Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
  • C23C4/067—Metallic material containing free particles of non-metal elements, e.g. carbon, silicon, boron, phosphorus or arsenic
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
  • C23C4/08—Metallic material containing only metal elements
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
  • C23C4/11—Oxides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
  • C23C4/129—Flame spraying
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
  • C23C4/134—Plasma spraying
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12611—Oxide-containing component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12611—Oxide-containing component
  • Y10T428/12618—Plural oxides

Definitions

• the invention relates to protective layers for metals or metallic alloys which can be used at high temperatures and in aggressive gaseous, liquid and solid media. More particularly, the present invention relates to a thermally sprayed, gas-tight protective layer for metallic substrates, in particular those based on Fe, Ni, Al, Mg and / or Ti, wherein the spray powder for this purpose comprises at least two components, of which the first is a silicate Mineral or rock and the second is a metal powder and / or another silicate mineral or rock.
• Emailes are known as non-metallic protective layers for various metals and alloys (see [1]: A. Petzold, H. Pöschmann, enamel and enamel technique, Wiley-VCH; Edition 2, (1992 )). These protective layers have good adhesion to the substrate and reliably protect the metallic base materials up to approx. 400 ° C against many aggressive media.
• silicate glasses with a relatively low SiO 2 content and a high content of alkali oxides are used as enamel for steels and cast iron (see [1]).
• Typical enamels for white enamelling of sheet steel consist of a base and a top enamel and have the following compositions: basic email ceiling mail material Proportion of (%) material Proportion of (%) SiO 2 47-53 SiO 2 56 Al 2 O 3 4 - 6 Al 2 O 3 7 B 2 O 3 17-19 B 2 O 3 7 Na 2 O + K 2 O 15-18 Na 2 O + K 2 O 22.5 TiO 2 2-8 CaO 7 CaO + MgO rest F 0.5
• Ceramic layers of refractory corrosion-resistant materials which are applied to metallic substrates by means of thermal spraying (flame spraying, high-velocity flame spraying (HVOF), plasma spraying) or PVD or CVD method.
• thermal spraying flame spraying, high-velocity flame spraying (HVOF), plasma spraying
• PVD vapor deposition
• YSZ yttrium-stabilized zirconia
• thermal spraying [ UK 2100621 A ; US 4,377,371 ; W0 91/05888 ; US 5,169,689 ]
• PVD yttrium-stabilized zirconia
• YSZ layers A difference in the coefficients of thermal expansion of the layer and the substrate is compensated in YSZ layers by a porous structure with a crack network. Thanks to this property, these layers are thermoshock resistant. However, they do not guarantee protection against oxidation and corrosion and can only be used as pure thermal barrier coatings at temperatures up to 1200 ° C.
• a second important disadvantage of YSZ layers is weak adhesion to the substrate. Together with a low mechanical strength (due to cracks and pores) this means poor erosion resistance.
• Ceramic layers such as e.g. TiN, TiC, CrC, CrN, DLC, and the like, which are produced by PVD / CVD method, have low coefficients of thermal expansion and therefore can not be operated at high temperatures; in fact, when the temperature increases, the layer tears because a metallic substrate expands much more than the layer. For this reason, these very thin layers with layer thicknesses of less than 5 microns are mainly used at room temperature as wear and corrosion protection.
• These glass-metal / ceramic layers are used as thermal barrier coatings for turbine blades.
• An advantage over YSZ layers lies in an oxidation protection for the substrate through the gas-tight layer structure.
• these layers are not suitable as a corrosion protection layer.
• alkaline glasses had to be selected in order to achieve the highest possible coefficient of thermal expansion for adaptation to the substrate. When used as a thermal barrier coatings, this is not critical.
• thermally sprayed protective layers of the type mentioned which were developed specifically as corrosion protection against extremely aggressive media at normal and especially at high temperatures and which are characterized in that the proportion of silicate mineral or rock in Spray powder has an alkali content of less than 6 weight percent.
• Alkaline content is to be understood as meaning the proportion by weight of oxides of alkali metals or of alkali metals as such.
• These coatings provide protection for metallic base materials against all aqueous salt solutions and acids (excluding HF) in a low temperature range and against many corrosive ashes, molten salts, and corrosive gases in a high temperature range. Since the layers have a low thermal conductivity and can be applied with a large layer thickness, their use is also possible as thermal insulation.
• the production method according to the invention comprises applying the protective layer to the metallic substrate by means of flame spraying, high-velocity flame spraying (HVOF) or plasma spraying and is characterized in that during the application of the protective layer an adaptation of the thermal expansion coefficients of the layer and substrate by a controlled partial devitrification the mineral components of the spray powder takes place.
• HVOF high-velocity flame spraying
• the thermal expansion coefficient of the layer is thus adjusted by growing in the layer, new crystalline phases, that it is adapted to the substrate.
• the targeted crystallization of the silicate components makes it possible-even without having to accept a high proportion of alkali in the at least one silicate component-to produce a wide range of thermal expansion coefficients.
• For a controlled crystallization is thus no longer only a suitable choice of mineral materials crucial; rather, in particular, their particle size distribution is of crucial importance. Because a variation of the grain size, the temperatures of the particles in the flame or in the plasma and thus the crystallization behavior in the resulting layer are strongly influenced, which ultimately allows an adjustment of the coefficient of thermal expansion.
• the protective layers of the present invention have all the advantages of the already known glass-metal / ceramic layers, because during the layer construction the mineral or rock component is present as glass.
• This glass contributes to a good wetting of the substrate and the metal particles and thus a good Adhesion to the substrate, can be plastically deformed and forms a perfect non-porous mixture with the possibly existing metal component.
• the partial crystallization takes place in the still plastic layer in such a way that no mechanical stresses develop in the protective layer.
• the decisive advantage of the protective layer according to the invention and of the method according to the invention over glass-metal / ceramic layers and enamels is that in the context of the present invention also low-alkali and thus corrosion-resistant silicates are used, which in the prior art because of a low thermal expansion coefficient and high Melting temperatures were considered unusable for the coating of metals.
• a metal component in the spray powder for the protective layer are in principle all possible metals or metal alloys in question. However, it is preferably a metal powder of a nickel or copper-based alloy.
• the spray powder advantageously consists of a total of three components, namely a first and a second silicate mineral or rock and a metal powder.
• the glazing and the partial devitrification of the spray powder can be controlled for a protective layer optimally adapted to the respective substrate.
• the spray powder is preferably a proportion of at least 10 weight percent of a silicate component with high purity of silica present, which advantageously exceeds a proportion of 99% in the component.
• Protective layers according to the invention can advantageously have a thermal conductivity of between 0.8 and 5 W / mK which is also suitable for heat-insulating purposes and can be applied in a layer thickness of from 100 to 2500 ⁇ m. Layer thicknesses of more than 2 mm prove to be particularly advantageous in a protective layer according to the invention, in particular if its heat-insulating property is required.
• the present invention relates not only to a protective layer according to the invention but also to an at least two-component spray powder for the production thereof.
• the invention is also directed to the use of the protective layer for protecting parts of the combustion chamber of an internal combustion engine or of a gas turbine serving as substrate against high temperatures, corrosion and erosion.
• these are in particular valves, pistons and cylinder heads; in gas turbines, this relates in particular to the blades and plates.
• the protective layer according to the invention is also ideal for other machine parts serving as substrates, for example for protecting parts of steam turbines, chemical plants, heat exchangers, etc. effectively against temperature, corrosion and erosion.
• the substrate is made of a steel or a nickel-based alloy. Then an inventive mineral metal spray powder is sprayed by flame spraying, plasma spraying or HVOF. The spraying succeeds on a sandblasted, not preheated substrate without re-melting.
• the spray powder with a grain size ⁇ 50 ⁇ m is produced by spray-drying with subsequent sintering (850 ° C, shielding gas) from the following components: 65% Metal powder of gas-atomized 80Ni20Cr alloy (nickel chrome), grain size ⁇ 25 ⁇ m; 25% molten and finely ground artificial black basalt, wt%: SiO 2 -50, CaO-20, Al 2 O 3 -15, MgO-8, Fe 2 O 3 -7, grit ⁇ 10 ⁇ m; Alkali content ⁇ 0.5 wt.% 10% Ground and sieved natural quartz or crystallite (grain size 25-50 ⁇ m) with a purity of> 99% SiO 2 .
• the mineral-metal layer which results from this spray powder, is free of pores and cracks and has a thermal expansion coefficient of approx. 12x10 -6 K -1 at 20 ° C.
• the thermal conductivity of the layer at 700 ° C is about 3 W / mK.
• the layer thickness can be varied in the range 100 - 2500 microns.
• the maximum operating temperature in air is 1200 ° C.
• the coating is suitable as corrosion protection and thermal insulation for various high-temperature and thermal shock-stressed parts made of steels and nickel-based alloys.
• the substrate consists of a steel, cast or a nickel-based alloy. Then, an inventive, two-component mineral spray powder is sprayed by flame spraying or plasma spraying. The spraying success on a sandblasted, preheated to about 500 ° C substrate with a re-melting at about 1100 ° C.
• the spray powder with a grain size of ⁇ 100 ⁇ m is produced by mixing together the following mineral components: 67% molten, ground and sieved (grain size 25-50 ⁇ m) of artificial white basalt, wt%: SiO 2 -54, CaO-20, MgO-5, Al 2 O 3 -16, Na 2 O-5; Alkali content ⁇ 5 wt.% 33% ground and sieved (grain size 25-100 ⁇ m) crystallite with a purity of> 99% SiO 2 .
• wt .-% of the following oxides can be added to the spray powder for dyeing the layer: CoO, Cr 2 O 3 , TiO 2 , ZrO 2 , ZnO and Fe 2 O 3 .
• a mineral layer, which results from this spray powder, is pore-poor ( ⁇ 3%), free of cracks and has a thermal expansion coefficient at 20 ° C of approx. 11x10 -6 K -1 .
• the thermal conductivity of the layer is approx. 1 W / mK at 700 ° C.
• the layer thickness can be varied in the range 100-600 ⁇ m.
• the maximum operating temperature in air is approx. 1000 ° C. Since the coating contains no metallic component, it is less thermally shock resistant than metal-containing mineral-metal layers.
• the preferred field of application of the layer is thus corrosion protection, in particular against acids for medium thermally shock-stressed parts.
• the substrate is made of an aluminum or magnesium alloy. Then a mineral-metal spray powder is sprayed on by plasma spraying or HVOF. The spraying succeeds on a sandblasted, not preheated substrate without re-melting.
• the spray powder with a grain size ⁇ 50 ⁇ m is produced by spray-drying with subsequent sintering (620 ° C, inert gas) from the following components: 62% Metal powder made from gas-atomized 90Cu10Sn alloy (tin bronze), grain size ⁇ 25 ⁇ m; 18% finely ground (grain size ⁇ 10 ⁇ m) natural black basalt (basalt flour); Alkali content ⁇ 5 wt.% 20% Ground and sieved (grain size 25-50 ⁇ m) natural quartz or crystallite with a purity of> 99% SiO 2 .
• the mineral-metal layer that results from this spray powder is free of pores and cracks and has a coefficient of thermal expansion of approx. 18x10 -6 K -1 at 20 ° C.
• the thermal conductivity of the layer is at 400 ° C at about 5 W / mK.
• the layer thickness can be varied in the range 100 - 2500 microns.
• the maximum operating temperature of the protective layer in air is 700 ° C - apart from the substrate.
• the coating is suitable as corrosion protection and thermal insulation for various high thermal shock loaded parts made of aluminum and magnesium alloys.
• the substrate consists of a titanium alloy. This is followed by plasma spraying or HVOF a mineral-metal spray powder sprayed. The spraying succeeds on a sandblasted, not preheated substrate without re-melting.
• the spray powder with a grain size ⁇ 50 ⁇ m is produced by spray drying with subsequent sintering (800 ° C, shielding gas) from the following components: 57% Metal powder of gas-atomized 80Ni20Cr alloy (nickel chrome), grain size ⁇ 25 ⁇ m; 31% finely ground (grain size ⁇ 10 ⁇ m) natural black basalt (basalt flour) 12% Ground and sieved (grain size 25-50 ⁇ m) of natural spodumene with a purity of> 95% LiAlSi206.
• a mineral-metal layer which results from this spray powder, is free of pores and cracks and has a thermal expansion coefficient of approx. 7.5x10 -6 K -1 at 20 ° C.
• the alkali content of the mineral components is also here (including Li) at ⁇ 5 wt.%.
• the thermal conductivity of the layer is approx. 2 W / mK at 700 ° C.
• the layer thickness can be varied in the range 100 - 2500 microns.
• the maximum operating temperature in air is 900 ° C.
• the coating is suitable as high-temperature corrosion protection and thermal insulation for various highly thermally shock-stressed titanium alloy parts.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Coating By Spraying Or Casting (AREA)
• Laminated Bodies (AREA)

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• 2007
  • 2007-06-19 DE DE102007028109A patent/DE102007028109A1/de not_active Withdrawn
• 2008
  • 2008-04-11 EP EP08007173.1A patent/EP2006410B1/fr not_active Not-in-force
  • 2008-05-09 CN CN200810096440.6A patent/CN101328569B/zh not_active Expired - Fee Related
  • 2008-05-13 KR KR1020080043973A patent/KR20080112099A/ko not_active Abandoned
  • 2008-05-30 US US12/129,872 patent/US8784979B2/en active Active
  • 2008-06-18 JP JP2008159801A patent/JP5296421B2/ja not_active Expired - Fee Related
• 2014
  • 2014-06-20 US US14/310,411 patent/US20140302299A1/en not_active Abandoned

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