A.C. breakdown voltage of solidified alcohol aqueous-solution at 77K

The development of environment-friendly material has been proceeded in many fields. Our laboratory pays attention to electrical insulation system using ice. Ice is environment-friendly material, and it has excellent electrical breakdown strength at cryogenic region. However, it has problem that void or crack is easily formed. Mixture of water-soluble material is considered to prevent formation of void or clack as electrical weak point, and improve A.C. breakdown strength of insulation system using ice. Alcohols are chosen as water-soluble material; namely ethanol, ethylene glycol, 1-propanol, 2-propanol, propylene glycol, 1,3-propanediol and glycerin. These alcohols are easily dissolved in any ratio in water. A.C. breakdown voltage of solidified alcohol aqueous-solutions at 77 K are obtained. A.C. breakdown voltage of solidified alcohol aqueous-solution is higher than that of ice, except in the case of ethanol. Especially 1,3-propanediol aqueous-solution marks the highest, 66% higher value than ice.