The reactions occurred and growth process in the preparation of copper aluminum borate (Cu2Al6B4O17) whiskers based on flux method (Al-2(SO4)(3)/CuSO4/H3BO3 as raw materials, K2SO4 as flux) were investigated. The thermogravimetric and differential scanning calorimetry analysis (TG-DSC), inductively coupled plasma atomic emission spectrum analysis (ICP-AES) and X-ray diffraction analysis (XRD) results of reactants mixture quenched at various temperatures and phase diagrams of K2SO4-Al-2(SO4)(3) system and B2O3-Al2O3 system showed that the reaction process proceeds through three steps: the formation and decomposition of two different kinds of potassium aluminum sulfate (K3Al(SO4)(3) and KAl(SO4)(2)): the formation of aluminum borate (Al4B2O9) and decomposition of copper sulfate (CuSO4) and boric acid (H3BO3): growth and formation of copper aluminum borate (Cu2Al6B4O17) whiskers. The scanning electron microscopy (SEM) analysis results indicated that morphology in growth of Cu2Al6B4O17 whiskers develops through three stages: nanoparticles, fan-shaped whiskers and agminate-needlelike whiskers. Crown Copyright (c) 2012 Published by Elsevier Inc. All rights reserved.