High-purity silver-lithium alloy target material and preparation method thereof

Abstract

The invention discloses a high-purity silver-lithium alloy target material and a preparation method thereof, the high-purity silver-lithium alloy target material comprises the following raw materials in percentage by mass: 0.5-5% of high-purity lithium, 0.1-0.3% of an auxiliary agent and the balance of high-purity silver, and the high-purity lithium accounts for 0.5-5% of the raw materials, the auxiliary agent accounts for 0.1-0.3% of the raw materials and the balance of the high-purity silver. The preparation method comprises the following steps: sealing high-purity lithium by adopting part of high-purity silver in a dry oxygen-free environment; secondly, the auxiliary agent, the remaining high-purity silver and the high-purity lithium sealed by the high-purity silver are placed in a vacuum medium-frequency induction furnace to be smelted and cast, and a cast ingot is obtained; and thirdly, the cast ingot is sequentially subjected to homogenization, hot forging, rolling, finished product annealing, machining and binding operation, and the high-purity silver-lithium alloy target material is obtained. The high-purity silver-lithium alloy target material can be applied to an organic light-emitting diode anode material and / or a lithium ion battery anode.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material preparation, and specifically relates to a high-purity silver-lithium alloy target material and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of miniaturization, low energy consumption and lightweight of electronic devices, various types of high-precision electronic materials have gradually changed from bulk materials to thin film materials in the fields of semiconductors, information storage industry, microelectronics industry, new energy industry and other technical fields, which has led to the rapid development of coating devices. Sputtering deposition through target materials is one of the main technologies for preparing thin film materials. Using sputtering technology and different target materials to prepare a variety of composite thin films of different materials can achieve the special performance requirements of various electronic information products in terms of light, electricity, magnetism, force and other aspects.

[0003] Silver-lithium alloy target is a special electronic material with high added value. The alloy is widely used in electronic information, display devices, sensors, new energy lithium batteries and other fields. For example, metallic lithium is considered to be the most promising negative electrode material because of its extremely high theoretical capacity, lowest electrode potential and low density. Silver has good lithium affinity. Using silver-lithium alloy targets and sputtering to prepare lithium battery negative electrodes is one of the most economical and efficient preparation methods. Therefore, silver-lithium alloy targets have broad market demand and are being widely used in the new energy and electronic information industries.

[0004] However, it is difficult to prepare high-purity silver-lithium alloy, and there is no report on the preparation method of high-purity silver-lithium alloy target. Studies have shown that the purity, impurity type, density, grain size and orientation, magnetic permeability value, surface quality, etc. of the sputtering target directly affect the performance of the sputtering target. First of all, the purity of the silver-lithium alloy and the quality of the target directly determine the quality of the device prepared by the sputtering target. It is well known that lithium has the most negative electrode potential and the strongest metal activity among all known elements. The oxygen content in the target has a great influence on the stability of its sputtered film, so the oxygen content inside the silver-lithium alloy must be controlled. Therefore, controlling lithium oxidation, nitridation and sulfidation reactions is a key factor in the preparation of silver-lithium alloy. In addition, some researchers pointed out that alloys containing less than 1% lithium can withstand cold processing, and alloys containing more than 1% lithium have a rapid deterioration in processing performance as the lithium content increases [Editing Group of the Precious Metal Processing Manual. Precious Metal Processing Manual [M]. Beijing: Metallurgical Industry Press, 1978, 18.]. Alloy targets are generally polycrystalline materials with a wide range of grain sizes, ranging from micrometers to millimeters. Generally speaking, the sputtering rate of targets with fine grains is faster than that of targets with coarse grains. Therefore, the size and uniformity of the silver-lithium target grains are key factors affecting the sputtering deposition efficiency, and also directly affect the uniformity of the thickness distribution of the deposited film. It is worth pointing out that simultaneously solving the product quality problems of the silver-lithium alloy target, such as grain size, density, impurity content, and grain orientation distribution, is an important issue in the production of high-quality silver-lithium alloys.

[0005] Faced with such a wide market demand for high-purity silver-lithium alloy targets, how to control the purity, grain size, etc. of silver-lithium alloy and achieve low-cost, mass-produced silver-lithium alloy targets is an important issue that needs to be solved urgently. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a high-purity silver-lithium alloy target material and a preparation method thereof in view of the above-mentioned deficiencies of the prior art. The high-purity silver-lithium alloy target material prepared by the method has excellent oxidation resistance, corrosion resistance and reflectivity, and can be applied to organic light-emitting diode anode materials and / or lithium-ion battery anodes.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a high-purity silver-lithium alloy target, characterized in that the raw materials of the high-purity silver-lithium alloy target include high-purity silver, high-purity lithium and auxiliary agents, the mass percentage of lithium in the high-purity silver-lithium alloy target is 0.5% to 5%, the mass percentage of the auxiliary agent is 0.1% to 0.3%, and the remainder is silver and other inevitable impurities.

[0008] The above-mentioned high-purity silver-lithium alloy target is characterized in that the mass purity of the high-purity silver is not less than 99.99%, the mass purity of the high-purity lithium is not less than 99.95%, the mass purity of the auxiliary agent is not less than 99.95%, and the auxiliary agent is one or more of Ga, In, V, Pt, Mg, Sn, borax and calcium oxide.

[0009] Furthermore, the present invention provides a method for preparing the above-mentioned high-purity silver-lithium alloy target, characterized in that it comprises the following steps:

[0010] Step 1: In a dry and oxygen-free environment, partially seal high-purity lithium with high-purity silver for smelting;

[0011] Step 2: placing the auxiliary agent, the remaining high-purity silver and the high-purity lithium sealed with high-purity silver in step 1 in a vacuum medium-frequency induction furnace for smelting and casting to obtain an ingot;

[0012] Step 3: The ingot obtained in step 2 is homogenized, hot forged, rolled, annealed, machined and bound in sequence to obtain a high-purity silver-lithium alloy target.

[0013] The above method is characterized in that the oxygen content of the dry oxygen-free environment in step 1 is less than 6 ppm, the water content is less than 0.2 ppm, the sulfur content is less than 0.2 ppm, and the nitrogen content is less than 0.5 ppm.

[0014] The above method is characterized in that the smelting and casting process in step 2 specifically includes: at the beginning, the vacuum medium frequency induction furnace is evacuated to a vacuum degree of ≤10 -2 Pa, and then start heating. After the silver starts to melt, fill with argon to 0.05MPa~0.06MPa, continue to heat to 1100±50℃, reduce the current to keep warm, open the hopper, put in high-purity lithium sealed with high-purity silver, and refine after all the lithium is melted. The refining time is not less than 3min~8min, and finally pour it into a steel / graphite mold at 1100±50℃.

[0015] The above method is characterized in that during homogenization in step 3, the surface of the ingot is wrapped with copper foil, and the homogenization treatment is carried out in a vacuum annealing furnace, and the vacuum degree of the vacuum annealing furnace is ≤10 -2 Pa, raise the temperature to 50℃~80℃ lower than the melting point of the alloy, keep warm for 1h~3h, and quench with argon.

[0016] The above method is characterized in that the hot forging temperature in step three is 120°C to 300°C lower than the melting point of the alloy, and the holding time is 15min to 30min; during forging, the ingot is upset three times along the height direction, the upsetting amounts of the first two times are both greater than 50% to 60% of the height, and the last time is forged to a disc with a thickness of 10mm to 20mm, and cooled after forging is completed.

[0017] The above method is characterized in that the total rolling reduction rate in step three is 70% to 90%, and the rotary reversing rolling method is adopted during rolling, that is, after each rolling pass, the billet feeding direction is rotated until the rolling force is applied in all directions within a circle.

[0018] The above method is characterized in that the finished product is wrapped with copper foil or tantalum foil during annealing in step 3, the annealing temperature is 200°C to 400°C, the insulation time is 1h to 2h, and the vacuum degree is ≤10 -2 Pa.

[0019] Furthermore, the present invention provides an application of the above-mentioned high-purity silver-lithium alloy target in an organic light-emitting diode anode material and / or a lithium-ion battery anode.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. In the smelting of silver-lithium high-purity alloy, the present invention seals high-purity lithium in high-purity silver and loads it into the smelting furnace, which solves the problem of lithium element loss and increased oxygen content of the alloy due to lithium oxidation during the furnace loading process, and ensures the purity of the alloy.

[0022] 2. The present invention adds a small amount of auxiliary agent during the smelting of silver-lithium alloy, preferably one or more of Ga, In, V, Pt, Mg, Sn, borax and calcium oxide as auxiliary agents. On the one hand, these auxiliary agents can remove impurities of the alloy by forming slag; on the other hand, a small amount of Ga, In, Mg, V or Sn entering the silver base can improve the anti-sulfurization effect of the silver-lithium target.

[0023] 3. In the rolling process of the silver-lithium alloy target material, the present invention adopts reversing rolling, which can effectively reduce the preferential orientation of the silver-lithium target material and improve the uniformity of the grain size distribution.

[0024] 4. In the present invention, during the annealing process of the silver-lithium alloy target, copper foil or tantalum foil is used for wrapping, which can reduce the lithium volatilization of the silver-lithium alloy target during the heat treatment process and reduce the pollution to the vacuum heat treatment furnace.

[0025] 5. The high-purity silver-lithium alloy target prepared by the present invention has excellent oxidation resistance, corrosion resistance and reflectivity, and can be applied to organic light-emitting diode anode materials and / or lithium-ion battery anodes.

[0026] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of reversing rolling direction.

[0028] Figure 2Scanning electron microscope image of the alloy prepared in Example 1 of the present invention (after etching).

[0029] Figure 3 Scanning electron microscope image of the alloy prepared in Example 3 of the present invention (after etching). DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with specific embodiments, so as to more clearly explain the advantages of the present invention. The embodiments described are only exemplary and do not constitute any limitation to the scope of the present invention.

[0031] The mass purity of the silver used in the present invention is ≥99.99%, the mass purity of the lithium is ≥99.95%, and the mass purity of other raw materials is ≥99.9%.

[0032] Example 1

[0033] A high-purity silver-lithium alloy target material of this embodiment, the raw materials include high-purity silver, high-purity lithium and auxiliary agents, the mass percentage of lithium in the high-purity silver-lithium alloy target material is 2.62%, the mass percentage of the auxiliary agent is 0.15%, and the balance is silver and other inevitable impurities; the auxiliary agent is gallium, indium, magnesium, vanadium and borax; the mass purity of the high-purity silver is not less than 99.99%, the mass purity of the high-purity lithium is not less than 99.95%, and the mass purity of the auxiliary agent is not less than 99.95%. The melting point of the alloy is about 630°C.

[0034] The preparation process of the high-purity silver-lithium alloy target of this embodiment specifically includes the following steps:

[0035] Step 1: Put 1630g of high-purity silver can with a sealable lid into a glove box, weigh 168g of high-purity lithium (considering burnout) in the glove box, and put it into the weighed high-purity silver can and seal it; the oxygen content inside the glove box is less than 6ppm, the water content is less than 0.2ppm, the sulfur content is less than 0.2ppm, and the nitrogen content is less than 0.5ppm;

[0036] Step 2: According to the alloy composition ratio of this embodiment, 1g vanadium, 2g gallium, 2g indium, 2g magnesium, 3g borax and 4200g high-purity silver are weighed, and the total mass of the alloy is 6008g, wherein the indium, magnesium and borax are wrapped with high-purity silver foil, and then the high-purity silver and the auxiliary agent are loaded into the high-purity graphite crucible of the vacuum induction furnace, and the high-purity silver tank containing high-purity lithium in step 1 is temporarily stored in the hopper; at the beginning of smelting, the vacuum degree of the vacuum chamber is ≤10 -2 Pa, after the silver begins to melt, fill with argon gas to 0.05MPa~0.06MPa, continue to heat up to 1100±50℃, reduce the current to keep warm, open the hopper, put in a high-purity silver tank filled with high-purity lithium, and refine after all the lithium is melted. The refining time is not less than 8min, and finally pour into a steel mold at 1100±50℃ to obtain an ingot;

[0037] Step 3: The ingot obtained in step 2 is homogenized, hot forged, rolled, annealed, and machined into a round target with a thickness of 5 mm and a diameter of 101.6 mm, and bound with a copper back plate to obtain a high-purity silver-lithium alloy target;

[0038] In this embodiment, the surface of the ingot is wrapped with copper foil during homogenization, and homogenization is performed in a vacuum annealing furnace, and the vacuum degree of the vacuum annealing furnace is ≤10 -2 Pa, heating to 550 °C, keeping temperature for 1 h, quenching with argon;

[0039] In this embodiment, the hot forging temperature is 400°C, the holding time is 20 minutes, and during forging, three rounds of upsetting are performed along the height direction of the ingot, and each round is returned to the furnace for holding for 10 minutes. The upsetting amount of the first two rounds should be greater than 50% to 60% of the height. The last round is forged to a disc with a thickness of about 17 mm. After the forging is completed, the forging is buried in charcoal powder and slowly cooled;

[0040] In this embodiment, the surface of the blank is polished before rolling to remove the oxide layer and impurities on the surface, and then cold rolling is performed; the total cold rolling reduction rate is about 70%, and the reduction rate of each pass is controlled to be about 10% of the deformation; the "M" reversing rolling method should be used for rolling, and the reversing of different passes is as shown in the attached figure. Figure 1 As shown;

[0041] In this embodiment, the finished product is wrapped with copper foil during annealing, the annealing temperature is 250°C, the holding time is 1.5h, and the vacuum degree is ≤10 -2 Pa.

[0042] Example 2

[0043] A high-purity silver-lithium alloy target material of this embodiment, the raw materials include high-purity silver, high-purity lithium and auxiliary agents, the mass percentage of lithium in the high-purity silver-lithium alloy target material is 0.5%, the mass percentage of the auxiliary agent is 0.1%, and the balance is silver and other inevitable impurities; the auxiliary agent is indium, magnesium and borax; the purity of the material is consistent with that of Example 1. The melting point of the alloy is about 840°C.

[0044] The preparation process of the high-purity silver-lithium alloy target of this embodiment specifically includes the following steps:

[0045] Step 1: Put 1630g of high-purity silver can with a sealable lid into a glove box, weigh 33g of high-purity lithium (considering burnout) in the glove box, and put it into the weighed high-purity silver can and seal it; the oxygen content inside the glove box is less than 6ppm, the water content is less than 0.2ppm, the sulfur content is less than 0.2ppm, and the nitrogen content is less than 0.5ppm;

[0046] Step 2: According to the alloy composition ratio of this embodiment, 2g indium, 2g magnesium, 2g borax and 4340g high-purity silver are weighed, and the total mass of the alloy is 6009g, wherein the indium, magnesium and borax are wrapped with high-purity silver foil, and then the high-purity silver and the auxiliary agent are loaded into the high-purity graphite crucible of the vacuum induction furnace, and the high-purity silver tank containing high-purity lithium in step 1 is temporarily stored in the hopper; at the beginning of smelting, the vacuum degree of the vacuum chamber is ≤10 -2 Pa, after the silver begins to melt, fill with argon gas to 0.05MPa~0.06MPa, continue to heat up to 1100±50℃, reduce the current to keep warm, open the hopper, put in a high-purity silver tank filled with high-purity lithium, and refine after all the lithium is melted. The refining time is not less than 8min, and finally pour into a steel mold at 1100±50℃ to obtain an ingot;

[0047] Step 3: The ingot obtained in step 2 is homogenized, hot forged, rolled, annealed, and machined into a round target with a thickness of 5 mm and a diameter of 101.6 mm, and bound with a copper back plate to obtain a high-purity silver-lithium alloy target;

[0048] In this embodiment, the surface of the ingot is wrapped with copper foil during homogenization, and homogenization is performed in a vacuum annealing furnace, and the vacuum degree of the vacuum annealing furnace is ≤10 -2 Pa, heating to 790℃, keeping temperature for 1h, quenching with argon;

[0049] In this embodiment, the hot forging temperature is 540°C, the holding time is 20 minutes, and during forging, three rounds of upsetting are performed along the height direction of the ingot, and each round is returned to the furnace for holding for 10 minutes. The upsetting amount of the first two rounds should be greater than 50% to 60% of the height. The last round is forged to a disc with a thickness of about 20 mm. After the forging is completed, the forging is buried in charcoal powder and slowly cooled;

[0050] In this embodiment, the surface of the blank is polished before rolling to remove the oxide layer and impurities on the surface, and then cold rolling is performed; the total cold rolling reduction rate is about 75%, and the reduction rate of each pass is controlled to be about 10% of the deformation; the "M" reversing rolling method should be used for rolling, and the reversing of different passes is as shown in the attached figure. Figure 1 As shown;

[0051] In this embodiment, the finished product is wrapped with copper foil during annealing, the annealing temperature is 400°C, the holding time is 1h, and the vacuum degree is ≤10 -2 Pa.

[0052] Example 3

[0053] A high-purity silver-lithium alloy target material of this embodiment, the raw materials include high-purity silver, high-purity lithium and auxiliary agents, the mass percentage of lithium in the high-purity silver-lithium alloy target material is 4.5%, the mass percentage of the auxiliary agent is 0.2%, and the balance is silver and other inevitable impurities; the auxiliary agent is indium, vanadium, magnesium and calcium oxide; the purity of the material is consistent with that of Example 1. The melting point of the alloy is about 465°C.

[0054] The preparation process of the high-purity silver-lithium alloy target of this embodiment specifically includes the following steps:

[0055] Step 1: Put 1630g of high-purity silver can with a sealable lid into a glove box, weigh 278g of high-purity lithium (considering burnout) in the glove box, and put it into the weighed high-purity silver can and seal it; the oxygen content inside the glove box is less than 6ppm, the water content is less than 0.2ppm, the sulfur content is less than 0.2ppm, and the nitrogen content is less than 0.5ppm;

[0056] Step 2: According to the alloy composition ratio of this embodiment, 3g indium, 3g vanadium, 3g magnesium, 3g calcium oxide and 4100g high-purity silver are weighed, and the total mass of the alloy is 6020g, wherein the auxiliary agent is wrapped with high-purity silver foil, and then the high-purity silver and the auxiliary agent are loaded into the high-purity graphite crucible of the vacuum induction furnace, and the high-purity silver tank containing high-purity lithium in step 1 is temporarily stored in the hopper; at the beginning of smelting, the vacuum degree of the vacuum chamber is ≤10 -2 Pa, after the silver begins to melt, fill with argon gas to 0.05MPa~0.06MPa, continue to heat up to 1150±50℃, reduce the current to keep warm, open the hopper, put in a high-purity silver tank filled with high-purity lithium, and refine after all the lithium is melted. The refining time is not less than 3min, and finally pour into a steel mold at 1100±50℃ to obtain an ingot;

[0057] Step 3: The ingot obtained in step 2 is homogenized, hot forged, rolled, annealed, machined into a round target with a thickness of 2 mm and a diameter of 101.6 mm, and bound with a copper backing plate to obtain a high-purity silver-lithium alloy target;

[0058] In this embodiment, the surface of the ingot is wrapped with copper foil during homogenization, and homogenization is performed in a vacuum annealing furnace, and the vacuum degree of the vacuum annealing furnace is ≤10 -2 Pa, heating to 400 °C, keeping temperature for 3 h, quenching with argon;

[0059] In this embodiment, the hot forging temperature is 345°C, the holding time is 30 minutes, and during forging, three rounds of upsetting and drawing are performed along the height direction of the ingot, and each round is returned to the furnace for holding for 10 minutes. The upsetting amount of the first two rounds should be greater than 50% to 60% of the height. The last round is forged to a disc with a thickness of about 20 mm. After the forging is completed, the forging is buried in charcoal powder and slowly cooled;

[0060] In this embodiment, the surface of the blank is polished before rolling to remove the oxide layer and impurities on the surface, and then cold rolling is performed; the total cold rolling reduction rate is about 90%, and the reduction rate of each pass is controlled to be about 10% of the deformation amount; the "M" reversing rolling method should be used for rolling, and the reversing of different passes is as shown in the attached figure. Figure 1 As shown;

[0061] In this embodiment, the finished product is wrapped with copper foil during annealing, the annealing temperature is 200°C, the holding time is 1h, and the vacuum degree is ≤10 -2 Pa.

[0062] Example 4

[0063] A high-purity silver-lithium alloy target material of this embodiment, the raw materials include high-purity silver, high-purity lithium and auxiliary agents, the mass percentage of lithium in the high-purity silver-lithium alloy target material is 5%, the mass percentage of the auxiliary agent is 0.3%, and the balance is silver and other inevitable impurities; the auxiliary agent is indium, tin, magnesium and borax; the purity of the material is consistent with that of Example 1. The melting point of the alloy is about 467°C.

[0064] The preparation process of the high-purity silver-lithium alloy target of this embodiment specifically includes the following steps:

[0065] Step 1: Put 1630g of high-purity silver can with a sealable lid into a glove box, weigh 315g of high-purity lithium (considering burnout) in the glove box, and put it into the weighed high-purity silver can and seal it; the oxygen content inside the glove box is less than 6ppm, the water content is less than 0.2ppm, the sulfur content is less than 0.2ppm, and the nitrogen content is less than 0.5ppm;

[0066] Step 2: According to the alloy component ratio of this embodiment, 4g indium, 4g tin, 5g magnesium, 5g borax and 4070g high-purity silver are weighed, and the total mass of the alloy is 6033g, wherein the auxiliary agent is wrapped with high-purity silver foil, and then the high-purity silver and the auxiliary agent are loaded into a high-purity graphite crucible of a vacuum induction furnace, and the high-purity silver can containing high-purity lithium in step 1 is temporarily stored in a hopper; at the beginning of smelting, the vacuum degree of the vacuum chamber is ≤10-2Pa, and after the silver begins to melt, argon gas is filled to 0.05MPa~0.06MPa, and the temperature is continued to rise to 1150±50℃, the current is reduced to a heat preservation state, the hopper is opened, and the high-purity silver can containing high-purity lithium is put into it, and after the lithium is completely melted, it is refined, and the refining time is not less than 5min, and finally poured into a steel mold at 1100±50℃ to obtain an ingot;

[0067] Step 3: The ingot obtained in step 2 is homogenized, hot forged, rolled, annealed, machined into a round target with a thickness of 2 mm and a diameter of 101.6 mm, and bound with a copper backing plate to obtain a high-purity silver-lithium alloy target;

[0068] In this embodiment, the surface of the ingot is wrapped with copper foil during homogenization, and homogenization is performed in a vacuum annealing furnace, and the vacuum degree of the vacuum annealing furnace is ≤10 -2 Pa, heating to 410 °C, keeping temperature for 2 h, quenching with argon;

[0069] In this embodiment, the hot forging temperature is 300°C, the holding time is 15 minutes, and during forging, three rounds of upsetting are performed along the height direction of the ingot, and each round is returned to the furnace for holding for 10 minutes. The upsetting amount of the first two rounds should be greater than 50% to 60% of the height. The last round is forged to a disc with a thickness of about 10 mm. After the forging is completed, the forging is buried in charcoal powder and slowly cooled;

[0070] In this embodiment, the surface of the blank is polished before rolling to remove the oxide layer and impurities on the surface, and then cold rolling is performed; the total cold rolling reduction rate is about 80%, and the reduction rate of each pass is controlled to be about 10% of the deformation amount; the "M" reversing rolling method should be used for rolling, and the reversing of different passes is as shown in the attached figure. Figure 1 As shown;

[0071] In this embodiment, the finished product is wrapped with copper foil during annealing, the annealing temperature is 200°C, the holding time is 2h, and the vacuum degree is ≤10 -2 Pa.

[0072] Comparative Example 1:

[0073] A high-purity silver-lithium alloy target material has the following composition: lithium accounts for 2.68% of the total weight, no auxiliary agent is added, and the rest of the preparation process is the same as that of Example 1.

[0074] Comparative Example 2:

[0075] A high-purity silver-lithium alloy target material, whose composition is as follows: lithium accounts for 2.68% of the total weight, auxiliary agents magnesium and borax account for 0.15wt% of the total mass (magnesium accounts for about half of the auxiliary agents), high-purity lithium is directly wrapped with high-purity silver without sealing and wrapping, and the rest of the preparation process is consistent with Example 1.

[0076] Comparative Example 3:

[0077] A high-purity silver-lithium alloy target material, whose composition is as follows: lithium accounts for 2.68wt% of the total mass, gallium, indium, magnesium and borax account for 0.15wt% of the total mass (gallium, indium, magnesium and boron are added in equal weight proportions), unidirectional rolling is adopted, and the rest of the preparation process is consistent with Example 1.

[0078] The alloy composition and organization of the embodiment and the comparative example are compared and the results are shown in Table 1 and Figure 3 shown.

[0079] Table 1 Test results of alloy composition of Examples 1 to 4 and Comparative Examples 1 to 3 (wt%)

[0080]

[0081] As can be seen from Table 1, when an auxiliary agent is added and high-purity silver is used for sealing, the nominal composition and actual composition of the alloys of Example 1, Example 2, Example 3, Example 4 and Comparative Example 3 are relatively close, and the contents of O and N are relatively low. This is mainly because, when no auxiliary agent is added, a portion of the lithium in Comparative Example 1 reacts with a small amount of impurities in silver, resulting in a relatively low content of lithium. When high-purity silver is not used to seal high-purity lithium, the surface of the metal lithium in Comparative Example 2 is easily oxidized when it contacts the air, and the lithium has a high volatilization during smelting.

[0082] The oxidation resistance, corrosion resistance, reflectivity and grain size of the composite reinforced silver alloy targets of Examples 1 to 4 and Comparative Examples 1 to 3 were tested:

[0083] The oxidation resistance test method of silver-lithium alloy is to place the prepared target material in a water bath at 85°C, observe the time for the oxide layer to form on its surface, and analyze its oxidation resistance. The reflectivity test method of silver-lithium target sputtered film is to use ETD-800 fully automatic ion sputtering instrument to prepare silver-lithium alloy film. The reflectivity of silver-lithium alloy film (150nm) is tested under the wavelength of 380-800nm ​​using a spectrophotometer. The anti-sulfurization performance test method of silver-lithium alloy is to place the silver-lithium alloy film in a closed environment with sulfur vapor, observe and record the time for each silver alloy film to turn black due to contact with sulfur vapor. The better the anti-sulfurization performance, the longer the time required for the sulfurized surface to turn black. The grain size of silver-lithium alloy is tested using the intercept method.

[0084] Table 2 Performance test results of alloys of Examples 1 to 4 and Comparative Examples 1 to 3 (wt%)

[0085]

[0086]

[0087] It can be seen from the test results in Table 2 that by comparing Example 1 with Comparative Example 1, it can be found that the oxidation resistance and corrosion resistance of the silver-lithium alloy target are effectively enhanced by adding auxiliary agents. In addition, by comparing Example 1 and Example 2, it can be found that as the lithium content increases, the oxidation resistance of the alloy decreases. By comparing Example 3 with Comparative Example 1, it can be found that after adding auxiliary agents, the corrosion resistance of high-lithium alloys can reach the level of low-lithium alloys, which also shows that adding auxiliary agents can effectively improve the corrosion resistance of the alloy. By comparing Example 3 with Comparative Example 2, it can be found that the sealed alloy has a low content of gas elements such as O, which can effectively improve the reflectivity of the alloy. By comparing Example 1 with Comparative Example 3, it can be found that by reversing rolling, the uniformity of the alloy structure can be significantly improved, and the reflectivity of the silver-lithium alloy sputtering film can be improved.

[0088] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A high-purity silver-lithium alloy target, characterized in that: The raw materials of the high-purity silver-lithium alloy target include high-purity silver, high-purity lithium and auxiliary agents. The mass percentage of lithium in the high-purity silver-lithium alloy target is 0.5% to 5%, the mass percentage of the auxiliary agent is 0.1% to 0.3%, and the remainder is silver and other inevitable impurities.

2. A high-purity silver-lithium alloy target according to claim 1, characterized in that: The mass purity of the high-purity silver is not less than 99.99%, the mass purity of the high-purity lithium is not less than 99.95%, and the mass purity of the auxiliary agent is not less than 99.95%. The auxiliary agent is one or more of Ga, In, V, Pt, Mg, Sn, borax and calcium oxide.

3. A method for preparing a high-purity silver-lithium alloy target as claimed in claim 1 or 2, characterized in that: The following steps are involved: Step 1: In a dry and oxygen-free environment, partially seal high-purity lithium with high-purity silver for smelting; Step 2: placing the auxiliary agent, the remaining high-purity silver and the high-purity lithium sealed with high-purity silver in step 1 in a vacuum medium-frequency induction furnace for smelting and casting to obtain an ingot; Step 3: The ingot obtained in step 2 is homogenized, hot forged, rolled, annealed, machined and bound in sequence to obtain a high-purity silver-lithium alloy target.

4. The method according to claim 3, characterized in that The dry oxygen-free environment in step 1 has an oxygen content of less than 6 ppm, a water content of less than 0.2 ppm, a sulfur content of less than 0.2 ppm, and a nitrogen content of less than 0.5 ppm.

5. The method according to claim 3, characterized in that: The smelting and casting process in step 2 specifically includes: at the beginning, the vacuum medium frequency induction furnace is evacuated to a degree of ≤10 -2 Pa, and then start heating. After the silver starts to melt, fill with argon to 0.05MPa~0.06MPa, continue to heat to 1100±50℃, reduce the current to keep warm, open the hopper, put in high-purity lithium sealed with high-purity silver, and refine after all the lithium is melted. The refining time is not less than 3min~8min, and finally pour it into a steel / graphite mold at 1100±50℃.

6. The method according to claim 4, characterized in that In step 3, copper foil is used to wrap the surface of the ingot for homogenization, and the homogenization treatment is carried out in a vacuum annealing furnace. The vacuum degree of the vacuum annealing furnace is ≤10 -2 Pa, raise the temperature to 50℃~80℃ lower than the melting point of the alloy, keep warm for 1h~3h, and quench with argon.

7. The method according to claim 4, characterized in that In step 3, the hot forging temperature is 120°C to 300°C lower than the melting point of the alloy, and the holding time is 15min to 30min. During forging, the ingot is upset three times along the height direction, and the upsetting amount of the first two times is greater than 50% to 60% of the height. The last time is forged to a disc with a thickness of 10mm to 20mm, and cooled after forging.

8. The method according to claim 4, characterized in that The total rolling reduction rate in step three is 70% to 90%, and the rolling is carried out by the rotary reversing rolling method, that is, after each rolling pass, the billet feeding direction is rotated until the rolling force is applied in all directions within a circle.

9. The method according to claim 4, characterized in that In step 3, the finished product is wrapped with copper foil or tantalum foil during annealing. The annealing temperature is 200℃~400℃, the holding time is 1h~2h, and the vacuum degree is ≤10 -2 Pa.

10. Use of the high-purity silver-lithium alloy target material as claimed in claim 1 or 2 in an organic light-emitting diode anode material and / or a lithium-ion battery anode.

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