Erosion resistant blades for compressors

An impeller blade that includes an impeller blade body constructed of a first material. The impeller blade body defines a leading edge that faces a direction of rotation. A second material couples to the leading edge. The second material is a more erosion resistant material than the first material. The second material extends over the leading edge a distance to absorb high angle impacts of droplets and/or particulate. A third material couples to at least a portion of the impeller blade body.

BACKGROUND

Wells are drilled to extract oil and/or gas from subterranean reserves. These resources are extracted from the well bore through a wellhead that couples to the end of the wellbore. The flow of oil and/or gas out of the well is typically controlled by one or more valves on the wellhead. After flowing through the wellhead, the flow of oil and/or gas may be directed to a compressor that pumps the oil and/or gas to the surface, in a subsea environment, and/or pumps the fluid flow to another location, such as a refinery. Unfortunately, as oil and/or gas flow out of the well they may carry particulate, such as sand and/or rock. Over time, this particulate may wear the blades on the compressor, which may result in reduced performance of the compressor and increased maintenance of the compressor.

BRIEF SUMMARY

In one embodiment, a compressor that includes a first impeller section that rotates in a first direction and a second impeller section that rotates in a second direction that is opposite the first direction. The first and second impeller sections are axially aligned. The first impeller section and the second impeller section include an impeller blade with an impeller blade body constructed of a first material. The impeller blade body defines a leading edge that faces a respective direction of rotation. A second material couples to the leading edge. The second material includes a material that is more erosion resistant than the first material. The second material extends over the leading edge a distance to absorb high angle impacts of droplets and/or particulate.

In another embodiment, a method for manufacturing an erosion resistant impeller blade. The method includes obtaining a first material for an impeller blade body. The method also includes machining the first material to form the impeller blade body. The method continues by coupling a second material to a leading edge of the impeller blade body. The second material is more erosion resistant than the first material. The second material is configured to extend over the leading edge a distance to absorb high angle impacts of droplets and/or particulate.

In another embodiment, an impeller blade that includes an impeller blade body constructed of a first material. The impeller blade body defines a leading edge that faces a direction of rotation. A second material couples to the leading edge. The second material includes a material that is more erosion resistant than the first material. The second material extends over the leading edge a distance to absorb high angle impacts of droplets and/or particulate. A third material couples to at least a portion of the impeller blade body.

DETAILED DESCRIPTION

Reference will now be made in detail to specific embodiments illustrated in the accompanying drawings and figures. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

It will also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first object could be termed a second object, and, similarly, a second object could be termed a first object, without departing from the scope of the present disclosure.

The present disclosure relates to compressors, such as contra-rotating wet gas compressors. Contra-rotating wet gas compressors include inner and outer impeller sections that couple to separate shafts that rotate in opposite directions. The impeller sections are arranged so that alternating impeller sections rotate in opposite directions. This may enable the compressor to operate without static diffusers between the rotating impeller sections. Each impeller section includes impeller blades that rotate with the impeller sections. As the impeller blades rotate they transfer mechanical energy to the fluid (e.g., oil and/or gas), which compresses and drives the fluid through the contra-rotating wet gas compressor.

The impeller sections discussed below include erosion resistant blades. These erosion resistant blades are formed from multiple materials. These materials may be located at different positions on the blades enabling the blades to resist erosion from different types of particulate impact. More specifically, the different materials may reduce erosion from particulate impact at different angles relative to the blade.

FIG. 1is a schematic of a mineral extraction system10in a subsea environment. In some embodiments, to extract oil and/or natural gas from the sea floor12, the mineral extraction system10may include a subsea station14. The subsea station14is positioned downstream from one or more wellheads16that couple to wells18. After drilling the wells18, hydrocarbons (e.g., oil, gas) flow through the wells18to the wellheads16. The hydrocarbons then flow from the wellheads16through jumper cables20to the subsea station14. The subsea station14includes a compressor module22, which may be powered by an electric motor, such as an induction motor or permanent magnet motor. The compressor module22may include one or more contra-rotating wet gas compressors (e.g., surge free contra rotating wet gas compressor) that pump oil and/or natural gas flowing out of the wells18.

The subsea station14is connected to one or more flow lines, such as flow line24. As illustrated, the flow line24couples to a platform26, enabling oil and/or gas to flow from the wells18to the platform26. In some embodiments, the flow lines24may extend from the subsea station14to another facility such as a floating production, storage and offloading unit (FPSO), or a shore-based facility. The flow lines24can also be used to supply fluids, as well as include control and data lines for use with the subsea equipment. In operation, the compressor module22pumps oil and/or natural gas from the subsea station14to the platform26through the flow line24. In some embodiments, the compressor module22may also be located downhole, or in a subsea location such as on the sea floor in a Christmas tree at a wellhead16.

It should be understood that the compressor module22may be configured for other subsea fluid processing functions, such as a subsea pumping module, a seawater injection module, and/or a subsea separator module. It should also be understood that the compressor module22may pump single-phase liquids, single-phase gases, or multiphase fluids.

FIG. 2is a cross-sectional view showing further details of a contra-rotating wet gas compressor48of the compressor module22. The contra-rotating wet gas compressor48includes a first motor50, a second motor52, and a contra-rotating compressor section54. In operation, the first motor50drives a shaft56that rotates a plurality of inner impeller sections58within the compressor section54. Similarly, the second motor52drives a shaft60that rotates an outer sleeve62within the compressor section54. The outer sleeve62couples to and rotates a plurality of outer impeller sections64. In operation, the first motor50rotates the inner impeller sections58in a first direction, while the second motor52rotates the outer impeller sections64in a second direction. For example, the first motor50may rotate the inner impeller sections58in counterclockwise direction66, while the second motor52rotates the outer impeller sections64in clockwise direction68. It should be understood that the rotational directions of the inner impeller sections58and the outer impeller section64may be switched depending on the embodiment. As the inner impeller sections58and the outer impeller section64rotate in opposite directions fluid is pumped through the contra-rotating wet gas compressor48from an inlet70to an outlet72, enabling the contra-rotating wet gas compressor48two pump multiphase fluids without stationary impellers to control and drive fluid flow.

FIGS. 3 and 4are partial cross-sectional views of the compressor section54of the contra-rotating wet gas compressor48. As illustrated, fluid (e.g., mixture of fluids) enters the compressor section54via the inlet70in the housing90. The fluid then passes around and/or through a perforated wall92and through a manifold94where it enters an impeller unit96from the bottom in direction98. The impeller unit96includes the alternating rows of inner impeller sections58and outer impeller sections64. In operation, the inner impeller sections58and outer impeller section64are driven/rotate in opposite directions to drive the fluid in direction98. As the fluid progresses through the alternating rows of inner impeller section58and outer impeller section64, in direction98, the fluid is compressed to increasingly higher pressures. In other words, because the inner impeller sections58and the outer impeller sections64are alternatingly stacked and rotate in opposite directions, each inner impeller section58and outer impeller section64effectively forms a separate stage of the impeller unit96. After passing through these stages of inner impeller sections58and outer impeller sections64, the compressed fluid is directed through an outlet72in the housing90. The fluid may then enter flow line24for transmission.

As explained above, the shaft56couples to the plurality of inner impeller sections58within the compressor section54. As the shaft56rotates in counterclockwise direction66, the shaft56rotates the inner impeller section58in counterclockwise direction66. The rotation of the inner impeller section58rotates a plurality of impeller blades/airfoils100coupled to each inner impeller section58. It is these impeller blades/airfoils100that drive and compress the fluid. Unfortunately, as the impeller blades100rotate they may contact particulate carried by the fluid. The particulate may include sand, rock, and other hard materials that may contact the impeller blades100at high speeds. More specifically, because the inner impeller sections58rotate in a first direction and the outer impeller sections64rotate in a second direction opposite the first direction, the relative speed between the inner impeller sections58and outer impeller sections64increases. For example, if the inner impeller sections58are rotating at 50 m/s and the outer impeller sections64are rotating at 50 m/s the relative difference in speed between the inner impeller sections58and the outer impeller sections64is 100 m/s. Accordingly, particulate may contact the impeller blades100at high speeds as it is alternatingly driven from inner impeller sections58to the outer impeller sections64. To reduce the wear on these impeller blades100and thus increase the longevity of the contra-rotating wet gas compressor48, the impeller blades100may be coated and/or formed out of multiple materials placed at specific locations to reduce erosion caused by particulate striking the impeller blades100.

FIG. 4illustrates a partial cross-sectional view of the compressor section54with the inner impeller sections58removed. As explained above, the second motor52rotates the shaft60. For example, the second motor52may rotate the shaft60in a clockwise direction68. As the shaft60rotates, it rotates outer sleeve62. The outer sleeve62couples to the outer impeller sections64and therefore rotates the outer impeller sections64in clockwise direction68. As illustrated, each of the outer impeller hub section64includes a plurality of impeller blades/airfoils110. As the impeller blades110rotate, they may contact particulate carried by the fluid. The particulate may include sand, rock, and other hard materials that may contact the impeller blades110at high speeds. To reduce the wear on these impeller blades110and thus increase the longevity of the contra-rotating wet gas compressor48, the impeller blades110may be coated and/or formed out of multiple materials placed at specific locations to reduce erosion caused by particulate striking the impeller blades110.

FIG. 5is a perspective view of an inner impeller section58. As illustrated, the inner impeller section58includes a hub120with a plurality of impeller blades/airfoils100(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more). The impeller blades100may be integrally formed with the hub120(e.g., formed from one-piece) or may be separately coupled to the hub120. For example, the impeller blades100may be brazed and/or welded to the hub120, or connected through a dovetail joint or similar. The hub120defines an aperture122that enables the inner impeller section58to receive the shaft56illustrated inFIGS. 3 and 4and described above. In order to couple neighboring inner impeller sections58together, the hub120defines a counterbore124at a first end126and a circumferential groove128at a second end130. That is, the second end130with the circumferential groove128may be inserted into a counterbore124of a hub120of a neighboring inner impeller section58. In this way, the inner impeller sections58may be stacked one on top of the other. In order to block rotation of the inner impeller sections58relative to each other, the first end126and second end130may define a plurality of apertures132spaced about the circumference of the hub120. These apertures132may receive pins that couple neighboring inner impeller sections58together, facilitate alignment of neighboring inner impeller sections58to each other, as well as block rotation of the inner impeller sections58relative to each other. That is, pins placed in the apertures132on the first end126will also extend into apertures132on the second end130of a neighboring inner impeller section58.

FIG. 6is a perspective view of an outer impeller section64. As illustrated, the outer impeller section64includes a hub140that defines an aperture142. It is within this aperture142along the inner circumferential surface144that the outer impeller section64includes a plurality of impeller blades/airfoils110(e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more). These impeller blades110may be integrally formed with the hub140(e.g., made out of one-piece) or may be separately coupled to the hub140. For example, the impeller blades110may be brazed and/or welded to the hub140, or connected through a dovetail joint or similar.

In order to couple neighboring outer impeller sections64together, the hub140defines a plurality of apertures146on both the first end148and the second end150. These apertures146may receive pins that couple neighboring outer impellers sections64together, facilitate alignment of neighboring outer impeller sections64to each other, as well as block rotation of the outer impeller sections64relative to each other. That is, pins in the apertures146on the first end148will extend into apertures146on the second end150of a neighboring outer impeller section64.

FIG. 7is a side view of an impeller blade100,110. As explained above, impeller blades100,110rotate with the respective inner impeller sections58or the outer impeller sections64. As the impeller blades100,110rotate (e.g., move in direction168) about the central axis of the inner and outer impeller sections58,64, they drive and compress the fluid in the compressor section54. Furthermore, as the impeller blades100,110spin in the presence of liquid and solids, the leading edge170of each impeller blade100,110may be exposed to impacts from liquid droplets and/or solid particles in the fluid. These impacts on the leading edge170are high angle impacts, meaning that the velocity vector of the droplet or particle is oriented at a high angle relative to a tangential impact surface of the impeller blade100,110. For example, a velocity vector172of a particle (e.g., liquid droplet, solid particle) is shown inFIG. 7. The impact angle174is measured between the velocity vector172and the tangent176of the impact surface location178. A high impact angle174includes angles between 45° and 90°. Impacts at high angles on the impeller blade100,110may rapidly wear the leading edge170because the particulate and/or droplet does not glance off the impeller blade100,110. In other words, a droplet and/or a particulate strikes the impeller blade100,110with greater force. In contrast, a low impact angle179formed by the velocity vector180with a tangent to the impact surface location182reduces the force of the droplet and/or particulate when striking the impeller blade100,110. A low impact angle179includes angles between 0° and 45°.

Particle and/or droplet impacts at both high and low angles may cause erosion of the material of the impeller blades100and110. The erosion may depend on the mass of the particulate impacting a surface, and on the velocity of the impinging particles. The dependence on the impact angle of the impinging articles is more complex, and varies between different materials. Accordingly, different materials may erode at different rates depending also on the angle of each impact.

In general, hard and dense materials, such as tungsten carbide and diamond, resist erosion better than softer and less dense materials, such as metals or plastics. It could thus be desirable to manufacture the impellers from a dense and hard material, like tungsten carbide. Other materials used to manufacture the impeller blades100,110may include engineering ceramics such as silicon nitride, silicon carbide, boron carbide, aluminum oxide, and zirconia, or polycrystalline diamond. Such materials generally do not have desirable mechanical properties for mechanical parts exposed to high stress levels, such as the impellers blades100,110. For example, hard and dense materials tend to be brittle, meaning that they have relatively low tensile yield strength, and that fracture propagation may happen rapidly and cause failures. The impeller blades100,110of the present disclosure may include two or more different materials with different properties to increase erosion resistance. These materials may be placed at different locations on the impeller blades100,110to increase erosion resistance from low and high angle impacts of particulate and/or droplets.

FIG. 8is a cross-sectional view of an impeller blade along line8-8ofFIG. 5. The core/body200of the impeller blade100,110is made from a strong and tough material (e.g., a high-strength steel, nickel-based super alloy, or or a titanium alloy). It is complemented by a coating or insert202on the leading edge170. The first coating or insert202is made from a hard and dense material that resists impacts at high angles. Indeed, the coating or insert202extends a distance204(e.g., a few millimeters to several centimeters) along the length of the impeller blade100,110so that droplets and/or particulate striking the impeller blade100,110at high impact angles primarily contact the coating or insert202as the impeller blade100,110rotates in direction168(e.g., circumferential direction66or68) about the central axis of the inner and/or outer impeller sections58,64. As explained above, a high impact angle typically refers to an angle between 45° and 90° formed by the velocity vector of the droplet or particle and a tangent of the impact surface/point.

As illustrated, impeller blade100,110may define a groove206that extends over the leading edge170to accommodate the coating or insert202and to enable the coating or insert202to match the profile of the impeller blade100,110. The coating202may for example be attached to the impeller blade100,110over this groove206using high velocity oxygen fuel (HVOF), high velocity air fuel (HVAF), or D-Gun thermal spray, plasma spray, laser cladding, and Conforma Clad brazing. Many other application techniques are available. The coating202may for example be made from tungsten carbide, tungsten carbide-metal composite, polycrystalline diamond, or other ceramics or ceramic-metal composites. In some embodiments, if the coating202includes tungsten carbide the thickness of the coating202may be greater than 0.1 mm and less than 3 mm. A thickness greater than 3 mm may reduce the strength of the tungsten carbide coating.

In some embodiments, the coating202may be in form of an insert. The insert may be coupled to the impeller blade100,110by brazing, gluing, welding, and/or a mechanical joint, e.g. a dovetail joint. The insert may be made from tungsten carbide, polycrystalline diamond, a metal ceramic composite, silicon nitride, silicon carbide, boron carbide, aluminum oxide, zirconia, or another ceramic.

Other surfaces of the impeller blade100,110may be exposed to droplet and particle impacts at lower angles, as explained above. The surfaces may include the upper surface208and the lower surface210(e.g., side surfaces), as well as the trailing edge212, while hard and dense materials such as tungsten carbide resist erosion caused by low angle impacts as well and may be applied to the entire impeller blade surface. This may be expensive and complicated. Furthermore, impeller blades generally call for accurate tolerances on the geometry of the impeller surface. Poor tolerances or rough surfaces may have a negative effect on the performance of the impeller, and may cause mechanical interference between parts. The geometrical accuracy and finish of the coated surfaces may be improved after application by machining, polishing or grinding, but this is also expensive and complicated, and may be time consuming.

Accordingly, a second coating214may be applied to the other surfaces that encounter low-angle impacts. For example, sprayed or vapor-deposited coatings may be used. Vapor deposited coatings may be applied to large surfaces in one operation, and the resulting second coating214is largely uniform with a smooth surface finish. The second coating214may therefore not need polishing or grinding down after application. Other application methods to apply the second coating214may also be used, such as thermal spray methods or plasma spray methods.

In one embodiment, the second coating214may be titanium aluminum nitride. This coating may be applied through the physical vapor deposition method. The second coating214may be uniformly deposited and/or applied to the leading edge170, upper surface208, lower surface210, trailing edge212, and/or the tip. The thickness of second coating214may be between 0.001 mm and 0.5 mm. The coating214may extend over the coating202on the leading edge170or may not be applied over the coating on the leading edge170.

FIG. 9is a cross-sectional view of an impeller blade100,110along line8-8ofFIG. 5. As explained above, a core/body230of the impeller blade100,110is made from a strong and tough material (e.g., a high-strength steel, nickel-based super alloy, or a titanium alloy). Unfortunately, the impact of droplets and/or particulate at high angles on the leading edge232may erode the material of the core230impeller blade100,110. Accordingly, the impeller blade100,110may include an insert234that couples to the core230. The insert234may resist erosion from droplets and/or particulate that strikes against the leading edge232at high angles. The insert234extends a distance236(e.g., a few mm to several cm) from the end of the core230so that droplets and/or particulate striking the impeller blade100,110at high impact angles primarily contact the insert234as the impeller blade100,110rotates in direction168(e.g., circumferential direction66or68) about the central axis of the inner and/or outer impeller sections58,64.

As explained above, a high impact angle may refer to an angle between 45° and 90° formed by the velocity vector of the droplet or particle and a tangent of the impact surface point. The insert234may be coupled to the impeller blade100,110via a joint, such as a dovetail joint, or another joining method, e.g. gluing, brazing, or a fastener. The insert234may be made from tungsten carbide, polycrystalline diamond, a metal ceramic composite, silicon nitride, silicon carbide, boron carbide, aluminum oxide, zirconia, or another ceramic. In some embodiments, insert234may include an insert body238and a coating240coupled to the insert body238. The coating240may include tungsten carbide, polycrystalline diamond, engineering ceramics, or ceramic-metal composites. In some embodiments, if the coating240includes tungsten carbide the thickness of the coating240may be greater than 0.1 mm and less than 3 mm. A thickness greater than 3 mm may reduce the strength of the tungsten carbide coating. As explained above, a coating242may be applied to the other surfaces that encounter low-angle impacts. These surfaces include an upper or first side surface244, a lower or second side surface246, trailing edge248, and/or the tip. For example, the coating242may be a vapor-deposited coating of titanium aluminum nitride. In other embodiments, the coating242may be titanium nitride, chromium nitride, chromium aluminium titanium nitride, a diamond like coating, or multiple layers of various of these and other coatings. The thickness of coating242may be between 0.001 mm and 0.5 mm. The coating242may extend over the insert234or may not be applied over the insert234on the leading edge232.

FIG. 10is a cross-sectional view of an impeller blade100,110along line8-8ofFIG. 5. A core/body260of the impeller blade100,110is made from a strong and tough material (e.g., a high-strength steel, nickel-based super alloy, or a titanium alloy. Unfortunately, the impact of droplets and/or particulate at high angles on the leading edge262may erode the material of the core260. Accordingly, the impeller blade100,110may include an insert or coating264that couples to the core260. The insert or coating264may resist erosion from droplets and/or particulate that strikes against the leading edge262at high angles. The insert or coating264extends a distance266(e.g., a few mm to several cm) so that droplets and/or particulate striking the impeller blade100,110at high impact angles primarily contact the insert or coating264as the impeller blade100,110moves in direction168(e.g., circumferential direction66or68) about the central axis of the inner and/or outer impeller sections58,64. As explained above, a high impact angle may refer to an angle between 45° and 90° formed by the velocity vector of the droplet or particle and a tangent of the impact surface point.

As illustrated, impeller blade100,110may not include a groove; instead, the insert or coating264may taper in thickness as it extends over the leading edge262. The coating264may be attached to the impeller blade100,110using high velocity oxygen fuel (HVOF), high velocity air fuel (HVAF) and D-Gun thermal spray, plasma Spray, laser cladding, and Conforma Clad brazing. The coating264may be made from tungsten carbide, tungsten carbide-metal composite, polycrystalline diamond, or other ceramics or ceramic-metal composites. If the coating264is in the form of an insert, the insert may be coupled to the impeller blade100,110by brazing, gluing, welding, or mechanical joining, e.g. a dovetail joint. The insert may be made from tungsten carbide, polycrystalline diamond, a metal ceramic composite, silicon nitride, silicon carbide, boron carbide, aluminum oxide, zirconia, or another ceramic.

In some embodiments, if the coating264includes tungsten carbide the thickness of the coating264may be greater than 0.1 mm and less than 3 mm. A thickness greater than 3 mm may reduce the strength of the tungsten carbide coating. As explained above, a second coating268may be applied to other surfaces of the impeller blade100,110that receive low-angle impacts. These surfaces include an upper or first side surface270, a lower or second side surface272, trailing edge274, and/or the tip. For example, the coating268may be a vapor-deposited coating of titanium aluminum nitride. In other embodiments, the coating268may be titanium nitride, chromium nitride, chromium aluminium titanium nitride, a diamond like coating, or multiple layers of various of these and other coatings. The coating268may extend over the coating264on the leading edge262or may not be applied over the coating264on the leading edge262.

FIG. 11is a cross-sectional view of an impeller blade100along line11-11ofFIG. 5. As explained above and seen inFIGS. 2, 3, and 4, the inner and outer impellers sections58,64are stacked on top of each other with the inner impellers sections58resting within a neighboring outer impeller section64. This places a tip290of the impeller blade100proximate the interior circumferential surface144of the hub140of the outer impeller section64, and likewise the tip of impeller blade110proximate the hub120of the inner impeller section58. The clearance between the impeller blades100,110and the inner and outer impellers sections58,64is small (e.g., less than 1 mm or a few mm). As a result, the tip of the impeller blades100,110are exposed to abrasive wear cause by particles bouncing between the tips of the impeller blades100,110and the opposing hub120,140. In some embodiments, a coating or insert may therefore be applied to the tips of the impeller blades100,110in the same manner as that of the leading edge described above.

For example, a core292of the impeller blade100may be made from a strong and tough material (e.g., a high-strength steel, nickel-based super alloy, or a titanium alloy). The impeller blade100may include an insert or coating294that couples to the core292along the tip290. The insert or coating294may resist erosion from droplets and/or particulate that strikes and/or abrades against the tip290. The insert or coating294extends along the tip290between the leading edge296and the trailing edge298. The coating264may be attached to the impeller blade100using high velocity oxygen fuel (HVOF), high velocity air fuel (HVAF) and D-Gun thermal spray, plasma spray, laser cladding, and Conforma Clad brazing. The coating294may be made from tungsten carbide, tungsten carbide-metal composite, polycrystalline diamond, or other ceramics or ceramic-metal composites. If the coating264is in the form of an insert, the insert may be coupled to tip290of the impeller blade100by brazing, gluing, welding, and/or with a mechanical joint (e.g., dovetail joint or a joint using fasteners). The insert may be made from tungsten carbide, polycrystalline diamond, a metal ceramic composite, silicon nitride, silicon carbide, boron carbide, aluminum oxide, zirconia, or another ceramic.

As explained above, a coating300may be applied to the other surfaces that encounter low-angle impacts. For example, sprayed or vapor-deposited coatings may be used. Vapor deposited coatings may be applied to large surfaces in one operation, and the resulting coating is largely uniform with a smooth surface finish. The coating300may therefore not be polished or ground down after application. Other application methods may also be used, such as thermal spray methods or plasma spray methods. In some embodiments, the coating300may include titanium aluminum nitride. In other embodiments, the coating300may be titanium nitride, chromium nitride, chromium aluminium titanium nitride, a diamond like coating, or multiple layers of various of these and other coatings. The coating300may be uniformly deposited and/or applied to the leading edge296, upper surface, lower surface, trailing edge298, and/or the tip290. If desirable, parts of the surface may not be coated. This can for instance be avoided by masking certain parts of the surface before application of the coating300. While the discussion ofFIG. 11has focused on impeller blades100on the inner impeller sections58, the discussion is equally applicable to the impeller blades110of the outer impeller sections64.

FIG. 12is a method320of manufacturing an impeller blade (e.g.,100,110) or impeller (e.g.58,64). The method320begins by obtaining material for the impeller or impeller blade, block322. As explained above, the impeller blade material may include a high-strength steel, nickel-based super alloy, or a titanium alloy. The material may then be machined or otherwise formed to a target geometry, block324. However, in some embodiments the impeller and/or impeller blade may be made by additive manufacturing and therefore the step in block324may be optional. In some embodiments, the method320may include an optional step of machining/forming a groove or grooves in the impeller blade by removing material (e.g., leading edge, tip), block326. The grooves may facilitate placement of the coating and/or insert on the impeller blade. The method320then applies a first coating (i.e., hard and dense coating) or insert to the leading edge of the impeller blade, block328. As explained above, the hard and dense coating or insert may include carbide, tungsten carbide-metal composite, polycrystalline diamond, or other ceramics or ceramic-metal composites. In some embodiments, the method320may include an optional step of applying a first coating (i.e., hard and dense coating) or insert to the tip of the impeller blade, block330. As explained above, the tip of the impellers may be exposed to abrasive wear cause by particles bouncing between the tips of the impeller blades and the opposing hub. Accordingly, a coating or insert may therefore be applied to the tip in the same manner as to the leading edge as described above. After applying a hard and dense coating, the method320may include the optional step of grinding the coated surfaces (e.g., tip, leading edge) with the hard and dense material to obtain the final geometry and an acceptable surface, block332. The method320continues by preparing the impeller blade for application of a second coating (e.g., a vapor deposited coating), block334. This preparation may include masking coated surfaces (i.e., surfaces coated with the hard and dense coating) or inserts on the impeller blade. The method320may then apply a second coating to the impeller blade, such as by vapor deposition, block336. In some embodiments, the second coating may cover the hard and dense coating as well as previously uncoated surfaces of the impeller blade. These surfaces may include the upper or first side surface, the lower or second side surface, the leading edge, the trailing edge, and/or the tip. In still other embodiments, the second coating may not be used and thus the steps in block334and336may be optional.

As used herein, the terms “inner” and “outer”; “up” and “down”; “upper” and “lower”; “upward” and “downward”; “above” and “below”; “inward” and “outward”; and other like terms as used herein refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.”

The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. Moreover, the order in which the elements of the methods described herein are illustrate and described may be re-arranged, and/or two or more elements may occur simultaneously. The embodiments were chosen and described in order to best explain the principals of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.