A si c-coated cu 85 Sn 15 Alloy composite fiber and method for producing the same

Abstract

The application discloses a SiC-coated Cu 85 Sn 15 alloy composite fiber and a preparation method thereof. Firstly, Cu and Sn high-purity alloy are prepared into button 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 drawn into glass-coated metal microfilaments after induction heating. Next, the microfilaments are rapidly solidified through a cooling liquid and collected. Finally, the glass-coated Cu 85 Sn 15 alloy microfilaments are passed through CH4 gas in a tube furnace, and a SiC-coated Cu alloy composite fiber is prepared by vapor deposition at 800 DEG C for 24 hours. Based on the defects of the mechanical properties of the glass-coated Cu alloy filaments and the requirement of removing the surface glass, the brittle SiO2 which needs to be removed is used as a precursor, and CH4 is used as a reaction gas to synthesize a dense SiC film on the surface of the Cu alloy fiber, so that the SiC-coated Cu alloy composite fiber with higher mechanical properties and more functional properties is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of alloy materials, and particularly relates to a SiC-coated Cu 85 Sn 15 Alloy composite fiber and preparation method thereof. BACKGROUND

[0002] The glass outer layer of the alloy fiber prepared by the glass coating method is usually removed by HF or glass etchant, which can easily corrode the original alloy substrate and greatly reduce the mechanical properties. In addition, the Cu alloy substrate formed by the original liquid phase forming has low strength. In recent years, people pay more and more attention to how to synergistically optimize the mechanical properties and functional characteristics of SiC reinforced composite materials. Continuous hot filament chemical vapor deposition (CVD) is specially designed for synthesizing large-diameter SiC fibers. In this method, the deposition layer is directly grown on the heated Cu-based alloy microfilament substrate.

[0003] Silicon carbide (SiC) plays an important role in many industries and various fields of production due to its special physical and chemical properties. The most notable properties include: low density, high thermal conductivity, extremely low friction coefficient, refractoriness, low thermal expansion coefficient, high chemical resistance, corrosion resistance and radiation resistance, high hardness, etc. Silicon carbide has excellent mechanical properties, including strength, fracture toughness, hardness, etc., which improve the bulletproof properties, so it is used in the production of bulletproof vests and composite armor. Silicon carbide is used as a refractory material in the metallurgical industry, in the production of abrasives, cutting and grinding tools, in the nuclear power industry, heating elements, electronic products, etc. In addition, the high covalence of Si-C bonds and the wide band gap properties of SiC endow these reinforcements with excellent thermal conductivity, radiation resistance and microwave absorption efficiency.

[0004] Traditional SiC synthesis methods include combustion method, sintering method, selective method, sol-gel method, hydrothermal acid leaching method, thermal hydrolysis method, low-temperature synthesis, microwave synthesis, in-situ growth and arc synthesis, etc. However, most of the developed SiC whiskers or short-distance nano-SiC fibers cannot meet the production needs, and most SiC composite material fibers are grown in dependence on dispersed and random precursors, so they cannot be applied in practice. 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 excellent physical properties at different temperatures, including tensile strength, elastic modulus, and oxidation and creep resistance, and are therefore widely regarded as an ideal choice for reinforced structures. SUMMARY

[0005] The Cu alloy micro-wire produced by glass-coated wire production belongs to liquid phase forming method, is as-cast structure, and thus has poor mechanical property. On the other hand, the surface glass coating layer is a brittle material, and needs to be peeled or removed in a proper way in actual production. Based on the defects of the mechanical property of the glass-coated Cu alloy wire and the requirement of removing the surface glass, the application utilizes the brittle SiO2 which needs to be removed as a precursor and CH4 as a reaction gas to synthesize a dense SiC film on the surface of the Cu alloy fiber, so as to obtain the SiC-coated Cu alloy composite fiber with higher mechanical property and more functional performance.

[0006] The application is realized by the following technical scheme:

[0007] A SiC-coated Cu 85 Sn 15 alloy composite fiber and a preparation method thereof.

[0008] a. 99.9% high-purity alloy elements with an atomic ratio of Cu:Sn=85:15 are prepared into original alloy button ingots in a vacuum induction furnace;

[0009] b. 1-2g alloy materials are put into a glass tube, vacuumized to 2.5Pa, then filled with argon to 0.1MPa, and vacuumized again to 2.5Pa;

[0010] c. the glass tube enters the induction heating area at a certain speed, the metal is melted by high-frequency induction heating, and the end of the glass tube is softened by the heat of the metal;

[0011] d. the softened end of the glass tube is drawn into an extremely thin capillary tube, the molten metal enters the capillary tube to form a glass-coated metal micro-wire, the micro-wire passes through a cooling liquid, is rapidly solidified to obtain the glass-coated metal micro-wire, and is then wound on a winding wheel. The glass-coated Cu 85 Sn 15 alloy micro-wire (diameter 30±5μm, length 2±0.5m) is prepared by using the glass-coated wire technology;

[0012] e. 50±5mm long uniform glass-coated Cu 85 Sn 15 alloy micro-wires are put into a tube furnace, CH4 gas is introduced, and heated at 800℃ for 24h, so as to prepare the composite reinforcing fiber of copper alloy substrate+SiC coating layer by using the vapor deposition method.

[0013] The application further discloses a SiC-coated Cu 85 Sn 15 alloy composite fiber prepared according to the preparation method.

[0014] The application has the following beneficial effects:

[0015] (1)SiC has wide band gap, low density, low thermal expansion, excellent thermal shock / oxidation / chemical stability, high hardness and high thermal conductivity, etc. Excellent performance, widely used in abrasive tools, ceramics, insulation, metallurgy, refractory and wear-resistant materials and other fields;

[0016] (2) SiC material synthesis process is to use CVD method CH4 and precursor SiO2 reaction, generate H2O and SiO2, no other toxic and harmful substances generated, is a green environmental protection process;

[0017] (3) The melting point of copper-tin alloy and the softening temperature range of glass are relatively consistent, and the alloy has good fluidity, which is very suitable for glass-coated wire stretch forming;

[0018] (4) The SiC-coated Cu alloy composite fiber prepared by the application strengthens the mechanical properties and functional properties of the original glass-coated Cu alloy fiber. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Glass-coated Cu alloy micro-wire production schematic diagram;

[0020] Figure 2 CVD synthesis of SiC-coated copper alloy micro-wire schematic diagram;

[0021] Figure 3 The surface micro-morphology of glass-coated Cu85Sn15 wire, wherein (a) is the cross-sectional morphology of the alloy wire, and (b) is an enlarged view, and the wedge-shaped martensite structure can be seen;

[0022] Figure 4 The micro-morphology of the surface of the remaining alloy wire after HF etching of the glass surface. DETAILED DESCRIPTION

[0023] The application will be described in detail below in conjunction with the drawings and specific embodiments, which cannot be considered as limiting the specific implementation of the application only to these descriptions. For ordinary skilled persons in the technical field to which the application belongs, without departing from the concept of the application, a number of simple deductions or substitutions can be made, which should be considered as belonging to the protection scope of the application.

[0024] Example 1

[0025] A preparation method of SiC-coated Cu 85 Sn 15 alloy composite fiber, comprising the following steps:

[0026] a. Alloy preparation: alloy raw materials are prepared according to the atomic ratio of Cu: Sn = 85: 15, and then alloy smelting is carried out in a vacuum induction furnace to obtain an original alloy ingot;

[0027] b. Glass tube selection: The basic principle of glass-coated wire glass-coated wire technology is shown in Figure 1 Figure, the working temperature of the glass tube needs to be selected to match the alloy melting temperature, the ordinary quartz glass processing temperature is above 1700℃, which is not suitable for the glass cladding layer material of the alloy, so the Pyrex high borosilicate glass tube with a working temperature of 1200-1400℃ is selected;

[0028] c. Preparation before experiment: Check whether the water pressure condition of high-frequency induction equipment meets the requirements, ensure that the cooling water pipeline is unobstructed, adjust the cooling water to the appropriate position, and polish the pointed forceps for subsequent wire drawing;

[0029] d. Adjust the height and position of the glass tube at the bottom of the induction coil, set the descending speed of the lifting motor and the rotating speed of the winding wheel; adjust the position of the infrared temperature measuring instrument, and focus the measuring point on the alloy position in the test tube;

[0030] e. Put 1-2g of alloy into the glass tube, connect and fix the glass tube with the corrugated pipe, open the mechanical pump to vacuum to 2.5Pa, fill argon to 0.1MPa, vacuum again to 2.5Pa, and obtain a SiC-coated Cu 85 Sn 15 alloy composite fiber.

[0031] f. Start the high-frequency induction device attached to the induction coil, melt the alloy key by induction, Figure 1 and the bottom of the glass tube is softened at the same time;

[0032] g. Start the infrared temperature measuring instrument to monitor the alloy temperature, when the alloy ingot and the bottom of the glass tube reach the molten state, use the pre-prepared forceps with a sharp end to pull out the glass-coated alloy filament from the softened glass test tube at the bottom; at the same time, start the linear servo motor, and the lifting rod is constantly lowered under the action of the linear servo motor, so that the corrugated pipe is elongated, and the glass test tube is lowered, supplementing the consumed glass;

[0033] h. The continuously obtained glass-coated alloy filament is cooled by water cooling device, and then wound on the winding wheel through the guide roller;

[0034] i. Cut off 50mm of the prepared glass-coated copper-tin alloy wire, and ultrasonically clean it in acetone and anhydrous ethanol for 10min respectively, and then air dry; then immerse it in HF solution for 10min for etching, so that small corrosion pits are generated on the glass surface, and the specific surface area of the precursor SiO2 is increased;

[0035] j. Figure 2 is the schematic diagram of CVD method for synthesizing SiC-coated copper alloy microfilament, and about 50mm long uniform glass-coated Cu 85Sn 15 The alloy micro-wire is put into a tube furnace, and before CH4 gas is introduced, the system is kept in an argon gas environment of 300 sccm, and the temperature in the constant temperature zone is increased to 800 DEG C required for SiC growth within 50 min;

[0036] k.Closing Ar, introducing 50 sccm of CH4 gas, and adjusting the valve of the mechanical pump to keep the pressure of the system stable at 101 KPa; keeping at 850 DEG C for 12 h to prepare the composite reinforcing fiber of copper alloy substrate + SiC coating layer by the CVD method;

[0037] l.SiC-coated Cu 85 Sn 15 The tube furnace is purged after the alloy micro-wire, the mechanical pump is used to vacuumize to 2.5 Pa, argon gas is filled to 0.1 MPa, and vacuumization is performed again to 2.5 Pa; in order to obtain a stable SiO2 shell, heat annealing is performed for 1 h under the condition that the gas volume ratio of Ar:O2 is 500:1, and the temperature range of annealing is 800 DEG C.

[0038] The SiC-coated Cu 85 Sn 15 The surface micro-morphology of the alloy composite fiber is as shown in Figure 3 , wherein Figure 3 (a) is the cross-sectional morphology of the alloy wire material, Figure 3 (b) is an enlarged view, and the wedge-shaped martensite structure can be seen;

[0039] HF etching is performed on the surface of the SiC-coated Cu 85 Sn 15 alloy composite fiber prepared in Example 1, and the micro-morphology is as shown in Figure 4 , and it can be seen that the surface is relatively uniform, and the forming effect is good.

[0040] In the preparation process of the glass-coated Cu alloy micro-wire, the viscosity of the glass tube is adjusted by adjusting the temperature near the melting point of the alloy, so that the forming quality of the glass-coated Cu alloy micro-wire is improved; the uniformity of the glass-coated Cu alloy micro-wire is ensured by selecting a suitable and stable winding wheel speed; the thin copper-tin alloy wire (30±5 mu m) enables the substrate to realize a high energy density state with a relatively low input power, and its high specific surface area is conducive to internal heat dissipation to the environment gas phase. Therefore, in the Cu 85 Sn 15A steep, negative thermal gradient is generated around the filament substrate. Since the dispersed energy effectively promotes precursor decomposition and the established temperature field can largely suppress gas-phase nucleation at high precursor concentrations, it is possible to achieve high deposition rates (2–40 μm / min) in a hot-filament CVD reactor. Furthermore, this invention uses glass-coated SiO2 as a precursor and obtains a dense SiC coating at high temperature using CVD. This removes the original brittle glass layer; more importantly, the resulting SiC-reinforced composite material achieves comprehensive enhancement of both mechanical and functional properties.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A SiC-coated Cu 85 Sn 15 The preparation method of alloy composite fibers includes: a. Prepare original alloy button ingots by using 99.9% high-purity alloying elements in a vacuum induction furnace; b. Take 1-2g of the original alloy button ingot and put it into a glass tube. After evacuating the tube, fill it with argon gas and then evacuate the tube again. c. The glass tube enters the induction heating zone at a certain speed, and the alloy button ingot is melted by high-frequency induction heating, and the end of the glass tube is softened by the heat of the metal. d. The softened glass tube is drawn into an extremely fine capillary; molten metal enters the capillary, forming glass-coated metal microfilaments; Microfilaments are passed through a coolant and rapidly solidify to obtain glass-coated metal microfilaments, which are then wound onto a winding wheel. Glass-coated Cu microfilaments are thus prepared using glass-coated filament technology. 85 Sn 15 Alloy microwires; e. Cut a 50±5mm long piece of uniform glass-coated Cu 85 Sn 15 Alloy microwires were placed in a tube furnace, CH4 gas was introduced, and the furnace was heated and held. A SiC-coated Cu alloy was then prepared using chemical vapor deposition. 85 Sn 15 Alloy composite fiber.

2. The preparation method according to claim 1, wherein: The high-purity alloying elements mentioned in step a are composed of elements with an atomic ratio of Cu:Sn = 85:

15.

3. The preparation method according to claim 1, wherein: After evacuating to 2.5 Pa as described in step b, argon gas is introduced to 0.1 MPa, and then evacuated to 2.5 Pa again.

4. The preparation method according to claim 1, wherein: Step d describes the glass-coated wire Cu 85 Sn 15 The alloy microwires have a diameter of 30±5μm and a length of 2±0.5m.

5. The preparation method according to claim 1, wherein: The heating temperature in step e is 800℃, and it is maintained for 24 hours.

6. A SiC-coated Cu obtained by the preparation method according to any one of claims 1 to 5 85 Sn 15 Alloy composite fiber.

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