ESEM Hot Stage Evaluation of Sol-Gel Insulation Coatings for High Field HTS Magnets.

Abstract

High temperature, thin ceramic insulation coatings are necessary for the application of High Temperature Superconductors (HTS) in high field magnet technology. Especially in the so called “wind and react” technology, insulation coatings have to withstand the final heat treatment at about 900°C, otherwise turn to turn insulation will be broken. We have developed a sol-gel coating method for HTS tape conductors at NHMFL. Excellent adhesion at the interface due to the significant interfacial reactions, indicates that this sol-gel route is a feasible method for applying zirconia coatings. Sol-gel technology is a low temperature chemical route of preparing inorganic material. The stability and the coating characteristics of a organozirconium compound have been investigated to coat ZrO2 films on silver sheathed HTS tape conductors. This method was used to coat stainless steel with ZrO2.The ZrO2 coatings were obtained by dipping the silver sheathed HTS tape in a solution of zirconiumtetrabutoxide, isopropanol and acetylacetone.