Growth process of Cu2Al6B4O17 whiskers

The reactions occurred and growth process in the preparation of copper aluminum borate (Cu2Al6B4O17) whiskers based on flux method (Al2(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–Al2(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.