Quality Management in Production of Textured Templates for 2G HTS Wire

Two major in-line quality control tools implemented at SuperOx in the production of textured templates for 2G HTS wire are the digital processing of optical images of the electropolished substrate surface and reflected high energy electron diffraction (RHEED) analysis of the texture of the IBAD-MgO layer. In routine production, we use these tools for continuous screening and early rejection of defective material and thus reduce cost of the finished wire. Overlapping images of the surface of the moving tape exiting the electropolishing system are taken and processed, to yield three quality parameters. The parameter values correlate with the surface roughness of the tape and with the presence of macroscopic debris and scratches. The distribution of the surface quality parameters along the length of the tape is recorded, and the images of the areas where the parameter values lie outside the acceptable quality range are stored for defect analysis. A RHEED system is incorporated in buffer layer deposition to analyze the IBAD-MgO layer texture. Parameters of diffraction spots correlate with the texture of the IBAD-MgO layer, which ultimately determines the quality of the HTS layer. The RHEED tool enables closed loop control of the process thus ensuring a very high yield of textured template production.