EP2511401A2 - Method for producing a coating on the surface of a substrate on the basis of light metals by means of plasma electrolytic oxidation - Google Patents
Method for producing a coating on the surface of a substrate on the basis of light metals by means of plasma electrolytic oxidation Download PDFInfo
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- EP2511401A2 EP2511401A2 EP12163197A EP12163197A EP2511401A2 EP 2511401 A2 EP2511401 A2 EP 2511401A2 EP 12163197 A EP12163197 A EP 12163197A EP 12163197 A EP12163197 A EP 12163197A EP 2511401 A2 EP2511401 A2 EP 2511401A2
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/026—Anodisation with spark discharge
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/30—Anodisation of magnesium or alloys based thereon
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/34—Anodisation of metals or alloys not provided for in groups C25D11/04 - C25D11/32
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- 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
Definitions
- the present invention relates to a process for producing a coating on the surface of a substrate by plasma electrolytic oxidation.
- the plasma electrolytic oxidation of surfaces of light metals is a known method. In the process, predominantly hard, ceramic layers are produced, which offer protection against corrosion and wear.
- the prerequisite for the plasma electrolytic oxidation is the formation of an oxide layer (dielectric) in an electrolyte.
- the maintenance of a current can thus lead to voltage increase and discharges.
- the surface of light metal parts is converted into a ceramic matrix.
- an electrical voltage of at least 250 V is usually required, which causes a spark discharge at the parts surfaces; it comes to local plasma formation.
- the layers are formed by microdischarges, which melt the base material and reaction products of the electrolyte with the light metal and sinter into a crystalline ceramic.
- the electrolytes used are predominantly alkaline silicate or phosphate solutions.
- particles have also been incorporated into the layers.
- Srinivasan et al. Surface Engineering 2010, Vol. 26, no. 5, pages 367 to 370 the coating of magnesium alloys of the type AM50 in alkaline phosphate solutions with the addition of TiO 2 sol. These particles are stored and (partially) crystalline layers form.
- the object of the present invention is to further improve the corrosion protection for substrates of light metals or light metal alloys, in particular of magnesium or magnesium alloys.
- the object is achieved by a method for producing a coating on the surface of a substrate based on light metals by plasma electrolytic oxidation, in which the substrate immersed as an electrode together with a counter electrode in an electrolyte liquid and a sufficient electrical voltage for generating spark discharges at the Surface of the substrate is applied, and which is characterized in that the electrolyte comprises clay particles dispersed therein. It has been found that with the use of clay particles amorphous, glassy oxide layers can be produced on light metals or light metal alloys.
- Clay materials are well known in the art. With clay layered silicates are referred to have a layered crystal structure.
- the preferred phyllosilicates used are selected from the group consisting of vermiculite, talc and / or smectites, the smectites in particular Sodium montmorillonite, magnesium montmorillonite, calcium montmorillonite, aluminum montmorillonite, nontronite, beidellite, volkonskoite, hectorite, saponite, sauconite, sobockite, stevensite, svinfordite and / or kaolinite.
- phyllosilicates in the sense of the invention 1: 1 and 2: 1 sheet silicates understood.
- layers of SiO 4 tetrahedra are regularly linked to those of M (O, OH) 6 octahedra.
- M stands for metal ions, such as Al, Mg, Fe.
- 1: 1 layer silicates in each case one tetrahedral layer and one octahedral layer are connected to one another. Examples include kaolin and serpentine minerals.
- the clays preferably have an average particle size (volumetric) of from 1 nm to 100 ⁇ m, more preferably from 10 nm to 20 ⁇ m, and most preferably from 50 nm to 15 ⁇ m.
- average particle size is known.
- a common method for determining particle size is laser diffractometry. The particles to be measured are irradiated with laser light and the diffraction rings, which are formed by the irradiation of the particles, are detected. Laser diffractometry exploits the fact that the size of the diffraction angle is inversely proportional to the size of the particle.
- a preferred clay is available under the name "Cloisite ® Na +" by the company. Southern Clay Products, Inc (Texas, USA). Typically, more than 90% of the particles have a particle size of less than 15 ⁇ m and more than 50% have a particle size of less than 7.5 ⁇ m. Another preferred clay is available under the name Nanofil ® 116 from the Fa. Southern Clay Products, Inc (Texas, USA) having a mean particle size of about 12 microns.
- an aqueous electrolyte more preferably an aqueous alkaline electrolyte is used.
- This preferably contains NaOH, KOH, Mg (OH) 2 , Ca (OH) 2 and / or ammonia. Preference is given to the use of NaOH or NH 4 OH.
- the electrolyte preferably additionally contains phosphates and / or other silicates which are not clay materials. Preference is given to phosphates such as Na 3 PO 4 , K 3 PO 4 , Mg 3 (PO 4 ) 2 , and / or Ca 3 (PO 4 ) 2 or silicates such as Na 4 SiO 4 , K 4 SiO 4 , Mg 2 SiO 4 , and / or Ca 2 SiO 4 used.
- phosphate-containing electrolytes arise glassy layers, which resemble Biogläsern of the composition. The substrates therefore have increased biocompatibility and are suitable, for example, for use in bioimplant substrates.
- silicate-containing electrolytes the layers are also amorphous and more suitable for layers in industrial applications. The amorphous layers exhibit improved long-term stability and altered properties (eg wettability) under corrosive influence.
- glass refers to an amorphous alloy characterized by the absence of crystal structure and the material in a kind of arrangement without periodicity, ie, without long distance order. similar to the atoms in a melt remains.
- breakdown voltage For plasma electrolytic oxidation of the substrate, sufficient electrical voltage or current is applied to generate spark discharges on the surface of the substrate (breakdown voltage). Preference is given to working with a constant current density, thus the voltage during the coating is continuously increased to compensate for the increasing resistance (layer thickness increase).
- an initial breakdown voltage of at least 200 V, preferably at least 230 V, more preferably at least 250 V is applied.
- the final voltage is preferably at least 500 V, more preferably at least 520 V.
- the pulse duration is preferably 1 ms to 10 ms, more preferably 2 ms to 5 ms, the intervals between the pulses preferably being 1 ms to 100 ms, more preferably 10 ms to 30 ms.
- the current density should preferably be 10 mA cm -2 to 50 mA cm -2 , more preferably 20 mA cm -2 to 40 mA cm -2, and most preferably 25 mA cm -2 to 35 mA cm -2 .
- the temperature of the electrolyte is preferably 20 ° C to 30 ° C.
- the duration of the electrolysis is preferably 1 minute to 60 minutes, preferably 5 minutes to 20 minutes.
- the properties of the coating such as coating thickness can be varied and adapted to the intended purpose. It is within the skill of the art to set the necessary parameters.
- the properties of the coatings can be adjusted by varying the particle concentration.
- concentration of clay particles in the electrolyte is 1 wt% to 10 wt%, more preferably 2 wt% to 5 wt% Basis of the total weight of the electrolyte.
- the substrate material is magnesium or its alloys.
- the magnesium alloy of the magnesium substrate may be any amount, e.g. from 1 to 100 at% (at.%) of magnesium.
- the magnesium alloy of the magnesium component preferably contains at least 50 at.%, Particularly preferably at least 70 at.% Of magnesium. It is preferable, but not necessary, that the magnesium alloy further contains at least one element selected from the group consisting of the elements of the 3rd main group, the 3rd subgroup or rare earth elements of the periodic table.
- the magnesium substrate can be made of an AZ31, AZ91, AE42, ZM21, ZK31, ZE41 alloy or any other common magnesium alloy.
- the process according to the invention achieves surface coatings on substrates based on light metals with improved corrosion protection or with improved biocompatibility and the possibility of being able to better control the degradation of the substrate.
- Substrates may therefore be any engineered components made of a light metal such as magnesium or a magnesium alloy, automotive components, railway components, aircraft components, marine components, etc., or bio-implants such as bone replacement materials or medical bone screws.
- a light metal such as magnesium or a magnesium alloy
- automotive components railway components, aircraft components, marine components, etc.
- bio-implants such as bone replacement materials or medical bone screws.
- the substrates were sanded successively with 500, 800, 1200, and 2500 grit sandpaper and then cleaned with ethanol.
- the silicate-based electrolyte was prepared using Na 2 SiO 3 (10.0 g / L) and KOH (1.0 g / L) in distilled water and the phosphate-based electrolyte using Na 3 PO 4 (10.0 g / L) and KOH (1.0 g / L) in distilled water.
- Up to 10 g / l clay particles (Rockwood Nanofil ® 116 having an average particle size of 12 .mu.m of the nanoparticles-containing electrolytes were dispersed in these electrolytes for the preparation.
- the plasma electrolytic oxidation was carried out with a pulsating DC voltage source, the pulse ratio t on : t off being 2 ms: 20 ms.
- the plasma electrolysis was carried out for 30 minutes at a constant current density of 15 mA / cm -2 in both the silicate-based electrolyte and the phosphate-based electrolyte, each with and without the addition of clay particles.
- the temperature of the electrolyte was maintained at 10 ° C ⁇ 2 ° C by means of a water cooling system.
- the plasma electrolysis coated specimens were examined in a Cambridge Stereoscan 200 electron microscope.
- X-ray diffraction (XRD) was performed with a Cu-K ⁇ radiation to determine the phase composition.
- the structure of the coating was evaluated by TEM.
- the TEM specimens were prepared by removing a section from the coating using FIB (Focused Ion Beam), which reached to the interface of the substrate.
- Electrochemical investigations were carried out to determine the corrosion behavior of uncoated and PEO-coated specimens using a Gill AC potentiostat.
- a typical three-electrode cell was used with a saturated Ag / AgCl (saturated with KCl) as the reference electrode, a platinum network counter electrode (0.5 cm 2 ) and the samples as the working electrode.
- the electrochemical studies were carried out in 0.1 M NaCl solution.
- the SEM photographs show that the surface of the specimen produced by means of PEO using a phosphate-based electrolyte (without clay particles) has micropores with a size of 10-30 ⁇ m in diameter. The pore-free region, however, is smooth. On the surface of the phosphate-based electrolyte containing PEO using a 10 g / l clay particle, many small particles were seen; the surface was rough. The size of the small particles varied from a few hundred nm to a few mm. Cross-sectional images showed that the thickness of the clay particle-produced coating (20 ⁇ m ⁇ 2 ⁇ m) was lower than that of the coating without clay particles (25 ⁇ m ⁇ 2 ⁇ m). In the coating made with clay particles, many more pores were also observed.
- the hydrophilicity of the two PEO-coated specimens is different.
- the specimen produced by PEO using a phosphate-based electrolyte without clay particles is hydrophilic when the water contact angle is less than 90 °.
- the water droplet quickly spreads and immediately covers the surface. This means that the specimens produced by means of PEO using a phosphate-based electrolyte with clay particles are superhydrophilic.
- the electrochemical impedance spectroscopy study showed that the specimens produced by means of PEO using a phosphate-based electrolyte without clay particles already precipitated after 50 h in 0.1 M NaCl solution ( Fig. 1 ), while the specimens produced by PEO using a phosphate-based electrolyte with clay particles survived more than 175 hours in 0.1 M NaCl solution ( Fig. 2 ).
- the SEM photographs show that the surface of the specimen produced by means of PEO using a silicate-based electrolyte (without clay particles) has a larger number of micropores with a size of 5-15 ⁇ m in diameter. The pore-free region, however, is smooth without any heterogeneous particles.
- a silicate-based electrolyte containing 10 g / l clay particles many small particles were seen.
- Cross-sectional images showed that the thickness of the coating produced with clay particles and that of the coating produced without clay particles were approximately the same (17 ⁇ m ⁇ 3 ⁇ m). In the coating made with clay particles, many more pores were also observed.
- Example 1 it was found that the hydrophilicity of the two PEO-coated specimens is different.
- the specimen produced by PEO using a silicate based electrolyte without clay particles is hydrophilic when the water contact angle is less than 90 °.
- the water droplet spreads rapidly and covers the surface immediately, and the contact angle is obviously much lower.
- the i corr value of the specimen prepared by PEO using a silicate-based electrolyte with clay particles is an order of magnitude greater than that of the specimen produced by PEO using a silicate-based electrolyte without clay particles.
- X-ray diffraction (XRD) studies suggest that the coating structure changes from crystalline to amorphous as clay particles are added to the electrolytes.
- the sharp XRD peaks of the crystalline layer disappear successively with the addition of 3 g / l, 6 g / l and 10 g / l clay particles, revealing the typical broad diffraction spectrum of a vitreous material.
- the peaks are from the Mg substrate under the layer. This finding was confirmed by TEM examinations.
- compositions of the coatings were determined by EDX analysis and are shown in Table 3 below.
- Table 3 ⁇ / b> At.% O N / A mg al Si P C Fe P-PEO 50 7 27 0 0 12 4 0 + 3g / l sound 50 6 18 2 7 8th 7 1 + 10g / l tone 50 6 11 5 15 6 6 2 Si-PEO 47 4 21 1 18 0 10 0 + 10g / l tone 50 4 11 4 23 0 6 2
- Table 3 suggests that the compositions of the coatings are similar to those of bioglasses (mixed with Na 2 O, MgO, CaO, SiO 2 , Al 2 O 3 , P 2 O 5 ). Only Ca is missing as a typical ingredient. One can therefore expect similar biomedical applications. However, Ca can also be added to the electrolyte in the form of Ca (OH) 2 , so that it can also be introduced into the coating.
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Abstract
Description
Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung einer Beschichtung auf der Oberfläche eines Substrats durch plasmaelektrolytische Oxidation.The present invention relates to a process for producing a coating on the surface of a substrate by plasma electrolytic oxidation.
Die plasmaelektrolytische Oxidation von Oberflächen von Leichtmetallen ist ein bekanntes Verfahren. Dabei werden überwiegend harte, keramische Schichten erzeugt, die einen Korrosions- und Verschleißschutz bieten. Voraussetzung für die plasmaelektrolytische Oxidation ist die Ausbildung einer Oxidschicht (Dielektrikum) in einem Elektrolyt. Die Aufrechterhaltung eines Stroms kann so zu Spannungsanstieg und Entladungen führen. Auf diese Weise wird die Oberfläche von Leichtmetallteilen in eine Keramikmatrix umgewandelt. Dazu ist meist eine elektrische Spannung von mindestens 250 V erforderlich, die eine Funkenentladung an den Teileoberflächen bewirkt; es kommt zur lokalen Plasmabildung. Die Schichten entstehen über Mikroentladungen, die das Grundmaterial und Reaktionsprodukte des Elektrolyten mit dem Leichtmetall aufschmelzen und zu einer kristallinen Keramik sintern. Als Elektrolyte werden vorwiegend alkalische Silikat- oder Phosphatlösungen verwendet.The plasma electrolytic oxidation of surfaces of light metals is a known method. In the process, predominantly hard, ceramic layers are produced, which offer protection against corrosion and wear. The prerequisite for the plasma electrolytic oxidation is the formation of an oxide layer (dielectric) in an electrolyte. The maintenance of a current can thus lead to voltage increase and discharges. In this way, the surface of light metal parts is converted into a ceramic matrix. For this purpose, an electrical voltage of at least 250 V is usually required, which causes a spark discharge at the parts surfaces; it comes to local plasma formation. The layers are formed by microdischarges, which melt the base material and reaction products of the electrolyte with the light metal and sinter into a crystalline ceramic. The electrolytes used are predominantly alkaline silicate or phosphate solutions.
Die Erzeugung von Beschichtungen auf Leichtmetallbauteilen durch plasmaelektrolytische Oxidation ist beispielsweise in
Seit einiger Zeit werden auch Partikel mit in die Schichten eingebaut. Beispielsweise beschreiben
Aufgabe der vorliegenden Erfindung ist es den Korrosionsschutz für Substrate aus Leichtmetallen oder Leichtmetalllegierungen, insbesondere aus Magnesium oder Magnesiumlegierungen weiter zu verbessern.The object of the present invention is to further improve the corrosion protection for substrates of light metals or light metal alloys, in particular of magnesium or magnesium alloys.
Die Aufgabe wird durch ein Verfahren zur Herstellung einer Beschichtung auf der Oberfläche eines Substrats auf Basis von Leichtmetallen durch plasmaelektrolytische Oxidation gelöst, bei dem das Substrat als eine Elektrode zusammen mit einer Gegenelektrode in eine Elektrolytflüssigkeit eingetaucht und eine ausreichende elektrische Spannung zur Erzeugung von Funkenentladungen an der Oberfläche des Substrats angelegt wird, und das dadurch gekennzeichnet ist, dass das Elektrolyt darin dispergierte Tonpartikel umfasst. Es wurde gefunden, dass mit der Verwendung von Tonpartikeln amorphe, glasartige Oxidschichten auf Leichtmetallen oder Leichtmetalllegierungen erzeugt werden können.The object is achieved by a method for producing a coating on the surface of a substrate based on light metals by plasma electrolytic oxidation, in which the substrate immersed as an electrode together with a counter electrode in an electrolyte liquid and a sufficient electrical voltage for generating spark discharges at the Surface of the substrate is applied, and which is characterized in that the electrolyte comprises clay particles dispersed therein. It has been found that with the use of clay particles amorphous, glassy oxide layers can be produced on light metals or light metal alloys.
Tonmaterialien sind in der Technik gut bekannt. Mit Ton werden Schichtsilikate bezeichnet, eine schichtartige Kristallstruktur aufweisen. Die bevorzugt zum Einsatz kommenden Schichtsilikate sind dabei ausgewählt aus der Gruppe bestehend aus Vermiculit, Talk und/oder Smektiten, wobei die Smektite insbesondere Natrium-Montmorillonit, Magnesium-Montmorillonit, Calcium-Montmorillonit, Aluminium-Montmorillonit, Nontronit, Beidellit, Volkonskoit, Hectorit, Saponit, Sauconit, Sobockit, Stevensit, Svinfordit und/oder Kaolinit sind.Clay materials are well known in the art. With clay layered silicates are referred to have a layered crystal structure. The preferred phyllosilicates used are selected from the group consisting of vermiculite, talc and / or smectites, the smectites in particular Sodium montmorillonite, magnesium montmorillonite, calcium montmorillonite, aluminum montmorillonite, nontronite, beidellite, volkonskoite, hectorite, saponite, sauconite, sobockite, stevensite, svinfordite and / or kaolinite.
Bevorzugt werden unter Schichtsilikaten im erfindungsgemäßen Sinne 1:1- sowie 2:1-Schichtsilikate verstanden. In diesen Systemen sind Schichten aus Si04-Tetraedern mit solchen aus M(O,OH)6-Oktaedern in regelmäßiger Weise miteinander verknüpft. M steht dabei für Metallionen, wie Al, Mg, Fe. Bei den 1:1-Schichtsilikaten sind dabei jeweils eine Tetraeder- und eine Oktaederschicht miteinander verbunden. Beispiele hierfür sind Kaolin- und Serpentin-Minerale.Preference is given to phyllosilicates in the sense of the invention 1: 1 and 2: 1 sheet silicates understood. In these systems, layers of SiO 4 tetrahedra are regularly linked to those of M (O, OH) 6 octahedra. M stands for metal ions, such as Al, Mg, Fe. In the case of the 1: 1 layer silicates, in each case one tetrahedral layer and one octahedral layer are connected to one another. Examples include kaolin and serpentine minerals.
Bei den 2:1-Dreischichtsilikaten sind jeweils zwei Tetraedermit einer Oktaederschicht kombiniert. Sind nicht alle Oktaederplätze mit Kationen der benötigten Ladung zur Kompensation der negativen Ladung der Si04-Tetraeder sowie der Hydroxid-Ionen besetzt, treten geladene Schichten auf. Diese negative Ladung wird durch den Einbau einwertiger Kationen, wie Kalium, Natrium oder Lithium oder zweiwertiger Kationen, wie Calcium in den Raum zwischen den Schichten ausgeglichen. Beispiele für 2:1-Schichtsilikate sind Talkum, Vermiculite sowie Smectite, zu denen u.a. Montmorillonit und Hectorit gehören.In the case of 2: 1 three-layer silicates, two tetrahedra are combined with one octahedron layer. If not all octahedral sites are occupied by cations of the required charge to compensate for the negative charge of the Si04 tetrahedra and the hydroxide ions, charged layers occur. This negative charge is balanced by the incorporation of monovalent cations, such as potassium, sodium or lithium, or divalent cations, such as calcium, in the space between the layers. Examples of 2: 1 phyllosilicates are talc, vermiculites and smectites, among which i.a. Montmorillonite and hectorite belong.
Die Tone haben bevorzugt eine mittlere Teilchengröße (Volumetrisch) von 1 nm bis 100 µm, bevorzugter von 10 nm bis 20 µm und am meisten bevorzugt von 50 nm bis 15 µm. Viele Verfahren zur Partikelgrößebestimmung sind bekannt. Ein gängiges Verfahren zur Bestimmung der Partikelgröße ist die Laserdiffraktometrie. Dabei werden die zu messenden Teilchen mit Laserlicht bestrahlt und die Beugungsringe, die durch die Bestrahlung der Partikel entstehen detektiert. Laserdiffraktometrie nutzt die Tatsache, dass die Größe des Beugungs-winkels umgekehrt proportional zur Größe des Partikels ist.The clays preferably have an average particle size (volumetric) of from 1 nm to 100 μm, more preferably from 10 nm to 20 μm, and most preferably from 50 nm to 15 μm. Many methods for particle size determination are known. A common method for determining particle size is laser diffractometry. The particles to be measured are irradiated with laser light and the diffraction rings, which are formed by the irradiation of the particles, are detected. Laser diffractometry exploits the fact that the size of the diffraction angle is inversely proportional to the size of the particle.
Ein bevorzugter Ton ist unter der Bezeichnung "Cloisite® Na+" von der Fa. Southern Clay Products, Inc (Texas, U.S.A.) erhältlich. Typischerweise haben mehr 90% der Partikel eine Partikelgröße von kleiner als 15 µm und mehr als 50% eine Partikelgröße von kleiner als 7,5 µm. Ein anderer bevorzugter Ton ist unter der Bezeichnung Nanofil® 116 von der Fa. Southern Clay Products, Inc (Texas, U.S.A.) mit einer mittleren Teilchengröße von etwa 12 µm erhältlich.A preferred clay is available under the name "Cloisite ® Na +" by the company. Southern Clay Products, Inc (Texas, USA). Typically, more than 90% of the particles have a particle size of less than 15 μm and more than 50% have a particle size of less than 7.5 μm. Another preferred clay is available under the name Nanofil ® 116 from the Fa. Southern Clay Products, Inc (Texas, USA) having a mean particle size of about 12 microns.
Vorzugsweise wird ein wässriges Elektrolyt, bevorzugter ein wässriges, alkalisches Elektrolyt verwendet. Dieses enthält vorzugsweise NaOH, KOH, Mg(OH)2, Ca(OH)2 und/oder Ammoniak. Bevorzugt ist die Verwendung von NaOH oder NH4OH.Preferably, an aqueous electrolyte, more preferably an aqueous alkaline electrolyte is used. This preferably contains NaOH, KOH, Mg (OH) 2 , Ca (OH) 2 and / or ammonia. Preference is given to the use of NaOH or NH 4 OH.
Das Elektrolyt enthält vorzugsweise zusätzlich Phosphate und/oder weitere Silikate, die keine Tonmaterialien sind. Bevorzugt werden Phosphate wie Na3PO4, K3PO4, Mg3(PO4)2, und/oder Ca3(PO4)2 oder Silikate wie Na4SiO4, K4SiO4, Mg2SiO4, und/oder Ca2SiO4 verwendet. In phosphathaltigen Elektrolyten entstehen glasartige Schichten, die von der Zusammensetzung Biogläsern ähneln. Die Substrate haben daher eine erhöhte Bioverträglichkeit und sind beispielsweise für die Verwendung in Bioimplantatsubstraten geeignet. In silikathaltigen Elektrolyten sind die Schichten ebenfalls amorph und eher für Schichten in der industriellen Anwendung geeignet. Die amorphen Schichten zeigen unter korrosiven Einfluss eine verbesserte Langzeitbeständigkeit und geänderte Eigenschaften (z.B. Benetzbarkeit).The electrolyte preferably additionally contains phosphates and / or other silicates which are not clay materials. Preference is given to phosphates such as Na 3 PO 4 , K 3 PO 4 , Mg 3 (PO 4 ) 2 , and / or Ca 3 (PO 4 ) 2 or silicates such as Na 4 SiO 4 , K 4 SiO 4 , Mg 2 SiO 4 , and / or Ca 2 SiO 4 used. In phosphate-containing electrolytes arise glassy layers, which resemble Biogläsern of the composition. The substrates therefore have increased biocompatibility and are suitable, for example, for use in bioimplant substrates. In silicate-containing electrolytes, the layers are also amorphous and more suitable for layers in industrial applications. The amorphous layers exhibit improved long-term stability and altered properties (eg wettability) under corrosive influence.
Der Begriff "glasartig", "glasartige Legierung" oder "metallisches Glas" ist in der Technik geläufig und bezeichnet eine amorphe Legierung, die sich dadurch auszeichnet, dass sie keine Kristallstruktur ausbilden und das Material in einer Art Anordnung ohne Periodizität, d. h. ohne Fernordnung, ähnlich den Atomen in einer Schmelze, verbleibt.The term "glassy", "vitreous alloy" or "metallic glass" is well known in the art and refers to an amorphous alloy characterized by the absence of crystal structure and the material in a kind of arrangement without periodicity, ie, without long distance order. similar to the atoms in a melt remains.
Zur plasmaelektrolytischen Oxidation des Substrats wird eine ausreichende elektrische Spannung oder Strom zur Erzeugung von Funkenentladungen an der Oberfläche des Substrats (Durchschlagsspannung) angelegt. Bevorzugt wird mit konstanter Stromdichte gearbeitet, somit wird die Spannung während der Beschichtung kontinuierlich erhöht, um den steigenden Widerstand (Schichtdickenzunahme) auszugleichen. Vorzugsweise wird eine anfängliche Durchschlagsspannung von mindestens 200 V, bevorzugt mindestens 230 V, bevorzugter mindestens 250 V angelegt. Die Endspannung beträgt vorzugsweise mindestens 500 V, bevorzugter mindestens 520 V.For plasma electrolytic oxidation of the substrate, sufficient electrical voltage or current is applied to generate spark discharges on the surface of the substrate (breakdown voltage). Preference is given to working with a constant current density, thus the voltage during the coating is continuously increased to compensate for the increasing resistance (layer thickness increase). Preferably, an initial breakdown voltage of at least 200 V, preferably at least 230 V, more preferably at least 250 V is applied. The final voltage is preferably at least 500 V, more preferably at least 520 V.
Es ist bevorzugt, dass eine pulsierende Spannung angelegt wird. Die Pulsdauer beträgt vorzugsweise 1 ms bis 10 ms, bevorzugter 2 ms bis 5 ms, wobei die Intervalle zwischen den Pulsen bevorzugt 1 ms bis 100 ms, bevorzugter 10 ms bis 30 ms betragen. Die Stromdichte sollte vorzugsweise 10 mA cm-2 bis 50 mA cm-2, bevorzugter 20 mA cm-2 bis 40 mA cm-2 und am meisten bevorzugt 25 mA cm-2 bis 35 mA cm-2 betragen.It is preferable that a pulsating voltage is applied. The pulse duration is preferably 1 ms to 10 ms, more preferably 2 ms to 5 ms, the intervals between the pulses preferably being 1 ms to 100 ms, more preferably 10 ms to 30 ms. The current density should preferably be 10 mA cm -2 to 50 mA cm -2 , more preferably 20 mA cm -2 to 40 mA cm -2, and most preferably 25 mA cm -2 to 35 mA cm -2 .
Die Temperatur des Elektrolyten beträgt vorzugsweise 20°C bis 30°C. Die Dauer der Elektrolyse beträgt vorzugsweise 1 min bis 60 min, bevorzugt 5 min bis 20 min.The temperature of the electrolyte is preferably 20 ° C to 30 ° C. The duration of the electrolysis is preferably 1 minute to 60 minutes, preferably 5 minutes to 20 minutes.
Durch die Wahl der Spannung, Stromdichte und Behandlungs- bzw. Prozessdauer lassen sich die Eigenschaften der Beschichtung wie Beschichtungsdicke variieren und dem angestrebten Zweck anpassen. Es liegt im Bereich des fachmännischen Könnens die notwendigen Parameter einzustellen.By choosing the voltage, current density and treatment or process duration, the properties of the coating such as coating thickness can be varied and adapted to the intended purpose. It is within the skill of the art to set the necessary parameters.
Weiterhin lassen sich die Eigenschaften der Beschichtungen durch Variation der Teilchenkonzentration einstellen. Vorzugsweise beträgt die Konzentration an Tonpartikeln im Elektrolyten 1 Gew.% bis 10 Gew.%, bevorzugter 2 Gew.% bis 5 Gew.% auf Basis des Gesamtgewichts des Elektrolyten.Furthermore, the properties of the coatings can be adjusted by varying the particle concentration. Preferably, the concentration of clay particles in the electrolyte is 1 wt% to 10 wt%, more preferably 2 wt% to 5 wt% Basis of the total weight of the electrolyte.
Als Substratmaterialien können bevorzugt Magnesium, Aluminium, Titan oder deren Legierungen verwendet werden. Am meisten bevorzugt ist das Substratmaterial Magnesium oder seine Legierungen. Die Magnesiumlegierung des Magnesiumsubstrats kann jegliche Menge z.B. von 1 bis 100 Atom% (At.%) Magnesium enthalten. Vorzugsweise enthält die Magnesiumlegierung des Magnesiumbauteils mindestens 50 At.%, besonders bevorzugt mindestens 70 At.% Magnesium. Es ist bevorzugt, aber nicht notwendig, dass die Magnesiumlegierung weiterhin mindestens ein Element ausgewählt aus der Gruppe bestehend aus den Elementen der 3. Hauptgruppe, der 3. Nebengruppe oder Seltenenerdelemente des Periodensystems enthält. Beispielsweise kann das Magnesiumsubstrat aus einer AZ31-, AZ91-, AE42-, ZM21-, ZK31-, ZE41-Legierung oder jeder anderen gängigen Magnesiumlegierung gefertigt sein.As substrate materials, magnesium, aluminum, titanium or their alloys may preferably be used. Most preferably, the substrate material is magnesium or its alloys. The magnesium alloy of the magnesium substrate may be any amount, e.g. from 1 to 100 at% (at.%) of magnesium. The magnesium alloy of the magnesium component preferably contains at least 50 at.%, Particularly preferably at least 70 at.% Of magnesium. It is preferable, but not necessary, that the magnesium alloy further contains at least one element selected from the group consisting of the elements of the 3rd main group, the 3rd subgroup or rare earth elements of the periodic table. For example, the magnesium substrate can be made of an AZ31, AZ91, AE42, ZM21, ZK31, ZE41 alloy or any other common magnesium alloy.
Mit dem erfindungsgemäßen Verfahren erzielt man Oberflächenbeschichtungen auf Substraten auf Basis von Leichtmetallen mit verbessertem Korrosionsschutz oder mit verbesserter Biokompatibilität und der Möglichkeit die Degradation des Substrates besser kontrollieren zu können.The process according to the invention achieves surface coatings on substrates based on light metals with improved corrosion protection or with improved biocompatibility and the possibility of being able to better control the degradation of the substrate.
Substrate können daher jegliche aus einem Leichtmetall wie Magnesium oder einer Magnesiumlegierung gefertigte Maschinenbauteile, Automobilbauteile, Eisenbahnbauteile, Flugzeugbauteile, Schiffsbauteile, etc. oder Bioimplantate wie Knochenersatzmaterialien oder medizinische Knochenschrauben sein.Substrates may therefore be any engineered components made of a light metal such as magnesium or a magnesium alloy, automotive components, railway components, aircraft components, marine components, etc., or bio-implants such as bone replacement materials or medical bone screws.
Als Substrat für das folgende Beispiel wurde AM50-Probekörper der Größe 15 mm x 15 mm x 4 mm mit einem Masseanteil von 4,4%~5,5% Al, 0,26%~0,6%Mn, max. 0,22% Zn, max. 0,1% Si und Mg als Rest verwendet. Die Substrate wurden nacheinander mit Schleifpapier der Körnung 500, 800, 1200 und 2500 geschliffen und anschließend mit Ethanol gereinigt.As a substrate for the following example, AM50 specimens of size 15 mm × 15 mm × 4 mm with a mass fraction of 4.4% ~ 5.5% Al, 0.26% ~ 0.6% Mn, max. 0.22% Zn, max. 0.1% Si and Mg used as rest. The substrates were sanded successively with 500, 800, 1200, and 2500 grit sandpaper and then cleaned with ethanol.
Das Elektrolyt auf Silikatbasis wurde unter Verwendung von Na2SiO3 (10,0 g/l) und KOH (1,0 g/l) in destilliertem Wasser und das Elektrolyt auf Phosphatbasis wurde unter Verwendung von Na3PO4 (10,0 g/l) und KOH (1,0 g/l) in destilliertem Wasser hergestellt. Bis zu 10 g/l Tonpartikel (Rockwood Nanofil® 116 mit einer mittleren Teilchengröße von 12 µm wurden in diesen Elektrolyten zur Herstellung der Nanopartikel-enthaltenden Elektrolyte dispergiert.The silicate-based electrolyte was prepared using Na 2 SiO 3 (10.0 g / L) and KOH (1.0 g / L) in distilled water and the phosphate-based electrolyte using Na 3 PO 4 (10.0 g / L) and KOH (1.0 g / L) in distilled water. Up to 10 g / l clay particles (Rockwood Nanofil ® 116 having an average particle size of 12 .mu.m of the nanoparticles-containing electrolytes were dispersed in these electrolytes for the preparation.
Die plasmaelektrolytische Oxidation wurde mit einer pulsierenden Gleichstrom-Spannungquelle durchgeführt, wobei das Pulsverhältnis t on:t off 2 ms:20 ms betrug. Die Plasmaelektrolyse wurde jeweils 30 Minuten bei einer konstanten Stromdichte von 15 mA/cm-2 in sowohl den Elektrolyten auf Silikatbasis, als auch den Elektrolyten auf Phosphatbasis, jeweils mit und ohne Zugabe von Tonpartikeln durchgeführt. Die Temperatur des Elektrolyten wurde mittels eines Wasserkühlungssytems bei 10°C ± 2°C gehalten.The plasma electrolytic oxidation was carried out with a pulsating DC voltage source, the pulse ratio t on :
Alle beschichteten Proben wurden sofort nach der Plasmaelektrolyse mit destilliertem Wasser abgespült und in Umgebungsluft getrocknet.All coated samples were rinsed with distilled water immediately after plasma electrolysis and dried in ambient air.
Die durch Plasmaelektrolyse beschichteten Probekörper wurden in einem Cambridge Stereoscan 200 Elektronenmikroskop untersucht. Röntgenbeugung (XRD) wurde mit einer Cu-Kα-Strahlung zur Bestimmung der Phasenzusammensetzung durchgeführt.The plasma electrolysis coated specimens were examined in a Cambridge Stereoscan 200 electron microscope. X-ray diffraction (XRD) was performed with a Cu-K α radiation to determine the phase composition.
Die Struktur der Beschichtung wurde mittels TEM beurteilt. Die TEM-Probekörper wurden hergestellt, indem ein Abschnitt mittels FIB (Focused Ion Beam) aus der Beschichtung entfernt wurde, der bis zur Grenzfläche des Substrats reichte.The structure of the coating was evaluated by TEM. The TEM specimens were prepared by removing a section from the coating using FIB (Focused Ion Beam), which reached to the interface of the substrate.
Elektrochemische Untersuchungen wurden zur Bestimmung des Korrosionsverhaltens von unbeschichteten und PEO-beschichteten Probekörpern mittels eines Gill AC Potentiostaten durchgeführt. Es wurde eine typische Drei-Elektroden-Zelle mit einer gesättigten Ag/AgCl (gesättigt mit KCl) als ReferenzElektrode, einer Platinnetz-Gegenelektrode (0,5 cm2) und die Proben als Arbeitselektrode verwendet. Die elektrochemischen Untersuchungen wurden in 0,1M NaCl-lösung durchgeführt.Electrochemical investigations were carried out to determine the corrosion behavior of uncoated and PEO-coated specimens using a Gill AC potentiostat. A typical three-electrode cell was used with a saturated Ag / AgCl (saturated with KCl) as the reference electrode, a platinum network counter electrode (0.5 cm 2 ) and the samples as the working electrode. The electrochemical studies were carried out in 0.1 M NaCl solution.
Makroskopische Untersuchungen der Morphologie der korrodierten Oberfläche der Probekörper wurden mit einem optischen Stereomikroskop und im Cambridge Stereoscan 250 Elektronenmikroskop durchgeführt.
-
Fig. 1 zeigt das Resultat einer Elektrochemischen Impendanzspektroskopie Untersuchung von mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis ohne Tonpartikel erzeugten Probekörpers nach unterschiedlich langer Immersion in 0,1 M NaCl-Lösung; -
Fig. 2 zeigt das Resultat einer Elektrochemischen Impendanzspektroskopie Untersuchung von mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis mit Tonpartikeln erzeugten Probekörpers nach unterschiedlich langer Immersion in 0,1 M NaCl-Lösung; -
Fig. 3 zeigt das Resultat einer Elektrochemischen Impendanzspektroskopie Untersuchung von mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis ohne Tonpartikel erzeugten Probekörpers nach unterschiedlich langer Immersion in 0,1 M NaCl-Lösung; -
Fig. 4 zeigt das Resultat einer Elektrochemischen Impendanzspektroskopie Untersuchung von mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis mit Tonpartikeln erzeugten Probekörpers nach unterschiedlich langer Immersion in 0,1 M NaCl-Lösung;
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Fig. 1 shows the result of an electrochemical impedance spectroscopy investigation of specimens produced by means of PEO using a phosphate-based electrolyte without clay particles after immersion of different lengths in 0.1 M NaCl solution; -
Fig. 2 shows the result of an electrochemical impedance spectroscopy investigation of specimens produced by means of PEO using a phosphate-based electrolyte with clay particles after immersion of different lengths in 0.1 M NaCl solution; -
Fig. 3 shows the result of an electrochemical impedance spectroscopy investigation of specimens produced by means of PEO using a silicate-based electrolyte without clay particles after immersion of different lengths in 0.1 M NaCl solution; -
Fig. 4 shows the result of an electrochemical impedance spectroscopy Examination of specimens produced by PEO using a silicate-based electrolyte with clay particles after immersion in 0.1 M NaCl solution of different lengths;
Die REM-Aufnahmen zeigen, dass die Oberfläche des mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis (ohne Tonpartikel) erzeugten Probekörpers Mikroporen mit einer Größe von 10-30 µm im Durchmesser aufweist. Die Porenfreie Region ist hingegen glatt. Auf der Oberfläche des mittels PEO unter Verwendung eines 10 g/l Tonpartikel enthaltenden Elektrolyten auf Phosphatbasis waren viele kleine Partikel zu erkennen; die Oberfläche war rau. Die Größe der kleinen Partikel variierte von einigen hundert nm bis zu wenigen mm. Querschnittaufnahmen zeigten, dass die Dicke der mit Tonpartikeln erzeugten Beschichtung (20 µm ± 2 µm) geringer war, als die der ohne Tonpartikel erzeugten Beschichtung (25 µm ± 2 µm). In der mit Tonpartikeln erzeugten Beschichtung wurden auch viel mehr Poren beobachtet.The SEM photographs show that the surface of the specimen produced by means of PEO using a phosphate-based electrolyte (without clay particles) has micropores with a size of 10-30 μm in diameter. The pore-free region, however, is smooth. On the surface of the phosphate-based electrolyte containing PEO using a 10 g / l clay particle, many small particles were seen; the surface was rough. The size of the small particles varied from a few hundred nm to a few mm. Cross-sectional images showed that the thickness of the clay particle-produced coating (20 μm ± 2 μm) was lower than that of the coating without clay particles (25 μm ± 2 μm). In the coating made with clay particles, many more pores were also observed.
Ein weiteres interessantes Resultat ist, dass die Hydrophilie der beiden PEO-beschichteten Probekörper unterschiedlich ist. Der mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis ohne Tonpartikel erzeugte Probekörper ist hydrophil, wenn der Wasserkontaktwinkel weniger als 90° beträgt. Bei dem mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis mit Tonpartikeln erzeugten Probekörper verteilt sich der Wassertropfen schnell und überdeckt die Oberfläche sofort. Das bedeutet, dass die mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis mit Tonpartikeln erzeugten Probekörper superhydrophil sind.Another interesting result is that the hydrophilicity of the two PEO-coated specimens is different. The specimen produced by PEO using a phosphate-based electrolyte without clay particles is hydrophilic when the water contact angle is less than 90 °. In the case of PEO using a phosphate-based electrolyte with clay particles, the water droplet quickly spreads and immediately covers the surface. This means that the specimens produced by means of PEO using a phosphate-based electrolyte with clay particles are superhydrophilic.
Aus Tabelle 1 ist ersichtlich, dass der icorr -Wert des mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis mit Tonpartikeln erzeugten Probekörpers nur geringfügig unter dem des mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis ohne Tonpartikel erzeugten Probekörper liegt.
Die Elektrochemische Impendanzspektroskopie Untersuchung zeigte, dass die mittels PEO unter Verwendung eines Elektrolyten auf Phosphatbasis ohne Tonpartikel erzeugten Probekörper bereits nach 50h in 0,1 M NaCl-Lösung durchfielen (
Die SEM-Aufnahmen zeigen, dass die Oberfläche des mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis (ohne Tonpartikel) erzeugten Probekörpers eine größere Anzahl an Mikroporen mit einer Größe von 5-15 µm im Durchmesser aufweist. Die Porenfreie Region ist hingegen glatt ohne jegliche heterogene Partikel. Auf der Oberfläche des mittels PEO unter Verwendung eines 10 g/l Tonpartikel enthaltenden Elektrolyten auf Silikatbasis waren viele kleine Partikel zu erkennen. Querschnittaufnahmen zeigten, dass die Dicke der mit Tonpartikeln erzeugten Beschichtung und die der ohne Tonpartikel erzeugten Beschichtung in etwa gleich waren (17 µm ± 3 µm). In der mit Tonpartikeln erzeugten Beschichtung wurden auch viel mehr Poren beobachtet.The SEM photographs show that the surface of the specimen produced by means of PEO using a silicate-based electrolyte (without clay particles) has a larger number of micropores with a size of 5-15 μm in diameter. The pore-free region, however, is smooth without any heterogeneous particles. On the surface of the under PEO under Using a silicate-based electrolyte containing 10 g / l clay particles, many small particles were seen. Cross-sectional images showed that the thickness of the coating produced with clay particles and that of the coating produced without clay particles were approximately the same (17 μm ± 3 μm). In the coating made with clay particles, many more pores were also observed.
Wie auch in Beispiel 1, zeigte sich, dass die Hydrophilie der beiden PEO-beschichteten Probekörper unterschiedlich ist. Der mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis ohne Tonpartikel erzeugte Probekörper ist hydrophil, wenn der Wasserkontaktwinkel weniger als 90° beträgt. Bei dem mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis mit Tonpartikeln erzeugten Probekörper verteilt sich der Wassertropfen schnell und überdeckt die Oberfläche sofort und der kontaktwinkel is offensichtlich viel geringer.As in Example 1, it was found that the hydrophilicity of the two PEO-coated specimens is different. The specimen produced by PEO using a silicate based electrolyte without clay particles is hydrophilic when the water contact angle is less than 90 °. In the case of the specimen produced by PEO using a silicate-based electrolyte with clay particles, the water droplet spreads rapidly and covers the surface immediately, and the contact angle is obviously much lower.
Aus Tabelle 2 ist ersichtlich, dass der icorr -Wert des mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis mit Tonpartikeln erzeugten Probekörpers eine Größenordnung über dem der unter dem des mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis ohne Tonpartikel erzeugten Probekörpers liegt.
Die Elektrochemische Impendanzspektroskopie Untersuchung zeigte, dass die mittels PEO unter Verwendung eines Elektrolyten auf Silikatbasis ohne Tonpartikel erzeugten Probekörper bereits nach 100h in 0,1 M NaCl-Lösung durchfielen (
Röntgenbeugungsuntersuchungen (XRD) legen nahe, dass sich die Beschichtungsstruktur von kristallin zu amorph ändert, wenn Tonpartikel zu den Elektrolyten gegeben werden. Die scharfen XRD-Peaks der kristallinen Schicht verschwinden bei Zugabe von 3 g/l, 6 g/l und 10 g/l Tonpartikel sukzessiv und es zeigt sich das typische breite Beugungsspektrum eines glasartigen Materials. Die Peaks stammen von dem Mg-Substrat unter der Schicht. Dieser Befund wurde durch TEM-Untersuchungen bestätigt.X-ray diffraction (XRD) studies suggest that the coating structure changes from crystalline to amorphous as clay particles are added to the electrolytes. The sharp XRD peaks of the crystalline layer disappear successively with the addition of 3 g / l, 6 g / l and 10 g / l clay particles, revealing the typical broad diffraction spectrum of a vitreous material. The peaks are from the Mg substrate under the layer. This finding was confirmed by TEM examinations.
Die Zusammensetzungen der Beschichtungen wurden mittels EDX-Analyse bestimmt und sind in der nachfolgenden Tabelle 3 wiedergegeben.
Tabelle 3 legt nahe, dass sich die Zusammensetzungen der Beschichtungen denen von Biogläsern (gemischt aus Na2O, MgO, CaO, SiO2, Al2O3, P2O5) ähneln. Nur Ca fehlt als typischer Bestandteil. Man kann daher ähnliche biomedizinische Anwendungen erwarten. Ca kann aber auch in Form von Ca(OH)2 dem Elektrolyten zugegeben werden, so dass es auch in die Beschichtung eingebracht werden kann.Table 3 suggests that the compositions of the coatings are similar to those of bioglasses (mixed with Na 2 O, MgO, CaO, SiO 2 , Al 2 O 3 , P 2 O 5 ). Only Ca is missing as a typical ingredient. One can therefore expect similar biomedical applications. However, Ca can also be added to the electrolyte in the form of Ca (OH) 2 , so that it can also be introduced into the coating.
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015090267A1 (en) * | 2013-12-17 | 2015-06-25 | Meotec GmbH & Co. KG | Method for producing a protective layer on a thermally stressed component and component having such a protective layer |
WO2016197175A1 (en) * | 2015-06-09 | 2016-12-15 | Hirtenberger Engineered Surfaces Gmbh | Electrolyte for plasma electrolytic oxidation |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2500733B (en) * | 2012-06-25 | 2014-05-21 | Jemella Ltd | Hair styling appliance |
JP6546772B2 (en) * | 2014-04-23 | 2019-07-17 | カンパニョーロ・ソシエタ・ア・レスポンサビリタ・リミタータCampagnolo Societa A Responsabilita Limitata | Rim of bicycle wheel, bicycle wheel having the same, and method of manufacturing the same |
DK178658B1 (en) * | 2015-02-04 | 2016-10-17 | Tresu As | chamber Rachel |
CN104726925A (en) * | 2015-03-25 | 2015-06-24 | 西南石油大学 | Method for preparing HNTs/Ni-W coating film |
EP3347506A4 (en) * | 2015-09-11 | 2019-01-23 | Hewlett-Packard Development Company, L.P. | Light metal based multi-layer substrates |
CN105154951A (en) * | 2015-09-15 | 2015-12-16 | 广西大学 | Method for preparing nano SiO2 containing coating on surface of cast aluminium alloy through micro-arc oxidation |
DE102016223561A1 (en) | 2016-01-22 | 2017-07-27 | Ford Global Technologies, Llc | Method and device for producing a protective coating |
WO2017139883A1 (en) | 2016-02-17 | 2017-08-24 | Shimco North America Inc. | Plasma electrolytic oxidation (peo) coated peelable shims |
DE102016203195A1 (en) | 2016-02-29 | 2017-08-31 | Ford Global Technologies, Llc | Method for producing a forming tool |
DE102016203198A1 (en) | 2016-02-29 | 2017-08-31 | Ford Global Technologies, Llc | Method for producing a forming tool |
CN107050504A (en) * | 2017-03-27 | 2017-08-18 | 山东科技大学 | The preparation of AZ31 Mg alloy surface Na MMT coatings and assay method |
DE102018129604B3 (en) * | 2018-11-23 | 2020-03-12 | Meotec Gmbh | Biodegradable implant that includes a coated magnesium alloy product |
EP3719181A3 (en) | 2019-04-05 | 2020-11-18 | Eloxalwerk Ludwigsburg Helmut Zerrer GmbH | Oxide layer and method of forming a thermally relaxed oxide layer |
CN109943875A (en) * | 2019-04-30 | 2019-06-28 | 北京航天控制仪器研究所 | A kind of beryllium and its alloy surface differential arc oxidization processing method and processing device |
CN110760916B (en) * | 2019-11-18 | 2022-04-05 | 和县科嘉阀门铸造有限公司 | Method for improving corrosion resistance of magnesium alloy valve |
CN114262923B (en) * | 2020-09-16 | 2023-07-25 | 华中科技大学 | Double-layer composite film on magnesium alloy surface, preparation method and application thereof |
Family Cites Families (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2650975A (en) * | 1950-03-15 | 1953-09-01 | Sprague Electric Co | Electrically insulated conductor and production thereof |
CA1106795A (en) | 1975-06-27 | 1981-08-11 | Toshihiko Sato | Coloured pattern on anodized aluminium article with shade differences |
DD156003A1 (en) * | 1980-09-23 | 1982-07-21 | Peter Kurze | PROCESS FOR SURFACE TREATMENT OF TITANIUM AND ALLOYS |
US5147515A (en) | 1989-09-04 | 1992-09-15 | Dipsol Chemicals Co., Ltd. | Method for forming ceramic films by anode-spark discharge |
RU2038428C1 (en) | 1991-08-05 | 1995-06-27 | Малышев Владимир Николаевич | Electrolyte for microarc oxidation of aluminum and its alloys |
DE4200027A1 (en) * | 1992-01-02 | 1993-07-08 | Waldemar Dipl Chem Dr Krysmann | Electrochemical prodn. of diffusion layer systems - by anodically heating workpiece in aq. soln., suspension or emulsion |
JP3159517B2 (en) * | 1992-04-24 | 2001-04-23 | ディップソール株式会社 | Antifouling sheet |
RU2165484C1 (en) * | 2000-01-17 | 2001-04-20 | Залыгин Юрий Рэмович | Thin-layer ceramic coat: method of making such coat; friction surface on base of thin-layer ceramic coat and method of making such surface |
US6916414B2 (en) * | 2001-10-02 | 2005-07-12 | Henkel Kommanditgesellschaft Auf Aktien | Light metal anodization |
US6716490B2 (en) | 2002-01-30 | 2004-04-06 | Kawasaki Steel Metal Products & Engineering Inc. | Method for making enameled steel sheet |
JP4143306B2 (en) | 2002-01-30 | 2008-09-03 | Jfeスチール株式会社 | Method for producing coated steel sheet |
GB2386907B (en) * | 2002-03-27 | 2005-10-26 | Isle Coat Ltd | Process and device for forming ceramic coatings on metals and alloys, and coatings produced by this process |
US6919012B1 (en) * | 2003-03-25 | 2005-07-19 | Olimex Group, Inc. | Method of making a composite article comprising a ceramic coating |
US20070207267A1 (en) * | 2006-02-08 | 2007-09-06 | Laube David P | Disposable liners for etch chambers and etch chamber components |
EP1820882A1 (en) * | 2006-02-21 | 2007-08-22 | Technische Universiteit Delft | Self-healing layer on non-ferrous metals using polyoxometalates |
JP4125765B2 (en) * | 2006-09-28 | 2008-07-30 | 日本パーカライジング株式会社 | Method of coating ceramic film of metal, electrolytic solution used therefor, ceramic film and metal material |
GB0720982D0 (en) * | 2007-10-25 | 2007-12-05 | Plasma Coatings Ltd | Method of forming a bioactive coating |
CN101230474A (en) * | 2007-11-05 | 2008-07-30 | 南昌航空大学 | Method for depositing composite ceramic film by differential arc oxidation |
CN102105612A (en) | 2008-07-30 | 2011-06-22 | 国立大学法人东北大学 | Al alloy member, electronic device manufacturing device, and manufacturing method for Al alloy member with anodic oxide film |
-
2011
- 2011-04-14 DE DE201110007424 patent/DE102011007424B8/en not_active Expired - Fee Related
-
2012
- 2012-04-03 US US13/438,418 patent/US8828215B2/en not_active Expired - Fee Related
- 2012-04-03 CA CA2773434A patent/CA2773434C/en not_active Expired - Fee Related
- 2012-04-04 EP EP12163197.2A patent/EP2511401A3/en not_active Withdrawn
- 2012-04-11 CN CN201210106281.XA patent/CN102732929B/en not_active Expired - Fee Related
- 2012-04-13 JP JP2012091541A patent/JP5529916B2/en not_active Expired - Fee Related
Non-Patent Citations (2)
Title |
---|
BLAWERT ET AL., ADVANCED ENGINEERING MATERIALS, vol. 8, no. 6, 2006, pages 511 - 533 |
SRINIVASAN ET AL., SURFACE ENGINEERING, vol. 26, no. 5, 2010, pages 367 - 370 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015090267A1 (en) * | 2013-12-17 | 2015-06-25 | Meotec GmbH & Co. KG | Method for producing a protective layer on a thermally stressed component and component having such a protective layer |
WO2016197175A1 (en) * | 2015-06-09 | 2016-12-15 | Hirtenberger Engineered Surfaces Gmbh | Electrolyte for plasma electrolytic oxidation |
Also Published As
Publication number | Publication date |
---|---|
CA2773434C (en) | 2014-12-02 |
CN102732929A (en) | 2012-10-17 |
CN102732929B (en) | 2016-04-06 |
DE102011007424B8 (en) | 2014-04-10 |
US8828215B2 (en) | 2014-09-09 |
JP5529916B2 (en) | 2014-06-25 |
JP2012237059A (en) | 2012-12-06 |
EP2511401A3 (en) | 2014-05-14 |
DE102011007424B4 (en) | 2014-01-23 |
DE102011007424A1 (en) | 2012-10-18 |
CA2773434A1 (en) | 2012-10-14 |
US20120261266A1 (en) | 2012-10-18 |
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