关键词: 硼酸镁晶须, 助熔剂法, n(B)/n(Mg), L-S机理

Abstract: Magnesium borate whiskers were prepared by molten salt method using MgCl₂ · 6H₂O and Na₂B₄O₇ · 10H₂O as raw materials, KCl and NaCl as fluxes. The lengths of the above whiskers varied from 200μm to 800 μm, and the maximum aspect ratio reached 250. The produced samples were characterized by X-ray diffraction (XRD), microscope and scanning electron microscope (SEM). The effects of n(Mg)/n(B), reaction temperature and reaction time on the whisker growth process and product quality were explored. It was found that the best operating parameters of n(Mg)/n(B), reaction temperature and reaction time were 3.0, 900 ℃ and 6h, respectively. According to the XRD analysis, Mg₃B₇O₁₃Cl is the intermediate product, and the growth of Mg₂B₂O₅ whiskers needs a boron- enriched environment. The whisker growth process agrees to the liquid-solid (L-S) mechanism.

Key words: Mg₂B₂O₅ whiskers, molten salt method, <>n(B)/<>n(Mg), L-S mechanism