Improvement of copper sulfur corrosion resistant based on cold-rolled deformation

Much work has been done to prevent copper corrosion in insulating oil with corrosive sulfur. Most of the research has focused on the addition of metal inhibitor and absorbent. Besides, changing the grain size and micro-structure of copper winding was an effective method to enhance the copper corrosion resistant. In this study, pure copper annealed at elevated temperature (400°C/20min) after cold rolled with varied deformation and corrosion experiments were investigated according to the IEC 62535 standard. Compared and analyzed the different shape variable after annealing copper strip corrosion condition and its influence on mineral oil insulation characteristics. And the evolution of grain sizes and special grain boundaries after the processing and annealing have been particularly determined by means of electron back scatter diffraction (EBSD) techniques. The results show that deformation controlling could increase the number of special grain boundary, and improve the grain size at the same time. Then, the corrosion resistance performance of copper enhanced dramatically.