| 摘要 |
990,841. Cooling electrical components. SIEMENS & HALSKE A.G. July 26, 1963 [July 31, 1962], No. 29722/63. Heading F4U. [Also in Division H1] Unwanted heat arising during the operation of electrical components such as capacitors, resistances and semi-conductor components, e.g. transistors and diodes, housed within an outer protective casing is conveyed to the casing by an electrically-insulating, heat conducting medium which fills the interspace or interspaces between the component and the inner wall of the casing, the medium comprising a suspension of powdered, high density magnesium oxide in an electrically insulating liquid. The magnesium oxide which is prepared from voluminous magnesium oxide powder by sintering, by melting and recrystallization or by sublimation, is in a compact, mostly coarsely crystalline form of grain size preferably in the range 20 to 100 Ám. The liquid is preferably silicon oil and/or paraffin oil, the suspension preferably being of pasty consistency, although a suspension of 20% magnesium oxide is effective. To enhance the stability of the components siccatives such as calcium or boron oxide, calcium or sodium aluminium silicates or silica gel may be added whilst, when the component consists of or includes a semiconductor material, small amounts of substances having a stabilizing action on the material surface such as quinonoid or ketonoid ring compounds having an -OH group in the 2-position to the CO group, e.g. alizarin or 1,2,7- trihydroxyanthraquinone, may also be added. |
