INSTALLATION FOR THE DEPOSIT OR MODIFICATION OF A SOLID MATERIAL FROM A VAPOR PHASE, IMPLEMENTATION METHOD AND CORRESPONDING MANUFACTURING ASSEMBLY

Abstract

This installation includes a processing chamber (5) which forms an internal volume for processing the substrate (SUB) in the form of a sheet or strip, the inlet (E') and outlet (S') of the installation communicating respectively with the inlet (E) and outlet (S) of the processing chamber, means (6) for injecting an active gas mixture into the processing volume of the substrate intended for the deposition, growth or modification of the material, and means (7) for heating the internal volume of the processing chamber.The treatment chamber (5) extends in a generally vertical manner, with the inlet and outlet of the treatment chamber located at different altitudes (ZE, ZS), while free spaces (37, 38) are provided on either side of the substrate path, in order to separate the respective faces of the substrate from the front walls (50, 51) of the chamber, the injection and heating means being provided on the front walls (50, 51) and the injection means being equipped with cooling means (65, 66). Figure for the abbreviation [Fig. 9].

Description

Title of the invention: INSTALLATION FOR DEPOSITTING OR MODIFYING A SOLID MATERIAL FROM A VAPOR PHASE, METHOD OF IMPLEMENTATION AND CORRESPONDING MANUFACTURING ASSEMBLY Technical field of the invention

[0001] The invention relates to the field of reactors for the deposition or modification of solid materials from a vapor phase. More specifically, it relates to the field of reactors for the continuous deposition of nanostructured materials, such as carbon nanotubes or nanofibers, from a vapor phase onto a solid substrate. In particular, it relates to an installation for manufacturing a material comprising carbon nanotubes or nanofibers fixed to a substrate, notably vertically aligned carbon nanotubes (VACNTs), deposited typically in a scrolling fashion. Such a material may be composite in nature, it being understood that the invention is applicable to other types of materials. The invention also relates to a method for implementing this installation, as well as an assembly for manufacturing a nanostructured material, which includes this installation. State of the art

[0002] Carbon nanotubes (often abbreviated as "CNTs") have walls formed by graphitic monolayers (graphene sheets). Whether single-layer or multi-layered, they exhibit particular mechanical, thermal, electronic, and structural properties; these properties reflect their strong structural anisotropy. Numerous applications have been envisioned that take advantage of these particular properties. For example, polymer materials loaded with nanotubes have been prepared and used in the manufacture of tennis rackets, which benefit from mechanical properties combining strength and flexibility.We also considered taking advantage of their high electronic and thermal conductivity in the length direction of the tubes and conversely a lower electronic and thermal conductivity in the transverse direction to the nanotubes which makes them a particularly interesting and unique anisotropic material for applications in the fields of energy (supercapacitors, batteries, fuel cell or electrolyzer and more generally support for catalysts of all kinds, organic, inorganic, biological).

[0003] For about twenty years, it has been possible to deposit vertically aligned carbon nanotubes (CNTs) onto a substrate; this product is known as VACNT (Vertically Aligned Carbon Nanotubes) and is described as a carpet, forest, or array. Hu et al. ("3-omega measurements of vertically oriented carbon nanotubes on Silicon," J. Heat Transf. 128 (2006) pl 109-1113) describe the possibility of using a carpet of VACNTs as a thermal interface material (TIM). Thermal interface materials are used to dissipate the heat produced by electronic components with which they are in thermal contact. The authors observe that, on a carpet of VACNTs deposited on a silicon crystal, the thermal conductivity in the thickness direction (i.e., parallel to the length of the aligned tubes) is much higher than that of commercially available thermal interface materials.

[0004] A process for the continuous fabrication of nanostructures aligned on a moving support is known from FR 3013 061 A1. This process comprises conveying the support through a heated space and synthesizing the nanostructures aligned with the support in this space by catalytic chemical vapor deposition. According to this process, the heated space is divided into at least two consecutive zones in the direction of support conveyance. The synthesis of the nanostructures results from heating and injection operations, in each of the aforementioned zones, of a stream of an aerosol containing a catalytic precursor and a source precursor of the material of the nanostructures to be formed, carried by a carrier gas.

[0005] A continuous CNT synthesis installation is also known from US 2011 / 3182560, comprising a coating and drying zone, a synthesis zone, and a collection zone. Within the synthesis zone, the gas mixture is injected through tubes in a direction perpendicular to the flow of the substrate. Gas extraction lines are also provided on either side of the synthesis zone so as to evacuate the gas also in a direction perpendicular to the flow of the substrate.

[0006] The applicant has proposed, by WO 2017 / 187 080, a modular installation for manufacturing a material comprising CNTs. According to this solution, the active mixture is transported in a first direction within the processing chamber by means of circulation means. Furthermore, this active mixture can be extracted from the chamber in a second direction by means of the same circulation means, which can adopt a different configuration. Typically, the first direction is perpendicular to the direction of substrate flow, while the second direction is parallel to it.

[0007] Although this solution is particularly satisfactory in terms of modularity, it nevertheless presents certain drawbacks. Indeed, it has been noted that it This does not allow for optimal uniformity of the final material. Uniformity can be defined as the absence of spatial variations, within the plane of the substrate, in the material's properties once obtained. These properties include the number of tubes, their length, their density, and their diameter. More specifically, it would be desirable to improve the homogeneity of the VACNT deposition aligned on both faces of the substrate as it is passed through. Furthermore, if this reactor is used to deposit a thin layer of another material, for example, a pretreatment layer such as a metallic catalyst layer, its thickness is also not entirely homogeneous.

[0008] In view of the foregoing, one objective of the present invention is therefore to remedy, at least partially, the disadvantages of the prior art mentioned above.

[0009] Another objective of the invention is to propose an installation which, while allowing simple implementation, guarantees an improvement in the final quality of a material comprising CNTs, in particular an improvement in the uniformity of this material.

[0010] Another objective of the invention is to propose such an installation which makes it possible to cover the two opposite faces of the treated substrate, by means of two materials which may be identical or different.

[0011] Yet another objective of the invention is to propose such an installation which, while providing the improvements presented in the preceding paragraphs, allows the implementation of a continuous "roll to roll" type process in which the catalyst and the reactive gases are injected simultaneously.

[0012] Objects of the invention

[0013] According to the invention, at least one of the above objectives is achieved by means of an installation for the deposition, growth or modification of a material on a substrate, in particular a composite material comprising nanotubes or nanofibers fixed to a substrate, such as carbon nanotubes or nanofibers, this installation comprising

[0014] at least one treatment chamber, or reaction chamber, which forms an internal volume for treating said substrate which is in the form of a sheet or strip, this treatment chamber comprising an inlet and an outlet,

[0015] an inlet and an outlet of the installation, this inlet and this outlet of the installation communicating respectively with the inlet and outlet of said treatment chamber,

[0016] means for injecting an active gaseous mixture into the substrate treatment volume, this gaseous mixture being intended for the deposition, growth or modification of said material,

[0017] heating means, suitable for heating the internal volume of the treatment chamber,

[0018] said installation being characterized in that

[0019] the treatment chamber extends in a generally vertical manner, with the inlet and outlet of the treatment chamber located at different altitudes,

[0020] free spaces are provided, in service, on either side of the substrate path, the free spaces separating in service each the respective faces of the substrate with respect to front walls facing the chamber, said front walls bordering the internal volume of substrate treatment,

[0021] both the injection means and the heating means being provided on said front walls, and

[0022] the injection means are equipped with cooling means, which are suitable for cooling these injection means.

[0023] This installation forms the first object of the invention. It can be implemented with numerous variations.

[0024] In variants, which can be combined with each other:

[0025] - the front walls are arranged opposite each other without the interposition of a base of the substrate, so as to delimit said free spaces in use;

[0026] - the installation further includes thermal insulation means, suitable for insulating the injection methods in relation to heating methods;

[0027] - the injection means comprise several injection modules, each module injection comprising at least one circulation channel allowing the circulation of the heat transfer fluid, as well as at least one injection channel allowing the transport of the gaseous mixture, this injection channel opening onto at least one injection nozzle; in this variant each injection module may comprise a body, in which are provided the circulation channel and the injection channel, as well as a thermal insulation casing extending to the periphery of at least a part of this body, said casing the said thermal insulation means;

[0028] - the heating means comprise several heating modules, while the injection means comprise several injection modules, the heating modules and the injection modules being arranged alternately on at least the majority of the same front wall; in this variant, on at least the majority of each front wall, the heating modules and the injection modules can advantageously be placed in a staggered pattern.

[0029] In one embodiment, the installation according to the invention may comprise a lower zone bordered by said inlet of the installation and said inlet of the treatment chamber, respectively the outlet of the installation and the outlet of the treatment chamber, as well as an upper zone bordered by said outlet of the installation and said exit of the treatment chamber, respectively the inlet of the installation and the inlet of the treatment chamber, this lower zone and this upper zone being arranged on either side of an intermediate zone comprising the treatment chamber,

[0030] the installation showing, in side view,

[0031] a form of C or

[0032] an S-shape, or

[0033] an L-shape, or

[0034] an inverted L shape, or even

[0035] a form of I.

[0036] This embodiment can be combined with all the variants described above.

[0037] The installation according to the invention advantageously lacks a base capable of contacting the substrate in use; thus, the substrate is heated essentially by thermal radiation, which ensures better thermal homogeneity than a mechanical friction contact. In other words, the heating means are advantageously arranged directly opposite the substrate in use, that is, without the interposition of a mechanical element such as a base. The active gas mixture in the internal volume of the treatment chamber is heated solely by thermal radiation.

[0038] Advantageously the treatment chamber is symmetrical with respect to a vertical axis.

[0039] According to an advantageous embodiment of the invention, the installation may comprise a main frame equipped with both said inlet and said outlet, an insert adapted to cooperate with the main frame, and removable fastening means between this frame and this insert. In this embodiment, the frame and the inserts may have respective recesses, forming said processing chamber.

[0040] Another object of the invention is a method for implementing the above installation, in which:

[0041] - the substrate is scrolled through said chamber in said vertical direction, in providing said free spaces between each face of the substrate is a respective front wall facing the chamber

[0042] - the internal volume of the treatment chamber is heated, via the heating methods

[0043] - active gaseous mixture is injected into the internal volume of the chamber, by the intermediary of the injection means, while cooling the injection means, through the means of circulating the heat transfer fluid, so as to form carbon nanotubes preferentially on the surface of this substrate.

[0044] Yet another object of the invention is an assembly for the deposition, growth or modification of a material on a substrate, in particular a composite material, in particular a composite material comprising nanotubes or nanofibers fixed on a substrate, such as carbon nanotubes or nanofibers,

[0045] said assembly comprising

[0046] - an installation according to the first object of the invention, possibly taken according to the any of its variants and combinations of variants,

[0047] - means for scrolling the substrate intended to form said material, along the installation,

[0048] - means for supplying a gaseous mixture, suitable for supplying a mixture gaseous injection methods,

[0049] - means for admitting a heat transfer fluid, adapted to admit the heat transfer fluid into the circulation means equipping the injection means. Description of the figures

[0050] The invention will be described below, with reference to the accompanying drawings, given solely by way of non-limiting examples, in which:

[0051] [Fig.1] is a schematic view, illustrating from above an assembly for the manufacture of a material comprising carbon nanotubes, according to the invention.

[0052] [Fig.2] is a schematic view illustrating more particularly, from the side, a manufacturing installation according to the invention, which belongs to the manufacturing assembly illustrated in [Fig.1].

[0053] [Fig.3] is a schematic side view, analogous to [Fig.2], illustrating separately certain constituent elements of the manufacturing installation according to the invention.

[0054] [Fig.4] is a schematic view, illustrating a chassis belonging to the installation of fabrication of figures 2 and 3, according to arrow IV on the [Fig.3].

[0055] [Fig.5] is a cross-sectional view along line VV in [Fig.4].

[0056] [Fig.6] is a vertical cross-sectional view, illustrating on a larger scale the parts respectively upper and lower of the installation of figures 2 to 5.

[0057] [Fig.7] is a cross-sectional view, analogous to [Fig.5] but larger scale, illustrating more precisely the lateral part of the installation in figures 2 to 6.

[0058] [Fig.8] is a perspective view, illustrating a mixture injection module gaseous equipment used in the installation shown in the previous figures.

[0059] [Fig. 9] is a schematic view, similar to [Fig. 2], illustrating the implementation of the installation according to the invention, as well as the changes in direction of the substrate at the inlet and outlet of the chamber.

[0060] [Fig. 10] is a schematic view, similar to [Fig. 2], illustrating another possible geometry, in the shape of an S, of the installation according to the invention.

[0061] [Fig. 11] is a schematic view, similar to [Fig. 2], illustrating another possible geometry, in the shape of an L, of the installation according to the invention.

[0062] [Fig. 12] is a schematic view, similar to [Fig. 2], illustrating another possible geometry, in the shape of an inverted L, of the installation according to the invention.

[0063] [Fig.

[13] is a schematic view, analogous to [Fig.2], illustrating another possible geometry, in the shape of an I,of the installation according to the invention.

[0064] [Fig. 14] is a graph on which are plotted different curves illustrating the variations of the temperature of the substrate, as a function of the distance separating the substrate from the surface of the facing walls, for different temperatures of these walls.

[0065] The following numerical references are used in this description:

[0066] I Manufacturing assembly

[0067] 1 Installation according to the invention 5 Processing chamber

[0068] 6 Injection modules 7 Heating modules

[0069] 8 Corner bearing 10 Lower zone

[0070] 11 Front edge of 10 12 Base of 1 (lower wall of 10)

[0071] 14 Lower corridor 15, 16 Plate layers

[0072] 20 Upper zone 21 Front edge of 20

[0073] 22 Roof of 1 (upper wall of 20) 24 Upper corridor

[0074] 25, 26 Plate layers

[0075] 30 Processing zone (intermediate) 31 Bottom of 1 (rear wall of 30)

[0076] 35, 36 Additional layers 37,38 Spaces

[0077] 40 Main frame 41, 46 Recess

[0078] 42, 47 Shoulders delimited by 41, 46 45 Insert

[0079] 50, 51 Front wall of 5 52, 53 Side wall of 5

[0080] 54, 55 Lower and upper walls of 5 60 Body of 6

[0081] 61 Thermal insulation cladding 62 Edge of 60

[0082] 63 Injection channel in 60 64 Injection nozzle

[0083] 65, 66 Heat transfer fluid circulation channels

[0084] 80, 81 Angles of 8 82 Path for substrate passage

[0085] 83, 84 Orifices in 81 86 Housing

[0086] 87 Means Suction inlet

[0087] 200 Enclosure wall 202 Access door of 200

[0088] 300 Gaseous compound supply unit 302 Pipe opening into 300 ,

[0089] 400 Gaseous compound outlet unit 402 Conduit opening into 400

[0090] 500 Heat transfer fluid reservoir 502, 504 Pipe

[0091] 600 Substrate scrolling means 700 Control unit Detailed description

[0092] The accompanying figures describe an installation for manufacturing a material comprising carbon nanotubes, which is in accordance with the invention, as well as a manufacturing assembly comprising this installation. With reference to [Fig. 1], this manufacturing assembly, designated by reference numeral I, essentially comprises:

[0093] - the manufacturing installation according to the invention, designated as a whole by reference 1

[0094] - an enclosure wall 200, which is equipped with an access door 202

[0095] - a unit 300 allowing the supply of gaseous compounds, in the direction of installation 1;

[0096] - a unit 400 allowing the exit of gaseous compounds, outside of this installation 1;

[0097] - a reservoir 500 containing a heat transfer fluid;

[0098] - means 600 and 602 allowing the scrolling of a SUB substrate, intended to be processed within facility 1; and

[0099] - a 700 control unit.

[0100] With reference now in particular to [Fig. 2], the installation 1 generally has a C-shape when viewed from the side. Thus, with reference to the direction of substrate flow, a lower zone 10, an upper zone 20, and a treatment or intermediate zone 30 can be distinguished. By convention, these are denoted:

[0101] - 11 and 21 the front edges of the installation, which correspond to the front edges of the zones 10 and 20,

[0102] - 12 the base of the installation, which corresponds to the lower wall of the upstream zone 10,

[0103] - 22 the roof of the installation, which corresponds to the upper wall of the downstream zone 20,

[0104] - 31 the bottom of the installation, which corresponds to the rear wall of the treatment area 30.

[0105] According to an advantageous feature of the invention, the installation 1 comprises a main frame 40, located at the front, and an insert 45 located at the rear. Advantageously, the frame 40 and the insert 45 are removably fixed to each other. For this purpose, any suitable type of fastening is provided, in particular by locking with a latch. Furthermore, this fastening is ensured in a sealed manner, so as to prevent any entry of ambient air towards the treatment chamber described below. To ensure this sealing, any suitable means may be provided, in particular the use of high-temperature resistant seals, by examples made of vermiculite. In [Fig.2] the frame and the insert are mutually assembled, whereas in [Fig.3] they are separated from each other.

[0106] This frame and insert are hollowed out by respective recesses 41 and 46, which extend over the entire height of the processing area 30, but only over a portion of its width. With reference to [Fig. 5], the shoulders delimited by these recesses are denoted 42 and 47 in the horizontal direction. The respective depths of the above recesses, which are typically equal, are also denoted e41 and e46. These recesses 41 and 46 define a processing chamber 5, along which the substrate is intended to move. This processing chamber is symmetrical with respect to a vertical axis Z5, visible in [Fig. 4].

[0107] In accordance with an advantageous feature of the invention, the installation is equipped with a plurality of injection modules 6, the structure of which will be detailed below. Each of these modules is capable of injecting, into the internal volume of the treatment chamber 5, a so-called active gas mixture of any suitable type, the nature of which will be detailed below. Furthermore, the installation is also equipped with a plurality of heating modules 7, enabling the internal volume of the treatment chamber to be heated in order to enhance the intended reaction. These heating modules, which are of a conventional type, are not illustrated in detail. Each module typically comprises a heating element, which can be heated by means of a resistor. This heating element is associated, for example, with a temperature probe, of the thermocouple or similar type.

[0108] As shown in particular in [Fig. 6], the injection modules 6 and the heating modules 7 are located on opposite front walls of the treatment chamber. On each front wall, the different modules are arranged alternately. Thus, on both the front walls 50 and 51, there is an alternating succession of injection modules and heating modules. In [Fig. 6], injection modules 6a to 6m and heating modules 7a to 7n are shown on wall 50, and injection modules 6'a to 6'm and heating modules 7'a to 7'n are shown on the opposite wall 51.

[0109] Typically, the number n of heating modules 7, present at each wall, is between 6 and 30. Preferably, these different modules are staggered over at least a major part of the height h5 of the treatment chamber 5. In other words, opposite a given injection module present on the first wall 50, for example that 6c, there is a heating module 7'd on the opposite wall 51. Moreover, opposite a given heating module present on the first wall 50, for example that 7c, there is an injection module 6'c on the opposite wall 51.

[0110] Advantageously, the modules are not staggered at the upper and lower ends of chamber 5, respectively. As shown in [Fig. 6], the lower heating modules, 7a and 7'a, are arranged opposite each other, as are the upper heating modules 7n and 7'n. Furthermore, the lower injection modules 6a and 6'a are arranged opposite each other, while being positioned immediately above the heating modules 7a and 7'a. Similarly, the upper injection modules 6m and 6'm are arranged opposite each other, while being positioned immediately below the heating modules 7n and 7'n.

[0111] According to an advantageous feature of the invention, the treatment chamber is symmetrical about a median horizontal axis, denoted XI in [Fig. 6]. This allows for so-called reversible use of this chamber, namely that the substrate can be treated by flowing not only from bottom to top, but also from top to bottom. In the case of bottom-to-top flow, the substrate is first heated by modules 7a and 7'a, before receiving the gas via injection modules 6a and 6'a. Similarly, in the case of top-to-bottom flow, the substrate is first heated by modules 7n and 7'n, before receiving the gas via injection modules 6m and 6'm. In other words, regardless of the direction of substrate flow, it is first heated before receiving the active gas.

[0112] We will now describe, particularly with reference to [Fig. 8], an injection module 6, it being understood that all modules have an identical structure. The module 6 comprises, first of all, a parallelepiped-shaped body 60, elongated in shape. This body is surrounded by a casing 61, shown schematically, which can be of any type known per se. This casing is, for example, formed by a stack of plates. It has an overall C-shape, so that it does not cover one 62 of the edges of the body 60, which edge is called the injection edge. This casing 61 forms a means of thermal insulation, allowing the injection module to be isolated from adjacent heating modules, thus maintaining the injection module at the appropriate temperature.

[0113] The body 60 is hollowed out with various longitudinal channels, namely, firstly, an injection channel 63. This channel 63, which is located adjacent to the edge 62, communicates with a plurality of injection nozzles 64, each of which opens onto the edge 62. There are also two channels 65 and 66, opposite the injection edge, which are intended for the circulation of a heat transfer fluid. The attachment of each injection module 6 to the wall, respectively 50 belonging to the frame 40 and 51 belonging to the insert 45, is achieved by any suitable means, as illustrated in [Fig. 7].

[0114] With reference to [Fig. 9], d6 denotes the distance, or lack thereof, between two injection modules 6b and 6c belonging to the same front wall of chamber 5. This distance is measured, along the vertical axis, between the outlets of the injection nozzles 64 shown in [Fig. 8]. Advantageously, this distance is between 30 mm and 200 mm, being in particular close to 120 mm. Advantageously, the distances between adjacent injection modules, provided on the same front wall of the treatment chamber, are identical. It should be noted that, given that the lower modules 6a, 6'a and the upper modules 6m, 6'm are respectively placed face-to-face, the distance separating each of these modules from the adjacent module is, however, different.

[0115] With particular reference to Figures 1 and 7, we will now describe the means for the flow of both the gas mixture and the heat transfer fluid within each module. As these figures show, a pipe 302, which opens into the gaseous compound supply unit 300, extends in the vicinity of the injection modules 6. This pipe 302 communicates with fittings (not shown), each of which is associated with a respective injection module, so as to admit the gaseous compound into the injection channel 63 of [Fig. 8]. At its end opposite the injection fitting (not shown), the channel 63 opens into an additional discharge fitting (also not shown). The various discharge fittings communicate with a pipe 402, visible in [Fig. 1], which opens into the discharge unit 400.

[0116] Furthermore, as shown schematically in [Fig. 1] and more precisely in [Fig. 7], two pipes 502 and 504 extend parallel to pipe 302 above. These pipes connect the heat transfer fluid reservoir 500 with a plurality of fittings, which are not shown. One of these fittings allows the heat transfer fluid to be delivered into channel 65, while the other allows this fluid to be discharged from channel 66.

[0117] The lower zone 10 and upper zone 20, respectively upstream and downstream in the case described below of a substrate moving from bottom to top in the treatment chamber, are each excavated by a substantially horizontal channel 14 and 24. The lower channel 14 extends from the front edge 11, at which point it delimits the inlet E' of the installation 1, to the inlet E of the treatment chamber 5 (see Figures 2, 3 and 6). Furthermore, the outlet S of this treatment chamber itself opens into the downstream channel 24, which extends to the other front edge 21 (see Figures 2 and 3), at which point it delimits the outlet S' of the installation 1.

[0118] Note, with reference in particular to the cross-sections in Figures 4 and 5:

[0119] - 50 and 51 the opposite front walls of chamber 5, which correspond respectively at the bottom of each recess 41 46

[0120] - 52 and 53 the opposite side walls of chamber 5

[0121] - 54 and 55 the lower and upper walls respectively of this chamber.

[0122] Furthermore, it should be noted, again with reference to Figures 4 and 5:

[0123] -e5 the depth of the chamber, namely the smallest distance between the walls frontal 50, 51. This depth is equal to the sum between the depths e41 and e46, defined above.

[0124] -15 the width of the chamber, namely the smallest distance between the side walls 52, 53; and

[0125] -h5 the height of the chamber (see [Fig.2]), namely the difference between the altitude ZS of the outlet S and the altitude ZE of the inlet of the treatment chamber 5. In the case of a substrate circulating from top to bottom, the outlet is located below the inlet so that this difference in altitudes is negative: in this case, we consider the absolute value of this difference.

[0126] The installation 1 according to the invention is further equipped with means for thermally insulating the treatment chamber from the outside. To this end, layers of radiant plates are provided, the nature of which is analogous to that of the stacks 61. Referring to [Fig. 6], there are layers 15 and 16, extending respectively above and below the corridor 14. Additional layers 35 and 36 are provided, respectively on the front face of the main frame 40 and on the rear face of the insert 45 (see [Fig. 7]). Finally, other layers 25 and 26, analogous to those 15 and 16, are positioned below and above the downstream upper corridor 24.

[0127] The installation also includes two corner bearings 8 and 8', located respectively at the junction between the treatment chamber 5 and the downstream corridor, and at the junction between the upstream corridor and this treatment chamber. The upper corner bearing 8 will now be briefly described with reference to [Fig. 9], it being understood that the other bearing 8' has a similar structure. In [Fig. 9], the mechanical elements of bearing 8', which are similar to those of bearing 8, are assigned the same numbers followed by the reference numeral "'". [Fig. 9] is primarily intended to illustrate the displacement of the substrate, as well as the flow of the various gases. Consequently, some of the mechanical elements already described above, in particular those visible in [Fig. 6], are not shown here.

[0128] This corner bearing 8 is formed by two angle brackets 80 and 81, in the shape of concentric arcs. These angle brackets define a curved path 82, forming an overall quarter circle, allowing the passage of the substrate SUB. The facing surfaces of the angle brackets are pierced with orifices 83, allowing the diffusion of a barrier gas of any appropriate type. For this purpose, there are planned pipes not shown, in connection with a gas source also not shown, which open into the aforementioned orifices 83.

[0129] In the vicinity of the outlet S (respectively the inlet E) of the treatment chamber, the opposing walls are pierced with orifices 84 (respectively 84') allowing the diffusion of a neutral gas of any suitable type. As above, pipes (not shown) extend between a gas source and these orifices 84. Finally, between the orifices 83 and 84, the installation includes a double wall defining a housing 86 equipped with suction means 87, schematically illustrated.

[0130] We will now describe, in particular with reference to [Fig. 9], the implementation of the installation 1 according to the invention as presented above. The substrate may be, in particular, a metal sheet or strip, or a carbon fabric. Its thickness may typically be between 15 µm and 200 µm, and its width between 10 mm and 1000 mm or more. The metal constituting the substrate is, for example, pure aluminum or any other grade of aluminum or any suitable aluminum alloy, or stainless steel.

[0131] Typically, the substrate SUB is moved using a roll-to-roll method. Such movement is achieved by means not shown, of any suitable known type. Figure 1 illustrates the movement of the substrate upstream of installation 1 by arrow F'sub, and downstream of the same installation by arrow F”sub.

[0132] According to the main embodiment of the invention, the reaction is carried out on a moving substrate. In other words, the substrate is admitted at the inlet E of the installation, then moves continuously through the treatment chamber 5 while undergoing the desired reaction, and is then discharged at the outlet S. In the illustrated example, the substrate SUB moves from bottom to top within the treatment chamber 5, as indicated by arrow Fsub in [Fig. 9]. As an alternative embodiment not shown, this substrate can be provided to move from top to bottom within the treatment chamber, therefore in the opposite direction to that indicated by arrow Fsub. However, the upward direction of movement is preferred.

[0133] As a subsidiary variant, the substrate may be admitted to the inlet of the installation and then come to a stop at a precise location. Once it is stationary, it is subjected to the reaction, and once this reaction is complete, the substrate is set in motion again to be discharged through the outlet of the installation. This main variant may be combined with this subsidiary variant. Modulation of the conveying speed may also be provided.

[0134] After being admitted at the inlet E, the substrate progresses along the downstream corridor 14 in which it is brought to a temperature suitable for treatment desired. For example, in the case of an aluminum substrate, it is preferable that this temperature be below the melting point of the metal, approximately 650 °C. To this end, the walls of this corridor 14 are equipped with heating devices (not shown in the figures).

[0135] As the substrate progresses in the channel 14, it carries with it on both sides a flow of ambient air, represented by the arrows AIR. This flow of ambient air opposes a flow of barrier gas, represented by the arrows Bl, which prevents any significant entry of this ambient air towards the treatment chamber 5. This barrier gas performs an additional function, namely that it improves the sliding of the substrate relative to the walls opposite the corners 80' and 81'.

[0136] This substrate is then subjected to the actual treatment in the reaction chamber 5. The reactive gases depend on the nature of the deposition or surface modification sought. For depositing carbon nanotubes or nanofibers, the reactive gases may include, in addition to the carbon source gas, a catalyst precursor. The catalyst precursor may advantageously be ferrocene; it decomposes into nanometer-sized iron particles, which act as a catalyst for the formation of carbon nanotubes from the carbon source gas. The carbon source gas may be C2H2. The injection of reactive gases is carried out as follows. Since the preferred catalyst precursor (in this case, ferrocene) is a rather poorly soluble solid, a sufficient concentration of catalyst precursor will not be obtained in solution to allow its evaporation into the carbon source carrier gas before introduction.It is dissolved in toluene and injected as an aerosol in such a way that, before coming into contact with the substrate, these droplets evaporate completely. The gaseous phase in contact with the substrate is therefore homogeneous.

[0137] An alternative technique is the prior deposition of the catalyst (in this case, a thin layer of iron or another metal acting as a catalyst for the deposition of VACNTs) onto the substrate surface in a separate process step; in this case, the "carbon source" gas can be introduced other than by aerosol (i.e., in a homogeneous gaseous phase). This process can be advantageous for VACNTs of relatively small height, for example, between approximately 10 pm and approximately 150 pm.

[0138] The injection of reactive gases, by modules 6 and 6', is schematically represented by the respective arrows F6 and F6' on [Fig.9]. This injection is carried out horizontally, i.e. perpendicular to the vertical direction of the substrate's movement.

[0139] Furthermore, the various heating modules 7 and 7' are activated in order to maintain an appropriate temperature in chamber 5 during the operation of the reaction itself. A suitable temperature range is typically between 400 °C and 900 °C. In practice, one or more temperature sensors, not shown in chamber 5, are used. The control means 700 then act on the heating modules, depending on whether the measured temperature value is lower or higher than a predefined setpoint.

[0140] According to the invention, the heating is implemented within spaces 37 and 38, each of which separates a front wall 50 and 51 from a respective face SUB1 and SUB2 of the substrate SUB. These spaces 37 and 38 are said to be free, meaning that they are not occupied by any intervening mechanical element; in other words, each front wall 50 and 51 is located directly opposite a respective face of the substrate, in the absence of any such intervening mechanical element. Advantageously, each dimension d1SUB and d2SUB, namely the smallest distance along a horizontal axis between each face SUB1 SUB2 and the opposite front wall 50, 51, is between approximately 1 mm and approximately 10 mm, preferably between approximately 1.5 mm and approximately 5 mm.

[0141] In [Fig. 9], the various injection modules 6 and 6', the various heating modules 7 and 7', and the front walls 50 and 51 are schematically illustrated. These various elements obviously conform to the more detailed representation shown in [Fig. 6]. Simultaneously, the heat transfer fluid circulates in the body 60 of each injection module. This keeps the walls of the injection nozzles at a sufficiently low temperature to prevent clogging by carbon deposits. Typically, this temperature is between approximately 250 °C and approximately 350 °C. The heat transfer fluid can be an oil with a high heat capacity and sufficient temperature resistance.

[0142] In the vicinity of the outlet S of chamber 5, the substrate being treated carries with it, on both sides, the treatment gas. This gas is retained inside the chamber by the admission of neutral gas through the orifices 84, as indicated by the arrows NI. A gaseous fraction, composed of neutral gas and treatment gas, is drawn in by the suction means 87, as indicated by the arrow ASP in [Fig.9].

[0143] Downstream of the outlet S of the treatment chamber 5, the treated substrate progresses along the inner faces of the angles 80 and 81. Similar to what has been described above, the admission of barrier gas via arrows B2 (see always [Fig. 9]) improves the sliding of the substrate relative to the angles. Downstream of the angles 80 and 81, the substrate then flows into the downstream channel 24. The walls of this channel are equipped with cooling devices, allowing the temperature to be gradually lowered as it moves towards the outlet S' of the installation.

[0144] The invention provides many advantages over the prior art, embodied by the reactor conforming to the teaching of WO 2017 / 187 080. It should be noted first of all that it is to the credit of the applicant, having identified the origin of the disadvantages of this specific prior art.

[0145] More precisely, the applicant realized that, when the substrate circulates horizontally as in WO 2017 / 187 080, the contact between the substrate and the base, which is theoretically perfect, is in practice variable. Indeed, even if the substrate is supported by a flat part, this contact is not uniform because the substrate is thin, deformable, lightweight, and does not have perfect flatness. Furthermore, it is subjected to mechanical stresses, as well as deformations during its passage through the reactor, due to its expansion and contraction under the effect of temperature changes. In other words, there are indeed places where there is effective contact between the substrate and the base, but also other places where these parts are separated from each other.

[0146] The applicant has endeavored to better understand the influence of this distance on the substrate temperature, which is likely to determine the uniformity of the properties. It should be noted that the more homogeneous the substrate temperature, the more uniform the final properties of the VACNTs.

[0147] Figure 14 illustrates the variations in the substrate temperature Tsub as a function of the distance d'sub separating the substrate from the facing surface, namely the base in the case of the reactor conforming to WO 2017 / 187 080. In this Figure 14, the temperature Tsub increases from 540°C for a zero ordinate, with a difference of 10° between two horizontal dashed lines, while the distance d'sub increases from 0 for a zero abscissa with a difference of one millimeter between two vertical dashed lines. In this Figure 14, an additional parameter has been introduced, namely the temperature of the wall facing the substrate but opposite the base, i.e., the perforated plates in this reactor.

[0148] This allows access to four curves, referenced Cl to C4, for different TPI to TP4 wall temperatures, belonging to the perforated plates mentioned above. It can be seen that, for the TPI temperature of 460 °C, which we want to avoid exceeding to prevent any unwanted reaction in the injectors, the substrate temperature changes significantly as a function of the sub-distance. More precisely, in a first RI region, the temperature decreases rapidly from the point with zero abscissa corresponding to perfect contact, down to a first threshold point close to 1.5 millimeters. Then, as the distance increases between this first threshold and a second threshold slightly less than 3 millimeters, the temperature decreases less significantly in a second region marked R2. Finally, beyond the second threshold, in a region marked R3, the substrate temperature no longer varies significantly.

[0149] For curve C4, with a perforated plate temperature of 600°C, the temperature is essentially invariant with respect to the sub-distance. For the intermediate curves C2 and C3, with respective temperatures of 520°C and 550°C, there are variations depending on the regions RI to R3, which are, however, less significant than in the case of curve Cl.

[0150] As can be seen from the above, the temperature differences between areas of the substrate in contact with the support and other areas of the same substrate distant from the support can reach several tens of degrees. These temperature differences can also affect areas of the substrate that are only a few centimeters apart. To achieve temperature uniformity in the horizontal configuration described in WO 2017 / 187 080, homogeneous contact could be ensured at the interface between the substrate and its support, over the entire extent of the latter. This could be achieved using a mechanical system forcing the substrate to be pressed against its support, such as a magnetic or pneumatic chuck. However, such a solution would be very difficult, if not entirely incompatible, with continuous movement of the substrate within the reactor.

[0151] Based on this observation, the inventors chose, as is clear from the present description, to position the substrate vertically. This arrangement allows the substrate to be mechanically held in place by its own weight and the tension applied to it in the median plane of the reactor, without it being in physical contact with any support component. This absence of physical contact is particularly advantageous, since the substrate's thermal equilibrium is achieved solely through heat transfer by radiation and convection. This makes it possible to achieve temperature uniformity at the substrate level, which is practically impossible to obtain when there are point contacts between the substrate and one or more support components.Furthermore, the vertical arrangement of the substrate, according to the invention, represents a technically more realistic solution than that involving a mandrel for plating the substrate onto its support.

[0152] Furthermore, thanks to the vertical positioning of the substrate in the treatment chamber, each surface of the substrate is at a distance from its respective opposite wall. Under these conditions, as shown in [Fig. 14], the invention makes it possible to work in the R3 region regardless of the wall temperature TP. In other words, in this region of the curves, the substrate temperature undergoes little variation, even if the distance between the substrate and the opposite walls is not perfectly constant. This is advantageous with regard to the uniformity of the properties of the final substrate.

[0153] In conclusion, the VACNT deposit on the substrate, obtained in accordance with the installation according to the invention, exhibits a much superior quality, in particular a significantly improved uniformity, compared to the prior art.

[0154] The invention also allows for the simultaneous coating of the two opposite faces of the substrate with the synthesized material. Indeed, these two faces can be placed simultaneously under similar reaction conditions, particularly with regard to temperature, flow rate, and gas concentration. The materials deposited on the two faces are typically identical; however, alternatively, mutually different reaction conditions can be used, allowing different materials to be deposited on the opposite faces.

[0155] Furthermore, the use of cooling means, in particular the circulation of a heat transfer fluid, prevents the injection nozzles from clogging due to unwanted carbon deposits. Consequently, the active gas mixture passing through the injection means does not exceed a threshold value beyond which such a risk of carbon deposition exists, while the temperature inside the treatment chamber is well above this threshold value.

[0156] The alternation between, on the one hand, zones for injecting the gaseous reaction mixture and, on the other hand, zones for radiant heating constitutes a preferred feature of the invention. To this end, these zones are stabilized at different temperatures, respectively below and above the activation temperature threshold of the chemical reactions occurring during the synthesis (in this case, approximately 450°C for carbon nanotubes). This alternation results in a temperature profile of the substrate that varies depending on whether the substrate is located near an injection zone or a heating zone.

[0157] In order to minimize these variations and, advantageously, to allow synthesis on both sides of the substrate, a staggered arrangement is particularly preferred. As can be seen in particular from Figures 6 and 9, an injection module located on one wall of the treatment chamber is positioned opposite a heating module located on the opposite wall. In this way, temperature variations are minimized. In essence, in this particularly preferred configuration, the invention provides, on each wall of the treatment chamber, an alternation between so-called cold zones, corresponding to the injection modules, and so-called hot zones, corresponding to the heating modules.

[0158] In the example described above, the installation according to the invention has a C-shape, namely that the intermediate zone 20 is vertical, while not only the lower zone 10 but also the upper zone 30 extend horizontally, directly above each other. This C-shaped geometry minimizes the overall height of the installation, thereby facilitating its operation. As can be seen from the above, it is therefore necessary to provide a so-called turning zone, corresponding to the presence of the angles 80 and 81, which allows the substrate to move from a vertical arrangement to a horizontal arrangement.

[0159] To this end, the presence of orifices 83 and 83', ensuring the diffusion of barrier gas, is particularly advantageous. Indeed, this gas then performs, in addition to its initial barrier function, an additional function known as a gas cushion. More precisely, this prevents any contact between the substrate and a mechanical part, which could create a sudden temperature difference, while facilitating the movement of this substrate.

[0160] Figures 10 to 13 illustrate different variants with regard to the architecture of the installation according to the invention. In these figures 10 to 13, the mechanical elements, similar to those in the preceding figures, are assigned the same reference numbers augmented respectively by the numbers 1000, 2000, 3000 and 4000.

[0161] In [Fig. 10], we find the same geometry as in the example above, except that the upper zone 1030 extends in the opposite direction from the lower zone 1010. In [Fig. 11], we find the same geometry as in [Fig. 10] except that the upper zone 2030 extends vertically in line with the intermediate zone 2020. In [Fig. 12], we find a geometry symmetrical to that of [Fig. 11] with respect to a median horizontal axis, namely that the lower zone 3010 is vertical while the upper zone 3030 is horizontal.

[0162] Finally, in [Fig. 13], we find an overall rectilinear geometry, namely that the successively lower zone 4010, intermediate zone 4020, and upper zone 4030 extend vertically in line with one another. This completely vertical configuration proves simpler since it eliminates any curve imposed on the substrate.

[0163] As an alternative not shown, such a bend could be relocated to an area of ​​the installation where the film is either not yet heated or has already cooled. In this case, the overall installation can be simplified mechanically, since this allows the substrate to be brought into contact with mechanical parts, in particular rollers.

[0164] In the example described and illustrated, the substrate flows from bottom to top in the treatment chamber. Consequently, the lower zone 10 and upper zone 20 are located upstream and downstream of the treatment chamber, respectively. As an alternative (not shown), the substrate may flow from top to bottom. In this case, the lower zone 10 and upper zone 20 are located upstream and downstream of the treatment chamber, respectively. Furthermore, the locations, referenced in these figures as inputs E and E', become outputs S and S'. Symmetrically The referenced output locations S and S' become inputs E and E', in the case of a substrate flowing from top to bottom.

[0165] The installation according to the invention can be used in various ways. The deposition of VACNTs has been described in detail above. The installation can also be used to deposit the growth catalyst for carbon nanotubes or nanofibers onto a substrate; this deposition can be followed, in a second step, by the decomposition of a gaseous carbon precursor to grow carbon nanotubes or nanofibers on this substrate. The installation can also be used to modify a nanostructured carbon deposit (for example, VACNTs prepared in this same installation, with or without a continuous supply of a catalyst precursor, or VACNTs prepared in a different reactor), this modification being, for example, an oxidation of their surface. Materials, possibly nanostructured, other than carbon can also be deposited.

Claims

Demands

1. An installation (1) for the deposition, growth or modification of a material on a substrate (SUB), in particular of a composite material comprising nanotubes or nanofibers fixed to a substrate (SUB), such as carbon nanotubes or nanofibers, this installation comprising at least one processing chamber (5), or reaction chamber, which forms an internal volume for the processing of said substrate (SUB) which is in the form of a sheet or strip, this processing chamber comprising an inlet (E) and an outlet (S), an inlet (E') and an outlet (S') of the installation, this inlet and outlet of the installation communicating respectively with the inlet (E) and outlet (S) of said processing chamber, means (6) for injecting an active gas mixture into the processing volume of the substrate, this gas mixture being intended for the deposition, growth or modification of said material, heating means (7),suitable for heating the internal volume of the treatment chamber, said installation being characterized in that the treatment chamber (5) extends in a generally vertical manner, the inlet and outlet of the treatment chamber being located at different altitudes (ZE, ZS), free spaces (37, 38) are provided, in operation, on either side of the path of the substrate, the free spaces separating in operation each the respective faces of the substrate with respect to front walls (50, 51) facing the chamber, said front walls bordering the internal volume of treatment of the substrate, both the injection means and the heating means being provided on said front walls (50, 51), and the injection means are equipped with cooling means (65, 66), which are suitable for cooling these injection means.

2. Installation according to the preceding claim, in which the front walls are arranged opposite each other without the interposition of a substrate support base, so as to delimit said free spaces (37,38) in service.

3. Installation according to claim 1 or 2, further comprising thermal insulation means (61), suitable for insulating the injection means from the heating means.

4. An installation according to any one of the preceding claims, wherein the injection means comprise several injection modules, each injection module comprising at least one circulation channel (65, 66) allowing the circulation of the heat transfer fluid, and at least one injection channel (63) allowing the transport of the gaseous mixture, this injection channel opening onto at least one injection nozzle (63).

5. Installation according to claim 4, wherein each injection module comprises a body (60), in which the circulation channel and the injection channel are provided, as well as a thermal insulation casing (61) extending to the periphery of at least a part of this body.

6. An installation according to any one of the preceding claims, wherein the heating means comprise several heating modules, while the injection means comprise several injection modules, the heating modules and the injection modules being arranged alternately on at least the majority of the same front wall.

7. Installation according to claim 6 in which, on at least the majority of each front wall, the heating modules and the injection modules are placed in a staggered pattern.

8. An installation according to any one of the preceding claims, comprising a lower zone (10) bounded by said inlet (E') of the installation and said inlet (E) of the treatment chamber, respectively the outlet of the installation and the outlet of the treatment chamber, and an upper zone (30) bounded by said outlet (S') of the installation and said outlet (S) of the treatment chamber, respectively the inlet of the installation and the inlet of the treatment chamber, said lower zone and upper zone being arranged on either side of an intermediate zone (20) comprising the treatment chamber (5), the installation (1) having, in side view, a C-shape or an S-shape, or an L shape, or an inverted L shape, or even an I shape.

9. A method of implementing an installation according to any one of the preceding claims, wherein: - the substrate is moved through said chamber in said vertical direction, providing said free spaces between each face of the substrate and a respective front wall facing the chamber - the internal volume of the treatment chamber is heated, by means of the heating means - active gas mixture is injected into the internal volume of the chamber, by means of the injection means, while the injection means are cooled, by means of the heat transfer fluid circulation means, so as to form carbon nanotubes preferentially on the surface of this substrate.

10. Assembly for the deposition, growth or modification of a material on a substrate, in particular of a composite material, in particular of a composite material comprising nanotubes or nanofibers fixed on a substrate (SUB), such as carbon nanotubes or nanofibers, said assembly comprising - an installation according to any one of claims 1 to 8, - means for moving the substrate intended to form said material along the installation, - means for supplying a gas mixture, suitable for supplying the injection means with a gas mixture, - means for admitting a heat transfer fluid, suitable for admitting the heat transfer fluid into the circulation means equipping the injection means.

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