Preparation Of Magnesium Hydroxide Sulfate Hydrate Whisker By Ammonia Precipitation And Its Application

Magnesium hydroxide sulfate hydrate whisker is an artificially synthesized inorganic functional material with a certain aspect ratio,because its addition to the material can enhance the toughness.Therefore,its application is very wide,more and more attention.In this word,the effects of reaction temperature,ammonia time,solution concentration and aging time on the morphology of whiskers were studied by gas-phase ammonia precipitation method to prepare Mg SO₄·5Mg（OH）₂·3H₂O whiskers.At 100℃,Mg SO₄·5Mg（OH）₂·3H₂O with length of 10～30μm,diameter of0.05～0.3μm and aspect ratio of 30～150 was obtained.The obtained products were characterized by XRD,TG,IR and other characterization methods,and simple application of products.The crystallization process of the crystal was that the formed Mg（OH）₂ colloidal particles were crystallized into 153 magnesium hydroxide sulfate hydrate whiskers with the molar ratio of Mg SO₄ and H₂O at 5:1:3.The whiskers gradually changed from cluster-like morphology to slender strip-like morphology,and then gradually aggregated into broadband products,and then changed into fish fin-like whisker products.The morphology of whiskers was reformed,and finally rod-like magnesium hydroxide sulfate hydrate whiskers were grown.The whisker growth mechanism is spiral dislocation growth mechanism,which is consistent with the first principle analysis.The advantage of ammonia precipitation is to form NH₄⁺-NH₃ buffer system,eliminate the local OH^-ion concentration difference,so that whiskers are not forced directional growth.Provide a stable solution environment,simplify the experimental process,save experimental costs,reduce security risks,and lay the foundation for the production of basic magnesium sulfate whiskers with low energy consumption.