Clarify the influence and mechanism of the metal materials on the SF

6

decomposition under direct current partial discharge is one of the key problems in the fault diagnosis method for SF

6

decomposed components analysis（DCA）. In this paper

three kinds of metal materials

aluminum

copper and 18/8 stainless steel

were made intoneedle-plate electrons respectively and used to carry out the SF

6

positive DC partial discharge decomposition experi-ments respectively. The influence of metal materials on th

e five main characteristics decomposition component

CF

4

CO

2

SOF

2

SO

2

F

2

and SO

2

was obtained by the gas chromatograph-mass spectrometry（GC/MS）quantitative detec-tion method. It was found that there was no significant correlation between the formation of CO

2

and the kinds of metalmaterials;but the kinds of metal materials had a great influence on the formation of the other four kinds of character-istic gases. The difference of SF

6

decomposition characteristics under different metal electrodes is probably mainlycaused by the two factors

namely

the difference of anti-halogenation ability of metals and the passive film. There-fore

when using SF

6

decomposed components analysis for the condition monitoring and fault diagnosis of DC gas insulated equipment

it is necessary to consider the impact of different metal materials.