KR20080025013A - Method for preparing strain tolerant coatings from a green material - Google Patents

Abstract

A method for producing strain tolerant coatings from green materials is provided to increase the strain tolerance of the coating by executing mechanical, chemical, thermal treatment for the green material, or combined treatment at the same time. A base material coating method comprises a step for disposing a first coating with first strain tolerance, on a base material and a step for increasing the strain tolerance of the first coating up to second strain tolerance higher than the first strain tolerance by executing at least one including mechanical, chemical, thermal treatment, and combined treatment, on the first coating. A metal combining coating is additionally disposed on the metal base material. The first coating is disposed on the surface of the metal combining coating opposite to the metal base material.

Description

METHODS FOR PREPARING STRAIN TOLERANT COATINGS FROM A GREEN MATERIAL}

This application is related to US Application No. 11 / 386,424, filed March 22, 2006 and assigned to the current assignee.

The present invention relates to a method of making a strain resistant coating and to a product produced thereby. In particular, the present invention relates to a method for producing a strain resistant coating having a "green" state and to a product produced thereby. The present invention also relates to a method for producing a strain resistant coating having a raw state that can be used for heat barrier coatings and to the products produced thereby.

Metals can be oxidized, corroded and brittle when exposed to relatively high temperatures (ie, above about 700 ° C.), especially when present in an oxidizing environment. Environments of such temperature and oxidizing environments can be created in gas turbines, such as gas turbines for power generation. In the field of power generation technology, it has been recognized that when a thermal barrier coating (TBC) is applied to a metal turbine component, the effect that a high temperature oxidizing environment has on the metal component can be reduced.

Thermal barrier coatings typically include at least two components, a metal bond coating and a ceramic coating. The metal bond coating may contain an anti-oxidation and / or anti-corrosion material (including but not limited to one or more of, for example, aluminum and chromium). For example, the metal bond coating can be chromium, aluminum, yttrium or combinations thereof, such as MCrAlY, where M is nickel, cobalt or iron (Hecht, U.S. Patent Nos. 4,034,142, and Gupta). US Pat. No. 4,585,481, et al., Discloses several coating materials). Metal-bonded coatings can be applied via thermal spraying techniques (Gupta et al. Disclose a coating material comprising silicon and hafnium particles applied through plasma spraying).

In addition, the ceramic coating of the thermal barrier coating can be applied to the metal bond coating. Application methods include, but are not limited to, known methods such as air plasma spray (APS) or electron beam physical vapor deposition (EB-PVD).

A “raw” state as defined herein is a state in which the chemistry / characteristic of the coating is “un-finished”, regardless of the number of components and layers applied, or fully processed into the final desired form with the desired chemistry / characteristics. But not necessarily refers to a condition requiring subsequent active processing to achieve the desired chemistry / characteristics. Subsequent active processing is carried out so that the resulting coating achieves the final desired properties. Subsequent processing as defined herein further includes the steps required to "finish" the coating.

All coatings having a raw state are vulnerable when in an unfinished or raw state. In the raw state, the coating may not possess the same properties as the final state. Such properties include the optical and / or mechanical and / or chemical and / or thermal properties of the coating. The fragility causes the coating to deform, sometimes permanently, even under conditions that would normally have no effect when the coating is in its final state. If the TBC is to be applied using a material that exhibits a raw state, its final desired properties are not achieved.

Conventional coating methods for obtaining strain resistant TBCs can be very expensive and / or very difficult to manufacture. Coatings made via the EB-PVD method create a highly strain resistant structure, but this method is expensive and may not be feasible especially for components with large or unique shapes. In addition, strain resistant coatings are modified in-situ or after final processing, both of which are expensive and difficult. In addition, known coating methods for obtaining strain resistant TBCs do not raise the need to process raw coatings that produce strain resistance.

Therefore, what is needed is a method of applying strain resistant TBCs to metal turbine components and other structures that would benefit from the presence of TBCs. In addition, there is a need to provide a coating method of processing a raw coating to obtain a strain resistant TBC that isolates the strain resistance produced in the coating.

The substrate coating method of the present invention provided as an embodiment to meet the above needs comprises the steps of: disposing a coating exhibiting a first strain resistance on a substrate; And treating the coating to increase the strain resistance of the coating to a second strain resistance. The second strain resistance is greater than the first strain resistance. In addition, the treatment step includes one or more of mechanical treatment, chemical treatment, thermal treatment and combinations thereof.

According to the present invention, a coating method is provided in which a raw coating is subjected to mechanical treatment, chemical treatment, thermal treatment or a combination thereof to increase the deformation resistance of the coating.

The above and other features are exemplified through the following detailed description.

Disclosed herein is a method of making a strain resistant coating from a first coating material that exhibits a raw or unfinished state. The term “raw” is referred to as the state of the material before treatment, for example by heat, mechanical and / or chemical means. Typically, but not limited to, heat treatment of raw materials is sintering.

As an embodiment of the present invention, the coating of the material exhibiting the raw state can be any coating, including but not limited to sol-gels, slurries and pastes. Methods for forming a coating from a material exhibiting a raw state include, but are not limited to, a suspension method, a painting method, a dipping method, a spraying method, and a deposition method. It doesn't work. Electro-plating processing, as an embodiment of the present invention, is another method of forming a coating from a material exhibiting a raw state.

Injection may include, but is not limited to, the most common injection methods, such as thermal spraying, APS, VPS, LPPS, HVOF, flames, Arc Wire, Detonation and cold cooling. In addition, the deposition method as an embodiment of the present invention may include physical vapor deposition as well as evaporative, sputtering and pulsating laser deposition.

In addition, as an embodiment of the present invention, the deposition method may include chemical vapor deposition (CVD). As an embodiment of the present invention, chemical vapor deposition may include atomic layer, aerosol assisted, hot wire assisted, and microwave plasma assisted chemical vapor deposition treatments.

In general, a method of making a strain resistant thermal barrier coating on a metal substrate includes disposing a raw coating on the metal substrate; And treating the raw coating to form a strain resistant coating. Treatment as an embodiment of the present invention includes at least one of mechanical treatment, chemical treatment, thermal treatment and combinations thereof. The resulting coating provides oxidation resistance to the metal bond coating and the substrate.

In an embodiment of the invention, the coating treatment increases the deformation resistance of the raw coating from the first deformation resistance to the second deformation resistance. At this time, the second deformation resistance is greater than the first deformation resistance.

In one embodiment, the first raw coating may be hot-balanced pressurized prior to or during the sintering step to minimize the possibility of cracks forming in the coating. This step allows the thicker coating to be dried and sintered, without uncontrolled or undesirable cracking.

As an embodiment of the present invention, the treatment step may include mechanical treatment. Mechanical treatment includes scratching; Imprinting; Screening; Cutting; Application of a removable, non-wetting pattern or mesh; Or combinations comprising one or more of these.

As an embodiment of the present invention, the treating step may comprise a chemical treatment. Chemical treatment may include controlled cracking of the coating during the treatment process, including one or more of the application of a non-wetting pattern and the inclusion of a binder.

In addition, the treatment step as an embodiment of the present invention may comprise a thermal treatment. Thermal treatment includes applying one or more of a laser and an electron beam.

The metal substrate can be any of a variety of components that may benefit from adding a barrier coating, such as a combustion liner or transition piece, a bucket, a nozzle, a blade, Vanes, shrouds, and other components, such as components disposed in hot gas flows in turbine engines. The metal substrates above are used in applications comprising nickel, cobalt, iron and combinations comprising at least one of these, and alloys comprising at least one of these, such as nickel based superalloys, and / or cobalt based superalloys. It can include various metals.

As an embodiment of the present invention, the metal bond coating material forming the barrier coating includes nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), aluminum (Al), yttrium (Y) and one of them. Alloys containing the above, and may also include combinations comprising one or more of these. For example, metal bond coatings include, but are not limited to, MCrAlY, wherein M consists of nickel, cobalt, iron, and combinations comprising one or more thereof. MCrAlY coatings include silicon (Si), ruthenium (Ru), iridium (Ir), osmium (Os), gold (Au), silver (Ag), tantalum (Ta), palladium (Pd), rhenium (Re), and hafnium ( Elements such as Hf), platinum (Pt), rhodium (Rh), tungsten (W), and alloys comprising one or more of these, and also combinations comprising one or more of these. For example, but not limited to, the metal bond coating may comprise sufficient aluminum to form an alumina scale at the metal bond coating surface. Aluminum optionally includes ruthenium (Ru), iridium (Ir), osmium (Os), gold (Au), silver (Ag), palladium (Pd), platinum (Pt), rhodium (Rh) and one or more of these It may be in the form of an aluminide comprising an alloy, and also a combination comprising one or more of these.

The application of the raw metal bond coating to the substrate, which can be performed in a single or multiple steps, can be carried out in various forms as an embodiment of the present invention. Application of the coating method may include vapor deposition (e.g., electron beam physical vapor deposition (EB-PVD), chemical vapor deposition (CVD), electroplating, ion plasma deposition (IPD), plasma spraying (e.g. For example, vacuum plasma spray (VPS), low pressure plasma spray (LPPS), air plasma spray (APS, etc.), thermal deposition (e.g. high velocity fuel) oxidation fuel (HVOF) deposition), and combinations including one or more of these methods, for example, a metal bond coating component may be combined (eg, by induction of melting, etc.), or a powder (E.g., by powder atomization), or plasma sprayed onto the substrate Alternatively, or in addition, the metal bond coating element can be incorporated into the deposited target and ion plasma. At the same time, the same or different elements may be applied to the substrate during each step As an example, precious metals (e.g. platinum) may be applied via techniques to reduce waste and then other methods of applying residual elements. The precious metal may be electroplated onto the substrate surface and other elements may be applied by thermal deposition (eg HVOF) of the powder composition, followed by aluminum to achieve intermixing of the precious metal with the residue of the coating composition. Aluminizing may be performed.

For example, wires, rods, and similar types of metallic materials may be applied to the substrate. The metal material may be mammaled into an oxy-acetylene flame. The flame melts the metal material and atomizes the particle melt into an auxiliary stream of high pressure air which deposits the material as a coating on the substrate. It is also possible to use non-flame spraying devices such as those disclosed in US Patent No. 5,285,967 to Weidman. The HVOF method produces a preferred smooth coating, for example a coating having R _a of about 1 μm (50 μin) or less.

The thickness of the metal bond coating varies depending on the application and application technique in which the coating component is used. The coating may be applied to the turbine component in a thickness of about 50 μm to 625 μm, or more specifically in a thickness of about 75 μm to 425 μm. The metal bond coating can be treated to roughen the surface prior to application of the sol-gel coating. In particular, the metal bond coating may be roughened to _a roughness average (R _a ) of about 100 to about 400 μin (about 2.54 to about 10.16 μm) to provide a suitable bond for application of the coating.

In an exemplary embodiment, the metal substrate is coated with a "raw" strain resistant TBC using a sol-gel type process, as long as there is no intention to limit the invention. First, the metal substrate is coated by a metal bond coating with any number of treatments, including for example HVOF or VPS. The sol containing the inorganic metal oxide powder is then coated on the opposite surface of the metal substrate during metal bond coating. The sol coating is treated to induce removal of the liquid and other volatile components of the "raw" sol. The final step involves the treatment of forming a strain resistant TBC on the metal substrate by sintering the "raw" coating. Such deformation resistance can act to inhibit the formation and propagation of cracks and fractures of the coating during engine service life of turbine engine components.

In addition, as an embodiment of the present invention, a “raw” coating can be hot-balanced pressed to form a strain resistant coating before or during the sintering of the coating. The coating can be a thermal barrier coating, a corrosion resistant coating or any other desired coating for the intended application.

A method of making a strain resistant coating from a material exhibiting a raw state using a sol-gel type process can be used to make a thermal barrier coating. This method is disclosed in US Application No. 11 / 386,424, filed March 22, 2006 and assigned to the current assignee herein. Additional description of the sol-gel type process is omitted for ease of description. See US Application No. 11 / 386,424 to the art.

The methods described herein are illustrative only for the purpose and are not intended to limit the disclosure in any way. This method facilitates the manufacture of coated articles having complex and huge shapes, for example turbine components, because thermal barrier coatings can be applied using techniques. Such techniques include, but are not limited to, immersion coating, spray coating, roll coating, inkjet printing, spin coating, painting, and the like. The following description relates to coatings and methods for thermal barrier coatings. However, the application of TBC coatings and methods is merely illustrative and is not intended to limit the invention in any way. The coating can be used for corrosion resistance or any other similar function. This method can also be used to apply the coating to any suitable substrate in any suitable application.

Terms such as "first" and "second" herein are not used to indicate any order, quantity, or importance, but are used to distinguish one element from another element, where "singular" refers to a quantity limit. Rather than one or more of the items listed. The modifier “about” used in conjunction with the quantity includes the stated value and has the meaning indicated by the context (eg, including the degree of error associated with the measurement of a particular quantity). As used herein, the suffix "(s)" is intended to include both the singular and the plural of the term it modifies, and therefore includes one or more of the term (eg, the metal (s) includes one or more metals). ). The ranges described herein are inclusively and independently combinable (eg, up to about 25 weight percent, or more specifically from about 5 weight percent to about 20 weight percent range from about 5 weight percent to about 25 weight percent End point of% and all intermediate values).

Once the raw coating is formed, a pattern can be induced on or in the coating where patterning can occur before or after treatment. By "pattern induction" is meant herein modifying the surface morphology and coating. The pattern derivation method is not particularly limited and may be selected by those skilled in the art without undue experimentation using known guidelines. Pattern derivation methods can be provided through various mechanical, chemical, or thermal methods.

Mechanical methods are, for example, scratching, stamping, screening, cutting, or means using strippable meshes that inhibit coating at the desired location on the substrate and burn off during physical removal or heat treatment after the coating has been completed. It may include. Imprinting may include pressing a mold that imparts a pattern to the surface, wherein the mold contains a negative object pattern. Chemical means may include methods such as, for example, the application of a non-wetting pattern or the inclusion of specific binders. Thermal deformation can be performed using means such as, for example, laser or electron beam etching. The resulting pattern, regardless of how it is performed, can enhance and better tolerate changes in thermal expansion of the coated component.

While various embodiments have been disclosed herein, combinations, variations, or improvements of various components may be made by those skilled in the art from the disclosure herein and are within the scope of the present invention. In addition, various modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from the essential scope thereof. Therefore, it is intended that the present invention not be limited to the particular embodiments disclosed as the best mode for carrying out the invention but to include all embodiments within the appended claims.

Claims (10)

Disposing a first coating on the substrate exhibiting a first strain resistance; And Subjecting the first coating to at least one of mechanical treatment, chemical treatment, thermal treatment, and combinations thereof to increase the strain resistance of the first coating to a second strain resistance that is greater than the first strain resistance. Including, the method of coating the substrate. The method of claim 1, Disposing a metal bond coating on the metal substrate, wherein the first coating is disposed on the metal bond coating surface opposite the metal substrate. The method of claim 1, And drying the first coating after inducing a pattern on or in the first coating. The method according to any one of claims 1 to 3, Treatment steps including mechanical treatment include the scratching method; Stamp method; Screening method; Cutting method; Application of a removable, non-wetting pattern or mesh; And combinations comprising one or more of these, or Including at least one of the application of a non-wetting pattern and the inclusion of a binder, resulting in controlled cracking of the coating during the treatment process, or Applying at least one of a laser and an electron beam. The method according to any one of claims 1 to 4, Disposing the first coating on the substrate comprises one or more of immersion coating, spray coating, roll coating, inkjet printing, spin coating, painting, and a combination comprising one or more of these. The method according to any one of claims 1 to 5, Removing the volatile components of the coating; Providing a pattern on or in the coating; Hot-balancing the coating; And And at least one of the steps of sintering the coating. The method according to any one of claims 1 to 6, Disposing the metal bond coating comprises vapor deposition, electroplating, ion plasma deposition, plasma spray, thermal deposition, or a combination of one or more of the metal bond coating elements on the metal substrate. The method according to any one of claims 2 to 7, The metal bond coating comprises MCrAlY, wherein M is selected from the group consisting of nickel, cobalt, iron and combinations comprising one or more of them, and the metal bond coating comprises silicon (Si), ruthenium (Ru), Iridium (Ir), osmium (Os), gold (Au), silver (Ag), tantalum (Ta), palladium (Pd), rhenium (Re), hafnium (Hf), platinum (Pt), rhodium (Rh), And an element selected from the group consisting of tungsten (W), and alloys comprising at least one of these, and combinations comprising at least one of these. The method according to any one of claims 1 to 8, Further comprising forming a coating on the substrate into the thermal barrier coating. The method according to any one of claims 1 to 9, Further comprising forming a coating on the substrate into a corrosion resistant coating.