Contact-based corrosion mechanism leading to copper sulphide deposition on insulating paper used in oil-immersed electrical power equipment

摘要

XPS and EDX were used to study Cu_xS deposition in Kraft insulating paper obtained from ageing paper samples in contact with a copper sheet, in mineral oil containing dibenzyl disulphide (DBDS). Qualitative and quantitative evidence of Cu_xS were obtained from bulk and surface analyses of insulating paper provided by the different depth resolution of the techniques used. The influence of [DBDS], oxygen, time, and Cu-paper contact upon the formation and mobilisation of Cu_xS were studied. A contact-based mechanism to explain Cu_xS contamination on paper and its displacement was proposed. The role of O_2 in enhancing Cu, S displacement was also investigated.