
US4895625A (en) | 1990-01-23 |
JPH0364497A (en) | 1991-03-19 |
JP3027600B2 (en) | 2000-04-04 |
EP0341456B1 (en) | 1994-11-30 |
ES2086348T3 (en) | 1996-07-01 |
DE3815976A1 (en) | 1989-11-23 |
DE3815976C2 (en) | 1990-02-15 |
JPH03173798A (en) | 1991-07-29 |
DE3935957C1 (en) | 1991-02-21 |
EP0424863A1 (en) | 1991-05-02 |
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