The effect of YBa2Cu3O7-x powder characteristics on thick coatings prepared by atmospheric plasma spraying

The development of superconducting YBa2Cu3O7-x, plasma sprayed coatings on metal substrates can be very useful for applications such as targets for th in-film deposition techniques (sputtering, laser ablation, ion assisted dep osition) or magnetic shielding, due to the brittle nature of bulk supercond uctors. The plasma spraying technique is very flexible and can be used for manufacturing components with a large variety of geometries. This technique requires the use of powders with good rheological characteristics. In this study, YBa2Cu3O7-x powders were produced by using the conventional solid-s tate reaction route and also by spray drying a solution of nitrate precurso rs. Both powders, as well as mixtures of them, were plasma sprayed to devel op coatings on stainless-steel substrates, with the aim of studying the eff ect of the feedstock powder characteristics on the coating properties. It w as found that by optimizing the plasma spraying conditions, good quality co atings could be obtained. However, the powder morphology and homogeneity si gnificantly affect the coating quality. More homogeneous powders lead to be tter results, the spray-dried powder being the best because of its enhanced rheological properties and good morphology.