CN102383085A - Method of preparing NiO buffer layer of double-sided texture coated conductor by oxidation epitaxy - Google Patents

Abstract

The invention discloses a method for preparing a NiO buffer layer of a double-sided texture coating conductor by self-oxidation epitaxy, which comprises the following steps: a. Surface corrosion modification of the base band: biaxially textured NiW alloy (200) base band after annealing treatment ( Width is 10mm), the front and back sides have been washed with alcohol and acetone successively, suspended and dipped in a diluted nitric acid solution with a concentration of 30%-50% for 40-120s, taken out and cleaned, and dried on both sides. Then it is suspended and dipped in the mixed modification solution prepared by 150 volumes of ammonia water and 1-4 volumes of hydrogen peroxide for 20-60s, taken out, washed, and dried on both sides; b. Oxidation heat treatment: the surface corrosion modified in step a The NiW alloy (200) base tape (10mm wide) is placed in the air into a ceramic tube with an inner diameter greater than 10mm and less than 13mm, and then the ceramic tube is pushed into a tubular atmosphere sintering furnace at a temperature of 740-800°C in an argon atmosphere. Oxidation heat treatment for 20-50 minutes, take it out and get it. The method has low production cost and simple process, and is easy to prepare a double-sided NiO(200) buffer layer film with good quality, and the thickness is easy to control, and can effectively play the role of the coating conductor buffer layer. In addition, the method of placing the ceramic tube suspended in the air is also suitable for preparing double-sided buffer layers or superconducting layers of other coated conductors.

Description

A method for preparing double-sided textured coating conductor NiO buffer layer by self-oxidation epitaxy

technical field

The invention belongs to the technical field of high-temperature superconducting material preparation, and in particular relates to the preparation technology of a high-temperature superconducting coating conductor buffer layer film.

Background technique

The second-generation high-temperature superconducting tape, that is, the REBCO coated conductor, has a higher critical current density and better superconducting performance in a magnetic field than the first-generation BSCCO-based superconducting tape. It is used in superconducting cables, Superconducting motors and superconducting transformers will have great application prospects. Developed countries are vigorously promoting the research and practical application of second-generation high-temperature superconductors based on their own technological innovation and long-term interests in electric energy. The international competition is becoming more and more fierce.

However, the REBCO superconducting layer relies heavily on oxygen during the preparation process, and it is easy to oxidize the metal substrate. At the same time, metal ions will also diffuse into the superconducting layer, which will seriously affect the superconducting performance of REBCO. Therefore, a layer of buffer layer material must be added between the metal substrate and REBCO, which not only serves as an intermediate template for the epitaxial growth of the metal substrate from the REBCO, but also blocks the mutual diffusion of the two materials, so as to ensure the preparation of excellent performance REBCO HTS coated conductors. Therefore, high-temperature superconducting coated conductors have a three-layer structure of substrate, buffer layer (at least one layer) and REBCO superconducting coating, and developed such as CeO ₂ , LaAlO ₃ , MgO, La ₂ Zr ₂ O ₇ , BaZrO ₃ and other buffer layer materials. On the other hand, as the use of RABiTS (rolling-assisted biaxial texturing method) to prepare biaxially textured Ni-based alloy substrates has become increasingly mature, epitaxial growth of high-quality buffer layers on Ni-based alloy substrates of RABiTS and subsequent superstructure The conductive layer has gradually become the main technical trend of preparing the second-generation high-temperature superconducting tape.

In addition, when the oxide buffer layer is deposited on the Ni-based alloy substrate, due to the spontaneous non-directional oxidation of the Ni-based alloy substrate, it is easy to generate NiO with disordered orientation, which seriously affects the texture growth of the subsequent superconducting layer. In order to solve this problem, it is usually prepared in a reducing atmosphere or a pure argon atmosphere to avoid the formation of NiO, which undoubtedly increases the preparation cost. Another effective solution is to use self-oxidation epitaxy (SOE) technology to pre-generate textured NiO, so that the textured NiO film can be used as a growth template for the subsequent buffer layer and superconducting layer texture, and can also play a role. The role of the buffer layer to prevent Ni diffusion, and self-oxidation epitaxy (SOE) technology will also become a simple, effective, and low-cost technology for preparing coated conductor buffer layers

Foreign Matsumoto et al [Physica C.2000, 335:39] first proposed in 2000 that a NiO buffer layer with a good biaxial texture was prepared on the Ni baseband of RABiTS by using the SOE method, and MgO was sequentially deposited on it. With YBCO, Jc(77K, 0T)=3×10 ⁵ A/cm ² is obtained. In recent years, Huhne et al [Supercond.Sci.Technol.2006, 19:169] [Appl.Phys.Lett.2007, 90:012510] developed the work of Mastsumoto et al. in Ni-Ag, Ni-C, Ni -V, Ni-Ce and Ni-Mo alloy substrates were successfully prepared NiO buffer layer with good biaxial texture, and subsequent buffer layers such as BaZrO ₃ and SrZrO ₃ were deposited. However, most of them are prepared at a high temperature of 1000°C-1200°C, which not only requires high industrial equipment, but also high metal deformation at high temperature, and it is also difficult to transition to the preparation temperature range of the superconducting layer around 800°C. The development of a low-temperature self-oxidative epitaxy technique to prepare a well-textured NiO buffer layer will play a very important role in the large-scale application of coated conductors.

In addition, in the application and development of the second-generation superconducting tape, the lack of reliable, cost-effective, and easy-to-promote tape preparation technology is the bottleneck restricting its large-scale application. On the one hand, the longer the tape, the better. How to prepare a double-sided textured buffer layer on the base tape is an urgent technical problem to be solved.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a NiO(200) buffer layer of a double-sided texture coating conductor by self-oxidation epitaxy. The method has low production cost and simple process, and is easy to prepare a good-quality double-sided NiO(200) buffer layer film, and the thickness is easy to control, and can effectively play the role of the coating conductor buffer layer.

The technical solution adopted by the present invention to realize its object of the invention is a kind of method for preparing double-sided texture coating conductor NiO (200) buffer layer from oxidation epitaxy, and its steps are:

a. Surface corrosion modification of the baseband: After the annealed biaxially textured NiW alloy (200) baseband (10mm in width), the front and back sides have been washed with alcohol and acetone successively, and the concentration after dilution is 30%-50%. Suspend and immerse in nitric acid solution for 40-120s, take it out, wash it, and dry it on both sides. Then suspend and immerse it in the mixed modification solution prepared by 150 volumes of hydrogen peroxide and 1-4 volumes of ammonia water for 20-60s, take it out, wash it, and dry it on both sides;

b. Oxidation heat treatment: put the NiW alloy (200) base strip (10mm wide) after the surface corrosion modification in step a into the ceramic tube with an inner diameter greater than 10mm and less than 13mm, and then push the ceramic tube into the tubular atmosphere sintering furnace Under the temperature condition of 740-800°C in an argon atmosphere, oxidize heat treatment for 20-50 minutes, and then take it out.

Compared with prior art, the beneficial effect of the present invention is:

1. Compared with the high temperature process of 1000°C and above, the NiO(200) buffer layer is prepared at a medium temperature of 740-800°C, the temperature is low, the cost is low, and the heat treatment time is 20-50 minutes, which is easy to control and is also conducive to the preparation of the superconducting layer The transition temperature range is around 800°C, which is conducive to the continuous preparation of long tapes.

2. A new corrosion and modification solution has been developed, which can easily remove W on the surface of NiW alloy, prevent the formation of too much monoclinic structure NiWO ₃ , improve the texture, and help the subsequent buffer layer and superconducting layer deposition.

3. During the preparation process, the thickness of the NiO(200) buffer layer can be conveniently controlled by controlling the heat treatment atmosphere flow, heat treatment time and temperature.

4. A NiO(200) buffer layer with good double-sided texture coating conductor can be easily and effectively prepared by placing it in the air in the ceramic tube, and this method is also suitable for preparing buffer layers or superconducting layers of other double-sided thin films.

The specific method of oxidation heat treatment in the above b step is: quickly raise the temperature of the tubular atmosphere sintering furnace to the above-mentioned temperature, and when the temperature and the gas flow rate of the atmosphere are stabilized, then corrode the modified NiW alloy on both sides of the suspension placed (200) The base tape is pushed into the furnace. When the time of the base tape in the furnace reaches the oxidation heat treatment time, the oxidized base tape is pushed out from the furnace and cooled to room temperature.

The method of placing the ceramic tube suspended in the above b step means that the inner diameter of the ceramic tube used is about 3 mm larger than the width of the baseband itself, so that the baseband can be suspended in the air. This method is also suitable for preparing buffer layers or superconducting layers of other double-sided thin films.

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is the front and back X-ray diffraction patterns of the NiO(200) buffer layer prepared in Example 1.

Fig. 2 is a 50000 times scanning electron microscope (SEM) photo of the front and back sides of the NiO(200) buffer layer prepared in Example 1.

Fig. 3 is the X-ray diffraction patterns of the front and back sides of the NiO(200) buffer layer prepared in Example 2.

4 is a 50000 times scanning electron microscope (SEM) photo of the front and back sides of the NiO(200) buffer layer prepared in Example 2.

Fig. 5 is the X-ray diffraction patterns of the front and back sides of the NiO(200) buffer layer prepared in Example 3.

Fig. 6 is a 50000 times scanning electron microscope (SEM) photograph of the front and back sides of the NiO(200) buffer layer prepared in Example 3.

The vertical coordinates of Figures 1, 3 and 5 are diffraction intensity (Intensity), arbitrary unit (a.u.); the horizontal coordinates are diffraction angle 2θ, and the unit is degree (deg).

Detailed ways

Embodiment one

The first embodiment of the present invention is a method for preparing a double-sided texture coating conductor NiO (200) buffer layer from oxidation epitaxy, the steps of which are:

a. Surface corrosion modification of the baseband: After the annealed biaxial textured NiW alloy (200) baseband (10mm in width), the front and back sides have been cleaned by alcohol and acetone, and then diluted in a nitric acid solution with a concentration of 30%. Soak in the air for 40s, take it out, wash it, and dry it on both sides. Then suspend and immerse it in a mixed modification solution prepared with 150 volumes of hydrogen peroxide and 1-4 volumes of ammonia water for 60 seconds, take it out, wash it, and dry it on both sides;

b. Oxidation heat treatment: Put the NiW alloy (200) base strip (10mm wide) after surface corrosion modification in step a into a ceramic tube with an inner diameter of 11mm, and then push the ceramic tube into a tubular atmosphere sintering furnace in argon gas Under the temperature condition of 740°C in the atmosphere, oxidize heat treatment for 50 minutes, and then take it out.

The specific method of oxidation treatment in this example is: quickly raise the temperature of the tubular atmosphere sintering furnace to 740 °C, and when the temperature and the flow rate of the atmosphere are stable, then corrode the modified NiW alloy (200 ) The baseband is pushed into the furnace, and when the time of the baseband in the furnace reaches 50 minutes, the oxidized baseband is pushed out from the furnace and cooled to room temperature.

Fig. 1 is the front and back X-ray diffraction patterns of the NiO(200) buffer layer in Example 1 of the present invention. It can be seen from Figure 1 that both the front and back sides of the prepared NiO have similar good (200) textures, and NiWO ₃ also grows with a good texture. Fig. 2 is a 50000 times scanning electron microscope (SEM) photo of the front and back sides of the NiO(200) buffer layer in Example 1 of the present invention. It can be seen from Figure 2 that the front and back sides of the buffer layer film sample are flat, dense, and seamless without holes. It can be seen that in Example 1, the front and back buffer layers of NiO(200) with good texture and dense and smooth surface were prepared.

Embodiment two

The preparation method of this example consists of the following steps in turn:

a. Surface corrosion modification of the baseband: after the annealing treatment, the biaxially textured NiW alloy (200) baseband (10mm in width) is washed successively by alcohol and acetone on both sides, and diluted in a nitric acid solution with a concentration of 40%. Soak in the air for 100s, take it out, wash it, and dry it on both sides. Then suspend and immerse it in a mixed modification solution prepared with 150 volumes of hydrogen peroxide and 1-4 volumes of ammonia water for 30 seconds, take it out, wash it, and dry it on both sides;

b. Oxidation heat treatment: Put the NiW alloy (200) base strip (10mm wide) after surface corrosion modification in step a into a ceramic tube with an inner diameter of 12mm, and then push the ceramic tube into a tubular atmosphere sintering furnace in argon gas Under the temperature condition of 770°C in the atmosphere, oxidize heat treatment for 30 minutes, and then take it out.

The specific method of oxidation treatment in this example is: quickly raise the temperature of the tubular atmosphere sintering furnace to 770 °C, and when the temperature and the flow rate of the atmosphere are stable, the NiW alloy (200 ) the baseband into the furnace, when the time of the baseband in the furnace reaches 30 minutes, the oxidized baseband is pushed out from the furnace and cooled to room temperature.

Fig. 3 is the front and back X-ray diffraction patterns of the NiO(200) buffer layer in Example 2 of the present invention. It can be seen from Figure 3 that both the front and back sides of the prepared NiO have similar good (200) textures, and NiWO ₃ also grows with a good texture. Fig. 4 is a 50000 times scanning electron microscope (SEM) photo of the front and back sides of the NiO(200) buffer layer in Example 2 of the present invention. It can be seen from Figure 4 that the front and back sides of the buffer layer sample are flat, dense, and seamless without holes. It can be seen from this that in Example 2, the front and back buffer layers of NiO(200) with good texture and dense and smooth surface were prepared.

Embodiment Three

The preparation method of this example consists of the following steps in turn:

a, the surface corrosion modification of the baseband: after the annealing treatment, the biaxially textured NiW alloy (200) baseband (10mm in width), the front and back sides have been washed with alcohol and acetone successively, and then diluted in a nitric acid solution with a concentration of 50%. Soak in the air for 120s, take it out, wash it, and dry it on both sides. Then suspend and immerse it in a mixed modification solution prepared with 150 volumes of hydrogen peroxide and 1-4 volumes of ammonia water for 20 seconds, take it out, wash it, and dry it on both sides;

b. Oxidation heat treatment: put the NiW alloy (200) base strip (10mm wide) after surface corrosion modification in step a into a ceramic tube with an inner diameter of 13mm, and then push the ceramic tube into a tubular atmosphere sintering furnace in argon Under the temperature condition of 800°C in the atmosphere, oxidize heat treatment for 20 minutes, and then take it out.

The specific method of oxidation treatment in this example is: quickly raise the temperature of the tubular atmosphere sintering furnace to 800 °C, and when the temperature and the flow rate of the atmosphere are stable, then corrode the NiW alloy (200° C. ) the baseband into the furnace, when the time of the baseband in the furnace reaches 20 minutes, push the oxidized baseband out of the furnace and cool to room temperature.

Fig. 5 is the front and back X-ray diffraction patterns of the NiO(200) buffer layer in Example 3 of the present invention. It can be seen from Figure 5 that both the front and back sides of the prepared NiO have similar good (200) textures, and NiWO ₃ also grows with a good texture. Fig. 6 is a 50000 times scanning electron microscope (SEM) photo of the front and back sides of the NiO(200) buffer layer in Example 3 of the present invention. It can be seen from Figure 6 that the front and back sides of the buffer layer sample are flat, dense, and seamless without holes. It can be seen that in Example 3, the front and back buffer layers of NiO(200) with good texture and dense and smooth surface were prepared.

The concentration of ammonia water used in the preparation process of the method for preparing a NiO(200) buffer layer of a double-sided textured coating conductor by self-oxidation epitaxy of the present invention is 25%-28% of analytical purity, and the concentration of hydrogen peroxide is 30% of analytical purity. The inner diameter of the selected ceramic tube is preferably about 3mm larger than the baseband itself, so that the baseband can be fully suspended in the ceramic tube. The method of placing the ceramic tube suspended in the air is also suitable for preparing double-sided buffer layers or superconducting layers of other coated conductors. During the whole sintering process, argon gas is fed into the sintering furnace, and the purity of the argon gas is preferably 99.999%, so that the performance of the finished product is guaranteed; otherwise, the performance of the finished product will be reduced.

Claims (3)

1. A method for preparing double-sided texture coating conductor NiO buffer layer from oxidation epitaxy, its steps are: a. Surface corrosion modification of the baseband: after the annealed NiW alloy baseband with a biaxial texture width of 10mm, the front and back sides are washed with alcohol and acetone successively, and then diluted in a nitric acid solution with a concentration of 30%-50%. Soak in the air for 40-120s, take it out, wash it, and dry it on both sides; then soak it in the mixed modification solution prepared by 150 volumes of hydrogen peroxide and 1-4 volumes of ammonia water for 20-60s, take it out, wash it, and dry it on both sides Dry; b. Oxidation heat treatment: Put the NiW alloy base strip after the surface corrosion modification in step a into a ceramic tube with an inner diameter greater than 10mm and less than 13mm, and then push the ceramic tube into a tubular atmosphere sintering furnace in an argon atmosphere at 740-800 Under the temperature condition of ℃, oxidation heat treatment is carried out for 20-50 minutes, and the buffer layer is obtained after taking it out. 2. A kind of method for preparing double-sided texture coating conductor NiO buffer layer film from oxidation epitaxy as claimed in claim 1, it is characterized in that: the specific method of oxidation heat treatment in the described b step is: sintering in tubular atmosphere The furnace is heated up to the stated temperature rapidly, and when the temperature and the gas flow into the atmosphere are stabilized, the NiW alloy base tape after the front and back double-sided corrosion modification placed in the air is pushed into the furnace, and when the time of the base tape in the furnace reaches the required After the above oxidation heat treatment time, the oxidized base tape is pushed out from the furnace and cooled to room temperature. 3. a kind of self-oxidation epitaxy as claimed in claim 2 prepares the method for double-sided texture coating conductor NiO buffer layer, it is characterized in that: in the b step, suspended placement means that the inner diameter of the ceramic tube used is greater than the width of the base band itself About 3mm makes the baseband hang in the air.

Images