Preparation method of SnO2@CuO reinforced silver-based composite material

Abstract

The present invention discloses a method for preparing a SnO2@CuO-reinforced silver-based composite material. The present invention adopts an in-situ reaction synthesis preparation technology to obtain the SnO2@CuO-reinforced silver-based composite material; first, a SnO2@Cu core-shell structure is obtained by high-energy ball milling, and then the SnO2@CuO-reinforced silver-based composite material is obtained by in-situ reaction synthesis and sintering, and then the composite material round rod, strip or wire is obtained by processing techniques such as extrusion, rolling or drawing. The SnO2@CuO core-shell structure-reinforced silver-based composite material can be obtained by in-situ reaction synthesis. The formed composite material has a clean interface and a strong interface bonding, which greatly exerts the synergistic effect of the core-shell structure, and finally obtains a SnO2@CuO-reinforced silver-based composite material with excellent mechanical properties and substantially no reduction in electrical conductivity.

Description

Technical Field

[0001] The invention relates to a preparation method of a SnO2@CuO reinforced silver-based composite material, belonging to the field of new electronic information materials. Background Art

[0002] The contact materials used in low-voltage electrical switches are primarily silver-based composites. The earliest developed and applied Ag / CdO electrical contact materials are restricted by the EU's ROS Directive due to the presence of the element Cd, which can cause environmental pollution and harm human health. There is an urgent need to develop new, environmentally friendly silver-based composites with enhanced microstructures.

[0003] Currently, the preparation processes for silver metal oxide composites on the market include powder metallurgy, internal alloy oxidation, and powder pre-oxidation. Powder metallurgy is the most basic process for preparing silver metal oxide materials. It features a simple process, relatively easy element addition, and is not constrained by material composition. However, the simple powder mixing process struggles to ensure uniform distribution of the reinforcing phase within the silver matrix. Furthermore, the raw materials are susceptible to external contamination and numerous defects during the preparation process, leading to poor electrical contact performance. Silver metal oxide materials prepared using the internal alloy oxidation method often suffer from incomplete oxidation, which compromises their performance. Powder pre-oxidation, another type of powder metallurgy method, also suffers from the disadvantages of raw materials being susceptible to external contamination and numerous defects, leading to poor electrical contact performance. To address the shortcomings of traditional preparation processes, researchers have developed novel silver metal oxide preparation methods, including chemical co-precipitation, electroless plating, high-energy ball milling, and sol-gel methods. While these novel preparation processes have somewhat addressed the shortcomings of traditional processes, the silver metal oxides produced by these methods still fall significantly short of expectations. The main reason is that no matter which preparation method is used to obtain the silver-based electrical contact material, its comprehensive performance cannot reach the excellent level of traditional electrical contact material AgCdO.

[0004] Based on this industry background, the present invention proposes a method for preparing a core-shell structured metal oxide-reinforced silver-based material using in-situ reaction synthesis technology. This method has the advantages of utilizing existing traditional production equipment, eliminating the need for secondary investment, and achieving excellent mechanical properties. Summary of the Invention

[0005] The present invention aims to provide a method for preparing a SnO2@CuO-reinforced silver-based composite material, which specifically comprises the following steps: under inert gas protection, commercially available nano-SnO2 and copper powder are mixed in proportion, and the mixture is ball-milled in a high-energy ball mill to obtain SnO2@Cu powder; the SnO2@Cu powder is then uniformly mixed with silver powder and silver oxide powder in proportion, pressed into an ingot, and then sintered in an in-situ reaction sintering furnace to obtain a SnO2@CuO-reinforced silver-based composite material sintered blank; and finally, the sintered blank is densified, extruded, drawn, or rolled to prepare a wire or strip, specifically comprising the following steps:

[0006] (1) Weigh nano-SnO2 powder, copper powder, silver powder, and silver oxide powder and set aside.

[0007] (2) The nano-SnO2 in step (1) is mixed with copper powder in a mass ratio of 12:(0.5-3.5) or SnO2:Cu in a mass ratio of 10:(2.5-4.5), and then ball milled at a speed of 400-800 r / min for 0.5-3 h under the protection of inert argon to obtain SnO2@Cu powder.

[0008] (3) The SnO2@Cu powder in step (2) and the silver powder and silver oxide powder in step (1) are prepared according to the mass percentage of SnO2@CuO generated in the silver matrix being 12%-18%, and ball milling is performed at a speed of 100-500 r / min for 0.5-2 h to obtain a composite powder with uniform mixing.

[0009] (4) The composite powder in step (3) is loaded into a mold, formed under a pressing pressure of 150-500 MPa, and the formed ingot is placed in an in-situ reaction sintering furnace and sintered at 100-850° C. to obtain a SnO2@CuO reinforced silver-based composite material sintered ingot; finally, the sintered ingot is densified, extruded, drawn or rolled to prepare a wire or strip.

[0010] Preferably, the commercially available nano-SnO2 powder of the present invention has a particle size of 40-80 nm and a purity of 99.9%; the copper powder has a particle size of 0.5-50 μm and a purity of 99.9%; the silver powder has a particle size of 10-80 μm and a purity of 99.9%; and the silver oxide powder has a particle size of 10-50 μm and a purity of 99.9%.

[0011] Preferably, the sintering process of the present invention selects multi-stage sintering, and the specific conditions are: sintering temperature and time are: 100°C for 1 hour, 300°C for 1 hour, and 830°C for 1 hour.

[0012] The method of the present invention can improve the interface wettability of SnO2-reinforced silver-based composite materials by taking advantage of the good interface wettability between shell CuO and silver, thereby improving the processing performance and yield rate of the silver-based composite materials; the obtained SnO2@CuO-reinforced silver-based composite materials have excellent mechanical properties.

[0013] The ball milling speed for synthesizing SnO2@Cu powder according to the present invention is 500 r / min and the ball milling time is 1.5 h.

[0014] The present invention has the following beneficial effects: Compared to traditional silver metal oxides, a SnO2@CuO core-shell structured metal oxide-reinforced silver-based composite material is obtained. Compared to AgSnO2 composites, this composite material not only improves the interfacial wettability between SnO2 and silver, enhancing the composite's processing performance, but also produces a SnO2@CuO core-shell structure-reinforced silver-based composite material with excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a process flow chart of the present invention.

[0016] Figure 2 This is a high-resolution transmission electron microscopy image of the prepared SnO2@CuO core-shell structure reinforced silver-based composite material. Specific implementation plan

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the protection content of the present invention is not limited to the scope described in the embodiments.

[0018] Example 1

[0019] like Figure 1 The process flow is as follows: commercially available nano-SnO2 and copper powder are mixed in a ratio of SnO2:Cu=12:2.5 (mass ratio), and then ball-milled at a speed of 500r / min for 1.5h under the protection of inert argon to obtain SnO2@Cu powder; then SnO2@Cu powder is prepared with silver powder and silver oxide powder according to the standard of generating 14.7% (mass percentage) SnO2@CuO in the silver matrix, and ball-milled at a speed of 300r / min for 1h to obtain a uniformly mixed composite powder; and then the composite is mixed with silver powder and silver oxide powder. The mixed powder is loaded into a mold and formed under a pressing pressure of 350 MPa, and the formed ingot is placed in an in-situ reaction sintering furnace and sintered according to a sintering process of 100°C (keeping warm for 1 hour) → 300°C (keeping warm for 1 hour) → 830°C (keeping warm for 1 hour) to obtain a SnO2@CuO reinforced silver-based composite material sintered billet; finally, the sintered billet is densified, extruded and drawn (or rolled) to prepare it into a wire (or strip); through this process, a silver metal oxide composite material with a tensile strength of 380 MPa can be obtained.

[0020] Example 2

[0021] like Figure 1 The process flow is as follows: commercially available nano-SnO2 and copper powder are mixed in a ratio of SnO2:Cu=12:0.5 (mass ratio), and then ball-milled at a speed of 400r / min for 3h under inert argon protection to obtain SnO2@Cu powder; then SnO2@Cu powder is prepared with silver powder and silver oxide powder according to the standard of generating 13% (mass percentage) of SnO2@CuO in the silver matrix, and ball-milled at a speed of 200r / min for 2h. A uniformly mixed composite powder is obtained; the composite powder is then loaded into a mold and formed under a pressing pressure of 500 MPa, and the formed ingot is placed in an in-situ reaction sintering furnace and sintered according to a sintering process of 150°C (keeping warm for 1 hour) → 360°C (keeping warm for 1 hour) → 840°C (keeping warm for 1 hour) to obtain a SnO2@CuO reinforced silver-based composite material sintered billet; finally, the sintered billet is densified, extruded, drawn (or rolled) to prepare it into a wire (or strip).

[0022] Example 3

[0023] like Figure 1 The process flow is as follows: commercially available nano-SnO2 and copper powder are mixed in a ratio of SnO2:Cu=12:3.5 (mass ratio), and then ball-milled at a speed of 800r / min for 0.5h under the protection of inert argon to obtain SnO2@Cu powder; then SnO2@Cu powder is prepared by mixing with silver powder and silver oxide powder according to the standard of generating 16% (mass percentage) of SnO2@CuO in the silver matrix, and ball-milled at a speed of 500r / min for 0.5h. h to obtain a uniformly mixed composite powder; the composite powder is then loaded into a mold and formed under a pressing pressure of 500 MPa, and the formed ingot is placed in an in-situ reaction sintering furnace and sintered according to a sintering process of 200°C (keeping warm for 2 hours) → 500°C (keeping warm for 1 hour) → 850°C (keeping warm for 0.5 hours) to obtain a SnO2@CuO reinforced silver-based composite material sintered billet; finally, the sintered billet is densified, extruded, drawn (or rolled) to prepare a wire (or strip).

[0024] Example 4

[0025] like Figure 1The process flow is as follows: commercially available nano-SnO2 and copper powder are mixed in a ratio of SnO2:Cu=10:4.5 (mass ratio), and then ball-milled at a speed of 600r / min for 3h under inert argon protection to obtain SnO2@Cu powder; then SnO2@Cu powder is prepared with silver powder and silver oxide powder according to the standard of generating 16% (mass percentage) SnO2@CuO in the silver matrix, and ball-milled at a speed of 400r / min for 1h. A uniformly mixed composite powder is obtained; the composite powder is then loaded into a mold and formed under a pressing pressure of 500 MPa, and the formed ingot is placed in an in-situ reaction sintering furnace and sintered according to a sintering process of 100°C (keeping for 2 hours) → 380°C (keeping for 1 hour) → 830°C (keeping for 3 hours) to obtain a SnO2@CuO reinforced silver-based composite material sintered billet; finally, the sintered billet is densified, extruded, drawn (or rolled) to prepare it into a wire (or strip).

Claims

1. A method for preparing a SnO2@CuO reinforced silver-based composite material, characterized in that: Specifically, the method comprises the following steps: under the protection of an inert gas, commercially available nano-SnO2 and copper powder are mixed in proportion, and the mixture is ball-milled in a high-energy ball mill to obtain SnO2@Cu powder; the SnO2@Cu powder is then uniformly mixed with silver powder and silver oxide powder in proportion, pressed into an ingot, and then sintered in an in-situ reaction sintering furnace to obtain a SnO2@CuO reinforced silver-based composite material sintered blank; and finally, the sintered blank is densified, extruded, and drawn to prepare a wire, or the sintered blank is densified and rolled to prepare a strip. Specifically, the method comprises the following steps: (1) Weigh nano-SnO2 powder, copper powder, silver powder, and silver oxide powder for later use; (2) After mixing the nano-SnO2 and copper powder in step (1) in a mass ratio of 12: (0.5-3.5) or 10: (2.5-4.5), the mixture was ball-milled at a speed of 400-800 r / min for 0.5-3 h under the protection of inert argon gas to obtain SnO2@Cu powder; (3) The SnO2@Cu powder in step (2) is mixed with the silver powder and silver oxide powder in step (1) to prepare a SnO2@CuO with a mass percentage of 12%-18% in the silver matrix, and the mixture is ball-milled at a speed of 100-500 r / min for 0.5-2 h to obtain a uniformly mixed composite powder; (4) The composite powder in step (3) is loaded into a mold and formed under a pressing pressure of 150-500 MPa, and the formed ingot is placed in an in-situ reaction sintering furnace. The sintering temperature and time are: 100-200°C for 1 hour, 300-380°C for 1 hour, and 830-850°C for 1 hour to obtain a SnO2@CuO reinforced silver-based composite material sintered billet; finally, the sintered billet is densified, extruded and drawn to prepare a wire, or the sintered billet is densified and rolled to prepare a strip.

2. The method for preparing the SnO2@CuO reinforced silver-based composite material according to claim 1, characterized in that: The particle size of commercially available nano-SnO2 powder is 40~80nm and the purity is 99.9%; the particle size of copper powder is 0.5-50µm and the purity is 99.9%; the particle size of silver powder is 10-80µm and the purity is 99.9%; the particle size of silver oxide powder is 10-50µm and the purity is 99.9%.

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