Abstract：The composite powders of Mg and Al with molar ratios of 5∶1,4∶1,3∶1,2∶1,1∶1 as well as single magnesium hydroxide and aluminum hydroxide were prepared via chemical coprecipitation method under the same processing conditions by changing the amount of Al³⁺ with fixed concentration of Mg²⁺.The samples were characterized through the means of XRD,TEM,TG-DTA,N2adsorption test specific surface area and bulk density.The results indicate that the samples show the curly sheet morphology based on hydrotalcite structure with Mg₆Al₂(OH)_18.4.5H₂O as the main content.The powders prepared at the condition that Mg and Al with molar ratio of 4∶1 are mixtures of Mg(OH)₂and Mg₆Al₂(OH)₁₈.4.5H₂O,which have good dispersion and high decomposition temperature,and are good flame retardants.

Keywords：superfine powder;flame retardant;chemical coprecipition