Polygonal Single‐Crystal Aluminum Borate Microtubes

Abstract

In this paper we report the synthesis of polygonal single‐crystal aluminum borate microtubes by the direct calcination of alumina and boron nitride powders in air. The diameters of the obtained tubes vary between 1 and 15 μm; and the lengths are in the range of tens to hundreds of micrometers. The cross‐sections of the microtubes are in the shapes of rectangular, hexagonal, and quasi‐circle. A new solid–liquid–solid growth mechanism was proposed to account for the formation of microtubes instead of whiskers.