A single crystal high-oxide-content silver tin oxide indium material and a method for preparing the same

Abstract

The application discloses a single-crystal high-oxide-content silver tin indium oxide material and a preparation method thereof, and finally obtains a required wire product through raw material pretreatment, melt growth, isobaric temperature difference oxidation, plastic processing and annealing. The single-crystal AgSnIn matrix is obtained by using a direct pulling method, and the oxide reinforced phase of the silver tin indium oxide electrical contact material is uniformly distributed and has good interface bonding under the condition of super high pressure and isobaric temperature difference, so that the high anti-welding performance and super high electric life times are ensured. With the increase of the oxide content of the existing high-oxide-content silver tin indium oxide, the oxide is unevenly distributed and has poor interface wettability, while in the application, the single-crystal matrix is introduced, and the super high pressure isobaric temperature difference method is used to solve the problems of coarse grain boundary oxide and poor wettability of the oxide and the matrix, so that the microstructure with uniformly distributed oxide reinforced phase is obtained, and the silver tin indium oxide material has the characteristics of high anti-welding performance, high electric life times and the like, and can be widely applied to automobile relays and the like.

Description

Technical Field

[0001] This invention relates to the field of electrical contact materials technology, specifically to a single-crystal silver oxide-tin oxide-indium oxide material with high oxide content and its preparation method, which is suitable for electrical contact scenarios such as high-performance automotive relays that require high resistance to welding and ultra-high electrical life. Background Technology

[0002] Silver oxide, tin oxide, and indium oxide electrical contact materials are widely used in automotive relays, photovoltaic inverters, and other fields, exhibiting excellent resistance to arc erosion and material transfer.

[0003] With the increase of oxide content, silver oxide, tin oxide, and indium oxide electrical contact materials exhibit problems such as uneven oxide distribution and weak interfacial bonding, resulting in a decrease in anti-welding performance under conditions of high anti-welding performance and ultra-high electrical life cycle, thus failing to meet the requirements of ultra-high electrical life cycle. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the present invention provides a single-crystal silver oxide tin oxide indium oxide material with high oxide content and its preparation method.

[0005] The technical solution adopted in this invention is: a method for preparing a single-crystal silver oxide-tin oxide-indium oxide material with high oxide content, comprising the following steps:

[0006] Step 1: Plasma pretreatment of raw materials containing silver, tin, indium, and additives; Step 2: Place the pretreated raw material in a vacuum induction melting furnace and evacuate it with high-purity argon gas for protection; heat it to 1200-1250℃ to completely melt the raw material and hold it at that temperature for 30-40 minutes; immerse a single-crystal AgSnIn alloy seed crystal into the surface of the melt and pull it up at a speed of 0.5-1.0 mm / min while rotating the seed crystal at 15-20 rpm; control the temperature gradient to 50-80℃ / cm to form a single-crystal ingot with a diameter of 10-15 mm; Step 3: After cutting the single crystal ingot blank processed in Step 2, perform isobaric differential temperature internal oxidation treatment; Step 4: Perform plastic processing and annealing on the blank after step 3 to obtain the single-crystal high oxide content silver tin oxide indium oxide material.

[0007] Furthermore, the specific steps of the plasma pretreatment of silver, tin, indium and additives in step 1 are as follows: weigh 99.99% high-purity silver ingots, tin ingots, indium ingots and additives in proportion and place them in the plasma treatment chamber; introduce a mixture of argon and hydrogen gas and perform plasma treatment at 300-500℃ for 30-60 minutes to remove surface oxide impurities.

[0008] Furthermore, the mass ratio of silver, tin, indium, and additives is 60-85:5-33:6-8:1-2, and the additives are three or more of La, Ce, Ti, Nb, V, and Cr.

[0009] Furthermore, the specific steps of step 3, which involves cutting the processed single crystal ingot blank and then performing isobaric differential temperature internal oxidation treatment, are as follows: the single crystal ingot is cut into 5-10mm wires and placed in an ultra-high pressure oxidation furnace for isobaric differential temperature internal oxidation treatment; wherein the first stage is oxidation for 4-6 hours at 750-800℃ and 5-10MPa; the second stage is oxidation for 30-40 hours at 650-700℃ and 5-10MPa; and the third stage is oxidation for 20-30 hours at 550-600℃ and 5-10MPa.

[0010] Furthermore, the specific steps of step 3, which involves plastic processing and annealing of the processed billet, are as follows: the oxidized wire is pressed into ingots, sintered, and extruded into wire with a diameter of 2.0 mm at 800-900℃; it is then hot-drawn into wire with a diameter of 1.5 mm, during which intermediate annealing is performed at 600-900℃.

[0011] Furthermore, in step 2, the high-purity argon gas evacuation protection is performed by evacuating to a vacuum level of 10. - After ³Pa, high-purity argon gas is introduced for protection.

[0012] Furthermore, in step 1, the volume ratio of the argon gas to the hydrogen gas mixture is 9:1.

[0013] A single-crystal silver tin oxide indium oxide material with high oxide content prepared by the preparation method described above.

[0014] The beneficial effects of this invention are as follows: This invention provides a single-crystal silver-tin-indium oxide material with high oxide content and its preparation method, including raw material pretreatment, melt growth, isobaric temperature differential oxidation, plastic processing and annealing, and finally obtaining the desired wire product. This invention uses the Czochralski method to obtain a single-crystal AgSnIn matrix, and obtains a silver-tin-indium oxide electrical contact material with uniform oxide reinforcement phase distribution and good interfacial bonding under ultra-high pressure and isobaric temperature differential conditions, thereby ensuring high anti-welding performance and ultra-high electrical life cycle requirements. Existing high oxide content silver-tin-indium oxide materials exhibit uneven oxide distribution and poor interfacial wettability as the oxide content increases. However, this invention introduces a single-crystal matrix and uses the ultra-high pressure isobaric temperature differential method to solve the problems of coarse oxide at grain boundaries and poor wettability between oxides and the matrix, obtaining a microstructure with uniform oxide reinforcement phase distribution, which has the characteristics of high anti-welding performance and high electrical life cycle, and can be widely used in automotive relays, etc. Attached Figure Description

[0015] Figure 1 The preparation process flow diagram of the present invention.

[0016] Figure 2 Table 1 shows a comparison of the electrical performance of the examples and comparative examples. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: (1) The mass parts of silver, tin, indium and additives are 85, 5, 8 and 2 respectively, and the mass parts of the additives are La, Ce, Ti, Nb, V and Cr, which are 20 respectively. After weighing, they are placed in a plasma treatment chamber; a mixture of argon and hydrogen gas (volume ratio 9:1) is introduced, and plasma treatment is carried out at 300°C for 60 minutes to remove surface oxide impurities.

[0019] (2) Load the pretreated raw materials into a graphite crucible, place it in a vacuum induction melting furnace, and evacuate to 100°C. - After 3Pa, high-purity argon gas is introduced for protection; the raw material is heated to 1250℃ to completely melt it and held for 30 minutes; the seed crystal (single crystal AgSnIn alloy) is immersed in the surface of the melt and pulled at a speed of 0.5mm / min while rotating the seed crystal at 15rpm; the temperature gradient is controlled at 50℃ / cm to form a single crystal ingot with a diameter of 10mm.

[0020] (3) Cut the single crystal ingot into 5mm wire and place it in an ultra-high pressure oxidation furnace; First stage: Oxidation at 750℃ and 10MPa for 6 hours; Second stage: Oxidation at 650℃ and 10MPa for 40 hours; Third stage: Oxidation at 550℃ and 10MPa for 30 hours; (4) The oxidized wire is pressed into ingots, sintered, and extruded into wire with a diameter of 2.0 mm at 800°C; then hot-drawn to wire with a diameter of 1.5 mm, during which intermediate annealing is carried out at 600°C. The mass fractions of silver, tin, indium, and additives are 60-85%, 5-33%, 6-8%, and 1-2%, respectively. Example 2: (1) The mass parts of silver, tin, indium and additives are 60, 33, 6 and 1 respectively, and the mass parts of the additives are La, Ti, Nb and Cr, which are 25 respectively. After weighing, they are placed in a plasma treatment chamber; a mixture of argon and hydrogen gas (volume ratio 9:1) is introduced, and plasma treatment is carried out at 500°C for 60 minutes to remove surface oxide impurities.

[0021] (2) Load the pretreated raw materials into a graphite crucible, place it in a vacuum induction melting furnace, and evacuate to 100°C. - After 3Pa, high-purity argon gas is introduced for protection; the raw material is heated to 1200℃ to completely melt it and held for 40 minutes; the seed crystal (single crystal AgSnIn alloy) is immersed in the surface of the melt and pulled at a speed of 1.0mm / min while rotating the seed crystal at 20rpm; the temperature gradient is controlled at 80℃ / cm to form a single crystal ingot with a diameter of 15mm.

[0022] (3) Cut the single crystal ingot into 10mm wire and place it in an ultra-high pressure oxidation furnace; First stage: Oxidation at 800℃ and 5MPa for 4 hours; Second stage: Oxidation at 700℃ and 5MPa for 30 hours; Third stage: Oxidation at 600℃ and 5MPa for 20 hours; (4) The oxidized wire is pressed into ingots, sintered, and extruded into wire with a diameter of 2.0 mm at 900 °C; then hot-drawn to wire with a diameter of 1.5 mm, during which intermediate annealing at 900 °C is carried out. Example 3: (1) The mass fractions of silver, tin, indium and additives are 72.5, 19, 7 and 1.5 respectively, and the mass fractions of the additives are Ce, V, Cr and Nb, which are 25 respectively. After weighing, the mixture is placed in a plasma treatment chamber; a mixture of argon and hydrogen gas (volume ratio 9:1) is introduced, and the mixture is plasma treated at 400°C for 45 minutes to remove surface oxide impurities.

[0023] (2) Load the pretreated raw materials into a graphite crucible, place it in a vacuum induction melting furnace, and evacuate to 100°C. - After ³Pa, high-purity argon gas is introduced for protection; the raw material is heated to 1225℃ to completely melt it and held for 35 minutes; a seed crystal (single crystal AgSnIn alloy) is immersed in the surface of the melt and pulled at a speed of 0.75mm / min while rotating at 17.5rpm; the temperature gradient is controlled at 65℃ / cm to form a single crystal ingot with a diameter of 12.5mm.

[0024] (3) Cut the single crystal ingot into 7.5mm wire and place it in an ultra-high pressure oxidation furnace; First stage: Oxidation at 7750℃ and 7.5 MPa for 5 hours; Second stage: Oxidation at 675℃ and 7.5MPa for 34 hours; Third stage: Oxidation at 575℃ and 7.5MPa for 25 hours; (4) The oxidized wire is pressed into ingots, sintered, and extruded into wire with a diameter of 2.0 mm at 850°C; then hot-drawn to wire with a diameter of 1.5 mm, during which intermediate annealing is carried out at 750°C. Comparative example: (1) Silver, tin and indium are continuously cast into AgSn ingots with mass fractions of 85, 7 and 8 respectively, and then extruded to obtain AgSn wire, which is then drawn into wire with a diameter of 1 mm. (2) The wire was oxidized at 800℃ and oxygen pressure of 0.5 MPa for 20 hours; (3) The oxidized wire is broken, pressed into ingots, hot-extruded to a diameter of 4 mm, and then hot-processed to a diameter of 1.5 mm.

[0025] The wires from the above embodiments were rivets and assembled into a relay. Electrical performance tests were conducted under the conditions of 48VDC, 20A, resistive load, 3s on / 3s off, and a sealing test. Specific results are as follows: Figure 2 As shown in Table 1, the arcing time and electrical lifetime of the three embodiments are superior to those of the comparative example. The arcing time is reduced by more than 48.3 ms, the Weibull distribution 95% confidence interval is met, and the electrical lifetime is increased by more than 46,000 cycles.

[0026] Please note to all technical personnel: Although the present invention has been described according to the specific embodiments above, the inventive concept of the present invention is not limited to this invention. Any modifications that utilize the inventive concept will be included within the scope of patent protection of this patent.

[0027] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a single-crystal silver oxide-tin oxide-indium oxide material with high oxide content, characterized in that, Includes the following steps: Step 1: Plasma pretreatment of raw materials including silver, tin, indium, and additives; Step 2: Place the pretreated raw material in a vacuum induction melting furnace and evacuate it with high-purity argon gas for protection; heat it to 1200-1250℃ to completely melt the raw material and hold it at that temperature for 30-40 minutes; immerse a single-crystal AgSnIn alloy seed crystal into the surface of the melt and pull it up at a speed of 0.5-1.0 mm / min while rotating the seed crystal at 15-20 rpm; control the temperature gradient to 50-80℃ / cm to form a single-crystal ingot with a diameter of 10-15 mm; Step 3: After cutting the single crystal ingot blank processed in Step 2, perform isobaric differential temperature internal oxidation treatment; Step 4: Perform plastic processing and annealing on the blank after step 3 to obtain the single-crystal high oxide content silver tin oxide indium oxide material.

2. The preparation method according to claim 1, characterized in that, The specific steps of the plasma pretreatment of silver, tin, indium and additive raw materials in step 1 are as follows: weigh 99.99% high-purity silver ingots, tin ingots, indium ingots and additives in proportion and place them in the plasma treatment chamber; introduce a mixed gas of argon and hydrogen and perform plasma treatment at 300-500℃ for 30-60 minutes to remove surface oxide impurities.

3. The preparation method according to claim 2, characterized in that, The mass ratio of silver, tin, indium, and additives is 60-85:5-33:6-8:1-2, and the additives are three or more of La, Ce, Ti, Nb, V, and Cr.

4. The preparation method according to claim 1, characterized in that, The specific steps of step 3, which involves cutting the processed single crystal ingot blank and then performing isobaric differential temperature internal oxidation treatment, are as follows: the single crystal ingot is cut into 5-10mm wires and placed in an ultra-high pressure oxidation furnace for isobaric differential temperature internal oxidation treatment; the first stage is oxidation at 750-800℃ and 5-10MPa for 4-6 hours; the second stage is oxidation at 650-700℃ and 5-10MPa for 30-40 hours; and the third stage is oxidation at 550-600℃ and 5-10MPa for 20-30 hours.

5. The preparation method according to claim 4, characterized in that, The specific steps of step 3, which involves plastic processing and annealing of the processed billet, are as follows: the oxidized wire is pressed into ingots, sintered, and extruded into wire with a diameter of 2.0 mm at 800-900℃; it is then hot-drawn into wire with a diameter of 1.5 mm, during which intermediate annealing is carried out at 600-900℃.

6. The preparation method according to claim 1, characterized in that, In step 2, the high-purity argon gas evacuation protection is performed by evacuating to a vacuum level of 10. - After ³Pa, high-purity argon gas is introduced for protection.

7. The preparation method according to claim 2, characterized in that, In step 1, the volume ratio of the argon gas to the hydrogen gas mixture is 9:

1.

8. A single-crystal silver tin oxide indium oxide material with high oxide content prepared by the preparation method described in claims 1-7.

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