Abstract: Magnesia whiskers with a diameter of 1--50μm and a length of 50--2000μm were synthesized via calcinations at different stages using MgCl₂·6H₂O as raw materials and KCl as flux. Through theoretical analysis of bischofite’s pyrolysis and chemical analysis of intermediate products during different sintering stages, anhydrous magnesium chloride was presumed to be the precursor, which was confirmed by the preparation of MgO whisker from anhydrous magnesium chloride. Three factors that influence the whiskers morphology were also discussed including MgCl₂, HCl and H₂O. During the whisker’s growth, heterogeneous nucleation of MgO occurs on the container-wall at initial stage, and then MgO whiskers are grown through VLS mechanism, finally dominated by VS mechanism.

Key words: whisker, intermediate products, growth mechanism