| 摘要 |
PROBLEM TO BE SOLVED: To obtain an electroviscous fluid having both high electroviscous effect and dielectric breakdown strength. SOLUTION: This electroviscous fluid is obtained by deaeration of a composition comprising carbonaceous powder of spherical particles, insulating oil and modified silicone oil; wherein the carbonaceous powder is obtained using, as raw materials, a solvent and a condensate prepared substantially through methylene-type linkage of an aromatic sulfonic acid or a salt thereof, and it is preferable that the spherical shape of the carbonaceous powder particles is such that the deviations of the maximum diameter and minimum diameter from the average diameter lie within 30% of the average diameter, and the average particle size of the carbonaceous powder is 0.1-20μm. |
