Study on the synthesis of Al2W2MoO12 by a simple stearic acid route and its negative thermal expansion property

The Sc2W3O12-type negative thermal expansion material attracts an extensive interest because of its thermodynamic stability and great chemical flexibility. In this paper, nanostructured Sc2W3O12-type negative thermal expansion material Al2W2MoO12 was synthesized by a convenient method, the stearic acid method. The thermodynamic property of the precursor was studied by thermogravimetric and differential scanning calorimetric methods. The structure and the size of the resulted products were characterized by powder X-ray diffraction and transmission electron microscopy, respectively. The negative thermal expansion property was studied by high temperature powder X-ray diffraction. Results show that nanostructured Al2W2MoO12 powders with average size about 10 nm were first synthesized here by the stearic acid method and the nanoparticles would be rearranged to form large rods by prolonging the heat-treatment time. The obtained nanoparticles exhibited negative thermal expansion property in the temperature range of 20-600 °C.