CN119615107A

CN119615107A - A SiC-coated Cu85Sn15 alloy composite fiber and preparation method thereof

Info

Publication number: CN119615107A
Application number: CN202411655481.XA
Authority: CN
Inventors: 张勇; 李荣智
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2024-11-19
Filing date: 2024-11-19
Publication date: 2025-03-14

Abstract

The invention discloses a SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber and a preparation method thereof. Firstly, preparing the Cu and Sn high-purity alloy into button cast ingots in a vacuum induction furnace. Then, a small amount of alloy material is put into a glass tube, vacuumized and filled with argon, and the glass-coated metal microfilaments are obtained after induction heating. The microwires are then rapidly solidified by a cooling fluid and collected. Finally, introducing CH ₄ gas into a tubular furnace, and performing vapor deposition at 800 ℃ for 24 hours to prepare the SiC-coated Cu alloy composite fiber. Based on the defects of the mechanical property of the glass-coated Cu alloy wire and the requirement of surface glass removal, the invention utilizes the brittle SiO ₂ which needs to be removed on the surface as a precursor and CH ₄ as a reaction gas to synthesize a compact SiC film on the surface of the Cu alloy fiber, thereby obtaining the SiC-coated Cu alloy composite fiber with higher mechanical property and more functional property.

Description

SiC-coated Cu 85Sn15 alloy composite fiber and preparation method thereof

Technical Field

The invention belongs to the technical field of alloy materials, and particularly relates to a SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber and a preparation method thereof.

Background

The glass outer layer of the alloy fiber prepared by the glass cladding method is usually removed by HF or glass corrosive agent, and the method easily corrodes the original alloy substrate to greatly reduce the mechanical property of the alloy fiber. And the strength of the Cu alloy substrate formed by the original liquid phase forming is lower. In recent years, attention has been paid to how to synergistically optimize the mechanical properties and functional characteristics of SiC reinforced composites. Continuous filament Chemical Vapor Deposition (CVD) is specifically designed for the synthesis of large diameter SiC fibers. In this method, the deposited layer is grown directly on a heated Cu-based alloy microfilament substrate.

Silicon carbide (SiC) plays an important role in a number of industries and various fields of production due to its special physicochemical properties. Among the most notable properties are low density, high thermal conductivity, very low coefficient of friction, fire resistance, low coefficient of thermal expansion, high chemical resistance, corrosion and radiation resistance, high hardness, etc. Silicon carbide has excellent mechanical properties including strength, fracture toughness, hardness, etc., and improved ballistic properties, and is therefore used in the production of ballistic vests and composite armor. Silicon carbide is used as a refractory material in the metallurgical industry, and is used in the fields of abrasive materials, cutting and grinding tools, nuclear power industry, heating elements, electronic products and the like. Furthermore, the high degree of covalency of the si—c bonds and the wide forbidden band characteristics of SiC give these reinforcements excellent thermal conductivity, radiation resistance and microwave absorption efficiency.

The traditional SiC synthesis method comprises a combustion method, a sintering method, a selective method, a sol-gel method, a hydrothermal acid leaching method, a thermal hydrolysis method, low-temperature synthesis, microwave synthesis, in-situ growth, electric arc synthesis and the like. However, most of developed SiC whiskers or short-distance nano SiC fibers cannot meet the production requirements, and most of SiC composite fibers grow by attaching dispersed random precursors, so that the SiC composite fibers cannot be practically applied. Among them, CVD is a commonly used method for preparing low-dimensional SiC materials such as nanowires, whiskers, and continuous fibers. SiC fiber materials exhibit outstanding physical properties at various temperatures, including tensile strength, elastic modulus, and oxidation and creep resistance, and are therefore widely regarded as ideal choices for reinforcing structures.

Disclosure of Invention

The Cu alloy microfilament produced by the glass coated yarn belongs to a liquid phase forming method and is an as-cast structure, so that the mechanical property is poor. On the other hand, the glass coating layer on the surface is a brittle material, and in actual production, it is necessary to peel off or remove the glass coating layer in an appropriate manner. Based on the defects of the mechanical property of the glass-coated Cu alloy wire and the requirement of surface glass removal, the invention utilizes the brittle SiO ₂ which needs to be removed on the surface as a precursor and CH ₄ as a reaction gas to synthesize a compact SiC film on the surface of the Cu alloy fiber, thereby obtaining the SiC-coated Cu alloy composite fiber with higher mechanical property and more functional property.

The invention is realized by the following technical scheme:

a preparation method of SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber comprises the following steps:

a. preparing an original alloy button cast ingot from 99.9% high-purity alloy elements with atomic ratio of Cu to Sn=85:15 in a vacuum induction furnace;

b. Putting 1-2 g of alloy material into a glass tube, vacuumizing to 2.5Pa, then filling argon to 0.1MPa, and vacuumizing again to 2.5Pa;

c. The glass tube enters an induction heating zone at a certain speed, metal is melted by high-frequency induction heating, and the tail end of the glass tube is softened by the heat of the metal;

d. The softened glass tube end is drawn into a superfine capillary tube, molten metal enters the capillary tube to form glass coated metal microfilaments, and the microfilaments pass through cooling liquid to be quickly solidified to obtain the glass coated metal microfilaments which are then wound on a wire winding wheel. Glass coated wire Cu ₈₅Sn₁₅ alloy microfilaments (diameter 30+/-5 μm and length 2+/-0.5 m) are prepared by using a glass coated wire technology;

e. Cutting out uniform glass coated Cu ₈₅Sn₁₅ alloy microfilaments with the length of 50+/-5 mm, putting the filaments into a tube furnace, introducing CH ₄ gas, heating to 800 ℃ and keeping for 24 hours, thereby preparing the composite reinforced fiber of the copper alloy matrix and the SiC coating layer by using a vapor deposition method.

The invention also discloses the SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber prepared by the preparation method.

The invention has the beneficial effects that:

(1) SiC has excellent properties of wide forbidden band, low density, low thermal expansion, excellent thermal shock resistance/oxidation/chemical stability, high hardness, high thermal conductivity and the like, and is widely used in the fields of grinding tools, ceramics, insulation, metallurgy, refractory materials, wear-resistant materials and the like;

(2) The synthesis process of the SiC material is to react with a precursor SiO ₂ by using a CVD method CH ₄ to generate H ₂ O and SiO ₂, and other toxic and harmful substances are not generated, so that the process is a green and environment-friendly process;

(3) The melting point of the copper-tin alloy is matched with the softening temperature interval of the glass, and the alloy has good fluidity and is very suitable for stretch forming of glass coated wires;

(4) The SiC-coated Cu alloy composite fiber prepared by the invention strengthens the mechanical property and the functional property of the original glass-coated Cu alloy fiber.

Drawings

FIG. 1 is a schematic diagram of glass-coated Cu alloy microfilaments;

FIG. 2 is a schematic diagram of a CVD method for synthesizing SiC-coated copper alloy microfilaments;

FIG. 3 shows the surface micro-morphology of glass-coated wire Cu85Sn15, wherein (a) is the alloy wire cross-sectional morphology and (b) is an enlarged view, and wedge-shaped martensitic structure can be seen;

fig. 4 microscopic morphology of the remaining alloy wire surface after HF etching of the glass surface.

Detailed Description

The present invention will be described in detail below with reference to the drawings and the detailed description, and it should not be construed that the invention is limited to the embodiments. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.

Example 1

a. Preparing an alloy, namely proportioning 99.9% of raw materials according to the atomic ratio of Cu to Sn=85 to 15, and then smelting the alloy in a vacuum induction furnace to obtain an original alloy cast ingot;

b. The basic principle of the glass tube selection is shown in figure 1, a glass tube with the working temperature matched with the melting temperature of the alloy is required to be selected, and the common quartz glass is processed at the temperature of over 1700 ℃ and is not suitable for being used as a glass coating material of the alloy, so that a Pyrex high borosilicate glass tube with the working temperature of 1200-1400 ℃ is selected;

c. Checking whether the water pressure condition of the high-frequency induction equipment meets the requirement, ensuring the smoothness of a cooling water pipeline, adjusting the proper position of cooling water, polishing the nippers with sharp mouths for subsequent threading;

d. Adjusting the height and position of the bottom of the glass tube in the induction coil, setting the descending speed of the lifting motor and the rotating speed of the wire winding wheel, adjusting the position of the infrared thermometer, and focusing the temperature measuring point on the alloy position in the test tube;

e. And (3) placing 1-2 g of alloy material into a glass tube, connecting and fixing the glass tube with a welded corrugated tube, vacuumizing to 2.5Pa by a mechanical pump, filling argon to 0.1MPa, and vacuumizing again to 2.5Pa to obtain the SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber.

F. starting a high-frequency induction device attached to an induction coil to induce and melt alloy bonds, wherein FIG. 1 is a physical photograph of the alloy melted at the bottom of a test tube in the preparation process, and simultaneously the bottom of a glass tube is softened;

g. The method comprises the steps of starting an infrared thermometer to monitor alloy temperature, drawing out glass coated alloy filaments from the bottom of a softened glass test tube by using a prepared nipper tip when an alloy ingot and a bottom glass tube reach a molten state, starting a linear servo motor, continuously descending a lifting rod under the action of the linear servo motor to extend a corrugated tube, and descending the glass test tube to supplement consumed glass;

h. Spraying water to cool the continuously obtained glass coated alloy filaments by a water cooling device, and winding the cooled glass coated alloy filaments on a filament winding wheel by a guide wheel;

i. Cutting 50mm of prepared glass-coated copper-tin alloy wire, respectively ultrasonically cleaning the glass-coated copper-tin alloy wire in acetone and absolute ethyl alcohol for 10min, taking out and air-drying the glass-coated copper-tin alloy wire, and then immersing the glass-coated copper-tin alloy wire in an HF solution for 10min for etching to enable a small corrosion pit to be generated on the surface of the glass, so that the specific surface area of a precursor SiO ₂ is increased;

j. FIG. 2 is a schematic diagram of a CVD method for synthesizing SiC-coated copper alloy microfilaments, wherein a uniform glass-coated Cu ₈₅Sn₁₅ alloy microfilaments with the length of about 50mm is cut, and the temperature of a constant temperature area is raised to 800 ℃ required by SiC growth in 50min under the condition of 300sccm argon gas before CH ₄ gas is introduced into a tube furnace;

k. Closing Ar, introducing 50sccm of CH ₄ gas, and adjusting a valve of a mechanical pump to ensure that the pressure of the system is stabilized at 101KPa, and keeping for 12 hours at 850 ℃, so that the composite reinforced fiber of the copper alloy matrix and the SiC coating layer is prepared by using a CVD method;

and I, after synthesizing SiC coated Cu ₈₅Sn₁₅ alloy microfilaments, washing a tubular furnace, vacuumizing to 2.5Pa by a start pump, filling argon to 0.1MPa, vacuumizing again to 2.5Pa, and performing thermal annealing for 1h under the condition that the gas volume ratio of Ar to O ₂ is 500:1 in order to obtain a stable SiO ₂ shell, wherein the annealing temperature range is 800 ℃.

The surface microscopic morphology of the SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber prepared by the invention is shown in figure 3, wherein figure 3 (a) is the cross-sectional morphology of an alloy wire, and figure 3 (b) is an enlarged view, so that a wedge-shaped martensitic structure can be seen;

the surface of the SiC coated Cu ₈₅Sn₁₅ alloy composite fiber prepared in the embodiment 1 is subjected to HF etching, the microstructure is shown in figure 4, the surface is uniform, and the forming effect is good.

In the preparation process of the glass-coated Cu alloy microfilaments, the viscosity of a glass tube is regulated by regulating and controlling the temperature near the melting point of the alloy, so that the forming quality of the glass-coated Cu alloy microfilaments is improved, the uniformity of the glass-coated Cu alloy microfilaments is ensured by selecting proper and stable filament winding wheel rotation speed, the substrate can realize a high energy density state with relatively low input power by the fine copper-tin alloy filaments (30+/-5 mu m), and the high specific surface area of the substrate is favorable for the dissipation of internal heat into an environment gas phase. Thus, a steep, negative thermal gradient is created around the Cu ₈₅Sn₁₅ wire substrate. Since the dispersed energy effectively promotes the decomposition of the precursor and the established temperature field can suppress the gas phase nucleation at high precursor concentrations to a large extent, it is possible to achieve high deposition rates (2-40 μm/min) in hot filament CVD reactors. In addition, the SiO ₂ of the glass coating is used as a precursor, a compact SiC coating is obtained at high temperature by using a CVD method, on one hand, the original surface brittle glass thin layer can be removed, and more importantly, the generated SiC reinforced composite material realizes comprehensive enhancement of mechanical property and functional property.

The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A preparation method of SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber comprises the following steps:

a. preparing 99.9% high-purity alloy elements into an original alloy button cast ingot in a vacuum induction furnace;

b. Putting 1-2 g of an original alloy button cast ingot into a glass tube, vacuumizing, filling argon, and vacuumizing again;

c. The glass tube enters an induction heating zone at a certain speed, alloy button cast ingots are melted by high-frequency induction heating, and the tail ends of the glass tube are softened by heat of metal;

d. The softened glass tube end is drawn into a superfine capillary, molten metal enters the capillary to form glass coated metal microfilaments, the microfilaments pass through cooling liquid and are rapidly solidified to obtain glass coated metal microfilaments, and then the glass coated metal microfilaments are wound on a winding wheel to prepare glass coated yarn Cu ₈₅Sn₁₅ alloy microfilaments by utilizing a glass coated yarn technology;

e. Cutting out uniform glass coated Cu ₈₅Sn₁₅ alloy microfilaments with the length of 50+/-5 mm, putting the microfilaments into a tube furnace, introducing CH ₄ gas, heating and maintaining, and preparing the SiC coated Cu ₈₅Sn₁₅ alloy composite fiber by using a vapor deposition method.

2. The method of manufacturing according to claim 1, wherein:

the high-purity alloy element in the step a is composed of elements with atomic ratio of Cu to Sn=85 to 15.

3. The method of manufacturing according to claim 1, wherein:

And b, vacuumizing to 2.5Pa, then filling argon to 0.1MPa, and vacuumizing again to 2.5Pa.

4. The method of manufacturing according to claim 1, wherein:

and d, the diameter of the glass coated wire Cu ₈₅Sn₁₅ alloy microfilament is 30+/-5 mu m, and the length of the glass coated wire Cu ₈₅Sn₁₅ alloy microfilament is 2+/-0.5 m.

5. The method of manufacturing according to claim 1, wherein:

The heating temperature in step e was 800 ℃ while maintaining for 24 hours.

6. A SiC-coated Cu ₈₅Sn₁₅ alloy composite fiber produced according to the production method of any one of claims 1 to 5.