Edge cracking behavior of Y2O3 films based on the stress intensity factor.

Hastelloy C-276 alloy is the preferred substrate for YBa 2 Cu 3 O 7-δ (YBCO) coated conductors prepared by Ion-beam-assisted deposition (IBAD) route, but its surface is too rough to meet application requirements. Y(CH 3 COO) 3 ·4H 2 O precursor solution has a low flattening efficiency, and its film edges are prone to crack formations. In this paper, a model for the stress intensity factor was established to study the effect of the presence of cracks on film stress. The simulation results showed that increasing the coating thickness reduced the overall stress, but increased the stress concentration at the crack. The larger bottom layer defects also made it easier for cracks to be generated. Then, 10-m long Hastelloy C-276/Y 2 O 3 strips were prepared by colloidal-solution deposition planarization (CSDP), with an average surface roughness Rq of 0.427 and only 10 coating layers. This improved the flattening efficiency by 40 %, and a CeO 2 layer with a good biaxial texture was finally prepared. [ABSTRACT FROM AUTHOR]