Crystal growth of tungsten carbide plates by condensation of high-temperature ultrasupersaturated gas

Fine plates of tungsten carbide with hexagonal structure were prepared by condensation of a high-temperature ultra-supersaturated gas derived from tungsten carbide powder by means of a cylindrical shock wave method. The majority of the plates were equilateral trigonal shape in the basal face. Equilateral or scalene hexagonal, pentagonal, trapezoidal, and rhombic plates were also observed. Trigonal and hexagonal plates had growth directions 〈101¯0〉 and 〈112¯0〉 in the basal faces, respectively. It is inferred that the difference between the growth directions of trigonal plates and hexagonal plates is due to differences in the local environment during crystallization. Moreover, the thickening of the plates in a direction perpendicular to the basal face is discussed on the basis of the vapor-liquid-solid growth mechanism.