Multifunctional nanocellular single crystal nickel for turbine applications

Abstract

A nanocellular single crystal nickel based material is provided having a thermal diffusivity in the range of 0.0002 cm{circumflex over ( )}2/s to 0.02 cm{circumflex over ( )}2/s and a thermal conductivity in the range of 0.024 W/mK to 9.4 W/mK. The nanocellular single crystal nickel based material may be used to form turbine engine components. The nanocellular single crystal nickel based material may be produced by providing a first solution containing a nickel precursor and deionized water, providing a second solution containing a structure controlling polymer/surfactant and an alcohol, mixing the first and second solutions into a solution containing a reducing agent to form a third solution, and processing the third solution to create the nanocellular single crystal based material.

Claims

1. A material comprising a nanocellular single crystal nickel based material comprising pores and ligaments in the range of 0.05 to 100 microns having a thermal diffusivity in the range of 0.0002 cm{circumflex over ( )}2/s to 0.02 cm{circumflex over ( )}2/s and a thermal conductivity in the range of 0.024 W/mK to 9.4 W/mK.

2. The material according to claim 1, further having a strength in the range of 5.0 GPa to 114 GPa.

3. The material according to claim 1, further having a porosity in the range of 15% to 70%.

4. The material according to claim 1, further having a plurality of pores with each said pore having a size in the range of 50 nm to 25 microns.

5. The material according to claim 4, wherein said pores have a size in the range of 50 nm to 6.0 microns.

6. A turbine engine component comprising a structure at least partially formed from a nanocellular single crystal nickel based material having a plurality of pores and ligaments in the range of 0.05 to 100 microns, an overall cooling effectiveness in the range of from 0.4 to 1.0 and a mass flow rate in the range of from 1e-2 to 1e-7.

7. The turbine engine component of claim 6, wherein said structure comprises at least one coupon joined to another portion of said turbine engine component.

8. The turbine engine component of claim 6, wherein said structure comprises at least one window joined to another portion of said turbine engine component.

9. The turbine engine component of claim 6, wherein said component comprises one of a BOAS, a vane, a blade, a fan blade, a combustor liner, a rotor for a blade, and a knife edge seal.

10. The turbine engine component of claim 6, wherein said turbine engine component is entirely formed from said nanocellular single crystal nickel based material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic representation of a reaction vessel used to form a multifunctional nanocellular single crystal nickel based material.

(2) FIG. 2 is a schematic representation of a continuous flow reactor that may be used to form a multifunctional nanocellular single crystal nickel based material.

(3) FIG. 3 is a schematic representation of a process for manufacturing a nanocellular single crystal nickel based material.

(4) FIG. 4 is a schematic representation of a turbine engine component having a plurality of coupons formed from a nanocellular single crystal nickel based material.

(5) FIG. 5 is a schematic representation of another turbine engine component having a plurality of windows formed from a nanocellular single crystal nickel based material.

DETAILED DESCRIPTION

(6) Solution Processing with Templating Metal

(7) The fabrication of a single crystal nanocellular nickel coupon can be achieved using a reaction vessel similar to FIG. 1. The reaction vessel components may include a glass lined reactor 100 surrounded by a heating jacket 102. A thermocouple 104 may be placed in the reactor 100 or between the reactor 100 and the heating jacket 102. Together, the heating jacket 102 and the thermocouple 104 may be used to control the reaction temperature. An impeller 106 may be immersed in the solution 108 in the reactor 100. The impeller 106 vortexes the solution 108 to ensure a homogeneous isothermal mixture is maintained. The reactor 100 can be the batch reactor shown in FIG. 1. In another embodiment, the reactor 100′ can be a continuous flow reactor in which solution flows into the reactor 100′ via the inlet 110 and out of the reactor 100′ via the outlet 112.

(8) The nucleation of a single crystal nickel nanocellular material such as a coupon 114 can be achieved with or without a seed. The seed material provides a starting place for single crystal growth. In cases without a seed, homogeneous nucleation occurs to produce a porous single crystal nickel starting material. The starting material acts as the seed. The growth of the porous single crystal nickel continues as nickel ions in solution are reduced on the surface of the seed.

(9) Referring now to FIG. 3, there is shown a process for manufacturing a multifunctional nanocellular single crystal nickel based material. The nickel based material may be a single crystal nickel or a single crystal nickel alloy.

(10) The process may begin as shown in step 10 by preparing or providing a first solution containing a nickel precursor in deionized water. The nickel precursor may be selected from the group consisting of nickel nitrate hexahydrate, nickel chloride, nickel sulfate, nickel oxalate, and other nickel salts. The nickel precursor may be present in the deionized water in an amount from 0.05 mol. to 0.2 mol., and the balance of the solution may be the deionized water.

(11) In step 12, a second solution may be prepared or provided which contains an alcohol such as ethylene glycol and a structure controlling polymer, or a surfactant, such as polyvinyl pyrrolidine which may be present in the range of 1.0 wt % to 5.0 wt % with a molecular weight between 1000 g/mol and 10 million g/mol.

(12) In step 14, the first and second solutions may then be mixed into a solution of a reducing agent such as hydrazine to form a third solution. The hydrazine may be 35 wt % or 50 wt %. The third solution is placed in the reactor 100 or 100′. A stir may be performed using the impeller 106 at a temperature in the range of 100° C. to 130° C. for a time period in the range of 5.0 min to 15 min. The stir may be performed as a reflux operation.

(13) A physical change in the third solution can be observed after step 14 indicating a reaction has occurred. The light green clear solution changes to a colorless clear solution called the sol with a dark solid substance.

(14) In step 16, any excess sol which has been created may be removed from the third solution containing the reducing agent and the nickel precursor using a pipette.

(15) In step 18, the third solution may then be centrifuged at a speed in the range of 2000 rpm to 5000 rpm for a time period in the range of 5.0 min to 15 min.

(16) In step 20, any remnant sol separated during the centrifuging step may be removed from the third solution using a pipette. The product is a cellular structure material though it may be contaminated with salts and solvents.

(17) In step 22, washing of the solid mass of nickel may be performed with a washing solution. The washing solution may contain an alcohol and deionized water to remove soluble inorganic salts and organic solvents, such as ethylene glycol. The fourth solution may be subjected to sonication for a time period in the range of 5.0 min to 15 min. Then a filtration step may be performed to remove the washing solution from the cellular structure material.

(18) In step 24, there results a single crystal nickel based nanocellular material.

(19) The chemical reaction when using hydrazine to form the single crystal nickel based nanocellular material is:
Ni2.sup.++2e−.fwdarw.Ni;E.sup.0=−0.25V and
N.sub.2+4H.sub.2O+4e.sup.−.fwdarw.N.sub.2H.sub.4+4OH.sup.−E.sup.0=−1.16V.

(20) The single crystal nickel based nanocellular material formed in this manner has numerous beneficial properties. The single crystal nickel based nanocellular material has nanoporosity with pores having a size ranging from 50 nm to 25 microns. In one beneficial embodiment, the pores have a size which ranges from 50 nm to 6.0 microns. The foregoing dimensions are the diameter of an approximately cylinder shaped pore or the diameter of a spherically shaped pore.

(21) A single nickel nanocellular body formed as described herein may have a thermal diffusivity in the range of 0.0002 cm{circumflex over ( )}2/s to 0.02 cm{circumflex over ( )}2/s. It may also have a thermal conductivity in the range of 0.24 W/mK to 9.4 W/mK; a strength in the range of 5.0 GPa to 114 GPa; and a porosity in the range of 15% to 70%.

(22) If desired, the single crystal nickel based nanocellular material may be a nickel based alloy. The additives to the nickel may be one or more of aluminum for strength and oxidation resistance; cobalt for microstructural control; chromium for oxidation and corrosion resistance; tungsten, rhenium, and/or tantalum for improved creep strength; hafnium and/or yttrium for oxidation resistance; and hafnium and/or zirconium for grain boundary ductility. Cobalt, tungsten and rhenium may be added into the third solution to co-precipitate the alloy during the formation of porous single crystal nickel. Hafnium, yttrium, and zirconium may be reduced by another reducer or reducers in the third solution or prepared by other methods such as electrochemical routes. Other elements, such as aluminum, chromium can be fabricated as a coating via various preparation approaches, such as wet chemistry, electrochemistry, or chemical vapor deposition (CVD) methods.

(23) The single crystal nanocellular nickel based alloy material formed by the method described herein may be used to form all or a portion of a turbine engine component such as vanes, blades, BOAS, fan blades, combustor liners, rotors for blades, and knife edge seals. When used to form part of a turbine engine component, a piece of the single crystal nanocellular nickel based material may be machined into a desired shape and then brazed onto a component formed from a different material. For example, the single crystal nanocellular nickel based material may be used to form a skin for the turbine engine component. Referring now to FIG. 4, there is shown a turbine engine component 200 having a root portion 202, a platform 204 and an airfoil 206. A portion of the skin of the airfoil 206 is formed by single crystal nanocellular nickel based material coupons 208. There may be one or more coupons 208. In another exemplary embodiment, as shown in FIG. 5, pieces of the single crystal nanocellular nickel based material may be joined to the turbine engine component 200 as a plurality of windows 210 to provide a cooling benefit. The cooling benefit is due to the porosity of the single crystal nanocellular nickel based material which reduces the cooling fluid needed to cool the turbine engine component. Using the coupons 208, or the windows 210, the turbine engine component 200 may have an overall cooling effectiveness in the range of from 0.4 to 1.0 and a mass flow rate of in the range of from 1e-2 to 1e-7.

(24) There has been provided in this disclosure a multifunctional nanocellular single crystal nickel based material which may be used in turbine engine applications. While the nanocellular single crystal nickel based material has been described in the context of specific embodiments thereof, there may be unforeseen alternatives, modifications, and variations which will become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations as fall within the broad scope of the appended claims.