Laser heating for manufacturing or repair of turbine blades

Abstract

An apparatus for laser heating of a mechanical part (35) of the turbine blade or turbine blade element type is disclosed, the apparatus comprising: one or more laser emitters (11j,..., 11k) for respectively emitting at least a first laser radiation at a first predetermined power to a first target area of the part and for emitting a second laser radiation at a second predetermined power to a second target area of the part different from the first target area, the second predetermined power being different from the first predetermined power, the second predetermined power being different from the first predetermined power.

Description

Technical Field

[0001] This application relates to the field of manufacturing or repairing mechanical components, for which at least one heating step must be performed according to a precise heat distribution. In particular, this application applies to the manufacture of components, especially those made of metals and / or composite materials, that have complex shapes and may be subjected to significant thermal and mechanical stresses, such as turbine blades for aircraft engines. Background Technology

[0002] In the manufacturing process of blades, it is common practice to heat-treat the blade elements, which alters the properties of the blade element materials. For example, a so-called "preheating" heat treatment can be performed before welding operations or material addition operations to limit stress in the material and prevent cracking. Induction heating equipment is known to be used specifically to perform this step.

[0003] Examples of induction heating devices are in Figures 1A to 1B As shown in the cross-sectional view and longitudinal view respectively, it is possible to heat the main body 1 in a non-contact manner in the electromagnetic field generated by the coil 2.

[0004] In the example shown, coil 2 has a shape that fits the body 1 and replicates the geometry of the body. This allows heat to be distributed evenly.

[0005] A drawback of this type of equipment is that it is difficult to adapt to heating elements with different geometries. Furthermore, in some cases, a non-uniform but controlled heat distribution across different areas of the component may be desirable.

[0006] The problem has arisen in implementing new heating equipment that addresses one or more of the aforementioned shortcomings. Summary of the Invention

[0007] An embodiment of the present invention provides a laser heating device for heating a component or component element according to a predetermined thermal profile. The heating device includes: a given laser source, the given laser source being provided with one or more laser emitters to emit at least one first laser radiation in a direction to a first target region of the component or component element according to a first predetermined power, and to emit second laser radiation in a direction to a second target region of the component or component element that is different from the first target region according to a second predetermined power, the second predetermined power being different from the first predetermined power.

[0008] This device enables the precise control of heating temperature gradients or substantially uniform heating of components or component elements without having to replicate the geometry of the component.

[0009] This equipment can be used to perform "preheating," in other words, heat treatment during additive manufacturing prior to a given material addition step, particularly via powder bed melting technology or via LMD (for "Laser Metal Deposition").

[0010] This heating equipment can also be used, particularly for heat treatment during additive manufacturing after a given material addition step, via powder bed melting technology or via LMD.

[0011] In both cases, heating is performed at a temperature below the melting temperature of the given material or the powder.

[0012] In particular, the components under consideration can be metal and / or composite material components, especially those that are subject to significant thermal and mechanical stresses.

[0013] This laser heating equipment is particularly suitable for manufacturing or repairing turbine blade components of aircraft engines.

[0014] The heating device is equipped with a module for controlling the laser emitter element, the module being configured to:

[0015] - Obtain thermal profile data that correlates the geometric and / or positional data of the target region of the component with the corresponding heating temperature value.

[0016] - Modulate the emission power of the one or more laser emitters of the laser source according to the thermal profile data.

[0017] According to a possible embodiment, the first laser radiation according to the first power and the second laser radiation according to the second power can be continuously emitted by the same laser emitter. Therefore, heating time control can be achieved.

[0018] The first laser radiation with the first power and the second laser radiation with the second power can respectively and simultaneously originate from the first laser emitter and the second laser emitter. Therefore, spatial control of heating can also be achieved.

[0019] According to possible implementations, the laser source may be formed by one or more first emitters belonging to a first support and one or more second emitters belonging to a second support different from the first support, with a space provided between the first support and the second support to accommodate the component.

[0020] According to another possible implementation, the laser source includes laser emitters distributed on a region of the support that forms a closed profile around the cavity, the closed profile being particularly circular or oval, and the components can be arranged in the cavity.

[0021] Advantageously, the laser emitter is a VCSEL type laser diode.

[0022] Advantageously, the heating device as defined above can be associated with or integrated into a device for additive manufacturing via the direct deposition of materials of the type of metal powder or molten metal wire (advantageously LMD type materials).

[0023] Typically, such a system is configured with at least one material dispenser component and another laser source different from the given laser source.

[0024] Advantageously, the system also includes a control device for modulating the corresponding emission power of the one or more laser emitters based on the positioning data of the material dispenser component. According to a particular embodiment, these control devices are integrated into the control module defined above.

[0025] The laser heating equipment defined above can be used to perform different heat treatment steps to prepare components for welding, or for material addition, or for reinforcement, or to control cooling, particularly after any of the steps described above.

[0026] According to another aspect, embodiments of the present invention provide the use of the laser heating device as defined above for the repair or manufacture of blade components or blades of aircraft engines.

[0027] According to another aspect, embodiments of the present invention provide a method for manufacturing or repairing at least a portion of a blade of an aircraft engine, the method comprising one or more steps of additive manufacturing by laser-assisted powder coating, particularly by LMD-type laser-assisted powder coating, wherein at least one of the additive manufacturing steps is preceded or followed by heating using a laser heating device as defined above.

[0028] Advantageously, the heat treatment is performed at a temperature below the melting temperature of the powder. Attached Figure Description

[0029] The invention will be better understood from the following description and accompanying drawings, in which:

[0030] Figure 1A and Figure 1B Used to illustrate an induction heating device implemented according to the prior art;

[0031] Figure 2 Used to illustrate a laser heating device implemented according to an embodiment of the present invention;

[0032] Figure 3 For illustrating LMD-type additive manufacturing equipment, the laser heating device according to the present invention can be associated with the LMD-type additive manufacturing equipment, or the heating device can be integrated into the LMD-type additive manufacturing equipment;

[0033] Figure 4A and Figure 4B Different examples used to illustrate the thermal profile as a function of the coordinates of components that can be implemented in the heating device according to the invention;

[0034] Figure 5A , Figure 5B , Figure 5C and Figure 5D Used to illustrate different shapes of local areas that can be heated by a laser heating device implemented according to the present invention;

[0035] Figure 6 A specific example is provided to illustrate a support member for a laser emitter in a laser heating device according to an embodiment of the present invention;

[0036] Figure 7 Another specific example is used to illustrate the support for the laser emitter in a laser heating device implemented according to the present invention.

[0037] Identical, similar or equivalent parts in different figures have the same figure reference numerals to facilitate switching from one figure to another.

[0038] The different parts shown in the attached figures are not necessarily to a uniform scale, in order to make the figures easier to read. Detailed Implementation

[0039] Figure 2 An embodiment of a laser heating device implemented according to an embodiment of the present invention is illustrated schematically.

[0040] This device is used specifically in the manufacture or repair of component 5, which is particularly based on metals and / or composite materials and may be designed to withstand significant thermal and mechanical stresses and / or may have complex shapes. In particular, the component 5 under consideration may be a blade or blade element of a gas turbine designed to withstand high thermal and creep stresses.

[0041] The turbine blades being manufactured or repaired may be made of a metallic alloy, such as TiAl alloy, or, according to another example, an alloy based on nickel and one or more of the following elements: Cr, Co, Mo, W, Al, Ti, Ta, Hf, Re, Ru.

[0042] According to other examples, component 5 may be made of heat-resistant steel superalloy or a composite material made of a nickel-based superalloy reinforced with a low volume fraction (a few percent) of fiber. Alternatively, component 5 may be provided with a body made of a given material covered with one or more coatings of a material different from the given material, such as a metal body coated with a heat-insulating layer made of a ceramic material.

[0043] Laser heating equipment can be used in various heat treatment steps of methods for manufacturing blades, particularly at temperatures below the melting temperature of one or more present materials. Therefore, such heating equipment can be used to preheat, and particularly heat treat, a blank or component before adding material to it. In this case, preheating heat treatment is typically performed by the LMD method at a temperature below the melting temperature of the powder subsequently used for material addition.

[0044] Another example is the use of heating equipment to perform rapid annealing in preparation for welding, which is typically performed at temperatures between 700°C and 900°C, for example, at temperatures in the range of 800°C.

[0045] Heating equipment is not necessarily used for performing preheating steps, but can be used for steps following material addition. For example, heating equipment can be used during so-called "stress-relief" annealing, which is typically performed at temperatures between 600°C and 1000°C. Here, again, annealing is typically performed at temperatures below the melting temperature of one or more of the materials present.

[0046] Another example of using heating equipment is annealing performed during a coating operation, during which areas of a component lacking material are reconstructed or material is added to that component. For example, it might be desirable to coat a blade made of a single-crystal nickel-based superalloy by providing a coating microstructure having a crystal orientation consistent with the crystal orientation of the blade.

[0047] The coating operation can be performed using powder bed melting additive manufacturing techniques, such as LMD (laser metal deposition) type powder bed melting additive manufacturing techniques. Then, precise control of the spatial temperature distribution desired to be applied to part 5 can be obtained using laser heating equipment.

[0048] In order to heat the component 5 according to a predetermined thermal profile that can be adapted to the geometry of the component 5, the heating device is provided with a laser source 11 with adjustable power, and in this example, a plurality of laser emitters 111, ..., 11 distributed on the support 10. n form.

[0049] For example, laser emitters 111, ..., 11 n This can be a laser diode, particularly a VCSEL ("vertical-cavity surface-emitting laser") type laser diode; in other words, a semiconductor laser diode that emits laser beams perpendicular to the surface of an active semiconductor region. This region is associated with a laser resonator typically formed by a Bragg mirror with the plane of the surface. In the intended application, this type of emitter offers specific advantages such as: emitting a low-divergence beam, achieving high integration density, being able to be integrated in multiple rows or matrices, and facilitating spatial and temporal control of the amount of energy supplied to component 5 or to a target region of component 5 to be heated.

[0050] The number and density of the emitters depend on the type of part to be preheated and the forming system. According to a particular embodiment, the device can be configured with one to 20 groups of independent vertical or horizontal emitters, each group consisting of one to several hundred emitters. Each emitter can be spaced apart from the next emitter on the module by a distance, for example, in the range of 100 μm.

[0051] Given laser emitter 11 i Radiation with wavelength λa is generated, which is typically between 650 nm and 1300 nm, for example, in the range of 800 nm to 1000 nm. The power Pi of the laser is individually adjustable and, for example, between 100 W and 10 kW, depending on the desired heating temperature to which the target region 6i of the component is to be subjected.

[0052] In the example shown, laser emitters 111, ..., 11 n They are arranged on the support member 10 that forms a closed profile. Laser emitters 111, ..., 11 n Specifically, components 5 are arranged around a cylindrical surface defining cavity 17, within which components 5 are positioned during heating. The heating device also includes an optical system 13 for guiding the laser beam. For example, the optical system comprises lenses distributed on the cylindrical surface, each lens facing one or more laser emitters.

[0053] This heating device enables uniform heating of component 5, even though the geometry of the component differs from the geometry of all the heating elements distributed around it.

[0054] Therefore, by modifying laser emitters 111, ..., 11 nIndividual power control is implemented, with the first laser emitter 111 emitting radiation at a first predetermined power P1 in the direction of a first target region 61 located at a first distance d1 from the emitter 111, while another emitter emits radiation at a different power P5, different from the first power P1, in the direction of another target region 65 located at a second distance d2 from the component 5. The powers P1 and P5 are adjusted according to the positioning of the target regions 61 and 65 relative to the laser source; in other words, according to the shape of the exposed object. In the example shown, since distance d1 is less than distance d5, power P5 can be set, for example, to be higher than power P1, so that uniform or substantially uniform heating can be achieved between the target regions 61 and 65 of the component 5.

[0055] Using such a heating device, non-uniform heating of component 5 can also be performed, for example, by subjecting a local area of ​​component 5 to a given heating temperature, but with a controlled thermal gradient, while placing another area of ​​the component at a different temperature, or even not exposing it to the laser beam, with the emitter positioned relative to that other area not emitting the laser beam.

[0056] In order to enable the transmitter 111, ..., 11 n The power of the heating device is individually controlled, and the heating device is equipped with a control module 28 or associated with such a control module. Typically, the control module 28 includes a computer and / or a processor and / or at least one electronic circuit, such as an ASIC (Application-Specific Integrated Circuit), which has hardware and / or software components to enable the generation of power for the transmitters 111, ..., 11 n These signals control the emission and power. In the case of a VCSEL transmitter, these signals specifically act on the corresponding potentials of the electrodes of the laser diode.

[0057] The control module 28 may also be provided with or associated with at least one memory, the at least one memory being capable of storing geometric data related to the geometry of component 5 and / or positioning data of different target regions of component 5 in a given reference frame. A three-dimensional model of the component associated with structural data of the component's constituent materials may also be used.

[0058] Typically, the geometric and / or positioning data of a component are associated with heating temperature and / or laser energy and / or laser power data, respectively. More specifically, based on thermal profile data associated with the geometric data of component 5 and / or the positioning of the target area of ​​component 5, control module 28 can individually control laser emitters 111, ..., 11 n ...

[0059] In addition to individual transmit power control, “on / off” control can also be implemented to activate one or more of the laser emitters, that is, to make each emitter emit laser radiation, while deactivating one or more other emitters, in other words, not emitting any laser radiation.

[0060] Heating control by such devices can be achieved using temperature measurement sensors such as pyrometers, thermocouples, or thermal cameras. For example, servo control of the heating temperature can be achieved by modulating the power of a laser diode to keep the temperature in the component constant over time.

[0061] As previously mentioned, a specific application of heating equipment with a laser emitter is that the heating equipment is associated with or integrated into an additive manufacturing system, which is particularly based on the principle of depositing a powder jet on a molten surface heated by a high-power laser, or is an equipment or system that uses melting technology on a powder bed, such as LMD ("laser metal deposition") equipment.

[0062] Such devices may have distributor components made of metal, making the use of induction heating devices unsuitable. In fact, the use of such heating devices may generate parasitic eddy currents at the typical metal distributor components and interfere with the operation of the heating device by causing premature heating of the components.

[0063] Figure 3 A specific additive manufacturing apparatus using LMD technology is shown, and this specific additive manufacturing apparatus can be associated with a heating apparatus according to the invention (not shown in the figure). A laser 38 is used here to melt the projected powder to form or coat the blade element 35.

[0064] The operating parameters of the additive manufacturing equipment, particularly the operating parameters of the laser source 38, especially the power of the laser source throughout the process, can be modulated by means of a separate control unit. Alternatively, the same control module 28 as the control module of the aforementioned laser heating equipment can be used.

[0065] The control unit or control module 28 can also be configured to acquire positioning data from the material dispenser component and adjust the corresponding power of the laser emitter based on this positioning data. Positioning data of the component's support members can also be considered. In turn, this positioning data can originate from position sensors and / or motion sensors.

[0066] In this example, the apparatus for additive manufacturing by selective melting on a powder bed is designed to manufacture blade elements 35 by depositing material on a horizontal plate-shaped support 32. The apparatus is provided with a movable material dispenser component movable relative to the support 32 and carried, for example, by a robotic arm. The manufacturing apparatus is connected to a metal powder supply and a metal powder dispenser. The material dispenser component includes a nozzle 34 for projecting metal powder and at least one laser emitter 36 configured to emit a laser beam 38 through the nozzle 34. The powder is conveyed by a carrier gas and projected in the form of a powder stream. For example, the powder comprises a nickel-based alloy.

[0067] The laser beam 38 can be delivered to the nozzle 34 via an optical path defined, in the specific example shown, by an optical fiber 36a and lenses (e.g., having a collimating lens 36b and a focusing lens 36c). The beam 38 is intended to pass through the inner axial opening of the nozzle 34 and toward the support 32 on which powder is projected. The laser beam 38 is emitted at a predetermined wavelength λb and a predetermined power to melt the projected powder. For example, the wavelength λb is in the range of 1064 nm. For example, the beam 38 is a beam from a YAG laser having a power, for example, between 0.2 kW and 2 kW.

[0068] In the example shown, nozzle 34 has a generally conical or truncated conical shape, with one end of the nozzle having a smaller diameter forming a powder outlet. In this example, nozzle 34 includes a plurality of coaxial cones 34a, 34b, 34c, with the number of cones being three, one of which is mounted inside the other.

[0069] The inner cone 34a and the intermediate cone 34b surrounding the inner cone define an inner annular channel for injecting a protective gas flow 37a around the bundle 38. The channel is connected to a device for supplying the protective gas from the aforementioned supplier. Typically, the protective gas 37a is an inert gas such as argon, helium, or nitrogen. The intermediate cone 34b and the outer cone 34c surrounding the intermediate cone define an outer annular channel for injecting the powder flow 33. The intermediate cone 34b and the inner cone 34c surrounding the intermediate cone define an annular channel for allowing the forming gas 37b to pass through.

[0070] The heat source generates a significant thermal gradient in its path, for example, in the range of 10,000 K / s to 20,000 K / s, which can induce residual mechanical stress. During solidification and cooling, the material may shrink in the transverse direction, longitudinal direction, and throughout its thickness. The mechanical stress resulting from this shrinkage can be a source of transverse cracks (related to longitudinal shrinkage) or longitudinal cracks (related to transverse shrinkage). When the laser beam 38 passes through, causing the material to melt, the local mechanical stress depends on the thermal gradient and the clamping conditions of the element 35. In the case where the element 35 is not clamped, heating produces local expansion of the upper portion, which may result in a concave curvature. Due to this curvature, the upper surface experiences tensile stress.

[0071] To overcome undesirable stresses, the component 35 manufactured using the aforementioned additive manufacturing equipment can be subjected to a heat treatment step known as "post-heating" (in other words, performed after the material addition step). Thus, the component 35 then undergoes heat treatment with a controlled thermal gradient to limit stresses in the material. For example, post-heating annealing can be performed at a temperature, for example, between 500°C and 1000°C.

[0072] In addition to heat treatment controlled during the cooling of element 35 or heat treatment performed after the addition of material, the laser heating apparatus according to the present invention can also be used for preheating, in other words, a heat treatment step performed on the body or element before the addition of material. For example, preheating annealing can be performed at a temperature, for example, between 300°C and 1000°C.

[0073] The emission power of the laser source 38 of the aforementioned device can be adjusted based on the positioning data of the component 35 in a given reference frame and / or data related to the geometry of the component.

[0074] exist Figure 4A In the specific example shown, the power of the laser source 38 of the additive manufacturing equipment is adjusted according to a predetermined thermal profile P1 recorded and used by the control module, thereby enabling modulation of the power of the source laser 38. Here, the profile P1 is a linear function relating temperature data and positioning data, where the positioning data is related to the height or thickness of the component 35 (the dimension measured relative to the axis Y parallel to the reference frame [O; X; Y; Z]). According to the profile P1, the power of the laser 38 increases with the increase of the thickness of the component 35.

[0075] Figure 4B Another example of thermal profile P2 is given. Unlike P1, thermal profile P2 this time correlates temperature data with dimension X (e.g., the lateral dimension of part 35). According to profile P2, the power of laser 38 increases as it approaches the center region of the part, and decreases as it approaches the lateral region.

[0076] In particular, when the laser heating device described above is associated with or equipped with the control module described above, this power modulation following the change of the thermal profile can also be implemented by the laser heating device. The power control module can also use other profiles that correlate heating temperature with 2D or 3D coordinates, such as 2D or 3D profiles. Nonlinear thermal profiles following more complex distributions can also be provided.

[0077] Laser heating equipment also enables the heating of areas with very different corresponding shapes and distributions.

[0078] exist Figure 5A In the example, the region 136a of component 35 that undergoes laser heat treatment corresponds, for example, to the basic surface Si (cell) that the laser beam can illuminate when stationary.

[0079] exist Figure 5B In the example shown, the region 136b extending across the entire width of component 35 is subjected to the same power of laser radiation, for example, by scanning from the same laser source or by different laser emitters emitting simultaneously at the same power.

[0080] according to Figure 5C In another example shown, region 136c extending at a given height of component 35 is subjected to the same power of laser radiation.

[0081] Figure 5D Another example of the heating profile given in the text is provided, for example, for regions 136 located at different thicknesses. 21 136 31 Region 136, subjected to the same laser power but located at the same thickness but different levels, 31 136 37 It can receive different corresponding laser powers.

[0082] Different shapes can be provided for the support structure of laser emitter components. Figure 6 In a particular embodiment, the heating device includes one or more first emitters 11 distributed on a first support 61, for example, a parallelepiped-like rod. j And one or more second transmitters 11 k It is integrated into a second support member 62, which is similar to a parallelepiped rod 62. A space 67 or cavity 67 is provided between the two supports 61 and 62 to accommodate the component 5 to be heated.

[0083] Therefore, according to transmitter 11 j and 11 kThe corresponding power and / or the number of emitters activated and emitted from one support to another can heat target areas located on opposite surfaces F1, F2 of the same component 5, and may perform different heating profiles from one surface to another. For example, emitter 11 of the first support. j The transmitter 11 with the second support member k Different power transmissions. Alternatively, especially when the two surfaces F1 and F2 have different geometric profiles, the transmitter 11 of the first support 61... j The transmitter 11 of the second support member 62 is emitted according to the corresponding power distribution of the first power distribution. k It is transmitted according to the corresponding power of a second power distribution that is different from the first distribution.

[0084] exist Figure 7 In the specific embodiment given, laser emitters 11 are distributed on the region of the support 71 that forms a closed contour (particularly a circular or oval contour). j 11 k It can emit heat simultaneously or continuously at the same or different corresponding powers, depending on the desired heating profile. Such a device enables a more uniform heating distribution.

[0085] As previously stated, the heating apparatus according to the present invention does not retain the heat treatment steps for welding or material addition. The heating apparatus can also be used, for example, to perform heating during the component separation step.

Claims

1. A laser heating device for heating turbine blade elements or blades according to a predetermined thermal profile, the laser heating device comprising a given laser source, the given laser source being provided with a plurality of laser emitters (111, ..., 11...). j ,11 k , ..., 11 n The laser heating device further includes a control module (28) of the laser emitter, which emits at least one first laser radiation in the direction of a first target region (61) of the turbine blade element or blade according to a first predetermined power, and emits a second laser radiation in the direction of a second target region (65) of the turbine blade element or blade that is different from the first target region according to a second predetermined power. The control module is equipped with a memory that stores geometric data related to the geometry of the turbine blade elements or blades, and positioning data of different target regions of the turbine blade elements or blades. The control module is configured to: - generate a target region (61, 65, 6) for the turbine blade elements or blades. i Thermal profile data relating geometric and positioning data of turbine blade elements (61, 65, 66a, 136b, 136c) to corresponding heating temperature values, or thermal profile data relating the turbine blade elements or target areas of the blades (61, 65, 66a, 136b, 136c) to the corresponding heating temperature values. i The location data of 136a, 136b, 136c) and the thermal profile data associated with the corresponding heating temperature values. - The emission power of the plurality of laser emitters of the laser source is modulated according to the thermal profile data, wherein, The laser emitter of the laser source is arranged on a support (10) defining a cavity, and the blade elements or blades of the turbine can be arranged in the cavity, wherein the laser emitter is distributed along a closed profile surrounding the cavity.

2. The laser heating device according to claim 1, The first laser radiation according to the first predetermined power and the second laser radiation according to the second predetermined power are continuously emitted by the same laser emitter, or The first laser radiation according to the first predetermined power and the second laser radiation according to the second predetermined power respectively and simultaneously originate from the first laser emitter (11). j ) and the second laser emitter (11 k ).

3. The laser heating device according to claim 1, wherein, The given laser source includes laser emitters distributed in a region of the support that forms a closed profile around the cavity (77), and the turbine blade elements or blades can be arranged in the cavity.

4. The laser heating device according to claim 1, wherein, The laser emitter is a laser diode that emits laser beams perpendicular to the surface of an active semiconductor region; the laser diode is referred to as a VCSEL laser diode.

5. The laser heating device according to claim 3, wherein, The closed contour has a circular or oval shape.

6. An additive manufacturing system for additive manufacturing by direct deposition of materials of the type of metal powder or molten metal wire, the additive manufacturing system comprising the laser heating device according to claim 1.

7. The additive manufacturing system according to claim 6, wherein, The additive manufacturing system includes a material dispenser component and another laser source different from the given laser source. The laser heating device is configured such that the one or more laser emitters emit at a specific power to achieve heating at a temperature below the melting temperature of the material.

8. The additive manufacturing system according to claim 6, wherein, The material is of the LMD type.

9. The use of the laser heating device according to claim 1 for the repair or manufacture of blade components or blades of an aircraft engine.

10. A method for manufacturing or repairing blades or blade elements of an aircraft engine, the method comprising one or more steps of additive manufacturing by laser-assisted powder coating, wherein at least one of the steps is preceded or followed by heat treatment using the laser heating apparatus according to claim 1.

11. The method according to claim 10, wherein, The heat treatment is performed at a temperature lower than the melting temperature of the powder.

12. The method according to claim 10, wherein, The laser-assisted powder coating is an LMD type laser-assisted powder coating.

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