Critical current densities in YBaCuO coatings prepared using internal and external feed plasma spray systems

Abstract

Plasma spraying of high T c oxide superconductors offers scope for forming thin coatings over large areas. Sprayed YBaCuO coatings were formed on silver substrates using two systems; a system in which the powder is fed inside the plasma gun and a system in which the powder is fed externally. Observations indicate that the coatings formed by the external plasma spray are more consistent with respect to physical properties and chemical composition. X-ray fluorescence analysis shows that during internal spraying there is a loss of copper. The net results is that the critical current densities of the heat treated samples are in the range 50–200 A cm −2 for the external spray samples compared with values of less than 60 A cm −2 obtained for internal spray samples.