Preparation method of superconducting tape insulating coating

Abstract

The invention discloses a preparation method of a superconducting tape insulating coating. The insulating coating is boron nitride aerogel. The specific preparation method comprises the following steps: (1) preparation of boron nitride hydrosol; (2) preparation of a boron nitride hydrosol coating which coats the surface of a superconducting tape; and (3) preparation of a boron nitride aerogel coating on the surface of the superconducting tape. According to the scheme, the boron nitride aerogel with high heat conductivity and insulating characteristic is taken as a surface insulating coating, micropores in a porous structure of the aerogel are taken as bubble nucleation centers to inhibit formation of continuous large bubbles on the surface of the superconducting tape, and good heat transfer efficiency and stable insulating strength on the surface of the tape are maintained; the porous network structure of the boron nitride aerogel has high heat conductivity and insulating characteristic, rapid heat exchange between the superconducting tape and a liquid nitrogen medium can be realized, and quench recovery of the tape is accelerated; and a uniform insulating coating with the controllable thickness can be rapidly formed on the surface of the high-temperature superconducting tape through a repeated immersion-frictioning-freeze-drying process, and a technology is simple and easy toimplement.

Description

technical field [0001] The invention relates to a preparation method of a superconducting tape insulating coating, in particular to a preparation method of a superconducting tape porous high thermal conductivity insulating coating and its application in accelerating superconducting tape quench recovery. Background technique [0002] Superconducting cables, transformers, current limiters and other superconducting devices involved in the application of superconducting power technology are all faced with the problem of local overheating of strips caused by short-circuit fault currents, which in turn leads to rapid quenching of equipment. Although the core components of high-temperature superconducting power devices are mostly soaked in cheap liquid nitrogen to achieve the low temperature environment necessary for operation, liquid nitrogen can also be used as a low-temperature and high-voltage insulating medium. However, under transient transient conditions, the large resistanc...

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Problems solved by technology

However, under transient transient conditions, the large resistance exhibited by the superconductor transitioning to the normal state will lead to the rapid accumulation of heat on the surface of the superconducting strip, and in severe cases, it will cause the superconducting strip to burn and delaminate. The heat generated is difficult to be absorbed by the liquid. The main reasons for the rapid absorption of nitrogen refrigerant are as follows: 1) The rapid temperature rise on the surface of the superconducting strip will cause the surface liquid nitrogen to boil, and then form a bubble boiling area with low thermal conductivity on the surface of the strip, resulting in the failure of liquid nitrogen to dissolve the strip in time. 2) The insulating coating or insulating wrapping layer on the surface of the strip is usually made of polymer materials such as polyimide and biaxially oriented polypropylene with low thermal conductivity, which are not conducive to superconductivity. Heat exchange between strip and liquid nitrogen

At the same time, the bubbles generated on the surface of the superconducting strip may become longer, merge with nearby bubbles, and rupture during the ascent process to form discharge channels, resulting in breakdown of the main insulation

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