SANDING-FREE PREPARATION METHOD AND USE OF ULTRA-THIN DOUBLE-LAYER METAL COMPOSITE STRIP

Description

CROSS REFERENCE TO RELATED APPLICATION

This patent application claims the benefit and priority of Chinese Patent Application No. 2024117642076 filed with the China National Intellectual Property Administration on Dec. 3, 2024, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.

TECHNICAL FIELD

The present disclosure relates to the technical field of ultra-thin double-layer metal composite strips, and in particular to a sanding-free preparation method and use of an ultra-thin double-layer metal composite strip.

BACKGROUND

Ultra-thin double-layer metal composite strips are new composite materials formed from at least two alloys or metals with different physical, chemical, and mechanical properties by means of bonding technology. Through careful design and combination, such composite materials enable the full use of the performance advantages of each component material and effectively compensate for the limitations of a single material, thus giving the final product superior comprehensive performance. For this reason, the ultra-thin double-layer metal composite strip has shown wide application potential and value in many high-tech and industrial fields, such as aerospace, electronic communication, petrochemistry, etc.

Currently, the composite technology of ultra-thin double-layer metal composite strips mainly covers several methods, such as solid-solid phase bonding, solid-liquid phase bonding, and liquid-liquid phase bonding. Among them, the rolling process in the field of solid-solid phase bonding has become the mainstream production method for ultra-thin double-layer metal composite strips that is widely adopted in the art due to its significant advantages of low energy consumption and high efficiency. Specifically, the roll bonding process of ultra-thin double-layer metal composite strips could be subdivided into two categories: the first is pre-rolling to thin the raw materials, followed by roll bonding; and the second is directly subjecting the raw materials to roll bonding, followed by further rolling to thin the composite material. Both of the processes described above require fine sanding pre-treatment of the interface to be bonded before roll bonding, aiming to expose fresh metal surfaces and ensure the smooth operation of the roll bonding process. Therefore, the final results of the roll bonding closely correlate with the sanding process for the material surface and the surface state after the sanding treatment, thus complicating the entire preparation process for ultra-thin double-layer metal composite strips and leading to relative high production costs.

SUMMARY

In view of this, the present disclosure provides a sanding-free preparation method and use of an ultra-thin double-layer metal composite strip. The sanding-free preparation method according to the present disclosure eliminates the need for sanding the surface of a material, greatly simplifying the production process flow and improving the production efficiency. Moreover, the interface of the composite material prepared by the present disclosure exhibits a regularly distributed pit array structure, which not only improves the bonding strength of the composite interface, but also gives the material properties such as good hydrophobicity, reduced heat transfer, reduced air resistance, and reduced reflection and scattering of electromagnetic waves, etc., enabling the composite material to have unique advantages in high-end fields, such as aerospace and electronic industries, thereby having good application prospects.

Provided a method for sanding-free preparation of an ultra-thin double-layer metal composite strip, including the following steps:

• • S1, precisely cutting an ultra-thin metal strip to obtain a metal substrate;
  • S2, subjecting the metal substrate to pre-rolling annealing;
  • S3, cleaning a resulting metal substrate after pre-rolling annealing;
  • S4, subjecting a resulting cleaned metal substrates to stacking in pairs and then rolling using a texturing roller together with a conventional flat roller; and
  • S5, subjecting a resulting rolled metal substrate to post-rolling annealing and cooling to obtain an ultra-thin double-layer metal composite strip.

In some embodiments, the ultra-thin metal strip is any two selected from the group consisting of a copper foil, a titanium foil, and an alloy strip. In some embodiments, the alloy strip is a stainless steel strip.

In some embodiments, the pre-rolling annealing is carried out at a temperature of 500° C. to 950° C., and the pre-rolling annealing is held at the temperature of 500° C. to 950° C. for 5 min to 10 min.

In some embodiments, the texturing roller is fitted with a metal substrate with high hardness, and the conventional flat roller is fitted with a metal substrate with low hardness.

In some embodiments, the rolling is carried out with a rolling force of 7 kN to 12 kN at a rolling speed of 0.1 m/min.

In some embodiments, the post-rolling annealing is carried out at a temperature of 650° C. to 850° C., and the pre-rolling annealing is held at the temperature of 650° C. to 850° C. for 3 min to 10 min.

The present disclosure further provides use of an ultra-thin double-layer metal composite strip in aerospace and electronic industries, wherein the ultra-thin double-layer metal composite strip is the ultra-thin double-layer metal composite strip as described in the above technical solutions.

Compared with the prior art, the method according to the present disclosure only needs a greasy dirt removal operation on the surface of a rolled piece, eliminating the cumbersome step of sanding the material surface to be bonded, which not only greatly simplifies the production process flow, but also fundamentally improves the overall production efficiency of the ultra-thin double-layer metal composite strip. In addition, the present disclosure realizes the roll bonding of a variety of thin metal strip substrates at a low reduction rate, which breaks the stringent limitations of conventional processes on the material and reduction rate, thereby opening up a broader application space for the preparation of ultra-thin strip-like composite materials. Finally, the interface of the composite material prepared by the present disclosure has a regularly distributed pit array structure. This unique structure not only significantly improves the bonding strength of the composite interface, but also gives the material properties such as good hydrophobicity, reduced heat transfer, reduced air resistance, and reduced reflection and scattering of electromagnetic waves, etc., enabling the composite material to have unique advantages in high-end fields, such as aerospace and electronic industries, thereby having good application prospects.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be further described hereinbelow with reference to the accompanying drawings.

FIG. 1A to 1D show three-dimensional cross-sectional topographies of the ultra-thin bilayer metal composite strip of Example 1, with protrusions on the inner surface of the copper foil in FIG. 1A and FIG. 1B, and depressions on the inner surface of the 304 stainless steel in FIG. 1C and FIG. 1D;

FIG. 2 shows an SEM image of the surface of a rolled piece of the ultra-thin double-layer metal composite strip of Example 1 that is fitted with a texturing roller;

FIG. 3A to FIG. 3B show a three-dimensional contour morphology image of a texturing roll surface used in an embodiment of the present disclosure;

FIG. 4 shows a schematic diagram of a rolling process; and

FIG. 5 shows a schematic diagram of the surface structure of the texturing roller.

List of reference signs: 1 refers to a conventional flat roller; 2 refers to a metal substrate with low hardness; 3 refers to a metal substrate with high hardness; and 4 refers to a texturing roller.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions according to the present disclosure will be described clearly and completely below with reference to embodiments of the present disclosure. Apparently, the described embodiments are only some of, rather than all of, the embodiments of the present disclosure. On the basis of the embodiments in the present disclosure, all the other embodiments that would have been obtained by those of ordinary skill in the art without involving any inventive effort shall fall within the scope of the present disclosure.

The present disclosure provides a method for sanding-free preparation of an ultra-thin double-layer metal composite strip, including the following steps:

• • S1, precisely cutting an ultra-thin metal strip to obtain a metal substrate;
  • S2, subjecting the metal substrate to pre-rolling annealing;
  • S3, cleaning a resulting metal substrate after pre-rolling annealing;
  • S4, subjecting a resulting cleaned metal substrates to stacking in pairs and then rolling using a texturing roller together with a conventional flat roller; and
  • S5, subjecting a resulting rolled metal substrate to post-rolling annealing and cooling to obtain an ultra-thin double-layer metal composite strip.

The first step according to the present disclosure is to precisely cut an ultra-thin metal strip to obtain a metal substrate. Specifically, a metal material is selected as a composite metal substrate, which is precisely cut to ensure that the dimension of each substrate strip meets the pre-set standard, thus providing a good foundation for the subsequent bonding process.

In some specific embodiments of the present disclosure, the ultra-thin metal strip is any two selected from the group consisting of a copper foil, a titanium foil, and an alloy strip. In other specific embodiments of the present disclosure, the alloy strip is a stainless steel strip. In some embodiments of the present disclosure, the stainless steel strip is a 304 stainless steel strip. The metal substrate according to the present disclosure is not limited to a single material, and various materials are innovatively combined. Moreover, when two types of ultra-thin strips are bonded, the sanding-free preparation method according to the present disclosure is also not necessarily limited to the thickness of the metal substrate. This is because the present disclosure ensures that the two metal substrates could form good interfacial bonding during the rolling process by selecting texturing rollers of various roughness according to the thickness of metal substrates, thus realizing the preparation of an ultra-thin double-layer metal composite strip.

The second step according to the present disclosure is to subject the metal substrate to pre-rolling annealing. In some embodiments, the pre-rolling annealing is carried out in an inert gas atmosphere at a temperature of 500° C. to 950° C., and then held at the temperature of 500° C. to 950° C. for 5 min to 10 min. In some embodiments of the present disclosure, the inert gas is argon. In some embodiments, the metal substrate is stainless steel, the pre-rolling annealing is carried out at 950° C., and held at the 950° C. for 5 min. In some embodiments, under the condition that the metal substrate is a copper foil, the pre-rolling annealing is carried out at 500° C., and held at the 500° C. for 10 min. In some embodiments, under the condition that the metal substrate is a titanium foil. the pre-rolling annealing is carried out at 600° C., and held at the 600° C. for 10 min.

The present disclosure ensures that the microstructure inside the material is optimized by the pre-rolling annealing. In addition, the oxidation of the material during annealing is prevented by controlling the atmosphere.

The third step according to the present disclosure is to clean a resulting metal substrate after the pre-rolling annealing. In some specific embodiments of the present disclosure, absolute ethanol and/or dust-free paper are used in the cleaning. In the present disclosure, the resulting metal substrate after the pre-rolling annealing is cleaned to effectively remove the contaminants, such as impurities and greasy dirt, on the surface of the material, facilitating the subsequent rolling process.

The fourth step according to the present disclosure is to subject a resulting cleaned metal substrate to stacking in pairs and then rolling using a texturing roller together with a conventional flat roller. In some specific embodiments of the present disclosure, the texturing roller is fitted with a metal substrate with high hardness and the conventional flat roller is fitted with a metal substrate with low hardness. The two metal substrates are subsequently fed to a flat-roller rolling mill, and subjected to roll bonding. In some embodiments, the texturing roller has a toughness of 5 μm to 50 μm. In some specific embodiments of the present disclosure, the rolling is carried out with a rolling force of 7 kN to 12 kN at a rolling speed of 0.1 m/min. However, in the present disclosure, the roughness of the texturing roller is not strictly limited, and the texturing rollers of various specifications could be customized according to specific requirements and used for rolling, ultimately aiming to ensure the uniformity and consistency of the pit array structure on the surface of the ultra-thin double-layer metal composite strip. Generally, the thicker the thin strip, the greater the roughness of the corresponding texturing roller, so as to form an ideal pit array structure.

The fifth step according to the present disclosure is to conduct post-rolling annealing. In some specific embodiments of the present disclosure, the post-rolling annealing is carried out at a temperature of 650° C. to 850° C., and held at the temperature of 650° C. to 850° C. for 3 min to 10 min.

A metal composite material obtained in step S4 is subjected to post-rolling annealing treatment, and the post-rolling annealing is carried out in an inert gas atmosphere. In some embodiments of the present disclosure, the inert gas is argon.

In the present disclosure, the oxidation of the material during annealing is prevented by controlling the atmosphere of the post-rolling annealing.

The present disclosure further provides use of an ultra-thin double-layer metal composite strip in the fields of aerospace, electronic industries and petrochemistry, wherein the ultra-thin double-layer metal composite strip is the ultra-thin double-layer metal composite strip as described in the above technical solutions.

The ultra-thin double-layer metal composite strip of the present disclosure exhibits a pit array structure, which could be used as a coating material for the surface of an aircraft (e.g., airplanes, rockets, satellites, etc.). The regular pit array structure of the ultra-thin double-layer metal composite strip according to the present disclosure could reduce air resistance, thus improving the flight efficiency. Moreover, the pit array structure could improve the hydrophobicity of the material, which helps to prevent the fuselage from freezing and ensure flight safety. In the thermal protection system of spacecraft, the ultra-thin double-layer metal composite strip according to the present disclosure could be used as a constituent part of a thermal insulation layer or a thermal-resistance tile, and the regular structure and hydrophobicity thereof help to reduce heat transfer and protect the internal structure from high-temperature damage. In addition, the ultra-thin double-layer metal composite strip according to the present disclosure could be used as a coating material for the surface of an automotive body, which could reduce air resistance during driving and improve fuel efficiency. In addition, its hydrophobicity helps to prevent water build-up on the automotive body, reducing corrosion and abrasion. In addition, in radar and communication systems, the ultra-thin double-layer metal composite strip according to the present disclosure could be used as a radome material, the regular pit array structure of which helps to reduce the reflection and scattering of electromagnetic waves, thus improving signal transmission quality.

To further illustrate the present disclosure, the following detailed description is made by way of the examples below. The raw materials used in the following examples of the present disclosure are all commercially available.

Unless otherwise specified, all tests are repeated 3 times, and the results are expressed as averages.

Example 1

A method for sanding-free preparation of an ultra-thin copper/304 stainless steel composite strip was conducted by the following steps:

S1, a copper foil with a thickness of 20 μm and an ultra-thin 304 stainless steel strip with a thickness of 20 μm were precisely cut as composite metal substrates having a specification of 130 mm×15 mm.

S2, a resulting cut copper foil and a resulting cut ultra-thin 304 stainless steel strip were placed in an annealing furnace, and subjected to pre-rolling annealing under the protection of argon. The 304 stainless steel was subjected to the pre-rolling annealing at 950° C., and held at the 950° C. for 5 min. The copper foil was subjected to the pre-rolling annealing at 500° C., and held at the 500° C. for 10 min. After the annealing was completed, materials were cooled to room temperature with the furnace.

S3, surfaces of the copper foil and ultra-thin 304 stainless steel strip to be bonded were gently wiped using dust-free paper to remove any greasy dirt and impurities that might present.

S4, a resulting wiped ultra-thin 304 stainless steel strip was closely fitted with a texturing roller having a roughness of 15 μm, and a resulting wiped copper foil was fitted with a smooth flat roller. The above two materials were stacked in pairs, and then subjected to roll bonding with a rolling force of 12 kN and at rolling speed of 0.1 m/min to obtain an ultra-thin composite strip.

S5, the ultra-thin composite strip was placed in an annealing furnace, and subjected to post-rolling annealing under the protection of argon at 850° C., and held at the 850° C. for 3 min. After the heat treatment, the material was cooled to room temperature with the furnace to obtain the ultra-thin copper/304 stainless steel composite strip.

Bonding failed when the texturing roller was replaced with a smooth flat roller.

Example 2

A method for sanding-free preparation of an ultra-thin copper/304 stainless steel composite strip was conducted by the following steps:

S1, a copper foil with a thickness of 20 μm and an ultra-thin 304 stainless steel strip with a thickness of 10 μm were precisely cut as composite metal substrates having a specification of 130 mm×15 mm.

S2, a resulting cut copper foil and a resulting cut ultra-thin 304 stainless steel strip were placed in an annealing furnace, and subjected to pre-rolling annealing under the protection of argon, respectively. The 304 stainless steel was subjected to pre-rolling annealing at a temperature of 950° C., and held at the temperature of 950° C. for 5 min, and the copper foil was subjected to pre-rolling annealing at a temperature of 500° C., and held at the temperature of 500° C. for 10 min. After the annealing was completed, materials were cooled to room temperature with the furnace.

S3, surfaces of the copper foil and ultra-thin 304 stainless steel strip to be bonded were gently wiped using dust-free paper to remove any greasy dirt and impurities that might present.

S4, a resulting wiped ultra-thin 304 stainless steel strip was closely fitted with a texturing roller having a roughness of 10 μm, and a resulting wiped copper foil was fitted with a smooth flat roller. The above two materials were stacked in pairs, and then subjected to roll bonding with a rolling force of 8 kN at a rolling speed of 0.1 m/min to obtain an ultra-thin composite strip.

S5, the ultra-thin composite strip was placed in an annealing furnace, and subjected to post-rolling annealing under the protection of argon at 850° C., and held at the 850° C. for 3 min. After the heat treatment, the material was cooled to room temperature with the furnace to obtain the ultra-thin copper/304 stainless steel composite strip.

Bonding failed when the texturing roller was replaced with a smooth flat roller.

Example 3

A method for sanding-free preparation of an ultra-thin titanium/304 stainless steel composite strip was conducted by the following steps:

S1, a titanium foil with a thickness of 20 μm and an ultra-thin 304 stainless steel strip with a thickness of 20 μm were precisely cut as composite metal substrates having a specification of 130 mm×15 mm.

S2, a resulting cut titanium foil and a resulting cut ultra-thin 304 stainless steel strip were placed in an annealing furnace, and subjected to pre-rolling annealing under the protection of argon, respectively. The 304 stainless steel was subjected to pre-rolling annealing at a temperature of 950° C., and held at the temperature of 950° C. for 5 min, and the titanium foil was subjected to pre-rolling annealing at a temperature of 600° C., and held at the temperature of 600° C. for 10 min. After the annealing was completed, materials were cooled to room temperature with the furnace.

S3, surfaces of the titanium foil and ultra-thin 304 stainless steel strip to be bonded were gently wiped using dust-free paper to remove any greasy dirt and impurities that might present.

S4, a resulting wiped ultra-thin 304 stainless steel strip was closely fitted with a texturing roller having a roughness of 15 μm, and a resulting wiped titanium foil was fitted with a smooth flat roller. The above two materials were stacked in pairs, and then subjected to roll bonding with a rolling force of 10 kN at a rolling speed of 0.1 m/min to obtain an ultra-thin composite strip.

S5, the ultra-thin composite strip was placed in an annealing furnace, and subjected to post-rolling annealing under the protection of argon at 650° C., and held at the 650° C. for 3 min. After the heat treatment, the material was cooled to room temperature with the furnace to obtain the ultra-thin titanium/304 stainless steel composite strip.

Bonding failed when the texturing roller was replaced with a smooth flat roller.

Example 4

A method for sanding-free preparation of an ultra-thin titanium/304 stainless steel composite strip was conducted by the following steps:

S1, a titanium foil with a thickness of 20 μm and an ultra-thin 304 stainless steel strip with a thickness of 10 μm were precisely cut as composite metal substrates having a specification of 130 mm×15 mm.

S2, a resulting cut titanium foil and a resulting cut ultra-thin 304 stainless steel strip were placed in an annealing furnace, and subjected to pre-rolling annealing under the protection of argon, respectively. The 304 stainless steel was subjected to the pre-rolling annealing at a temperature of 950° C., and held at the temperature of 950° C. for 5 min, and the titanium foil was subjected to the pre-rolling annealing at a temperature of 600° C., and held at the temperature of 600° C. for 10 min. After the annealing was completed, materials were cooled to room temperature with the furnace.

S3, surfaces of the titanium foil and ultra-thin 304 stainless steel strip to be bonded were gently wiped using dust-free paper to remove any greasy dirt and impurities that might present.

S4, a resulting wiped ultra-thin 304 stainless steel strip was closely fitted with a texturing roller having a roughness of 10 μm, and a resulting wiped titanium foil was fitted with a smooth flat roller. The above two materials were stacked in pairs, and then subjected to roll bonding with a rolling force of 8 kN at a rolling speed of 0.1 m/min to obtain an ultra-thin composite strip.

S5, the ultra-thin composite strip was placed in an annealing furnace, and subjected to post-rolling annealing under the protection of argon at 650° C., and held at the 650° C. for 3 min. After the heat treatment, the material was cooled to room temperature with the furnace to obtain the ultra-thin titanium/304 stainless steel composite strip.

Bonding failed when the texturing roller was replaced with a smooth flat roller.

Example 5

A method for sanding-free preparation of an ultra-thin titanium/copper composite strip was conducted by the following steps:

• • S1, a titanium foil with a thickness of 20 μm and a copper foil with a thickness of 20 μm were precisely cut as composite metal substrates having a specification of 130 mm×15 mm.
  • S2, a resulting cut titanium foil and a resulting cut copper foil were placed in an annealing furnace, and subjected to pre-rolling annealing under the protection of argon, respectively. The copper foil was subjected to the pre-rolling annealing at a temperature of 500° C., and held at the temperature of 500° C. for 10 min, and the titanium foil was subjected to the pre-rolling annealing at a temperature of 600° C., and held at the temperature of 600° C. for 10 min. After the annealing was completed, materials were cooled to room temperature with the furnace.
  • S3, surfaces of the titanium foil and copper foil to be bonded were gently wiped using dust-free paper to remove any greasy dirt and impurities that might present.
  • S4, a resulting wiped titanium foil was closely fitted with a texturing roller having a roughness of 15 μm, and a resulting wiped copper foil was fitted with a smooth flat roller. The above two materials were stacked in pairs, and then subjected to roll bonding with a rolling force of 7 kN at a rolling speed of 0.1 m/min to obtain an ultra-thin composite strip.
  • S5, the ultra-thin composite strip was placed in an annealing furnace, and subjected to post-rolling annealing under the protection of argon at 650° C., and held at the 650° C. for 3 min. After the heat treatment, the material was cooled to room temperature with the furnace to obtain the ultra-thin titanium/copper composite strip.

Bonding failed when the texturing roller was replaced with a smooth flat roller.

Example 6

A method for sanding-free preparation of an ultra-thin titanium/copper composite strip was conducted by the following steps:

S1, a titanium foil with a thickness of 10 μm and a copper foil with a thickness of 20 μm were precisely cut as composite metal substrates having a specification of 130 mm×15 mm.

S2, a resulting cut titanium foil and a resulting cut copper foil were placed in an annealing furnace, and subjected to pre-rolling annealing under the protection of argon, respectively. The copper foil was subjected to the pre-rolling annealing at a temperature of 500° C., and held at the temperature of 500° C. for 10 min, and the titanium foil was subjected to the pre-rolling annealing at a temperature of 600° C., and held at the temperature of 600° C. for 10 min. After the annealing was completed, materials were cooled to room temperature with the furnace.

S3, surfaces of the titanium foil and copper foil to be bonded were gently wiped using dust-free paper to remove any greasy dirt and impurities that might present.

S4, a resulting wiped titanium foil was closely fitted with a texturing roller having a roughness of 10 μm, and a resulting wiped copper foil was fitted with a smooth flat roller. The above two materials were stacked in pairs, and then subjected to roll bonding with a rolling force of 7 kN at a rolling speed of 0.1 m/min to obtain an ultra-thin composite strip.

S5, the ultra-thin composite strip was placed in an annealing furnace, and subjected to post-rolling annealing under the protection of argon at 650° C., and held at the 650° C. for 3 min. After the heat treatment, the material was cooled to room temperature with the furnace to obtain the ultra-thin titanium/copper composite strip.

Bonding failed when the texturing roller was replaced with a smooth flat roller.

Test Example 1

The properties of the ultra-thin composite strips obtained in Examples 1-5 were tested. The results are shown in Table 1.

As can be seen from Table 1, the ultra-thin composite strip according to the present disclosure has good electrical and thermal conductivity. The ultra-thin steel/titanium composite strip has an electrical conductivity that is inferior to that of the ultra-thin copper/steel composite strip and the ultra-thin copper/titanium composite strip but has superior mechanical properties. The ultra-thin copper/titanium composite strip has both excellent electrical conductivity and thermal conductivity and has mechanical properties that are inferior to the ultra-thin steel/titanium composite strip but better than the ultra-thin copper/steel composite strip. Thus, the thinner the ultra-thin composite strip, the worse its electrical conductivity, and the thicker it is, the worse its thermal conductivity. The order of the electrical conductivity of the ultra-thin composite strips made of different materials is copper/steel>copper/titanium>steel/titanium, and the order of the thermal conductivity is copper/titanium>copper/steel>steel/titanium.

The above embodiments merely represent several embodiments of the present disclosure, giving specific and detailed description, but should not be understood as limiting the scope of the present disclosure thereby. It should be noted that several variations and improvements could also be made by those of ordinary skill in the art without departing from the spirit of the present disclosure, and these all fall within the scope of the present disclosure. Therefore, the scope of the present disclosure shall be in accordance with the appended claims.