We report on the morphological and structural properties of multi-seeded melt textured NdBa2Cu3O7-? bars. In particular, by means of pole figures X-ray diffraction analysis, we have studied the misorientation angles between the crystallographic axes of adjacent domains, induced by the single-crystal MgO seeds. Polarised light microscopy has been used to study the precipitate particles distribution and their segregation mechanism. We focused the attention on the domains boundary regions, where the growth dynamics is expected to differ from single-domain's one, and a different precipitates distribution may occur. The absence of secondary phases and precipitate deposits in this region has been observed. Connections of mechanical fragility with the preferential formation of cracks along the crystallographic axes' directions have also been investigated.
Study of structural properties and morphology of multi-seeded NdBaCuO bars
Marcello Gombos;Antonio Vecchione;Sandro Pace
2002
Abstract
We report on the morphological and structural properties of multi-seeded melt textured NdBa2Cu3O7-? bars. In particular, by means of pole figures X-ray diffraction analysis, we have studied the misorientation angles between the crystallographic axes of adjacent domains, induced by the single-crystal MgO seeds. Polarised light microscopy has been used to study the precipitate particles distribution and their segregation mechanism. We focused the attention on the domains boundary regions, where the growth dynamics is expected to differ from single-domain's one, and a different precipitates distribution may occur. The absence of secondary phases and precipitate deposits in this region has been observed. Connections of mechanical fragility with the preferential formation of cracks along the crystallographic axes' directions have also been investigated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.


