The interest of synchrotron x-ray microtomography for the study of defects in sapphire articles fabricated by bulk crystallization

We present a Synchrotron X-ray tomography investigation of sapphire crystals of a complicated shape. The concept of crystal shaping while the growth from the melt allows avoiding tooling and associated loss of material. However, the elimination of gas bubbles and dislocations remains a severe problem. In the present communication, we show and analyze the distributions of bubbles in sapphire tubes and ribbons grown with the Stepanov technique. We approve that microtomography implemented with Synchrotron Radiation using a conventional algorithm can give good results concerning the visualization of µm-sized bubbles.