Processing technology
Electrolytic copper production process: electrolysis is completed by electroplating process. Electrolytic copper is formed by separating copper ions from copper sulfate solution with electric current, and then it is completed after oxidation resistance and roughening treatment.
Manufacturing process of calendered copper: calendered copper is produced by coating. Calendered copper is rolled from copper ingots, and then processed by forging, oxidation resistance, roughening, etc., with the thickness generally between 5um and 135um.
In terms of cost, Calendered copper foil The fixed assets of, Electrolytic copper foil It has advantages in cost. In terms of production technology, the production technology of calendered copper foil has high requirements, complex process and long process. At the same time, the production technology is mostly in the hands of Japanese and American enterprises, and the production is mostly limited by patents.
High precision calendered copper foil is mainly produced by foreign manufacturers. Due to the high technical threshold of high-precision rolled copper foil, the main rolled copper foil in the book is concentrated in several manufacturers: NipponMining, Fukuda, Olibrass and Hitachi Cable. It can be seen that Japanese enterprises are in the leading position in the field of rolled copper foil.
The microstructure of copper foil materials is different due to different processing technologies. The cross section of the material is observed under a 1000 times microscope, and the atomic structure of the calendered copper is irregular layered strong crystal. For the recrystallization after heat treatment, it is not easy to form cracks, and the bending property is good; The electrolytic copper material presents columnar crystal structure in the thickness direction, which is easy to crack and fracture when bending.
In view of the shortcomings of electrolytic materials, some material suppliers have developed high elongation electrolytic materials, that is, after conventional processing, the materials are heat treated again to recrystallize copper atoms, but its columnar structure still remains. Therefore, there is still a big gap between the flexibility and calendered copper foil.
