Fabrication of YBCO coated conductors using advanced TFA-MOD process

We have investigated the influence of the heating rate in the calcination process on the superconducting properties in order to optimize an advanced TFA-MOD process. The increase of the heating rate makes Jc values lower, and the maximum values of HF gas generation rate higher. From TEM observation of the precursor film, the large pores and segregation of Cu elements were observed in the films at high heating rates. Consequently, it is clear that the increase of the heating rate during calcination process caused abrupt HF gas generation leading to degradation of the surface morphologies, formation of large pores and segregation of Cu elements. These morphological and microstructual differences could be one of the reasons for a reduction in Jc values of the YBCO films.