KR100512474B1 - Ceramic coating solution and the mathod for superconductivity wire - Google Patents

Abstract

The present invention is in the power field, such as a power line capable of several tens of times the current carrying capacity and large power transport, a transformer that can reduce power loss and weight and volume less than half compared to a copper conductor of the same cross-sectional area, a motor generator capable of high efficiency, high output and small size The present invention relates to a ceramic coating solution for superconducting wires and a method of manufacturing the same, which can greatly improve the electrical properties in the manufacture of widely used superconducting wires, and a solution obtained by mixing glacial acetic acid in strontium acetate hemihydrate and maintaining it at a constant temperature. And glacial acetic acid are mixed with zirconium propoxide (zirconium propoxide), and acetylacetone (acetyl acetone) is added to a solution in which 2 times the number of moles of zirconium propoxide is added. After cooling to room temperature while adding predetermined distilled water, ethyl cellulose (ethyl cellulose) was added. The present invention relates to a ceramic coating liquid for superconducting wires prepared by adding an organic compound consisting of a) and an alpha-terpineol or using water as a solvent and polyvinyl pyrrolidone as a binder, and a method of manufacturing the same.

Description

Ceramic coating solution for superconducting wire and its manufacturing method {Ceramic coating solution and the mathod for superconductivity wire}

The present invention is in the power field, such as a power line capable of several tens of times the current carrying capacity and large power transport, a transformer that can reduce power loss and weight and volume less than half compared to a copper conductor of the same cross-sectional area, a motor generator capable of high efficiency, high output and small size The present invention relates to a ceramic coating liquid for superconducting wires and a method of manufacturing the same, which can greatly improve electrical characteristics in the process of manufacturing a widely used superconducting wire.

More specifically, by improving the bonding strength of the coating liquid applied to the superconducting wire and making the thickness uniform, the sausage phenomenon generated in the manufacture of the multi-conducting superconducting wire used for the filament, the critical characteristic deterioration due to the local cross-sectional area reduction of the superconducting wire, The present invention relates to a ceramic coating liquid for superconducting wires and a method of manufacturing the same, which can prevent contamination during microcracking and heat treatment of filaments.

Superconducting wire is mainly used for AC power equipment. To reduce power loss caused by magnetic history and induction current, magnetic history loss is reduced by filamentizing a plurality of superconducting wires. Phosphorous superconducting wire is coated to reduce it. However, in the conventional superconducting wire coating material, high purity BaZrO ₃ or SrZrO ₃ which does not cause chemical reaction with the superconducting wire is used, but SrZrO ₃ which is inexpensive is mostly used.

However, in the case of the coating material made of SrZrO ₃ , the adhesive performance with the superconducting wire is poor, so that the coating thickness becomes uneven in the repeated coating process to enhance the adhesive strength. As a phenomenon occurs, the electrical characteristics of the superconducting wires are deteriorated, which causes problems in improving the performance of AC power devices.

The present invention has been invented to solve the above problems, and an object of the present invention is to improve the adhesion performance with the superconducting wire and to improve the adhesion to maintain a uniform thickness of the coating layer is a ceramic coating liquid added with an organic compound and its Another object of the present invention relates to a ceramic coating liquid which maintains similar bonding strength as when using an organic compound, using polyvinyl pyrrolidone instead of the organic compound, and a method of manufacturing the same.

Hereinafter, the configuration and operation of the present invention will be described in detail.

The present invention for achieving the above object relates to a ceramic coating liquid and a method for producing the same, which optimizes the molar ratio of Sr and Zr, the drying temperature and time, the amount of the organic compound, etc. The configuration is as follows.

A solution of strontium acetate hemihamidate and glacial acetic acid (A), a mixture of zirconium propoxide (zirconium propoxide) and glacial acetic acid, and then a solution of acetylacetone (B) added It is achieved by providing a ceramic coating solution prepared by adding an organic compound consisting of a binder ethyl cellulose and a solvent alpha-terpineol to the mixed solution mixed with

In order to achieve another object of the present invention by providing a ceramic coating solution prepared by adding water with a binder polyvinylpyrrolidone and a solvent to a mixed solution of the solution (A) and (B) by providing a method Is achieved.

As described above, the ceramic coating liquid according to the present invention has better adhesion and uniformity with the superconducting wire than the conventional ceramic coating liquid consisting of SrZrO ₃ alone, and improves the bonding strength with the metal oxide particles and the physical strength of the coating layer. Microcracks do not occur.

However, when the weight ratio of ethyl cellulose, the added organic compound, exceeds 9% by the weight ratio of Sr and Zr, the density of the surface of the coating layer is deteriorated, and the binder polyvinylpyrrolidone is also described above. For the same problem, the weight ratio of the mixed solution is preferably within 20% to 40%.

On the other hand, in order to improve the adhesion between the superconducting wire and the coating layer made of ceramic coating solution, the amount of Sr and Zr should be less than 1, but the heat treatment temperature and the temperature may be affected by the fact that it affects the characteristics of the coating layer by drying and heat treatment processes. It is preferable to carry out the time below the temperature at which the phase change of the superconductor occurs.

Hereinafter, the present invention will be described in detail with reference to Examples, and it should be understood that the present invention is not limited only to the Examples.

Example 1 Ceramic Coating Solution Added Organic Compound

0.5-15-1.203 parts by weight of strontium acetate hemihydrate and 2.623-3.672 parts by weight of glacial acetic acid were mixed and stirred at a temperature of 80 ° C. (A) 0.3-0.7 mol and zirconium propoxide 0.482- 1.83 parts by weight of glacial acetic acid and 1.574∼2.623 parts by weight of a solution (B) 0.7-0.3 mol, which was added 0.482-1.124 parts by weight of acetyl acetone, a chilizing agent, were sufficiently stirred at 80 ° C. After adding 3 parts by weight of distilled water as much as evaporated to lower the temperature to the next room temperature, the binder ethyl cellulose (0.060 ~ 0.164 parts by weight and alpha-) to 3 to 7% by weight of the mixed solution 3.724 parts by weight of terminal (α-terpineol) is mixed, but when the solution is heated to 60 ℃ sufficiently stirred and the organic cellulose prepared so that the ethyl cellulose (ethyl cellulose) completely dissolved in the alpha-terpineol (α-terpineol) The mixture was stirred for 1 hour while adding the mixture to the mixed solution to finally prepare a ceramic coating solution.

As a result of analyzing the characteristics of the coating layer of the ceramic coating solution prepared by adding the organic compound as described above to the superconducting wire coated with silver, no defect or crack of the coating layer occurred despite the thickness of 10 μm. Adhesion strength (ASTM C-633-79) with superconducting wire was improved to 3.3%.

Example 2 Ceramic Coating Solution Preparation Method

 0.3-0.7 mol of solution (A) and zirconium (IV) proposide (zirconium propoxide) mixed and stirred at 0,515-1.203 parts by weight of strontium acetate hemihydrate and 2.623-3.672 parts by weight of glacial acetic acid ) A mixed solution containing 0.786 to 1. mol by weight of 0.786 to 1.24 parts by weight of 0.786 to 1.835 parts by weight of glacial acetic acid and 0.482 to 1.124 parts by weight of acetyl acetone, which is a chilegent agent, is sufficient at a temperature of 80 ° C. 3 parts by weight of distilled water as much as evaporated to lower the temperature to room temperature, and then add 0.398-0.94 parts by weight of polyvinyl pyrrolidone, a water-soluble binder, and then 20-30 at a temperature of 30-40 ° C. The ceramic coating solution was prepared by stirring for a minute, and the ceramic coating solution prepared by the above method was coated on the superconducting wire, and then the characteristics of the coating layer were analyzed.

On the other hand, in order to derive the optimum composition ratio required to prepare a ceramic coating solution of the same method as in the above example, the known Taguchi method, dispersion analysis method and X-ray diffraction analysis method were applied.

First, the experiment by the Taguchi method was carried out using six control factors after setting the mixed solution to three levels. The six control factors were the molar ratio of Sr / Zr (a) the amount of organic compound added (b) the drying temperature ( c) and time (d), heat treatment temperature (e) and time (f) are expressed, and the control factors of the mixed solution for each level are shown in Table 1 below.

On the other hand, when preparing a ceramic coating solution using polyvinyl pyrrolidone as a binder as in Example 2, polyvinyl pyrrolidone is 20, 25 of the Sr / Zr molar ratio at each of the three levels of the Sr / Zr molar ratio The experiment was divided into 30, 35 and 40% by weight.

The adhesive strength value measured by the tape testing method according to ASTM C633-79 is converted into the noise ratio (S / N ratio) with the tower feature of the Taguchi method (QC = B), and the average value and contribution for each level are measured. As a result, as shown in Table 2, the experiment numbers with the high noise ratio were 17, 8, and 9, and the combination of the optimum control factors was a ₃ b ₂ c ₁ d ₃ e ₁ f ₂ , a ₃ b ₂ c ₃ d ₂ e ₁ f ₃ and a ₃ b ₃ c ₁ d ₃ e ₂ f ₁

Also, as shown in Fig. 1, the variation in contribution of each control factor is increased from f (1.00) → b (4.44) → c ((4.50) → d (4.91) → e (5.17) → a (22.86). In the present invention, the amount of organic compounds added is less than 7% by weight, which is relatively insignificant in the present invention. Influencing factors were demonstrated by the molar ratio of Sr / Zr, which is a.

Second, as a result of analyzing the ceramic coating liquid added with the organic compound by dispersion analysis, the results before pooling are shown in Table 3, and the error terms are the terms generated during pooling. The control factors (a, b, c, d, e, f) ) Is the smallest term that compares the average sum of squared values and is defined as the process factor (f) that has a relatively small influence on the coating among the process factors set during process design, and pools the term with the smallest value as the error term. The f-value obtained from the F-distribution table with 90% confidence interval is shown in Table 4, and F = 9.29, which is smaller than 9.59 of control factor C with the smallest significance level. It can be seen that it can be recognized as a 90% trust process.

In addition, as a result of X-ray diffraction analysis of the coating layer coated with the ceramic coating solution prepared by the experimental values derived from Taguchi method and dispersion analysis, the crystal phase peak of the ceramic coating solution was not found in the specimen No. 17 as shown in Fig. 2. Therefore, except for experiment number 17 of the ceramic coating liquid having the best adhesion strength with the superconducting wire, the experiment number 8 of which the crystal phase peak of the ceramic coating liquid was well grown was a ₃ b ₂ c ₃ Combination with d ₂ e ₁ f ₃ shows the best characteristics of ceramic coating solution, so the molar ratio of Sr / Zr of ceramic coating solution for superconducting wire is 0.3 / 0.7 and the amount of organic compound added is 5% by weight The 160 ℃ drying time is 10 minutes, the heat treatment temperature is 500 ℃ heat treatment time is 20 minutes to derive the manufacturing method having the best electrical properties of the coating liquid.

The ceramic coating liquid for superconducting wires and the method of manufacturing the same according to the present invention can be widely used for coating the insulation layer of multi-conducting superconducting wires because they have excellent adhesive strength and uniform coating thickness without chemical reaction with the superconducting wires. It is a very useful invention that greatly improves the electrical characteristics of the alternator, motor, power cable, etc. for AC power.

Claims (3)

0.3-0.7 mole of solution and 0.786-1.835 parts by weight of zirconium propoxide with 0.5623-1.203 parts of strontium acetate hemihydrate added to 2.623-3.672 parts by weight of glacial acetic acid and kept at 80 ° C To a mixed solution containing 0.7 to 0.3 mol of acetyl acetone 0.482 to 1.124 parts by weight to 1.574 to 2.623 parts by weight, distilled water was added to 3 parts by weight of ethyl cellulose (ethyl cellulose). 0.398 to 0.94 parts by weight of an organic compound or polyvinyl pyrrolidone consisting of 0.06 to 0.164 parts by weight and 3.724 parts by weight of alpha -terpineol to be 3 to 7% of the solution. Ceramic coating liquid for superconducting wires, characterized in that the addition. Addition of Glacial Acetic Acid to Strontium Acetate Hemihydrate and the solution of zirconium (IV) zirconium propoxide, glacial acetic acid, and acetyl acetone at 80 ° C. are mixed for 2 hours at 80 ° C. Stir enough, but distilled water is added to the mixed solution cooled to room temperature while ethyl cellulose, an organic compound, is 3 to 7% of the weight ratio of the mixed solution. α-terpineol) was prepared to dissolve ethyl cellulose (ethyl cellulose) completely while heating to 60 ℃ and then stirred sufficiently for 30 to 40 ℃ and stirred for 2 hours while adding to the mixed solution Method for producing a ceramic coating liquid for superconducting wires, characterized in that cooled to room temperature sufficiently. Addition of Glacial Acetic Acid to Strontium Acetate Hemihydrate and the solution of zirconium (IV) zirconium propoxide, glacial acetic acid, and acetyl acetone at 80 ° C. are mixed for 2 hours at 80 ° C. While stirring sufficiently for a while, distilled water was added to the mixed solution cooled to room temperature while adding distilled water, and 0.398-0.94 parts by weight of polyvinylpyrrolidone, which is 20-40% by weight of the mixed solution, was added directly to the mixed solution. And then a method of producing a ceramic coating liquid for superconducting wire, characterized in that for 20 to 30 minutes by stirring at a temperature of 30 ~ 40 ℃.