Use of gas plasmas to increase breakdown strengths in polycarbonate film/foil capacitors

It is shown that the electrical breakdown voltages of polycarbonate film/metal foil capacitors can be increased. This can be achieved by briefly exposing the metal foil in these spirally wound film foil sections to a low-pressure, low-temperature gas plasma. Exposure of tin/lead foil to a 96% CF/sub 4//4% O/sub 2/ gas plasma for four min, for example, produced >500% increase in breakdown voltage of sealed polycarbonate capacitors.<
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