PURPOSE: To provide the subject fluid exhibiting a stable electric viscosity effect over a wide temperature range by dispersing fine particles in an electrically insulating fluid, the fine particles being prepared by forming an electrically conductive layer on the surfaces of fine particles and further coating the surfaces of the fine particles with an electrically insulating coating film.
CONSTITUTION: (A) Fine particles are dispersed in (B) an electrically insulating liquid such as silicone oil, transformer oil, engine oil, ester or dihydric alcohol in an amount of 5-50vol.%, (preferably 10-40vol.%) to provide the objective fluid, the fine particles A being prepared by forming an electrically conductive layer using Cu, Ni, Al, graphite, etc., on the surfaces of fine particles such as polystyrene beads, phenolic resin particles, ceramic particles or ceramic hollow particles preferably having particle sizes of 0.01-500μm (especially 0.1-100μm) by a non-electrolytic plating method, sputtering method, a CVD method, etc., and further forming an electrically insulating coating film comprising silica, titania, alumina, tantalum, a resin such as a polystyrene or epoxy resin, etc., on the surfaces of the fine particles.
HATTORI EIJI
OGURI YASUO
