Method and system for manufacturing electrical conductive body on substrate

Abstract

Methods and systems for fabricating an electrical conductor on a substrate are disclosed. A method of manufacturing an electrical conductor on a substrate by cold spraying includes propelling a solid powder composition including copper and highly oriented pyrolytic graphite using a gaseous propellant, and directing the solid powder composition to the substrate at a velocity sufficient to cause the solid powder composition to undergo plastic deformation and adhere to the substrate to deposit the electrical conductor thereon.

Description

[0001] This application is a divisional application of the patent application with the application date of April 20, 2020, the application number of 202010310648.4, and the invention name of "Method and System for Manufacturing Conductors on a Substrate", the entire content of which is incorporated herein by reference. Technical Field

[0002] This application relates to methods and systems for manufacturing conductors on a substrate and products formed thereby. Background Art

[0003] Most electrical interconnections are made of metals with high electrical conductivity, such as copper (6×10 7 S / m), and its density is about 9 g / cm 3 . It is desirable to be able to replace copper with a material that provides electrical properties as good as or better than copper but with a much lower density.

[0004] Therefore, those skilled in the art continue to conduct research and development in the field of conductor manufacturing. Summary of the Invention

[0005] In one example, a method for manufacturing a conductor on a substrate by cold spraying is disclosed, which includes: heating a gas propellant; using the heated gas propellant to propel a solid powder composition including copper and highly oriented pyrolytic graphite; and guiding the solid powder composition to the substrate at a speed sufficient to cause the solid powder composition to undergo plastic deformation and adhere to the substrate to deposit a conductor on the substrate.

[0006] In one example, a system for spraying a coating material onto a substrate is disclosed. The system includes an optical sensor, a controller, a first regulator, a heater, a second regulator, and an actuator. The optical sensor is positioned to monitor the thickness of the coating material coated on the substrate. The controller communicates with the optical sensor and, based on the measured thickness, generates a first command signal corresponding to the amount of the gas propellant to be heated, a second command signal corresponding to the temperature to which the gas propellant will be heated, a third command signal corresponding to the amount of the solid powder composition to be mixed with the heated gas in the nozzle, and a fourth command signal corresponding to the distance between the nozzle and the substrate. The first regulator receives the first command signal and provides a certain amount of the gas propellant corresponding to the first command signal. The heater receives a certain amount of the gas propellant supplied from the first regulator, receives the second command signal, and heats the gas propellant to the temperature corresponding to the second command signal. The second regulator receives the third command signal and provides a certain amount of the solid powder composition corresponding to the third command signal to the nozzle. The actuator receives the fourth command signal and moves the nozzle along the substrate at a distance between the nozzle and the substrate corresponding to the fourth command signal.

[0007] In one example, a cold spray product is disclosed that includes a substrate and a conductor deposited on the substrate by cold spraying. The conductor includes a copper matrix and highly oriented pyrolytic graphite flakes dispersed in the copper matrix.

[0008] Other examples of the disclosed methods, systems, and products will become apparent from the following detailed description, the drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a flow chart illustrating one example of the disclosed method for fabricating a conductor on a substrate.

[0010] Figure 2 is a schematic diagram of one example of the disclosed system for spraying a coating material onto a substrate.

[0011] Figure 3 is a perspective view of one example of the disclosed cold spray product.

[0012] Figure 4 is a flow chart of an aircraft manufacturing and service method.

[0013] Figure 5 is a block diagram of an aircraft. DETAILED DESCRIPTION

[0014] Figure 1 is a flow chart describing one example of the disclosed method 100 for fabricating a conductor 304 ( Figure 3 ) on a substrate 302 ( Figure 3 ) by cold spraying. Method 100 includes heating (102) a gas propellant; propelling (104) a solid powder composition including copper and highly oriented pyrolytic graphite (HOPG) using the heated gas propellant; and directing (106) the solid powder composition to the substrate 302 at a velocity sufficient to cause the solid powder composition to undergo plastic deformation and adhere to the substrate 302 to deposit the conductor 304 on the substrate. By the steps of propelling (104) and directing (106) the solid powder composition to the substrate 302, method 100 deposits the conductor 304 on the substrate 302 by copper and highly oriented pyrolytic graphite.

[0015] The step of heating (102) the gas propellant facilitates the step of propelling (104) the solid powder composition to a sufficient velocity. The gas propellant expands when heated, and thus, increases the acceleration of the gas propellant, thereby increasing the velocity of the solid powder composition. Additionally, heating the gas propellant also heats the solid powder composition. Heating the solid powder composition is beneficial for the plastic deformation of the solid powder composition and its adhesion to the substrate 302 ( Figure 3 ) to deposit the conductor 304 ( Figure 3 ) on the substrate.

[0016] The step 102 of heating the gas propellant can be carried out in any way. In an example, the gas propellant is heated to a suitable temperature by passing the gas propellant through a heat exchanger. In one example, the gas propellant is heated to a temperature in the range of 450 to 535 °C. If the gas propellant is heated to a temperature higher than 535 °C, it will have an adverse effect on the solid powder composition. In particular, the performance of highly oriented pyrolytic graphite deteriorates. Moreover, during the process of depositing the conductor 304 ( Figure 3 ) on the substrate, the substrate 302 ( Figure 3 ) may deteriorate. If the gas propellant is not heated sufficiently and is lower than 450 °C, sufficient gas propellant velocity may not be obtained, and the solid powder composition may not plastically deform and adhere to the substrate 302.

[0017] The step (104) of using the gas propellant to propel the solid powder composition including copper and highly oriented pyrolytic graphite can be carried out in any way. In an example, the gas propellant is accelerated to a high speed by releasing the gas propellant from a high-pressure state such as a high-pressure gas state, a liquid state, or a solid state. Before, after, or during the acceleration of the gas propellant, the gas propellant is mixed with the solid powder composition to push the solid powder composition.

[0018] The step of guiding (106) the solid powder composition to the substrate 302 ( Figure 3 ) at a speed sufficient to cause the solid powder composition to undergo plastic deformation and adhere to the substrate 302 to deposit the conductor 304 ( Figure 3 ) on the substrate can be carried out in any way. In an example, a nozzle such as a de Laval nozzle is used to direct the solid powder composition towards the substrate 302. Plastic deformation is the process of causing permanent deformation in a solid. Plastic deformation produces a permanent change in the solid without breaking, while fracture is caused by applying a stress beyond the elastic limit. In this specification, the solid powder composition is guided to the substrate 302 at a sufficient speed to cause the solid powder composition to undergo plastic deformation and adhere to the substrate 302 to deposit the conductor 304. By undergoing severe plastic deformation, the solid powder composition adheres to the substrate 302.

[0019] In an example, the solid powder composition is directed towards the substrate 302 at a speed of 500 m / s - 1,000 m / s. If the speed is lower than 500 m / s, the solid powder composition may not undergo plastic deformation and may not adhere properly to the substrate 302 ( Figure 3 ). If the speed is higher than 1,000 m / s, the substrate 302 may be damaged when impacted.

[0020] According to the present disclosure, the solid powder composition comprises copper and highly oriented pyrolytic graphite. The copper may include pure copper, a copper-based alloy, or any alloy including copper. By selecting the solid powder composition to include copper, the solid powder composition can undergo plastic deformation and adhere to the substrate 302 ( Figure 3 ) when impacting the substrate 302. Additionally, the copper helps deposit the resulting highly conductive conductor 304 ( Figure 3 ) on the substrate 302.

[0021] In an example, the current density of the copper material is about 500 amperes per square centimeter (500 A / cm 2 ), making it an ideal material for highly conductive matrix materials, especially in aircraft maintenance, aircraft repair, and aircraft life monitoring applications.

[0022] Highly oriented pyrolytic graphite (HOPG) is a high-purity and ordered form of synthetic graphite. Its characteristics are defined by the IUPAC Compendium of Chemical Terminology as a pyrolytic graphite with an angular spread of less than 1 degree for the c-axis of its crystal. Highly oriented pyrolytic graphite has high conductivity. By selecting the solid powder composition to include highly oriented pyrolytic graphite, the conductor 304 deposited on the substrate 302 from the solid powder composition has high conductivity.

[0023] In an example, the highly oriented pyrolytic graphite includes intercalated highly oriented pyrolytic graphite, such as bromine-intercalated highly oriented pyrolytic graphite. Due to the layered form of graphite, different atomic or molecular species can be inserted between the graphite layers. The process of inserting such dopant substances into graphite is called intercalation. Intercalation of highly oriented pyrolytic graphite is effective in changing the properties of highly oriented pyrolytic graphite. It has been determined that bromine-intercalated highly oriented pyrolytic graphite is suitable for inclusion in the solid powder composition of the present disclosure because bromine-intercalated highly oriented pyrolytic graphite remains stable for a long time.

[0024] In an example, the content of copper particles is 55 - 65% by weight. If the content of copper particles is less than 55% by weight, the highly oriented pyrolytic graphite will not be completely captured in the copper matrix 306 ( Figure 3 ), and the adhesion of the conductor 304 to the substrate 302 ( Figure 3 ) will deteriorate. If the content of copper particles is greater than 65% by weight, the total conductivity of the conductor 304 ( Figure 3 ) decreases and the weight of the conductor 304 increases.

[0025] In an example, the average particle size of the copper particles ranges from 15 μm to 25 μm. If the average particle size is less than 15 μm, the copper particles may not adhere to the substrate 302 ( Figure 3 ). If the average particle size is greater than 25 μm, the substrate 302 may be damaged when impacted.

[0026] In an example, the solid powder composition includes a number of highly oriented pyrolytic graphite flakes, and the content thereof is 35-45% by weight. If the highly oriented pyrolytic graphite flakes are included in the solid powder composition in an amount less than 35% by weight, the total conductivity of the conductor 304( Figure 3 ) will decrease and the weight of the conductor 304 will increase. If the highly oriented pyrolytic graphite flakes are included in the solid powder composition in a content greater than 45% by weight, the adhesion of the conductor 304 to the substrate 302( Figure 3 ) will become poor.

[0027] In another example, the highly oriented pyrolytic graphite flakes have an average flake diameter in the range of 5 μm to 25 μm. It is determined that this range is optimal for the maximum adhesion and maximum conductivity of the conductor 304.

[0028] The gas propellant is any gas propellant suitable for propelling the solid powder composition. In an example, the gas propellant is an inert gas propellant. By selecting the gas propellant as an inert gas propellant, a chemical reaction between the solid powder composition and the gas propellant can be avoided.

[0029] In another example, the inert gas propellant has an atomic number greater than 17. By selecting the gas propellant as an inert gas propellant with an atomic number greater than 17, the inert gas has a suitably high density sufficient to propel the solid powder composition. For example, the inert gas propellant includes argon, which has an atomic number greater than 17 and is a high-purity inert gas. Therefore, compared with helium or nitrogen, when the solid powder composition impacts the substrate 302, it causes less oxidation or less trapped oxygen. The use of argon or other gas propellants with an atomic number greater than 17 also reduces the possibility of corrosion caused by the introduction of different metals (for example, introducing copper particles into a metal substrate), and maximizes the conductivity of the highly oriented pyrolytic graphite by avoiding oxidation.

[0030] In another example, the conductor 304( Figure 3 ) has an average thickness T of 100 μm - 200 μm E . If the average thickness T E is less than 100 μm, the conductivity of the conductor 304( Figure 3 ) will decrease. If the average thickness T E is greater than 200 μm, the weight of the conductor 304( Figure 3 ) will increase, and the enhanced conductivity effect due to the inclusion of highly oriented pyrolytic graphite will begin to decline.

[0031] Figure 2 is an example of a schematic diagram of a system 200 that can be used to implement the method 100 depicted in Figure 1 .

[0032] As Figure 2 shown in Figure 2 , system 200 includes an optical sensor 216, a controller 218, a first regulator 204, a heater 206, a second regulator 210, and an actuator 214. System 200 may further include a third regulator 222, a fourth regulator 226, and a fifth regulator 230. Without departing from the scope of the present disclosure, additional components such as additional regulators may be included in system 200.

[0033] The optical sensor 216 communicates with the controller 218 via a communication line 250. The communication line 250, like all communication lines 251, 252, 253, 254, 255, 260, 262 in system 200, may be wired or wireless. The optical sensor 216 may transmit data indicating the thickness T of the coating material 303 applied to the substrate 302 C to the controller 218. Based at least on the measured thickness T of the coating material 303 applied to the substrate 302 C and the operator's input, the controller 218 generates command signals to control the amount of gas propellant to be heated, the temperature to which the gas propellant is to be heated, the amount of solid powder composition to be mixed with the heated gas in the nozzle 212, and the distance M between the nozzle 212 and the substrate 302.

[0034] The first regulator 204 communicates with the controller 218 via a communication line 251. The control of the first regulator 204 may control the amount of gas propellant supplied to the heater 206.

[0035] The heater 206 receives the gas propellant supplied by the first regulator 204 and heats the gas propellant to the desired temperature as indicated by the controller 218 via the communication line 260.

[0036] The second regulator 210 communicates with the controller 218 via a communication line 252. The control of the second regulator 210 may control the amount of solid powder composition introduced into the gas propellant.

[0037] The actuator 214 communicates with the controller 218 via a communication line 262. The command signal received by the actuator 214 from the controller 218 may cause the nozzle 212 to move relative to the substrate 302. For example, the actuator 214 may move the nozzle 212 to achieve the desired distance M between the nozzle 212 and the substrate 302.

[0038] Thus, system 200 may control method 100 in real time to provide uniform results.

[0039] System 200 may also include a canister 202 configured to store a gaseous propellant to be supplied by the first regulator 204. In one embodiment, the canister 202 supplies an inert gas propellant. In an exemplary embodiment, the canister 202 stores an inert gas propellant having an atomic number greater than 17 (e.g., argon).

[0040] The first regulator 204 includes any pressure or flow regulator that controls the output pressure or flow rate of a fluid to a desired value. For example, the first regulator 204 includes a valve. The output pressure or flow rate of the first regulator 204 can be adjusted based on a command signal received from the controller 218 via the communication line 251.

[0041] The heater 206 includes any heater capable of heating a gas to a controlled temperature. The temperature of the heater 206 can be adjusted based on a command signal received from the controller 218 via the communication line 260. In an example, the heater 206 is an electric heater. In another example, the heater 206 is a gas heater.

[0042] System 200 may further include a feeder 208. The feeder 208 is defined as any device for storing a solid powder composition. In one example, the feeder 208 stores the above mixture of copper particles and highly oriented pyrolytic graphite flakes. Thus, the system 200 including the feeder 208 for storing a solid powder composition can be employed to practice the method 100. However, the system 200 may optionally include a feeder 208 for storing a liquid composition such that the system 200 can be used to practice different methods.

[0043] The second regulator 210 includes any pressure or flow regulator that controls the output pressure or flow rate of a fluid or the flow rate of a solid powder composition to a desired value. In one example, the second regulator 210 includes a valve and a mass sensor. With the mass sensor, the second regulator 210 can precisely measure the amount of the solid powder composition passing through the second regulator 210. The amount of the solid powder composition passing through the second regulator 210 can be adjusted based on a command signal received via the communication line 252 from the controller 218.

[0044] System 200 further includes a nozzle 212. The nozzle 212 may include any device suitable for releasing the solid powder composition supplied from the feeder 208 onto the substrate 302 using the heated gaseous propellant from the heater 206. In one example, the nozzle 212 includes a de Laval nozzle for accelerating the hot pressurized gas passing through it to supersonic speed.

[0045] Actuator 214 may include any actuation means suitable for moving nozzle 212 along substrate 302 at a predetermined distance M from the substrate. In an example, actuator 214 may include a robotic actuator, such as a six-axis robotic actuator arm. Moving nozzle 212 using actuator 214 facilitates maintaining control of the distance M between nozzle 212 and substrate 302. For example, the distance M between nozzle 212 and substrate 302 is typically in the range of 1 mm to 100 mm, preferably 5 mm to 20 mm.

[0046] Optical sensor 216 includes any optical sensor capable of monitoring the thickness T of coating material 303 applied to substrate 302 C and communicating (via communication line 250) with controller 218. Optical sensor 216 produces a real-time visual measurement of the thickness of the material on the surface of substrate 302, either alone or in combination with controller 218. In particular, the thickness T of coating material 303 deposited on substrate 302 over time can be determined by subtracting the detected distance L0 between sensor 216 and substrate 302 obtained during an initial scan of substrate 302 from the distance L between sensor 216 and coating material 303 detected during subsequent scans X For example, during an initial scan, the initial distance L0 will represent the distance between sensor 216 and substrate 302 since no coating material 303 has been deposited on substrate 302 yet. In subsequent scans, the distance L C will represent the distance between sensor 216 and the exposed surface 305 of coating material 303. It should be understood that as the thickness T of coating material 303 increases during the spraying process, the distance L X between sensor 214 and the exposed surface 305 of coating material 303 C will decrease proportionally. X

[0047] Exemplary optical sensor 216 may be one or more optical distance sensors that use pulsed light signals to generate a signal (input to controller 218) that represents the distance L from the optical sensor to the exposed surface 305 of coating material 303 X The optical distance sensor operates by causing a light-emitting diode (LED) to produce a pulse to illuminate the target surface (which is initially the surface of substrate 302 and subsequently the exposed surface 305 of coating material 303) and measuring the intensity of the reflected signal. As the reflectivity of the target surface changes, the return value for the same distance will change. When coating material 303 is applied to substrate 302, the distance L X changes as the thickness T of the applied coating material C changes.

[0048] The controller 218 can be any device, system, multiple systems, or combination thereof (e.g., a microprocessor) capable of generating and transmitting command signals to obtain a desired result from a controlled device. As Figure 2 shown by the dashed line in

[0049] In an example, the feeder 208 includes a first material feeder 220 that stores copper particles, a third regulator 222 that controls the amount of copper particles from the first material feeder 220, a second material feeder 224 that stores highly oriented pyrolytic graphite flakes, a fourth regulator 226 that controls the amount of highly oriented pyrolytic graphite flakes from the second material feeder 224, and a mixer 228 that receives and mixes the copper particles provided by the third regulator 222 and the highly oriented pyrolytic graphite flakes provided by the fourth regulator 226. Thus, the system 200 can adjust the relative amounts of copper particles and highly oriented pyrolytic graphite flakes provided from the feeder 208.

[0050] The first material feeder 220 includes any device suitable for supplying copper particles. In an example, the first material feeder 220 is a gravity powder feeder.

[0051] The third regulator 222 includes any regulator suitable for controlling the flow rate of copper particles to a desired value. In an example, the third regulator 222 includes a valve and a mass sensor. With the aid of the mass sensor, the third regulator 222 can accurately measure the flow rate of copper particles passing through the third regulator 222.

[0052] The second material feeder 224 includes any device suitable for storing highly oriented pyrolytic graphite flakes. In an example, the second material feeder 224 is a gravity powder feeder.

[0053] The fourth regulator 226 includes any regulator suitable for controlling the flow rate of highly oriented pyrolytic graphite flakes to a desired value. In an example, the fourth regulator 226 includes a valve and a mass sensor. With the aid of the mass sensor, the fourth regulator 226 can precisely measure the flow rate of highly oriented pyrolytic graphite flakes passing through the fourth regulator 226.

[0054] The mixer 228 includes any device suitable for mixing the copper particles conveyed from the third regulator 222 and the highly oriented pyrolytic graphite flakes conveyed from the fourth regulator 226. In an example, the mixer 228 is a circular mixer.

[0055] In another example, a portion of the gas propellant supplied from the tank 202 passes through a fifth regulator 230 (e.g., a valve) and transports the solid powder composition supplied from the feeder 208 to the nozzle 212.

[0056] As described in the following operating steps of system 200, by using controller 218 based on the thickness T of coating material 303 measured by optical sensor 216 C to control various features of system 200, system 200 can control the process in real time to provide uniform results when manufacturing cold spray product 300 using method 100.

[0057] The method by which controller 218 operates system 200 includes: transmitting to controller 218 (via communication line 250) a signal indicating the thickness T of coating material 303 applied to substrate 302 C , for example, by using optical sensor 216. Based on the measured thickness T C and the operator's input, as well as other possible factors, controller 218 generates a command signal that controls the amount of gaseous propellant to be heated, the temperature to which the gaseous propellant will be heated, the amount of solid powder composition to be mixed with the heated gas in nozzle 212, and the distance M between nozzle 212 and the exposed surface 305 of coating material 303. First regulator 204 receives the command signal and provides the required amount of gaseous propellant. Heater 206 receives the gaseous propellant supplied from the first regulator and heats the gaseous propellant to the desired temperature. Second regulator 210 provides the required amount of solid powder composition. Actuator 214 moves nozzle 212 in accordance with the instructions of controller 218 to facilitate depositing coating material 303 on substrate 302.

[0058] For example, controller 218 can employ one or more of the following relationships to provide more uniform results for system 200.

[0059]

[0060] V g – Gas velocity at the nozzle exit

[0061] T – Temperature of the gas before it reaches the nozzle.

[0062] R – Ideal gas constant = 8.31 J / mol

[0063] P e – Gas pressure at the nozzle exit = 1 / 5 (P i *V i ) / (V e ), most suitable for metal matrix carbon-based composites

[0064] V i – Volume of the intake port

[0065] V e – Volume at the nozzle exit

[0066] P i – Gas pressure supplied to the spray gun (optimal pressure for argon / composite particles is 1 - 3 MPa)

[0067] M g – Molecular weight of the gas

[0068] γ–C p / C v (Isentropic expansion coefficient)

[0069] C p – Heat capacity of the gas at constant pressure (for argon C p = 0.52)

[0070] C v – Heat capacity of the gas at constant volume (for argon, C v = 0.312)

[0071]

[0072] V p – Particle velocity at the nozzle exit

[0073] C D – Constant assumed to be equal to 1 in this equation

[0074] ρ g – Gas density

[0075] ρ p – Average density of the particles

[0076] D p – Average diameter of the particles

[0077] x – Distance from the nozzle to the substrate M

[0078] ρ p = (%Wt m1 *ρ m1 ) + [(1 - (%Wt m1 )) * ρ m2 )

[0079] %Wt m1 – Weight percentage of Material 1 used

[0080] ρ m1 – Average density of Material 1 particles

[0081] ρ m2 – Average density of Material 2 particles

[0082] M fp = (ρ p *V e ) / t

[0083] M fp – Mass flow rate of particles at the nozzle exit

[0084] t – Time

[0085] For the system 200 described in this specification, putting all these together:

[0086]

[0087] and

[0088]

[0089] The controller 218 can utilize the above equations using a look-up table for the gases and materials used, and the controller 218 can optimize the components of the system 200 in real time to meet the desired output parameters.

[0090] An exemplary specific method for operating the system 200 to produce a cold spray product is provided as follows. The can 202 is filled with a predetermined amount of propellant gas (e.g., argon), and the feeder 208 stores a mixture of copper particles and bromine-intercalated highly oriented pyrolytic graphite flakes with a current density of 500 amperes per square centimeter.

[0091] The operator inputs various initial inputs to the controller 218. For example, the operator inputs the chemical composition of the material (e.g., copper) in the first material feeder 220 and the chemical composition of the material (e.g., highly oriented pyrolytic graphite) in the second material feeder 224, as well as the chemical composition of the substrate 302 and the desired thickness T Figure 3 of the conductor 304 E ( Figure 3 ) to the controller 218.

[0092] When actuating the system 200, the optical sensor 216 starts monitoring the substrate 302 and any coating material 303 coated onto the substrate 302. The optical sensor 216 transmits (via the communication line 250) in real time a signal representing the thickness T C of the coating material 303 (if any) on the substrate 302 to the controller 218.

[0093] Based on the real-time measured thickness T C of the coating material 303 on the substrate 302, and the various initial inputs entered by the operator, the controller 218 generates various command signals to form a conductor 304 with the desired thickness T E ( Figure 3 ) on the substrate 302 Figure 3)。The command signal is transmitted to the first regulator 204 (via communication line 251), the second regulator 210 (via communication line 252), the third regulator 222 (via communication line 253), the fourth regulator 226 (via communication line 254), the fifth regulator 230 (via communication line 255), the heater 206 (via communication line 260), and the actuator 214 (via communication line 262).

[0094] The command signal transmitted by the controller 218 to the first regulator 204 (via communication line 251) controls the amount of gaseous propellant heated by the heater 206 (supplied from the tank 202). For example, the command signal received by the first regulator 204 may cause the first regulator 204 to open partially or fully, allowing the propellant gas (e.g., argon) to flow to the heater 206.

[0095] The command signals transmitted by the controller 218 to the second regulator 210, the third regulator 222, the fourth regulator 226, and the fifth regulator 230 (via communication lines 252, 253, 254, 255 respectively) control the amount of solid powder composition mixed with the propellant gas, as well as the chemical composition of the solid powder composition. For example, in the feeder 208, according to the material ratio input by the operator to the controller 218, copper particles are provided from the first material feeder 220 to the mixer 228, and highly oriented pyrolytic graphite flakes are provided from the second material feeder 224 to the mixer 228. As an example, the operator may wish to fabricate a Cu / HOPG metal matrix composite 304 having 55 - 65% by weight of copper and 35 - 45% by weight of highly oriented pyrolytic graphite( Figure 3 )。In response to the operator's input, the controller 218 sends a command signal (via communication line 253) to the third regulator 222 and a command signal (via communication line 254) to the fourth regulator 226. The command signals (sent via communication lines 253, 254) are used to operate the third regulator 222 and the fourth regulator 226 respectively to ensure that the required amounts of copper particles (in the first material feeder 220) and highly oriented pyrolytic graphite flakes (in the second material feeder 224) are provided to the mixer 228. When the second regulator 210 and the fifth regulator 230 are at least partially open, the Cu / HOPG metal matrix composite meets the propellant gas (e.g., argon) and is supplied to the nozzle 212.

[0096] Command signals (sent via communication line 252) are used to operate the second regulator 210 to ensure that an appropriate amount of the mixture of copper particles and highly oriented pyrolytic graphite flakes is mixed with the propellant gas (e.g., argon) passing through the fifth regulator 230 and delivered to the nozzle 212. At the nozzle 212, the delivered mixture of copper particles and highly oriented pyrolytic graphite flakes is mixed with the heated propellant gas from the heater 206, such that the mixture of copper particles and highly oriented pyrolytic graphite flakes is accelerated to a speed of 500 m / s - 1,000 m / s. Thus, the mixture of copper particles and highly oriented pyrolytic graphite flakes is propelled using the heated gas propellant, and the mixture is directed by the nozzle 212 to the substrate 302 at a speed sufficient to cause the solid powder composition to undergo plastic deformation and adhere to the substrate 302 to deposit the conductor 304 on the substrate.

[0097] Thus, by sending command signals to the first regulator 204, the second regulator 210, the third regulator 222, the fourth regulator 226, and the fifth regulator 230, the controller 218 can control the delivery and composition of the materials moving towards the nozzle 212.

[0098] The command signal sent by the controller 218 to the heater 206 (via communication line 260) controls the temperature to which the gas propellant is heated. For example, the controller 218 can instruct the heater 206 to heat to a temperature in the range of 450 to 535 °C. Thus, the heater 206 heats the propellant gas (e.g., argon) to a temperature in the range of 450 to 535 °C, and the heated propellant gas enters the nozzle 212.

[0099] The command signal sent by the controller 218 (via communication line 262) to the actuator 214 controls the distance M between the nozzle 212 and the substrate 302.

[0100] Thus, the controller 218 receives real-time data from the optical sensor 216 indicating the thickness T C of the coating material 303 on the substrate 302, and controls the regulators 204, 210, 222, 226, 230, the heater 206, and the actuator 214, etc. As a result, a Figure 3 cold spray product 300 is formed, which includes the conductor 304 deposited on the substrate 302. The conductor 304 on the substrate 302 has a desired thickness T E ( Figure 3 ) and the required chemical composition. For example, the conductor 304 includes a copper matrix 306 and highly oriented pyrolytic graphite flakes 308 dispersed in the copper matrix 306.

[0101] Figure 3is a perspective view of an example of the disclosed cold spray product 300. The cold spray product 300 includes a substrate 302 and a conductor 304 deposited on the substrate 302, for example, by using the method 100 of the system 200.

[0102] The substrate 302 can include any metal substrate or any non-metal substrate. Preferably, the substrate 302 is selected from materials suitable for resisting the heat and impact applied by the cold spray process. In one example, the substrate 302 is a metal substrate. In another example, the substrate 302 includes aluminum, titanium, or steel. In other examples, the substrate 302 can be formed of aluminum alloy 7075 or aluminum alloy 7050.

[0103] The conductor 304 includes a copper matrix 306 and highly oriented pyrolytic graphite flakes 308 dispersed in the copper matrix 306. Thus, the conductor 304 provides a suitable alternative to conventional copper, but has better electrical properties than copper and a lower density.

[0104] The copper matrix 306 includes pure copper, a copper-based alloy, or any alloy including copper. By selecting the copper matrix 306 as the matrix, the copper matrix 306 contributes to the high conductivity of the conductor 304.

[0105] In an example, the current density of the copper matrix 306 is about 500 amperes per square centimeter (500 A / cm 2 ), which makes it an ideal material for high-conductivity matrix materials, especially in aircraft maintenance, aircraft repair, and aircraft life monitoring applications.

[0106] In an example, the copper matrix 306 is included in the conductor 304 at a content of 55 - 65% by weight. If the content of the copper matrix 306 is less than 55% by weight, the highly oriented pyrolytic graphite will not be completely trapped in the copper matrix 306 ( Figure 3 ), and the adhesion of the conductor 304 to the substrate 302 ( Figure 3 ) will deteriorate. If the content of the copper matrix 306 is greater than 65% by weight, the total conductivity of the conductor 304 ( Figure 3 ) will decrease and the weight of the conductor 304 will increase.

[0107] In an example, the highly oriented pyrolytic graphite flakes 308 are included in the conductor 304 at a content of 35 - 45% by weight. If the highly oriented pyrolytic graphite flakes 308 are included in the conductor 304 at a content less than 35% by weight, the total conductivity of the conductor 304 ( Figure 3 ) will decrease and the weight of the conductor 304 will increase. If the highly oriented pyrolytic graphite flakes 308 are included in the conductor 304 at a content greater than 45% by weight, the adhesion of the conductor 304 to the substrate 302 ( Figure 3 ) will deteriorate.

[0108] In an example, the highly oriented pyrolytic graphite flake 308 includes intercalated highly oriented pyrolytic graphite, such as bromine-intercalated highly oriented pyrolytic graphite. Due to the layered form of graphite, different atomic or molecular species can be inserted between the graphite layers. The process of inserting such a dopant substance into graphite is called intercalation. Intercalation of highly oriented pyrolytic graphite is effective in changing the properties of highly oriented pyrolytic graphite. It has been determined that bromine-intercalated highly oriented pyrolytic graphite is suitable for inclusion in the solid powder composition of the present disclosure.

[0109] In another example, the conductor 304 has an average thickness T of 100 - 200 μm E . If the average thickness T E is less than 100 μm, the conductivity of the conductor 304 will decrease. If the average thickness T E is greater than 200 μm, the weight of the conductor 304 will increase, and the enhanced conductivity effect due to the inclusion of highly oriented pyrolytic graphite will begin to decline.

[0110] In an example, the conductivity of the conductor 304 exceeds 7×10 7 S / cm 3 , preferably exceeds 1×10 8 S / cm 3 , more preferably exceeds 1.4×10 8 S / cm 3 . In another example, the density of the conductor 304 is in the range of 1.0 to 8.0 g / cm 3 , preferably in the range of 2.0 to 6.0 g / cm 3 , more preferably in the range of 3.0 to 4.0 g / cm 3 . Thus, the conductor 304 can provide a much higher conductivity and a much lower density compared to pure copper.

[0111] Examples of the present disclosure can be described in the context of an aircraft manufacturing and service method 1000 as shown in Figure 4 and an aircraft 1002 as shown in Figure 5 . During pre-production, the aircraft manufacturing and service method 1000 can include the specification and design 1004 of the aircraft 1002 and the material procurement 1006. During production, the component / subassembly manufacturing 1008 and system integration 1010 of the aircraft 1002 are carried out. Thereafter, the aircraft 1002 can undergo certification and delivery 1012 in order to be put into use 1014. When used by a customer, the aircraft 1002 is scheduled for routine maintenance and repair 1016, which can also include modification, reconfiguration, refurbishment, etc.

[0112] Each process of method 1000 may be performed or implemented by a system integrator, a third party, and / or an operator (e.g., a customer). For ease of explanation, the system integrator may include, but is not limited to, any number of aircraft manufacturers and prime system subcontractors; the third party may include, but is not limited to, any number of suppliers, subcontractors, and vendors; and the operator may be an airline, a leasing company, a military entity, a maintenance organization, etc.

[0113] The methods, systems, and products of the present disclosure may be employed in any one or more stages of the aircraft manufacturing and service method 1000, including the specification and design 1004 of the aircraft 1002, material procurement 1006, component / subassembly manufacturing 1008, system integration 1010, certification and delivery 1012, bringing the aircraft into service 1014, routine maintenance and repair 1016.

[0114] As Figure 5 shown, the aircraft 1002 produced by way of the exemplary method 1000 may include a fuselage 1018 having a plurality of systems 1020 and an interior 1022. Examples of the plurality of systems 1020 may include one or more of a propulsion system 1024, an electrical system 1026, a hydraulic system 1028, and an environmental system 1030. Any number of other systems may be included. The methods, systems, and products of the present disclosure may be used for any system of the aircraft 1002.

[0115] Furthermore, the present disclosure includes embodiments in accordance with the following:

[0116] Item 1. A method of manufacturing a (conductive body) 304 on a substrate (302) by cold spraying, the method comprising:

[0117] Heating a gas propellant;

[0118] Propelling a solid powder composition including copper and highly oriented pyrolytic graphite using the heated gas propellant; and

[0119] Directing the solid powder composition to the substrate (302) at a rate sufficient to cause the solid powder composition to undergo plastic deformation and adhere to the substrate (302) to deposit the conductive body 304 on the substrate.

[0120] Item 2. The method according to item 1, wherein the current density of the copper is about 500 amperes per square centimeter (500 A / cm 2 ).

[0121] Item 3. The method according to item 1, wherein the highly oriented pyrolytic graphite includes bromine-intercalated highly oriented pyrolytic graphite.

[0122] Item 4. The method according to item 1, wherein the solid powder composition includes copper particles and highly oriented pyrolytic graphite flakes.

[0123] Item 5. The method according to item 4, wherein the copper particles are included in the solid powder composition at a content of 55 - 65% by weight.

[0124] Item 6. The method according to item 4, wherein the highly oriented pyrolytic graphite flakes are included in the solid powder composition at a content of 35 - 45% by weight.

[0125] Item 7. The method according to item 4, wherein the copper particles have an average particle diameter in the range of 15 μm to 25 μm.

[0126] Item 8. The method according to item 4, wherein the highly oriented pyrolytic graphite flakes have an average flake diameter of 5 μm to 25 μm.

[0127] Item 9. The method according to item 1, wherein the gas propellant is an inert gas propellant.

[0128] Item 10. The method according to item 9, wherein the inert gas propellant has an atomic number greater than 17.

[0129] Item 11. The method according to item 9, wherein the inert gas propellant includes argon.

[0130] Item 12. The method according to item 1, wherein the gas propellant is heated to a temperature in the range of 450 °C to 535 °C.

[0131] Item 13. The method according to item 1, wherein the average thickness T of the conductor (304) E is 100 μm - 200 μm.

[0132] Item 14. The method according to item 1, wherein the solid powder composition is directed towards the substrate (302) at a speed of 500 - 1,000 m / s.

[0133] Item 15. A system (200) for spraying a coating material (303) onto a substrate (302), the system comprising:

[0134] An optical sensor (216) positioned to monitor the thickness (T C ) of the coating material (303) applied to the substrate (302);

[0135] A controller (218) in communication with the optical sensor (216), the controller being configured to at least based on the thickness (T C) generate a first command signal (251) corresponding to the amount of gaseous propellant to be heated, a second command signal (260) corresponding to the temperature to which the gaseous propellant is to be heated, a third command signal (252) corresponding to the amount of solid powder composition to be mixed with the heated gas in the nozzle (212), and a fourth command signal (262) corresponding to the distance (M) between the nozzle (212) and the substrate (302);

[0136] A first regulator (204) that receives the first command signal (251) and provides a certain amount of gaseous propellant corresponding to the first command signal;

[0137] A heater (206) that receives a certain amount of gaseous propellant supplied from the first regulator, receives the second command signal (260), and heats the gaseous propellant to a temperature corresponding to the second command signal (260);

[0138] A second regulator (210) that receives the third command signal (252) and supplies a certain amount of solid powder composition corresponding to the third command signal (252) to the nozzle (212); and

[0139] An actuator (214) that receives the fourth command signal (262) and moves the nozzle (212) along the substrate at a distance (M) between the nozzle (212) and the substrate (302) corresponding to the fourth command signal (262).

[0140] Item 16. The system according to item 15, further comprising: a tank (202) configured to store the gaseous propellant supplied by the first regulator (204).

[0141] Item 17. The system according to item 16, wherein the tank (202) supplies an inert gaseous propellant.

[0142] Item 18. The system according to item 16, wherein the tank (202) supplies an inert gaseous propellant having an atomic number greater than 17.

[0143] Item 19. The system according to item 16, wherein the tank (202) supplies argon.

[0144] Item 20. The system according to item 15, wherein the first regulator (204) includes a valve.

[0145] Item 21. The system according to item 15, wherein the second regulator (210) includes a valve and a mass sensor.

[0146] Item 22. The system according to item 15, further comprising a feeder (208) configured to store the solid powder composition to be supplied by the second regulator (210).

[0147] Item 23. The system according to item 22, wherein the feeder (208) stores a mixture of copper particles and highly oriented pyrolytic graphite flakes.

[0148] Item 24. The system according to item 23, wherein the feeder (208) comprises:

[0149] A first material feeder (220) that stores copper particles;

[0150] A third regulator (222) that supplies a certain amount of copper particles from the first material feeder (220);

[0151] A second material feeder (224) that stores highly oriented pyrolytic graphite flakes;

[0152] A fourth regulator (226) that supplies a certain amount of highly oriented pyrolytic graphite flakes from the second material feeder (224); and

[0153] A mixer (228) that receives and mixes the copper particles provided by the third regulator (222) and the highly oriented pyrolytic graphite flakes provided by the fourth regulator (226).

[0154] Item 25. The system according to item 24, wherein the third regulator (222) comprises a valve and a mass sensor.

[0155] Item 26. The system according to item 24, wherein the fourth regulator (226) comprises a valve and a mass sensor.

[0156] Item 27. The system according to item 15, wherein a part of the gas propellant from the tank (202) passes through a fifth regulator (230) and transports the solid powder composition supplied from the second regulator (210) to the nozzle (212).

[0157] Item 28. A cold spray product (300) comprising:

[0158] A substrate (302); and

[0159] A conductor (304) deposited on the substrate (302) by cold spraying, the conductor (304) comprising a copper matrix (306) and highly oriented pyrolytic graphite flakes (308) dispersed in the copper matrix (306).

[0160] Item 29. The product according to item 28, wherein the substrate (302) is a metal substrate.

[0161] Item 30. The product according to item 28, wherein the substrate (302) comprises aluminum, titanium, or steel.

[0162] Item 31. The product according to item 28, wherein the current density of the copper matrix (306) is about 500 amperes per square centimeter.

[0163] Item 32. The product according to item 28, wherein the content of the copper matrix (306) contained in the conductor (304) is 55-65% by weight.

[0164] Item 33. The product according to item 28, wherein the highly oriented pyrolytic graphite flakes (308) include bromine-intercalated highly oriented pyrolytic graphite flakes.

[0165] Item 34. The product according to item 28, wherein the highly oriented pyrolytic graphite flakes (308) are contained in the conductor (304) at a content of 35-45% by weight.

[0166] Item 35. The product according to item 28, wherein the average thickness T of the conductor (304) E is 100 μm - 200 μm.

[0167] Item 36. The product according to item 28, wherein the density of the conductor (304) is in the range of 3.0 to 4.0 g / cm 3 range.

[0168] Item 37. The product according to item 28, wherein the conductivity of the conductor (304) exceeds 1.4×10 8 S / cm 3 .

[0169] Although various examples of the disclosed methods, systems, and products have been shown and described, those skilled in the art can make modifications after reading the specification. This application includes such modifications and is limited only by the scope of the claims.

Claims

1. A method (100) for manufacturing a conductor (304) on a substrate (302) by cold spraying, the method (100) comprising: heating (102) a gas propellant to a temperature in the range of 450 to 535 °C, wherein the gas propellant is an inert gas propellant having an atomic number greater than 17; propelling (104) a solid powder composition using the heated gas propellant, the solid powder composition comprising copper particles having a content of 55%-65% by weight and bromine-intercalated highly oriented pyrolytic graphite flakes having a content of 35%-45% by weight; and directing (106) the solid powder composition to the substrate (302) at a rate sufficient to cause the solid powder composition to undergo plastic deformation and adhere to the substrate (302) to deposit coating material on the substrate to form a conductor (304) on the substrate, wherein the average particle size of the copper particles is in the range of 15 μm to 25 μm.

2. The method (100) according to claim 1, wherein, Propelling the solid powder composition further comprises propelling the solid powder composition comprising copper having a current density of 500 amperes per square centimeter.

3. The method (100) according to claim 1, wherein, Propelling the solid powder composition further comprises propelling the solid powder composition comprising highly oriented pyrolytic graphite containing bromine-intercalated highly oriented pyrolytic graphite.

4. The method (100) according to claim 1, wherein, Propelling the solid powder composition further comprises propelling the solid powder composition comprising copper particles and highly oriented pyrolytic graphite flakes.

5. The method (100) according to claim 1, wherein, Propelling the solid powder composition further comprises propelling the solid powder composition comprising copper particles having an average particle size in the range of 15 μm to 25 μm.

6. The method (100) according to claim 1, wherein Propelling the solid powder composition further comprises propelling the solid powder composition comprising highly oriented pyrolytic graphite flakes having an average flake diameter of 5 μm to 25 μm.

7. A system (200) for spraying a coating material (303) onto a substrate (302) to manufacture a conductor (304) on the substrate (302), the system comprising: An optical sensor (216) positioned to monitor the thickness (T) of a coating material (303) applied to the substrate (302) over time C ); A controller (218) in communication with the optical sensor (216), the controller being configured to generate a first command signal (251) corresponding to the amount of gaseous propellant to be heated, a second command signal (260) corresponding to the temperature to which the gaseous propellant is to be heated, a third command signal (252) corresponding to the amount of solid powder composition to be mixed with the heated gaseous propellant in the nozzle (212), and a fourth command signal (262) corresponding to the distance (M) between the nozzle (212) and the substrate (302), at least based on the thickness (T C ). a first regulator (204) that receives the first command signal (251) and provides the amount of gas propellant corresponding to the first command signal; a heater (206) that receives the amount of the gas propellant corresponding to the first command signal supplied from the first regulator, receives the second command signal (260), and heats the gas propellant to the temperature corresponding to the second command signal (260), the temperature being in the range of 450 to 535 °C, wherein the gas propellant is an inert gas propellant having an atomic number greater than 17; a second regulator (210) that receives the third command signal (252) and supplies the amount of the solid powder composition corresponding to the third command signal (252) to the nozzle (212); and an actuator (214) that receives the fourth command signal (262) and moves the nozzle (212) along the substrate at a distance (M) between the nozzle (212) and the substrate (302) corresponding to the fourth command signal (262) to manufacture the conductor on the substrate, Wherein, the solid powder composition comprises copper particles with a content of 55%-65% by weight and bromine-intercalated highly oriented pyrolytic graphite flakes with a content of 35%-45% by weight. Wherein, the average particle size of the copper particles is in the range of 15 μm to 25 μm.

8. The system (200) according to claim 7, further comprising a feeder (208) configured to store the solid powder composition to be supplied by the second regulator (210), and wherein, The feeder (208) comprises: A first material feeder (220) for storing copper particles; A third regulator (222) for feeding a certain amount of the copper particles from the first material feeder (220); A second material feeder (224) for storing highly oriented pyrolytic graphite flakes; A fourth regulator (226) for feeding a certain amount of the highly oriented pyrolytic graphite flakes from the second material feeder (224); and A mixer (228) for receiving and mixing the copper particles provided by the third regulator (222) and the highly oriented pyrolytic graphite flakes provided by the fourth regulator (226).

9. A cold-sprayed product (300) manufactured by using the method (100) according to any one of claims 1 to 6 or the system (200) according to any one of claims 7 to 8, the cold-sprayed product comprising: A substrate (302); And A conductor (304) deposited on the substrate (302) by cold spraying, the conductor (304) comprising a copper matrix (306) and bromine-intercalated highly oriented pyrolytic graphite flakes (308) dispersed in the copper matrix (306).

10. The cold spray product according to claim 9, wherein, The average thickness of the conductor (304) is 100 μm - 200 μm.

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