Study on Preparation and Growth Mechanism of MgSO₄·5Mg(OH)₂·3H₂O Whiskers in NH₄⁺–NH₃ Buffer System

Abstract

Magnesium hydroxide Sulfate hydrate (MHSH) whiskers are synthetic inorganic functional materials with certain aspect ratio. The formula is xMgSO₄·yMg(OH)₂·zH₂O. In the NH₄⁺–NH₃ buffer system, MgSO₄·5Mg(OH)₂·3H₂O with a length of 10–30 µm, a diameter of 0.05–0.3 µm and an aspect ratio of 30–150 are prepared by one step at atmospheric pressure for a short time. The products are characterized by XRD, SEM, TG, TEM, etc. The influence factors such as reaction concentration, reaction temperature, reaction time and aging time are studied by combining the characterization results. First-principles analysis of the growth mechanism of MHSH whiskers show that growth habits accord with the dislocation spiral growth mechanism. The buffer system stabilizes the acidity and basicity of the solution, reduces the non-ideality of the solution, and enables the crystals to grow directionally under non-forced conditions, which provides an important reference for further industrial application and low-energy consumption production of MHSH whiskers.