JP2015010278A - Multilayer coating having diamond-like carbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer coating to protect a compressor blade metal base from erosion and corrosion, like a gas-turbine engine, which suffers from a mechanical stress such as a high temperature and a severe operation condition.SOLUTION: A metal base 20 is coated with an adhesion base layer 12 and a top face layer 16 having a surface roughness Ra of about 0.0254 μm or less. A multilayer coating 10 includes the adhesion base layer 12 and the top layer 16, at least one of which includes diamond-like carbon and has sufficient adhesion to the metal base 20, a hydrophobic property and a lipophilic property to prevent corrosion, hardness for protecting from erosion, and a surface smoothness for preventing hindrance to an aerodynamic property during an operation. Furthermore, the multilayer coating 10 includes one or more middle layers 14 between the adhesion base layer 12 and the top face layer 16, and at least one of the middle layers 14 is selected from silicon and germanium, and at least one of the middle layers is a doped diamond-like carbon.

Description

  The subject matter disclosed herein relates to multilayer coatings, and more particularly to multilayer coatings having diamond-like carbon that can be applied to turbine compressor blades.

  In a gas turbine engine, the compressor portion typically has a number of paragraphs having a row of compressor blades (also referred to as “rotor blades” or “rotor airfoils”) and stator blades (also referred to as “stator airfoils”). Is included. The compressor blades rotate about the rotor and impart kinetic energy to the airflow through the compressor. Immediately following the compressor blade row is a row of stator blades that remain stationary. The compressor blades and stator blades work together, the compressor blades can turn the airflow, the stator blades can slow down the speed of air and increase the static pressure of the airflow through the compressor section. Multiple stages of compressor blades and stator blades can be stacked in an axial compressor to achieve the required exhaust to inlet air pressure ratio. The compressor and stator blade can be secured to the rotor wheel and stator case, respectively, by a dovetail or root or base fitting.

  In operation, the compressor blade can be subjected to mechanical stress and severe operating conditions due to the rotational speed of the compressor. These levels of stress, along with other operating conditions, can affect the level of erosion or corrosion experienced. For example, ambient air drawn through the compressor portion can include components that can be corrosive and abrasive to the compressor blades and other such portions. Certain components may also receive mixtures of hydrocarbon-based lubricants, carbonaceous soot, dust, rust, and the like.

  Articles such as compressor blades may be provided with a coating to provide additional protection for these elements. However, some tough but flat coatings such as diamond-like carbon can experience high levels of internal compressive stress as the thickness increases.

US Pat. No. 7,992,823

  Accordingly, alternative fluorinated coatings would be welcome in the art.

  In one embodiment, a multilayer coating is disclosed. The multilayer coating includes an adhesive base layer capable of adhering to a metal substrate and a top layer having a surface roughness of about Ra 1 μin or less, at least one of these layers including diamond-like carbon. .

  In another embodiment, a coated article is disclosed. The coated article includes a metal substrate that includes an outer surface and a multilayer coating that covers at least a portion of the outer surface of the metal substrate. The coating includes an adhesive base layer capable of adhering to a metal substrate and a top layer having a surface roughness of about Ra 0.0254 μm or less, at least one of these layers including diamond-like carbon. Yes.

  The above and additional features provided by the embodiments disclosed herein will be more fully understood from the following detailed description taken in conjunction with the drawings.

  The embodiments shown in the drawings are exemplary, and are not intended to limit the invention as defined by the claims. The following detailed description of exemplary embodiments can be understood when read in conjunction with the appended drawings. In the drawings, like structures are indicated with like reference numerals.

FIG. 1 is a schematic cross-sectional view of a multilayer coating on a metal substrate according to one or more embodiments shown or described herein. FIG. 2 is a cross-sectional schematic illustration of a multilayer coating on a metal substrate having an intermediate layer according to one or more embodiments shown or described herein. FIG. 3 is a perspective view of a compressor blade having a multilayer coating according to one or more embodiments shown or described herein.

  The following describes one or more specific embodiments of the present invention. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described herein. In the development of such an actual implementation, as with any engineering or design plan, a number of implementations are performed to achieve the developer's specific goals, such as compliance with system-related and business-related constraints that can vary from implementation to implementation. It will be appreciated that specific decisions must be made. It will also be appreciated that such development efforts may be complex and time consuming, but nevertheless are routine routine tasks of design, fabrication, and manufacture for those skilled in the art using the present disclosure.

  In introducing elements of the various embodiments of the invention, the singular form means that there are one or more of those elements. The terms “consisting of”, “including” and “having” are inclusive and mean that there may be additional elements other than the listed elements.

  Referring to FIG. 1, a schematic cross-sectional view of a coated article 5 including at least a metal substrate 20 and a multilayer coating 10 is shown.

  The multi-layer coating 10 provides sufficient adhesion to remain on the metal substrate 20, hydrophobicity and lipophilicity to help prevent corrosion, hardness to help protect against erosion, and aerodynamics during operation. It is prepared including diamond-like carbon (generally also referred to as “DLC”) and additional elements (elements) so as to have surface smoothness that does not impede performance. The multilayer coating 10 can generally include an adhesive base layer 12 that can adhere to the metal substrate 20 and a top layer 16 having a surface roughness Ra of about 0.0254 μm or less, at least one of these layers. Includes diamond-like carbon. In some embodiments, the multilayer coating 10 can further include one or more intermediate layers 14 between the adhesive base layer 12 and the top layer 16.

  The adhesive base layer 12 of the multilayer coating 10 comprises a first layer of the multilayer coating 10 that, once applied, adheres to the underlying metal substrate 20. The metal substrate 20 can comprise any type of metal and / or alloy, such as, for example, an iron-based alloy (eg, stainless steel), a nickel-based alloy, a cobalt-based alloy, and the like.

  In some embodiments, the adhesive base layer 12 can include LC. DLC refers to a commercially available film of amorphous hydrocarbons that can be formed, for example, by vapor deposition and can provide high hardness and wear resistance with a flat surface. In such embodiments, the DLC can be, for example, about 10 μm thick or less, or about 2 μm to about 10 μm thick, or even about 5 μm to about 10 μm thick.

  In other embodiments, the adhesive base layer 12 can include silicon. In such embodiments, the silicon can be, for example, less than about 0.5 μm thick, or about 0.3 μm to about 0.4 μm thick, or about 0.4 μm thick.

  The upper surface layer 16 of the multilayer coating 10 is composed of the outermost layer of the multilayer coating 10 and has a relatively flat surface roughness. For example, the top layer 16 may have an Ra of about 0.0254 μm (1 μin) or less, or about 0.00254 μm (0.1 μin) to about 0.0254 μm (1 μin) Ra, or about 0.00508 μm (0.2 μin) to about It can have a surface roughness of Ra of 0.01016 μm (0.4 μin) or generally about 0.0127 μm (0.5 μin) or less. As used herein, “Ra” refers to a surface roughness parameter determined by the arithmetic average of absolute values, as will be appreciated by those skilled in the art.

  In other embodiments, the top layer 16 may include DLC. While such embodiments can increase corrosion and soil resistance, they still provide a smooth surface finish for the entire multilayer coating 10. For example, if the adhesion base layer 12 includes silicon as described above, and / or if the multilayer coating 10 includes one or more intermediate layers as understood from this specification, the top layer 16 includes DLC. obtain. In such embodiments, the DLC can be, for example, about 10 μm to about 15 μm thick, or about 11 μm to about 13 μm thick, or about 10.5 μm thick.

  In other embodiments, the top layer 16 may include silicon carbide. Such an embodiment can increase the erosion resistance of the entire multilayer coating 10. For example, if the adhesive base layer 12 includes DLC as described above, the top layer 16 can include silicon carbide. In such embodiments, the silicon carbide can be, for example, about 10 μm thick, about 2 μm to about 10 μm thick, or even about 5 μm to about 10 μm thick.

  Referring now to FIG. 2, in some embodiments, the multilayer coating 10 can include one or more intermediate layers 14 between the adhesive base layer 12 and the top layer 16. The one or more intermediate layers 14 can include one or more layers of the same type of material, or multiple layers of multiple types of materials.

  For example, in some embodiments, at least one of the one or more intermediate layers 14 can include silicon, germanium, titanium, chromium, nitrogen, fluorine, sulfur, or combinations thereof.

  Using silicon as the intermediate layer 14 can increase the adhesion between the entire multilayer coating 10. In such embodiments, the one or more intermediate layers 14 comprising silicon are less than about 0.5 μm thick, or about 0.3 μm thick to about 0.4 μm thick, or about 0.4 μm thick. Can be. The intermediate layer 14 can be surrounded by layers of different composition, the same composition or a combination thereof. For example, in some embodiments, the one or more intermediate layers 14 can include from 1 to about 5 layers of silicon and are disposed on the base adhesive layer 12 (which can itself also include silicon). obtain.

  The use of silicon and germanium can reduce internal stress in the overall multilayer coating 10. In some embodiments, such as when the silicon and germanium intermediate layer 14 is disposed on a single layer of silicon (eg, when the adhesion base layer 12 includes silicon), the silicon and germanium 1 The intermediate layer 14 can have a thickness of less than about 0.5 μm or a thickness of about 0.2 μm to about 0.3 μm. In such embodiments, the multilayer coating 10 may include from 1 to about 3 intermediate layers 14 of silicon and germanium. In some embodiments, such as when the silicon and germanium intermediate layer 14 is disposed over multiple layers of silicon, the one or more intermediate layers 14 comprising silicon and germanium are about 8 μm to about 10 μm thick. Can be. In such embodiments, the multilayer coating 10 may include 1 to about 5 intermediate layers 14 of silicon and germanium.

  In some embodiments, at least one of the one or more intermediate layers 14 may include DLC or doped DLC or other suitable variations of DLC. Doped DLC can include DLC doped with one or more additional elements such as silicon and / or germanium. In some embodiments, the DLC can be doped with fluorine to increase hydrophobicity. In some embodiments, the DLC can be doped with polydimethylsiloxane (PDMS) to increase lipophilicity.

  For example, in some embodiments, at least one of the one or more intermediate layers 14 may include DLC doped with silicon and germanium. In such embodiments, the one or more intermediate layers 14 comprising DLC doped with silicon and germanium can be about 8 μm to about 10 μm thick. The one or more intermediate layers 14 can include a single layer of DLC doped with silicon and germanium, or can include multiple layers of DLC doped with silicon and germanium, which are adjacent to each other. It may be arranged, arranged with different intermediate layers 14 in between, or a combination thereof.

  In some embodiments, at least one of the one or more intermediate layers 14 may include DLC doped only with silicon. In such embodiments, the one or more intermediate layers 14 comprising silicon doped DLC can be about 1 μm to about 10 μm thick, or about 5 μm to about 7 μm thick. The one or more intermediate layers 14 can include a single layer of DLC doped with silicon and germanium, or can include multiple layers of DLC doped with silicon and germanium, which are disposed adjacent to each other. Or may be arranged with different intermediate layers 14 in between, or a combination thereof.

  Accordingly, the adhesive base layer 12, the top layer 16 and any one or more intermediate layers 14 of the multilayer coating 10 may have properties such as hardness, surface roughness, erosion / corrosion resistance, hydrophobicity, lipophilicity, etc. ) Can be utilized in a variety of different combinations including various elements and materials to suit a particular application.

  In one particular embodiment, the multilayer coating 10 can include a DLC adhesive base layer 12 and a silicon carbide top layer 16. In such embodiments, each layer can be about 5 μm to about 10 μm thick. In another embodiment, the multi-layer coating 10 includes DLC and carbonized such that the adhesive base layer 12 is DLC, the intermediate layer 14 includes both silicon carbide and DLC layers, and the top layer 16 includes silicon carbide. Multiple alternating layers of silicon can be included.

  In another particular embodiment, the multilayer coating 10 can include an adhesive base layer 12 of silicon having a thickness of about 0.3 μm to about 0.4 μm. The first intermediate layer 14 may have a thickness of about 0.2 μm to about 0.3 μm and include silicon and germanium. The second intermediate layer 14 may include DLC doped with silicon and germanium with a thickness of about 8 μm to about 10 μm. The third intermediate layer 14 may include the same or similar DLC doped with silicon and germanium in a thickness of about 8 μm to about 10 μm, or may have a thickness of about 8 μm to about 9 μm. The fourth intermediate layer 14 may include silicon doped DLC in a thickness of about 5 μm to about 7 μm, or may have a thickness of about 5 μm to about 7 μm. Finally, the multilayer coating 10 can include a top layer of DLC having a thickness of about 10 μm to about 12 μm.

  Although specific embodiments of the multi-layer coating 10 are shown herein, these are non-limiting examples and other multi-layer coatings 10 or additional and / or alternative layered configurations including additional and / or alternative materials are also included. Please understand that this is possible.

  Thus, the overall multilayer coating 10 can include a range of total thicknesses and various layers. For example, the entire multilayer coating 10 can have a total thickness of about 40 μm or less, about 30 μm or less, or about 20 μm to about 30 μm as a result of relatively low internal stress compared to a coating comprising a single DLC layer. The multilayer coating 10 may also have at least about 20 or less individual layers including the adhesive base layer 12, the top layer 16, and a plurality of intermediate layers 14 therebetween. In some embodiments, the multilayer coating 10 can include any other number of multiple layers. For example, in some embodiments, the multilayer coating 10 can comprise at least 10 layers, or at least 15 layers, or at least 20 layers, or even at least 25 layers. The number of layers in the multilayer coating can be selected based at least on the level of corrosion and erosion protection required for the part. Each layer may be arranged in any suitable manner as will be appreciated by those skilled in the art. For example, the layers of the multilayer coating 10 can be deposited at a temperature in the range of about 120 ° C. to about 200 ° C. using a variety of available deposition techniques.

  As a result of the multiple layers comprising the materials described herein, the multilayer coating 10 has a variety of properties to protect the underlying metal substrate 20 and to provide a relatively flat surface. Can be adapted. For example, the multilayer coating 10 can have a hardness of about 10 GPa to about 30 GPa to withstand erosion from foreign objects.

  The multilayer coating 10 can also be hydrophobic and oleophobic to help prevent the accumulation of fluids such as water and oil. “Hydrophobic” refers to the physical properties of a substance that repel water. “Oil repellency” refers to the physical property of repelling the oil of a substance. Specifically, a surface having a low surface energy for a contaminant (eg, water and / or oil) has a high contact angle and is wetted by the contaminant or a surface where the contaminant has a low contact angle. In comparison, it should provide reduced adhesion with the contaminant. As used herein, the term “contact angle” is the angle formed by static liquid droplets on the surface of a solid material. The higher the contact angle, the less interaction between the liquid and the surface. Thus, the higher the contact angle between the oil or other contaminant and the surface, the more difficult it is for the contaminant to wet or adhere to the surface. For example, the multilayer coating 10 can have a contact angle of at least about 80 °, at least about 92 °, or at least about 100 °. This can increase the corrosion resistance to external contaminants such as hydrogen sulfide, hydrofluoric acid and hydrochloric acid.

  As noted above, the metal substrate 20 of the coated article 5 can comprise any metal substrate 20 such as that utilized in gas turbines. Examples of the metal substrate 20 include, but are not limited to, an iron base alloy (for example, stainless steel), a nickel base alloy, and a cobalt base alloy. For example, referring to FIG. 3, in some embodiments, the metal substrate can comprise a compressor blade 50. The compressor blade 50 can include an airfoil 52 that imparts kinetic energy to the air flowing through the compressor as it rotates about the rotor, and a base or root 53. The airfoil 52 generally includes a suction surface 56 (ie, convex side) and a pressure surface 57 (ie, concave side).

  The root 53 can include a platform 54, which is the outer radial surface of the root 53, from which the airfoil 52 extends. The platform 54 may be integrally joined to the root portion 53 of the compressor blade 50. Platform 54 defines a radially inner boundary for airflow across airfoil 52. As will be appreciated by those skilled in the art, the root 53 is further generally connected via a complementary groove (not shown) in the rotor wheel to connect the compressor blade 50 to the appropriate compressor in the compressor. A dovetail 55 is included that locks into position.

  The substrate 10 (eg, compressor blade 50) can include a multilayer coating 10 that forms a coated article 5 over at least a portion of the outer surface 25 (eg, suction surface 56 and / or pressure surface 57). . That is, the multilayer coating 10 of the coated article 5 can include an adhesive base layer that can adhere to a metal substrate, a top layer having a surface roughness of about Ra 0.0254 μm or less, wherein these layers At least one of which comprises diamond-like carbon as described above.

  In some embodiments in which the metal substrate 20 comprises compressor blades 50, the compressor blades 50 may include late stage compressor blades 50. As used herein, “late paragraph” refers to one of the last or last few paragraphs of the compressor portion of the turbine. In such an embodiment, the coating described herein provides a relatively thick coating for strong erosion and corrosion protection for the compressor blade 50 while still being significant in its aerodynamics during operation. A flat surface can be provided without being affected.

  It will be appreciated that a multilayer coating can be provided to protect the underlying substrate from a variety of external forces and environmental conditions. Multilayer coatings embodying the compositions described herein can protect against corrosion and erosion from the outside while still providing a flat surface. Also, the multilayer coating is provided as a relatively thick layer, but can still include one or more layers of DLC.

  Although the invention has been described in detail in connection with only a limited number of embodiments, it will be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to include any number of variations, alterations, substitutions or equivalent combinations not heretofore described, but which are compatible with the spirit and scope of the invention. In addition, while various embodiments of the invention have been described, it should be understood that certain aspects of the invention may include only some of the described embodiments. Accordingly, the present invention is not limited by the above description, and is limited only by the scope of the following claims.

5 coated article 10 multilayer coating 12 adhesive base layer 14 (one or more) intermediate layer 16 top layer 20 substrate 25 (substrate) outer surface 50 compressor blade 52 airfoil 53 root 54 platform 55 dovetail 56 negative Pressure surface 57 Pressure surface

Claims (20)

A multilayer coating comprising: an adhesive base layer capable of adhering to a metal substrate; and a top layer having a surface roughness of about Ra 0.0254 μm or less, wherein at least one of said layers comprises diamond-like carbon.   The multilayer coating of claim 1 further comprising one or more intermediate layers between the adhesive base layer and the top layer.   The multilayer coating of claim 2, wherein at least one of the one or more intermediate layers is selected from the group consisting of silicon and germanium.   The multilayer coating of claim 3, wherein at least one of the one or more intermediate layers comprising silicon or germanium is about 0.1 μm to about 0.5 μm thick.   The multilayer coating of claim 2, wherein at least one of the one or more intermediate layers is doped diamond-like carbon.   The multilayer coating of claim 5, wherein at least one of the one or more intermediate layers comprising doped diamond-like carbon is about 5 μm to about 10 μm thick.   The multilayer coating of claim 2, wherein the adhesion base layer comprises silicon.   The multilayer coating of claim 2, wherein the top layer comprises diamond-like carbon.   The multilayer coating of claim 2, wherein the multilayer coating comprises at least 10 layers.   The multilayer coating of claim 1, wherein the adhesion base layer is selected from the group consisting of silicon and diamond-like carbon.   The multilayer coating of claim 1, wherein the top layer is selected from the group consisting of silicon carbide and diamond-like carbon.   The multilayer coating of claim 1, wherein the at least one layer comprising diamond-like carbon is about 5 μm to about 10 μm thick.   The multilayer coating of claim 1, wherein the multilayer coating is at least about 20 μm thick.   The multilayer coating of claim 1, wherein the multilayer coating has a hardness of at least about 10 GPa. A coated article comprising a metal substrate including an outer surface, and a multilayer coating covering at least a portion of the outer surface of the metal substrate,
The coating is
The coated article comprising an adhesive base layer capable of adhering to a metal substrate and a top layer having a surface roughness of about Ra 0.0254 μm or less, wherein at least one of the layers comprises diamond-like carbon.   The coated article of claim 15, wherein the metal substrate comprises a turbine compressor blade.   The coated article of claim 16, wherein the compressor blade is a late stage compressor blade.   The coated article of claim 15, further comprising one or more intermediate layers between the adhesive base layer and the top layer.   The coated article of claim 18, wherein at least one of the one or more intermediate layers is selected from the group consisting of silicon, germanium, titanium, chromium, nitrogen, fluorine, sulfur, and doped diamond-like carbon.   The coated article of claim 15, wherein the at least one layer comprising diamond-like carbon is about 5 μm to about 10 μm thick.