Synthesis of PMN by mechanochemical process

PMN (Pb(Mg_1/3Nb_2/3)O₃) is used in many high-tech fields due to its dielectric and other advantages, the preparation of PMN by traditional methods exists some problems, such as impurity phase. In this paper a novel mechanochemical method to synthesize PMN was reported, MgO, PbO and Nb₂O₅ without any purification utilized as raw materials were mixed by ball-milling in advance, and the mixture was characterized by XRD, BET and SEM to identify the structure and the dispersion. It was indicated that the materials were dispersed better and no crystal phase transformation was observed after pre-milling. Then the pre-milling powders were poured into the milling jar to grind under different conditions. As-received powders were examined by XRD and SEM. The influence of milling time on the structure of the products was analyzed, which could obviously indicate the solid-state reaction route during grinding. The radio of raw materials and the speed of milling were changed gradually, and their effects on solid-state reaction were studied in details. All samples synthesized at different conditions were testified by XRD to confirm the chemical composition. The morphology were analyzed by SEM, which revealed typical microstructure of nano scale. It was found that the speed of rotary was the key factor to influence the solid state reaction. It came to the conclusion that the pure PMN could be produced at the lower speed. It was considered that mechanochemical process was an efficient, fast and easy way to prepare the nano-scale PMN.