The growth mechanism of NaCl whiskers

Abstract The growth of NaCl whiskers grown from porous porcelains and a glass plate was studied. Only thin whiskers of less than 10 μm in thickness were examined. No axial holes could be optically detected. The axial regrowth of the whisker could not be observed either when the substrate porcelain was wetted or half of the whisker was immersed in a supersaturated solution. Base growth, however, was observed when the whisker was made to stand on a suitably wet porcelain. During growth the whisker often inclined to the substrate. Sears' mechanism is not plausible for the whiskers studied here. It is suggested that a nucleus is formed in a thin solution film on the substrate and two-dimensional nucleation takes place at the bottom. Thus thin dislocation-free whiskers are formed.