Method for manufacturing brake bands for brake discs, method for manufacturing brake discs, brake discs and brake bands for brake discs

Abstract

A method for manufacturing a brake band (2) for a brake disc (1) for a disc brake includes the steps of: a) providing a mould (10) having an internal cavity (11), said mould consisting of a first part (11a) of a shape corresponding to the brake band (2) to be produced; b) preparing a band preform (20) consisting of a central preform (200), an upper outer preform (201) and a lower outer preform (202), the central preform (200) being made of a porous ceramic material consisting of silicon carbide (SiC), the upper outer preform (201) and the lower outer preform (202) being made of a porous ceramic material consisting of silicon carbide (SiC) and infiltrated with silicon (SiC+Si), carbon barrier layers (201a, 200a, 200b, 202a) consisting of carbon being interposed between the upper outer preform (201) and the central preform (200) and between the lower outer preform (202) and the central preform (200), the preforms (200, 201, 202) having the shape of the brake band (2) to be manufactured; c) placing the band preform (20) in a mold at the first portion (11a) of the internal cavity (11); and d) injecting a liquid or semi-solid aluminum alloy into the entire inner cavity (11) of said mould (11) so as to infiltrate said central preform (200) of said band preform (20) made of porous ceramic material with said aluminum alloy, in order to obtain in the first part (11a) an aluminum metal matrix composite reinforced by said central preform (200) defining the brake band (2) to be manufactured. At least by the above-mentioned method, a brake band and a brake disc are manufactured.

Description

Technical Field

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[0003]

[0001] The present invention relates to a method for manufacturing a brake band of a brake disc, a method for manufacturing a brake disc, a brake disc, and a brake band of a brake disc manufactured by the above method.

Background Art

[0002] The brake disc of a vehicle's disc brake system consists of an annular structure, i.e., a brake band, and a central fixing element known as a bell. The disc is attached to a rotating part of the vehicle suspension, such as a hub, by this fixing element. The brake band has opposing brake surfaces suitable for cooperating with friction elements (brake pads), and is accommodated in at least one gripper body that is arranged across the brake band and integrated with a non-rotating part of the vehicle suspension. The controlled interaction between the opposing brake pads and the opposing brake surfaces of the brake band causes a braking action by friction, decelerating or stopping the vehicle.

[0003] Generally, brake discs are made of gray cast iron or steel. In fact, these materials can obtain relatively low cost and good brake performance (especially wear suppression). Discs made of carbon or carbon ceramic materials provide much higher performance but are much more costly.

[0004] As an alternative to gray cast iron or steel discs, aluminum discs have been proposed to reduce the weight of the disc. The aluminum disc is provided with a protective coating. The protective coating, on the one hand, reduces the wear of the disc and ensures the same performance as a cast iron disc, and on the other hand, protects the aluminum base from the temperature generated during braking, which far exceeds the softening temperature of aluminum (200 - 400°C).

[0005] Currently available protective coatings applied to aluminum discs, while providing wear resistance, often cause peeling, resulting in the coating detaching from the disc. This complicates the disc manufacturing process. In effect, the disc must undergo surface finishing and be prepared for connection to the bell.

[0006] As is clear from the above, aluminum or aluminum alloy discs with protective coatings cannot currently completely replace steel or gray cast iron discs.

[0007] However, because aluminum has a lower density than both steel and gray cast iron, there is considerable interest in aluminum among those in the brake system industry as an excellent potential substitute for both steel and gray cast iron.

[0008] Therefore, this field requires aluminum-based brake discs that, on the one hand, allow us to utilize aluminum's unique operational characteristics (primarily due to its low density), while on the other hand, provide mechanical strength and wear characteristics at least comparable to those of steel or gray cast iron discs. Furthermore, these discs must be manufactured using the simplest and most economical manufacturing process possible.

[0009] WO2019 / 123222A1 describes a method for manufacturing aluminum discs using porous ceramic preforms impregnated with molten aluminum (in a liquid or semi-solid state). Unfortunately, discs obtained by this method result in direct contact between the brake pad and the aluminum-based metal matrix, which can lead to localized degradation of the disc where the aluminum is overheated to its melting point due to friction. Disclosure of the invention

[0010] Therefore, there is a strong need in the industry for aluminum-based brake discs that do not degrade locally, that allow the use of aluminum's special operational characteristics (primarily its low density), and that provide mechanical strength and wear characteristics comparable to steel or gray cast iron discs, while simultaneously being manufactured using the simplest and most economical manufacturing process possible.

[0011] Along with the above requirements, there is also a need for brake discs that have higher corrosion resistance than cast iron or steel discs and emit fewer contaminating metal particles.

[0012] The aforementioned requirements are satisfied by the method for manufacturing a brake band for a brake disc, a method for manufacturing a brake disc, a brake disc for a disc brake, and a brake band according to the attached independent claims.

[0013] The method for manufacturing a brake band according to this invention consists of the following steps. a) A step of preparing a mold having an inner cavity that constitutes a first part of the shape corresponding to the brake band to be manufactured; b) A step of preparing a band preform comprising a central preform, an upper outer preform, and a lower outer preform, wherein the central preform is made of a porous ceramic material made of silicon carbide (SiC), and the upper outer preform and lower outer preform are made of a porous ceramic material made of silicon carbide impregnated with silicon (SiC+Si); a step of interposing a carbon barrier layer between the upper outer preform and the central preform, and between the lower outer preform and the central preform; c) The step of placing the band preform in the mold in the first part of the internal cavity; d) A step of injecting a liquid or semi-solid aluminum alloy into the entire inner cavity of the mold so as to impregnate the central preform of the band preform made of porous ceramic material with the aluminum alloy, to obtain a first portion of an aluminum metal matrix composite reinforced by the central preform defining the brake band to be manufactured, and filling a second portion of the aluminum alloy so as to obtain an aluminum composite fixing body integrally connected to the brake band made of the metal matrix composite defining the bell of the brake disc to be manufactured.

[0014] Advantageously, to manufacture a band preform, this method includes the following steps: a1) A step of preparing a central preform, an upper outer preform, and a lower outer preform, respectively, made of a porous ceramic material made of silicon carbide (SiC) having the shape of a brake band (2) of a brake disc (1) to be manufactured; a2) A process of impregnating the upper outer preform and the lower outer preform with silicon (Si) a3) A step of depositing particulate material made of carbon onto a central preform to obtain at least one carbon barrier layer made of carbon.

[0015] As an alternative to step a3), the present method advantageously provides step a4), which involves depositing particulate material made of carbon to obtain at least one carbon barrier layer made of carbon on the upper outer preform and the lower outer preform.

[0016] Furthermore, as an alternative to steps a3) and a4), the method advantageously comprises step A5), in which particulate material made of carbon is deposited on the central preform and the upper outer preform and / or the lower outer preform to obtain at least one carbon barrier layer (C) made of carbon on the central preform and the upper outer preform and / or the lower outer preform.

[0017] More preferably, the present method provides a step a6) of bonding a central preform, an upper outer preform, and a lower outer preform together by interposing silicon in each carbon barrier layer and heating the preform until a bond is formed between them in the carbon barrier layers, thereby obtaining a band preform.

[0018] Advantageously, the bonding between the central preform and the upper and lower outer preforms is formed by the fusion of silicon interposed in each carbon barrier layer, which reacts with the carbon deposited in the barrier to form silicon carbide (SiC). The silicon carbide (SiC) thus formed functions as a bonding surface between the preforms.

[0019] According to one embodiment, in step a2), the upper outer preform and the lower outer preform are placed in a crucible coated with a release layer, for example, boron nitride (BN), a predetermined amount of silicon (Si) powder is added to the crucible as a function of the size of the preforms, and the upper outer preform and the lower outer preform are heated to obtain fusion of the added silicon.

[0020] Preferably, the upper outer preform and the lower outer preform are heated at atmospheric pressure in an inert atmosphere, preferably in an argon atmosphere, to a temperature exceeding the melting point of Si (1414°C).

[0021] Advantageously, in step a3), a4), or a5), the step of depositing particulate material made of carbon to obtain at least one carbon barrier layer made of carbon (C) is obtained by chemical vapor deposition.

[0022] Preferably, gaseous methane is used as the carbon precursor for chemical deposition, the temperature is 1100°C to 1300°C, and the pressure is 10 to 50 millibars.

[0023] Advantageously, the contribution of the mixed gas during the chemical vapor deposition process is as follows: - 0.4 to 3 standard liters per minute (slm) of methane; - 0.2 to 5 standard liters per minute (slm) of hydrogen; - 0 to 4 standard liters per minute (slm) of argon; The ratio of methane to hydrogen is between 0.3 and 5.

[0024] According to an alternative embodiment, in step a3) or a4) or a5), the step of depositing a particulate material made of carbon to obtain at least one carbon barrier layer made of carbon (C) is obtained by sputtering or physical vapor deposition (PVD) techniques, or by laser cladding techniques.

[0025] According to an alternative embodiment, in step a3) or a4) or a5), the step of depositing a particulate material made of carbon to obtain at least one carbon barrier layer made of carbon (C) is achieved by an adhesion technique using a graphite-based adhesive.

[0026] Preferably, in step a6), the method provides heating the preform to a temperature of about 1450 °C for a time of about 2 hours while interposing a stoichiometric amount of silicon depending on the size of the carbon surface of the preform. Preferably, the step d) of placing the aluminum alloy in the mold is carried out according to a semi-solid or liquid infiltration technique or a squeeze casting technique.

[0027] Advantageously, the central preform, the lower outer preform, and the upper outer preform are obtained by successively subjecting a mass of granules made of a ceramic material surface-coated with a polymer binding composition to shaping, optionally debinding, and sintering.

[0028] Preferably, sintering is carried out in two separate sintering cycles, the first sintering cycle is carried out at a temperature of 1600 °C or higher, preferably about 1800 °C, and the second sintering cycle is carried out at a temperature in the range of 2000 °C or higher, preferably 2100 °C to 2200 °C, both being carried out in an inert atmosphere.

[0029] More preferably, in step d), the mold closes over the upper and lower outer preforms so that aluminum does not penetrate onto the upper and lower outer preforms during the injection of aluminum into the mold, so that there is no aluminum on the outer braking surface of the brake band. [Overview of the Initiative]

[0030] A method for manufacturing a brake disc consisting of a brake band and a bell according to one embodiment of this invention consists of the following steps. a) A step of preparing a mold having an internal cavity comprising a first portion shaped to correspond to a brake band to be manufactured and a second portion shaped to correspond to the bell of a brake disc to be manufactured, wherein the first and second portions of the internal cavity are in communication with each other; b) A step of preparing a band preform comprising a central preform, an upper outer preform, and a lower outer preform, wherein the central preform is made of a porous ceramic material made of silicon carbide (SiC), and the upper outer preform and lower outer preform are made of a porous ceramic material made of silicon carbide (SiC) impregnated with silicon (SiC+Si); wherein a carbon barrier layer is interposed between the upper outer preform and the central preform, and between the lower outer preform and the central preform, intended to react with silicon (Si) to function as a junction between the upper outer preform and the lower outer preform and the central preform, and furthermore, the preform has the same shape as the brake band of the brake disc to be manufactured; c) The step of placing the band preform into the mold of the first portion of the inner cavity; d) A step of injecting a liquid or semi-solid aluminum alloy into the entire inner cavity of the mold to permeate the aluminum alloy into the central preform of the band preform made of porous ceramic material to obtain an aluminum metal matrix composite reinforced by the central preform, which defines the brake band of the brake disc to be manufactured in a first portion, and filling the second portion with the aluminum alloy to obtain an aluminum alloy fusion which is integrally connected with the brake band made of the metal matrix composite and defines the bell of the brake disc to be manufactured.

[0031] The disc brake according to this invention consists of a brake band and a bell connected to the brake band.

[0032] Preferably, in an advantageous embodiment, the bell is integrally connected to the brake band and is composed of a co-cast product of a composite material metal matrix and an aluminum alloy forming the brake band.

[0033] According to this invention, the brake band is composed of a central band made of an aluminum metal matrix composite reinforced with a ceramic material made of silicon carbide (SiC). This composite is obtained by impregnating a central preform of a porous ceramic material having a shape corresponding to the brake band with an aluminum alloy. The brake band is further composed of an upper band and a lower band. The upper band is joined to the central band along an upper bonding layer. The upper band is made of silicon carbide (SiC) and consists of a porous ceramic material impregnated with silicon (SiC+Si), and covers one side of the central band. The lower band is joined to the central band along a lower bonding layer that is opposite to the upper bonding layer, i.e., positioned opposite. The lower band is made of silicon carbide (SiC) and consists of a porous ceramic material impregnated with silicon (SiC+Si), and covers the central band from the other side, i.e., the side opposite to the upper band.

[0034] Preferably, the aluminum alloy matrix has a structure in which it is homogeneously distributed within the composite. [Brief explanation of the drawing]

[0035] Further features and advantages of the present invention will become more apparent from the following detailed description of its preferred non-limiting embodiments: [Figure 1] Figure 1 is a perspective view of a brake disc according to an embodiment of the present invention; [Figure 2] Figure 2 schematically shows a part of the process of this method, in particular the initial steps for manufacturing a brake band for a brake disc according to an embodiment of the present invention; [Figure 2a] Figure 2a schematically shows the steps of a method for manufacturing a brake band for a brake disc according to a first embodiment of the method of the present invention; [Figure 2b] Figure 2b is a schematic diagram showing the steps of a method for manufacturing a brake band for a brake disc according to a second embodiment of the method of the present invention; [Figure 2c] Figure 2c is a schematic diagram showing the steps of a method for manufacturing a brake band for a brake disc according to a third embodiment of the method of the present invention; [Figure 2d] Figure 2d is a schematic diagram illustrating the steps of a method for manufacturing a brake band for a brake disc according to a fourth embodiment of the method of the present invention, wherein the step of impregnating the upper and lower outer preforms with silicon is performed after the step of mechanically joining the upper and lower preforms with the central preform; [Figure 2e] Figure 2e schematically shows the steps of a method for manufacturing a brake band for a brake disc according to a fifth embodiment of the method of the present invention, wherein the step of impregnating the upper and lower outer preforms with silicon is performed after the step of mechanically joining the upper and lower preforms with the central preform; [Figure 2f]Figure 2f is a schematic diagram showing the steps of a method for manufacturing a brake band for a brake disc according to a sixth embodiment of the method of the present invention, wherein the step of impregnating the upper and lower outer preforms with silicon is performed after the step of mechanically joining the upper and lower preforms with the central preform; [Figure 3] Figure 3 is a perspective view of a band preform according to an embodiment of the present invention; [Figure 4] Figure 4 shows the steps in a method for manufacturing a brake disc according to an embodiment of the present invention, and the steps are sequentially followed from Figure 4 to Figure 7. In particular, Figure 7 shows a cross-section of a rough brake disc made on the diameter plane of the rough brake disc. The rough brake disc is an intermediate product immediately preceding the final brake disc shown in Figure 1, and is obtained by removing unnecessary parts of the rough brake disc through subsequent machining. [Figure 5] Figure 5 shows the steps in the method for manufacturing a brake disc according to an embodiment of the present invention. [Figure 6] Figure 6 shows the steps in a method for manufacturing a brake disc according to an embodiment of the present invention. [Figure 7] Figure 7 shows the steps in a method for manufacturing a brake disc according to an embodiment of the present invention. In particular, Figure 7 shows a cross-section of a rough brake disc made on the diameter plane of the rough brake disc. The rough brake disc is an intermediate product immediately preceding the final brake disc shown in Figure 1, and is obtained by removing unnecessary parts of the rough brake disc through subsequent machining.

[0036] Elements or parts of elements common to the embodiments described below are denoted by the same reference numeral. [Modes for carrying out the invention]

[0037] Referring to the aforementioned figure, reference numeral 1 shows the brake disc according to this invention in its entirety.

[0038] According to a general embodiment of the present invention shown in the attached figures, the brake disc 1 comprises a brake band 2 having two opposing outer brake surfaces 2a and 2b, each brake surface 2a and 2b defining at least partially one of the two main surfaces of the disc.

[0039] The brake disc 1 further includes a bell 3 connected to the brake band 2.

[0040] According to a first aspect of the present invention, the brake band 2 is composed of a central band 200' made of an aluminum-based metal matrix composite material reinforced with a ceramic material made of silicon carbide (SiC).

[0041] The aforementioned composite material falls under the category of composite materials known in this industry as MMC (metal matrix composite).

[0042] By using the MMC composite material made of aluminum for the brake band 2, greater mechanical and chemical-physical properties (referring particularly to density, and therefore lightness) can be obtained with respect to aluminum, and at the same time, functional properties for heavy applications such as those required in a braking system can be added without requiring a protective coating on the braking surface (with respect to simple fusion in aluminum or its alloys).

[0043] Furthermore, the brake band 2 also consists of an upper band 201' which is joined to the central band 200' along the upper bonding layer 22a. The upper band 201' is made of a porous ceramic material consisting of silicon carbide (SiC) impregnated with silicon (SiC+Si). In addition, the upper band 201' covers the central band 200' on one side, so that on that side the central band 200' does not come into contact with the brake pad when the brake disc is mounted to the disc brake.

[0044] Furthermore, the brake band 2 consists of a lower band 202' joined to the central band 200' along a lower bonding layer 22b that is positioned opposite to the upper central layer 201'. The lower band 202' is also made of silicon carbide (SiC) and consists of a porous ceramic material impregnated with silicon (SiC+Si). Furthermore, the lower band 202' covers the central band 200' on the opposite side, i.e., the side opposite to the upper band 201'. In this way, the central band 200' is sandwiched between the upper band 201' and the lower band 202'. In particular, the outer brake surfaces 2a and 2b of the brake band 2 are the outermost surfaces of the lower band 202' and the upper band 201', respectively, which are not joined to the central band 200'.

[0045] Regarding brake bands made solely of aluminum or one of its alloys, the presence of a ceramic reinforcement in the central band 200', along with the upper band 201' and lower band 202, results in higher hardness, higher rigidity, a higher coefficient of friction, and higher wear resistance. These characteristics make this brake band suitable for use with brake discs.

[0046] In this way, it is possible to create brake bands that possess the advantageous properties of aluminum (in particular, refer to its lower density compared to steel and cast iron) while simultaneously avoiding the need for protective coatings on the brake surface and the production and operational constraints and inconveniences.

[0047] The ceramic material from which the reinforcing material is made is silicon carbide.

[0048] As will be discussed later, the MMC composite forming the central band 200' is obtained by impregnating a porous ceramic material preform with an aluminum alloy. Advantageously, the aforementioned ceramic materials containing silicon carbide can withstand the impregnation process with molten metal without altering their chemical and physical structure, and without any macroscopic or microscopic damage. For this reason, they are particularly suitable for the production of the aforementioned composite.

[0049] Preferably, the aluminum alloy is selected from the group consisting of alloys suitable for the fusion process, comprising at least silicon, at least manganese, and at least magnesium.

[0050] An advantageous embodiment provides that the aluminum alloy has a high magnesium (Mg) content, and more preferably a high magnesium and silicon (Si) content.

[0051] Preferably, the magnesium (Mg) content is less than 15%, more preferably less than 10%, but at least 0.2%. This improves mechanical properties and machinability on machine tools, as well as corrosion resistance and the ability to fill complex mold shapes by reducing the surface tension of the alloy in its liquid state. Preferably, the aluminum alloy is AlSi13Mg9Ti alloy.

[0052] Advantageously, the aluminum alloy matrix has a homogeneously distributed structure within the composite material. As will be discussed later, this can be achieved by impregnating an aluminum alloy into a preform made of a porous ceramic material having a homogeneous porosity throughout its entire volume. Through the impregnation process, the aluminum alloy penetrates the porosity of the ceramic material, forming a homogeneous structure.

[0053] According to another aspect of this invention, the brake disc 1 is provided such that the aforementioned bell 3 is integrally connected to the brake band 2, and is made of an aluminum alloy co-cast with a metal matrix of a composite material forming the brake band 2.

[0054] As will be discussed in the following description, in this modification, Bell 3 is obtained using the same aluminum alloy, within the same mold in which the aluminum alloy infiltration of the preform in the ceramic material is carried out. In this way, the molding of the composite material and the fusion of the Bell are performed in the same operating process, and a complete bond between the two materials is achieved.

[0055] By co-casting the bell with the brake band, the manufacturing process can be significantly simplified. In fact, it eliminates the need for both a dedicated production line for manufacturing the bell and an assembly line for attaching the bell to the band.

[0056] The combination of the two essential aspects of the present invention makes it possible to have an aluminum-based brake disc that, on the one hand, can utilize special operational characteristics derived from aluminum (first and foremost, lower density), on the other hand, can have mechanical and wear-resistant characteristics comparable to steel or gray cast iron discs, and at the same time can be manufactured using the simplest and most economical manufacturing process possible.

[0057] According to the embodiment, the brake band 2 according to the present invention can also be connected to a bell 3 that is not eutectic (or is integrally manufactured), but it is clear that the connection is made via a prior art bell-band connecting means (assembly, interlocking, riveting, etc.).

[0058] In other words, once the brake band 2 is manufactured, it is combined with the bell 3 in a known manner for manufacturing a brake disc, and thus suitable for obtaining a brake disc, for example, by a floating compound or interference fit.

[0059] Therefore, it is understood that this description also intends to protect a method for manufacturing a brake disc, including the final step of the method, in which the connection between the brake band 2 and the bell 3 according to the present invention is provided not by a single eutectic piece, but by bell-band connecting means such as assembly, interlocking, riveting, etc.

[0060] For the sake of simplicity, the brake band 2 and the brake disc 1 will be described in relation to their respective manufacturing methods according to this invention. The brake disc 1 is preferably manufactured by the method according to the present invention, which will be described below, but is not necessarily required.

[0061] According to a general embodiment of the method according to the present invention, a method for manufacturing a brake disc 1 comprises a first operating step a) for preparing a mold 10 having an inner cavity 11 including a first portion 11a shaped to correspond to the brake band 2 of the brake disc 1 to be manufactured and a second portion 11b shaped to correspond to the bell 3 of the brake disc 1 to be manufactured.

[0062] The first portion 11a and the second portion 11b of the internal cavity 11 communicate with each other, as shown in Figures 5 and 6 which schematically illustrate an example of a mold usable in the context of the method according to the present invention.

[0063] Advantageously, as shown in Figures 4 and 5, the mold includes one or more inlets 13 for directly injecting aluminum alloy into a second portion of the inner cavity 11 of the mold 10. The inlets 13 extend coaxially with the circumferential development of the second portion 11b, which has a shape corresponding to the bell 3 of the brake disc 1 to be manufactured. Thus, operationally, the injection of aluminum alloy can be performed from the inlet opening 13 and then propagate from the inlet opening 13 to the first portion 11a.

[0064] This method comprises a second operation step b) of preparing a band preform 20 consisting of a central preform 200, an upper outer preform 201, and a lower outer preform 202. The central preform 200 is made of a porous ceramic material made of silicon carbide (SiC). Furthermore, the upper outer preform 201 and the lower outer preform 202 are made of a porous ceramic material made of silicon carbide (SiC) impregnated with silicon (SiC+Si). Carbon barrier layers 201a, 200a, 200b, and 202a made of carbon are interposed between the upper outer preform 201 and the central preform 200, and between the lower outer preform 202 and the central preform 200.

[0065] Advantageously, the carbon barrier layers 201a, 200a, 200b, and 202a made of carbon make the bonding between the preforms 200, 201, and 202 more stable and reliable, and act as auxiliary barrier layers in the process of impregnating the central preform 200 with aluminum, further limiting the possibility of aluminum impregnating the upper outer preform 201 and the lower outer preform 202. The aforementioned preforms 200, 201, and 202 have substantially the same shape as the brake band 2 of the brake disc 1 to be manufactured.

[0066] This method further includes the following additional steps: c) A step of placing the band preform 20 in the mold of the first portion 11a of the internal cavity 11, d) A step of injecting a liquid or semi-solid aluminum alloy into the entire inner cavity 11 of the mold 10.

[0067] The injection of the aluminum alloy is carried out so as to permeate the central preform 200 of the band preform 20, thereby obtaining an aluminum-based metal matrix composite reinforced by the central preform 200 in the first portion 11a, which partially defines the brake band 2 of the brake disc to be manufactured, and by filling the second portion 11b with the aforementioned aluminum alloy, a fusion of aluminum alloy is obtained which is integrally connected with the brake band 2 made of the metal matrix composite and defines the bell 3 of the brake disc 1 to be manufactured.

[0068] According to a general embodiment, a method for manufacturing a brake band 2 for a brake disc 1 consists of a series of steps similar to the steps of a method for manufacturing a brake disc, except that the mold 10 is shaped for manufacturing only the brake band 2 and not for manufacturing the bell 3. As a result, with respect to the steps of the method for manufacturing a brake disc, in step a), the mold does not constitute a second portion 11b that corresponds to the shape of the bell 3 of the brake disc 1 to be manufactured. Furthermore, with respect to the method for manufacturing a brake disc 1, in step d), the infiltration of the aluminum alloy is carried out so as to infiltrate the central preform 200 of the band preform 20 with the aluminum alloy, and in the first portion 11a, an aluminum-based metal matrix composite is obtained that is reinforced by the central preform 200 which partially defines the brake band 2 of the brake disc to be manufactured. When manufacturing only a brake band, it is clear that there is no need to provide an aluminum alloy to fill the second portion 11b, since there is no need to simultaneously manufacture the bell of the brake disc 2 by co-casting. Although a mold for manufacturing a brake band is not shown in the attached figure, how to modify the aforementioned mold 10 so as to be absent from the second part 11b intended for manufacturing a bell can be clearly and obviously derived by those skilled in the art.

[0069] Therefore, in a general embodiment, the method for manufacturing a brake band according to this invention comprises a first operating step a) of preparing a mold 10 having an internal cavity 11 including a first portion 11a corresponding to the shape of the brake band 2 of the brake disc 1 to be manufactured.

[0070] In this case, the mold also includes one or more injection ports 13 for directly injecting the aluminum alloy into the second portion of the inner cavity 11 of the mold 10.

[0071] The method includes a second operating step b) for preparing a band preform 20 consisting of a central preform 200, an upper outer preform 201, and a lower outer preform 202. The central preform 200 is made of a porous ceramic material made of silicon carbide (SiC). Furthermore, the upper outer preform 201 and the lower outer preform 202 are made of a porous ceramic material made of silicon carbide (SiC) impregnated with silicon (SiC+Si). Carbon barrier layers 201a, 200a, 200b, and 202a made of carbon are interposed between the upper outer preform 201 and the central preform 200, and between the lower outer preform 202 and the central preform 200. The preforms 200, 201, and 202 have substantially the same shape as the brake band 2 of the brake disc 1 to be manufactured.

[0072] This method further includes the following additional steps: c) A step of placing the band preform 20 in the mold of the first portion 11a of the internal cavity 11, d) A step of injecting a liquid or semi-solid aluminum alloy into the entire inner cavity 11 of the mold 10.

[0073] The injection of the aluminum alloy is carried out so as to permeate the central preform 200 of the band preform 20, to obtain an aluminum metal matrix composite reinforced by the central preform 200 which partially defines the brake band 2 of the brake disc to be manufactured in the first portion 11a.

[0074] Advantageously, for both the manufacture of the brake disc 1 and the manufacture of the brake band 2, the step b) of injecting an aluminum alloy into a mold can be carried out according to any technique suitable for the purpose.

[0075] In particular, step b) can be carried out according to liquid state infiltration techniques, squeeze casting techniques, gravity infiltration techniques, semi-solid state infiltration techniques, or die casting using liquid aluminum. [In the case of gravity infiltration, infiltration is preferably carried out in an inert atmosphere, such as a nitrogen atmosphere.

[0076] Since the aforementioned infiltration technique is well known to those skilled in the art, its explanation will be omitted here.

[0077] Preferably, step b) in which the aluminum alloy is injected into the mold is carried out according to a semi-solid infiltration technique. In fact, this technique is suitable for infiltrating ceramic preforms, and as a result, the disc made of MMC material at the end of the process is found to have homogeneous characteristics throughout its entire structure. At the same time, this technique is suitable for forming bells in the same process.

[0078] More specifically, penetration in the semi-solid stage takes place at a temperature between the liquidus and solidus of the aluminum alloy being used, i.e., when the alloy is in a semi-solid state. Due to the low viscosity of the semi-solid mass, the injection and penetration processes into the mold proceed smoothly with minimal turbulence.

[0079] A particular advantage is that the presence of silicon-impregnated upper and lower outer bands prevents aluminum from impregnating these bands. As a result, the pair of opposing brake surfaces 2a and 2b are aluminum-free and have an improved coefficient of friction compared to prior art aluminum discs, making them particularly suitable for use as brake discs. In addition, the presence of a carbon barrier layer further advantageously ensures that no aluminum migration occurs from the central preform to the upper and lower outer preforms during the aluminum impregnation process.

[0080] According to a preferred embodiment of the method for manufacturing a brake band 2 or a brake disc 1, the aforementioned band preform 20, which is made of a porous ceramic material, is obtained by subjecting a mass of ceramic material granules, which is surfacely coated with a polymer binding composition, to the following sequential operations: molding, peeling (or degreasing), and sintering.

[0081] Advantageously, the aforementioned ceramic material granules are powder granules known as "Ready-to-Press." This type of commercially available powder allows for the production of "net-shape molded articles" without requiring any other components or additives besides the powder itself.

[0082] Preferably, the ceramic material on which the granules are formed is silicon carbide.

[0083] Preferably, the polymer binding composition coating the ceramic material granules is selected from the group consisting of thermoplastic polymers and thermosetting polymers.

[0084] Preferably, the formation of the mass of ceramic material granules is carried out uniaxially or isostatically, or by any other technique that enables obtaining a preform of such size and shape.

[0085] At the end of the molding process, aggregates of the aforementioned ceramic material granules are obtained, linked by ceramic microstructures facilitated by each coating of the polymer-binding composition. The aggregate contains organic residues from the granule coatings. These organic residues are removed in a debonding (or dewaxing) step.

[0086] Advantageously, the delamination is carried out at temperatures below 700°C and under airflow conditions until the organic phase present in the mass of ceramic material granules after molding is completely removed.

[0087] According to the modified example, the delamination is performed under inert atmospheric conditions.

[0088] At the end of the peeling process, a green body consisting essentially of only ceramic material is obtained. This green body is then subjected to a sintering stage, which transforms it into a continuous structure by forming bridges that connect the individual ceramic particles. As a result, a body exhibiting homogeneous properties throughout the entire structure is obtained.

[0089] Preferably, sintering is carried out in two separate sintering cycles. The first sintering cycle is carried out at a temperature of 1600°C or higher, preferably about 1800°C, and the second sintering cycle is carried out at a temperature of 2000°C or higher, preferably in the range of 2100°C to 2200°C, both under an inert atmosphere.

[0090] Advantageously, the resulting band preform 20, made of porous ceramic material, has a uniform density distribution and porosity throughout its entire volume. These characteristics make the preform suitable for producing a homogeneously distributed aluminum alloy matrix after infiltration with the alloy.

[0091] According to an advantageous embodiment, both the method for manufacturing a brake band and the method for manufacturing a brake disc include a series of operational steps performed prior to step b), schematically shown, for example, in Figures 2, 2a, 2b, and 2c. In particular, the aforementioned series of operational steps assume an initial operational step a1) in which a central preform 200, an upper outer preform 201, and a lower outer preform 202 are prepared. Each of the central preform 200, the upper outer preform 201, and the lower outer preform 202 is made of a porous ceramic material consisting of silicon carbide (SiC). Each of the preforms has a shape such that, when joined together, they form a shape substantially equivalent to the brake band 2 of the brake disc 1 to be manufactured.

[0092] Furthermore, the aforementioned series of operations provides a subsequent operation a2) for impregnating the upper outer preform 201 and the lower outer preform 202 with silicon (Si). The silicon impregnation prevents the existence of space for aluminum to impregnate the preform during the aluminum alloy impregnation process.

[0093] Preferably, in step a2), the upper outer preform 201 and the lower outer preform 202 are placed in a crucible coated with a release layer, for example, boron nitride (BN), and a predetermined amount of silicon (Si) powder is added to the crucible. Subsequently, the upper outer preform 201 and the lower outer preform 202 are heated to achieve fusion of the added silicon, thereby achieving penetration.

[0094] Advantageously, the upper outer preform 201 and the lower outer preform 202 are heated at atmospheric pressure in an inert atmosphere, preferably an argon atmosphere, to a temperature exceeding the melting point of Si (1414°C). This process can be achieved using an industrial furnace of appropriate size.

[0095] In a modified version, the upper outer preform 201 and / or lower outer preform 202 are heated to a temperature exceeding the melting point of Si (1414°C) even under pressures other than atmospheric pressure, such as a controlled vacuum.

[0096] Furthermore, preferably, following the infiltration process, the upper and lower outer preforms are optionally grounded before being subjected to the subsequent processes described below.

[0097] The aforementioned series of operations provides a further operation a3) to deposit particulate material made of carbon onto the central preform 200 in order to obtain at least one carbon barrier layer 200a, 200b made of carbon, as shown in Figure 2a, for example.

[0098] As an alternative to step a3), for example as shown in Figure 2b, step a4) may be provided, in which particulate material made of carbon is deposited on the upper outer preform 201 and the lower outer preform 202 in order to provide at least one carbon barrier layer 201a, 202a made of carbon (C) on each of the upper outer preform 201 and the lower outer preform 202.

[0099] Furthermore, as an alternative to steps a3) and a4), step a5) may be provided, for example as shown in Figure 2c, to deposit particulate material made of carbon on the central preform 200 and the upper outer preform 201 and / or lower outer preform 202 in order to achieve at least one carbon barrier layer 200a and / or 200b, 201a and / or 202a made of carbon (C).

[0100] In other words, preferably, in any variation of the method described herein, a carbon barrier layer can be formed between the upper outer preform 201 and the central preform 200, and between the lower outer preform 202 and the central preform 200, by depositing only on the upper and lower outer preforms, or by depositing only on two opposing surfaces 2000, 2001 of the central preform, or by depositing on both the central preform 200 and the upper outer preform 201 and the lower outer preform 202.

[0101] Preferably, the carbon barrier layer (and thus its deposition) is formed on only one of the two opposing surfaces 2010, 2011; 2020, 2021 of each of the upper and lower outer preforms.

[0102] Furthermore, it is clear that preferably the central preform 200, the upper outer preform 201, and the lower outer preform 202 have an annular disc shape and preferably have a central through hole 5. Preferably, the two opposing surfaces 2000, 2001; 2010, 2011; 2020, 2021 are two opposing surfaces with a disc shape having the largest extension.

[0103] Therefore, the two opposing surfaces 2000, 2001; 2010, 2011; 2020, 2021 of each preform consist of an upper surface 2000; 2010; 2020 and an opposing lower surface 2001; 2011; 2021, which are joined together by side walls 2002; 2012; 2022 that preferably unfold vertically, accompanying the upper surface 2000; 2010; 2020 and the lower surface 2001; 2011; 2021, i.e., forming the shell of the disk.

[0104] Preferably, if each preform already has a central through hole 5, then it is clear that the preform also has inner side walls 2003; 2013; 2023 facing the side walls 2002; 2012; 2022.

[0105] The aforementioned series of operations provides a further subsequent operation a6), which involves interposing silicon (Si) between each carbon barrier layer 200a and / or 200b, 201a and / or 202a, and heating the preforms 200, 201 and 202 until a joint is formed between them in the carbon barrier layers 200a and / or 200b, 201a and / or 202a, thereby joining the central preform 200, the upper outer preform 201, and the lower outer preform 202 to obtain a band preform 20. Therefore, preferably, silicon (Si), such as solid silicon, is interposed between each carbon barrier layer 200a and / or 200b and the upper outer preform 201 and the lower outer preform 202, or between each carbon barrier layer 201a and / or 202a and the central preform 200, or between each carbon barrier layer 200a and / or 200b and the corresponding opposing carbon barrier layer 201a and / or 202a.

[0106] Advantageously, step a6) forming a bond between the central preform 200 and the upper outer preform 201 and lower outer preform 202 provides heating the preforms 200, 201, and 202 to a temperature of about 1450°C for about 2 hours by interposing a stoichiometric amount of silicon between the preforms as a function of the size of the preforms.

[0107] For example, the stoichiometric amount of silicon (MSi) can be calculated as follows, given the total amount of carbon: VC = π(R² - r²)h Here, radii R and r are the outer radius R and inner radius r of the circular crown described by preform 200, 201, or 202, respectively, and h is the thickness of the carbon barrier layer (assuming the layer is compact and void-free). The mass of deposited carbon C can be calculated as follows: MC = VC x Dc Here, Dc is the carbon density.

[0108] Given the equation Si + C = SiC, and knowing that 1 mole of silicon (Si) reacts with 1 mole of carbon (C) to produce 1 mole of silicon carbide (SiC), and that the atomic weights of the components are known, the stoichiometric amount of silicon can be calculated as follows: MSi=MC×atomic weight Si / atomic weight C

[0109] For example, if the preform diameter is approximately 40 millimeters and the required amount of Si is approximately 3 grams, the above parameters can be used to obtain a suitable and reliable bond between the preforms.

[0110] Depending on the process employed, once the minimum stoichiometric amount of Si(MSi) required to react with carbon C is determined according to the aforementioned equation, it is clear that the reaction can be arbitrarily advanced by increasing the amount of silicon to bring about more or less hyperstoichiometric conditions in order to ensure the completion of the chemical reaction.

[0111] Clearly, once the band preform 20 is obtained as described above, the central preform 200 corresponds to the central band 200' of the brake band 20, and the upper outer band 201 and lower outer band 202 correspond to the upper outer band 201' and lower outer band 202' of the brake band 20, respectively.

[0112] In a preferred embodiment, in step a3), a4), or a5), the step of depositing particulate material made of carbon to obtain at least one carbon barrier layer 200a, 200b, 201a, 202a made of carbon (C) is achieved by chemical vapor deposition.

[0113] Preferably, gaseous methane is used as the carbon precursor for chemical vapor deposition, with a temperature of 1100°C to 1300°C and a pressure of 10 to 50 millibars.

[0114] More preferably, the contribution of the mixed gas during the chemical vapor deposition process is as follows: - 0.4 to 3 standard liters / minute (slm) of methane; - 0.2 to 5 standard liters (slm) of hydrogen per minute; - 0-4 standard liters (slm) of argon per minute; The ratio of methane to hydrogen is between 0.3 and 5.

[0115] The aforementioned parameters allow for the creation of a carbon barrier layer, i.e., a carbon coating, on the preform, thereby minimizing the risk of penetration in the preform as much as possible.

[0116] Advantageously, in step d) of the method according to the present invention, as can be seen, for example in Figures 5-6, the mold closes over the upper outer preform 201 and the lower outer preform 202 so as to prevent aluminum from entering onto the upper 201 and lower 202 outer preforms during injection of aluminum into the mold, so that there is no aluminum on the outer braking surfaces 2a, 2b of the disc. In other words, the aluminum alloy is prevented from flowing and creeping above the upper 201 and lower 202 outer preforms, i.e., on the side of each outer preform 201, 202 that is not joined to the central preform 200.

[0117] As can be seen more clearly in Figures 2d, 2e, and 2f, a modified version of the method is not intended to involve performing an operation step a2) to impregnate the upper outer preform 201 and the lower outer preform 202 with silicon (Si) before performing step a6) described above. However, in this modified version of the method, after step a1) and after steps a3), a4), or a5) described above, the method first includes an operation step a11) in which one or more regions of the upper outer preform 201, the lower outer preform 202, and the central preform 200 are protected with release layers 200", 201", and 202", preferably boron nitride (BN) based, and then step a6) is performed as described above. The release layers 200", 201", and 202" prevent silicon (Si) from penetrating the region to be protected through the release layer. This can be obtained, for example, with a boron nitride-based release layer.

[0118] Preferably, in step a11), protection of one or more regions of the upper outer preform 201, the lower outer preform 202, and the central preform 200 is achieved, if necessary, by placing the aforementioned preforms 200, 201, and 202 in a crucible coated with a release layer, for example, boron nitride (BN).

[0119] Preferably, the release layers 200", 201", 202" are positioned near the side walls 2002; 2012; 2022 of the central preform 200 and / or the upper outer preform 201 and / or the lower outer preform 202 to prevent silicon from penetrating through the disk in the radial R direction.

[0120] In this modified example, after step a6), i.e., after the bonding between preforms 200, 201, and 202 is formed by the carbon barrier layers 200a and / or 200b, 201a and / or 202a, the method comprises the following steps to obtain the band preform 20. a61) A step of protecting one or more areas of the central preform 200 by a previously used release layer 200, for example, based on boron nitride (BN), or by a different or additional release layer, for example, based on boron nitride (BN); a62) A step of impregnating the upper outer preform 201 and the lower outer preform 202 with silicon (Si) in the same manner as described in step a2). Silicon impregnation prevents the existence of space for aluminum to impregnate the preform during the aluminum alloy impregnation step.

[0121] The main difference in this modified version of the method is that, after performing the mechanical bonding between the lower outer preform and the central preform, and between the upper outer preform and the central preform along the carbon barrier layer, the silicon penetration process is carried out in the upper outer preform 201 and the lower outer preform 202.

[0122] Therefore, it is understood that additional steps, such as steps a3), a4), or a5), and all other steps and details of the method described above are equally valid and applicable to this modification of the method, as further clearly shown in Figures 2d to 2f.

[0123] In particular, according to the modified embodiment of the method described above, shown in Figures 2e and 2f, the method includes a step of shielding at least a portion of the upper outer preform 201 and / or lower outer preform 202 during step a3), a4), or a5) by, for example, placing graphite paper on each portion of the upper outer preform or the lower outer preform. This shields a portion of the upper and / or lower preform, after which silicon Si can be impregnated.

[0124] In particular, for example, this method provides for at least partially or completely masking the upper surfaces 2010;2020 and / or opposing lower surfaces 2011;2021 of the upper outer preform 201 and / or the lower outer preform 202.

[0125] As can be understood from the above explanation, the brake band, brake disc, and method for manufacturing the brake disc and brake band according to the present invention make it possible to overcome the shortcomings of the prior art.

[0126] In a particularly innovative aspect, the brake band and brake disc of the present invention, by interposing two outer brake bands made of a ceramic composite material between the brake pad and a central band made of a composite material having an aluminum alloy metal matrix, makes it possible to reduce, if not eliminate, the problems associated with localized degradation due to overheating of aluminum, which have been found in the prior art. Furthermore, by bonding the pad to a material with a high coefficient of friction, greater braking force can be generated simultaneously. At the same time, efficiency, simplicity, low implementation cost, and reduced corrosion problems are guaranteed. The reduction in corrosion is particularly advantageous in electric vehicles, where the introduction of regenerative braking involves discontinuous use of disc brakes, which could lead to corrosion.

[0127] Those skilled in the art may make numerous modifications and variations to the discs and disc brakes described above for incidental purposes and to meet specific needs, all of which fall within the scope of the present invention as defined by the following claims.

Claims

1. A method for manufacturing a brake band (2) for a brake disc (1) for a disc brake, wherein the method is: a) A step of preparing a mold (10) having an internal cavity (11), wherein the mold consists of a first portion (11a) having a shape corresponding to the brake band (2) to be manufactured; b) A step of providing a band preform (20) comprising a central preform (200), an upper outer preform (201), and a lower outer preform (202), The aforementioned central preform (200) is made of a porous ceramic material consisting of silicon carbide (SiC). The upper outer preform (201) and the lower outer preform (202) are made of silicon carbide (SiC) and are made of a porous ceramic material in which silicon (SiC + Si) is impregnated. Carbon barrier layers (201a, 200a, 200b, 202a) made of carbon are interposed between the upper outer preform (201) and the central preform (200), and between the lower outer preform (202) and the central preform (200). A process in which the central preform (200), the upper outer preform (201), and the lower outer preform (202) have the shape of the brake band (2) to be manufactured; c) The step of placing the band preform (20) in the mold in the first portion (11a) of the internal cavity (11); and d) A step of injecting a liquid or semi-solid aluminum alloy into the entire internal cavity (11) of the mold (10) to impregnate the central preform (200) of the band preform (20) made of porous ceramic material with the aluminum alloy, thereby obtaining an aluminum metal matrix composite in which the central preform (200) defines the brake band (2) to be manufactured in the first portion (11a), A method that includes this.

2. Before step b), in order to manufacture the band preform (20), a1) A step of providing the central preform (200), the upper outer preform (201), and the lower outer preform (202), wherein the central preform (200), the upper outer preform (201), and the lower outer preform (202) are each made of a porous ceramic material consisting of silicon carbide (SiC); a2) A step of impregnating the upper outer preform (201) and the lower outer preform (202) with silicon (Si); a3) A step of depositing particulate material made of carbon onto the central preform (200) to obtain at least one carbon barrier layer (200a, 200b) made of carbon; a4) A step in which, instead of step a3), particulate material made of carbon is deposited on the upper outer preform (201) and the lower outer preform (202) to provide at least one carbon barrier layer (201a, 202a) made of carbon (C) on each of the upper outer preform (201) and the lower outer preform (202); a5) A step of depositing particulate material made of carbon onto the central preform (200) and the upper outer preform (201) and / or the lower outer preform (202) instead of steps a3) and a4), thereby providing at least one carbon barrier layer (200a and / or 200b, 201a and / or 202a) made of carbon (C) on the central preform (200) and the upper outer preform (201) and / or the lower outer preform (202); a6) The method according to claim 1, comprising the step of inserting silicon into each carbon barrier layer (200a and / or 200b, 201a and / or 202a), and heating the central preform (200), the upper outer preform (201), and the lower outer preform (202) until a joint is formed between them in the carbon barrier layers (200a and / or 200b, 201a and / or 202a), thereby joining the central preform (200), the upper outer preform (201), and the lower outer preform (202) to obtain the band preform (20);

3. Before step b), in order to manufacture the band preform (20), a3) A step of depositing particulate material made of carbon onto the central preform (200) to obtain at least one carbon barrier layer (200a, 200b) made of carbon; a4) A step in which, instead of step a3), particulate material made of carbon is deposited on the upper outer preform (201) and the lower outer preform (202) to provide at least one carbon barrier layer (201a, 202a) made of carbon (C) on each of the upper outer preform (201) and the lower outer preform (202); a5) A step of depositing particulate material made of carbon onto the central preform (200) and the upper outer preform (201) and / or the lower outer preform (202) instead of steps a3) and a4), thereby providing at least one carbon barrier layer (200a and / or 200b, 201a and / or 202a) made of carbon (C) on the central preform (200) and the upper outer preform (201) and / or the lower outer preform (202); a11) A step of protecting one or more regions of the upper outer preform (201), the lower outer preform (202), and the central preform (200) with a release layer (200'', 201'', 202'', for example, boron nitride (BN); a6) A step of joining the central preform (200), the upper outer preform (201), and the lower outer preform (202) together by inserting silicon in each carbon barrier layer (200a and / or 200b, 201a and / or 202a) and heating the central preform (200), the upper outer preform (201), and the lower outer preform (202) until a bond is formed between them in the carbon barrier layers (200a and / or 200b, 201a and / or 202a); a61) A step of protecting one or more regions of the central preform (200) by a release layer (200'') used in step a11), for example, a boron nitride (BN) based release layer, or by a different or additional release layer, for example, a boron nitride (BN) based release layer; a62) The method according to claim 1, comprising the step of impregnating the upper outer preform (201) and the lower outer preform (202) with silicon (Si).

4. The method according to claim 2 or 3, wherein in step a2) or step a62), the upper outer preform (201) and the lower outer preform (202) are placed in a crucible coated with, for example, a boron nitride (BN) based release layer, a predetermined amount of powdered silicon (Si) is added to the crucible, and the upper outer preform (201) and the lower outer preform (202) are heated to obtain fusion of the added silicon (Si).

5. The method according to claim 4, wherein the upper outer preform (201) and the lower outer preform (202) are heated to a temperature exceeding the melting temperature of Si (1414°C) under atmospheric pressure, in an inert atmosphere, preferably in an argon atmosphere.

6. The method according to any one of claims 2 to 5, wherein in step a3) or a4) or a5), the step of depositing particulate material made of carbon to obtain at least one carbon barrier layer (201a, 202a) made of carbon (C) is achieved by chemical vapor deposition, sputtering, physical vapor deposition (PVD), or bonding with a graphite-based adhesive.

7. The method according to claim 6, wherein gaseous methane is used as a carbon precursor for chemical vapor deposition, the temperature is set between 1100°C and 1300°C, and the pressure is between 10 millibars and 50 millibars.

8. The contribution of the mixed gas in the chemical vapor deposition method is - Methane between 0.4 and 3 standard liters (slm) per minute; - 0.2 to 5 standard liters (slm) of hydrogen per minute - 0–4 standard liters (slm) of argon per minute; The method according to claim 7, wherein the ratio of methane to hydrogen is 0.3 to 5.

9. In step a6), the method is The process includes heating the central preform (200), the upper outer preform (201), and the lower outer preform (202) to a temperature of approximately 1450°C for approximately 2 hours. The method according to any one of claims 2 to 8.

10. The method according to any one of claims 1 to 9, wherein step d) of introducing the aluminum alloy into the mold is performed by a semi-solid or liquid infiltration method or by squeeze casting.

11. The method according to any one of claims 1 to 10, wherein the central preform (200), the lower outer preform (202), and the upper outer preform (201) are obtained by sequentially molding, degreasing, and sintering lumps of ceramic material granules surface-coated with a polymer-binding composition.

12. The sintering is carried out in two separate sintering cycles. The first sintering cycle is carried out at a temperature of 1600°C or higher, preferably about 1800°C. The second sintering cycle is carried out at a temperature of 2000°C or higher, preferably in the range of 2100°C to 2200°C. The method according to claim 11, wherein all are carried out in an inert atmosphere.

13. The method according to any one of claims 1 to 12, wherein in step d), the mold covers and closes the upper outer preform (201) and the lower outer preform (202) so that during the introduction of aluminum into the mold, the ingress of aluminum onto the upper outer preform (201) and below the lower outer preform (202) is prevented, and the outer brake surfaces (2a, 2b) of the brake disc (1) are freed from aluminum.

14. A method for manufacturing a brake disc (1), wherein the brake disc (1) includes a brake band (2) and a bell (3), a) A step of preparing a mold (10) having an internal cavity (11) consisting of a first portion (11a) shaped to correspond to the brake band (2) of the brake disc (1) to be manufactured, and a second portion (11b) shaped to correspond to the bell (3) of the brake disc (1) to be manufactured, wherein the first portion (11a) and the second portion (11b) of the internal cavity (11) are in communication with each other; b) A step of providing a band preform (20) comprising a central preform (200), an upper outer preform (201), and a lower outer preform (202), The aforementioned central preform (200) is made of a porous ceramic material consisting of silicon carbide (SiC), The upper outer preform (201) and the lower outer preform (202) are made of a porous ceramic material consisting of silicon carbide (SiC), and are impregnated with silicon (SiC + Si); A carbon barrier layer (201a, 200a, 200b, 202a) made of carbon is interposed between the upper outer preform (201) and the central preform (200), and between the lower outer preform (202) and the central preform (200), and the central preform (200), the upper outer preform (201), and the lower outer preform (202) have the shape of the brake band (2) of the brake disc (1) to be manufactured; c) The step of placing the band preform (20) into the mold of the first portion (11a) of the internal cavity (11); d) A method comprising the steps of: injecting a liquid or semi-solid aluminum alloy into the entire internal cavity (11) of the mold (10) to impregnate only the central preform (200) of the band preform (20) made of porous ceramic material to obtain an aluminum metal matrix composite in a first portion (11a) reinforced by the central preform (200) that partially defines the brake band (2) of the brake disc (1) to be manufactured; filling a second portion (11b) with the aluminum alloy to obtain a fusion of aluminum alloy that is integrally connected with the brake band (2) made of the composite metal matrix and defines the bell (3) of the brake disc (1) to be manufactured.

15. A brake band (2) for a brake disc (1) for a disc brake, wherein the brake band (2) is A central band (200') made of an aluminum metal matrix composite reinforced with a ceramic material made of silicon carbide (SiC), wherein the aluminum metal matrix composite is obtained by impregnating a central preform (200) made of a porous ceramic material having a shape corresponding to the brake band with an aluminum alloy, and the central band (200') An upper band (201') is joined to the central band (200') along the upper bonding layer (22a), wherein the upper band (201') is made of a porous ceramic material having silicon carbide (SiC) and impregnated with silicon (SiC + Si), and the upper band (201') covers the central band (200') on one side, A brake band (2) comprising: a lower band (202') joined to the central band (200') along a lower bonding layer (22b) located on the opposite side of the upper bonding layer (22a), wherein the lower band (202') is made of a porous ceramic material having silicon carbide (SiC) and impregnated with silicon (SiC + Si), and covers the central band (200') on the opposite side of the upper band (201').

16. A brake disc (1) for a disc brake, comprising a brake band (2) as described in claim 15 and a bell (3) connected to the brake band (2).

17. A brake disc (1) for a disc brake according to claim 16, wherein the bell (3) is integrally connected to the brake band (2) and is made of an aluminum alloy co-cast with the metal matrix of the aluminum metal matrix composite material constituting the brake band (2).

18. A brake disc (1) for a disc brake according to claim 16 or 17, wherein the aluminum alloy matrix is ​​uniformly distributed within the aluminum metal matrix composite.

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