| 摘要 |
PURPOSE:To convert a ferromagnetic substance to a highly stable colloid, and to obtain a magnetic fluid having excellent thermal and electrical conductivity, by evaporating a ferromagnetic substance with a heater, and contacting the vapor with a liquid containing a surfactant to effect the condensation of the ferromagnetic substance. CONSTITUTION:A crucible 7 is placed in a cylindrical drum 1, and the drum 1 is evacuated to high vacuum or substituted with an inert gas or oxygen gas having low pressure. A ferromagnetic metallic element such as Fe, a ferromagnetic alloy containing a metal such as Cr or a ferromagnetic compound (hereinafter referred to as ferromagnetic substance) 8 is charged in the crucible 7. A liquid 6 containing a surfactant is poured to the bottom of the cylinder 1 as the medium of the magnetic fluid. The drum 1 is revolved, and the liquid 6 is developed over the inner wall of the drum 1 to form a coating film. The vapor of the ferromagnetic substance evaporated by heating is made to condense on said coating film to form a ferromagnetic colloid. The operation is repeated until the objective magnetic fluid is obtained. |
