| 摘要 |
PURPOSE:To improve electroviscous effect by forming electrically insulating film on the surface of electrically conductive particles dispersed in an electrical]y insulating liquid by hydrolysis or polymerization of a metal alkoxide or its derivative. CONSTITUTION:An aqueous alcohol solution is prepared, which has 0.05 to 5mole% of metal alkoxide such as Si methoxide concentration, 0.1 to 10mole% of water concentration, and 1 to 100 of [H2O]/[alkoxide]. Electrically conductive fine particles of 0.01 to 500mum average particle size and more than 10<-10>OMEGA<-1>.cm<-1> such as Al, semiconductive Si or beta-Al2O3 particles are dispersed in the prepared aqueous alcohol solution to deposit the hydrolysate of the metal alkoxide or its derivative on the surface of the fine particles. Then, the particles are separated from the solution and dried below about 600 deg.C to give fine particles whose surfaces are coated with electrically insulating film in a thickness of 0.05 to 1mu. The fine particles are dispersed in an electrically insulating fluid such as silicone oil in a concentration of 5 to 50% by volume and an electric field is impressed to obtain the subject electroviscous fluid. |
