The Lattice Distortion of Ballmilled Zinc Oxide

Abstract

There have been hitherto many studies on the crystallite size and the lattice distortion of the ground zinc oxide powder by X-ray diffraction method. However, it seems that the thermal analysis is as effective for the study on the lattice distortion of the ground powder as the X-ray diffraction method.For this reason, the zinc oxide ground by a ball mill was studied by the thermal analysis, and the results were compared with the results obtained by the X-ray diffraction method. Moreover, the effects of heat-treatment of the ground zinc oxide on the disappearance of lattice distortion and on the growth of crystallite were also studied. As a result, an exothermal peak was found between 220° and 260°C in the heating process of the differential thermal analysis, but no change of the weight could be found at those temperatures. As the grinding time became longer, this exothermal peak shifted to a higher temperature and became larger. This exothermal peak in the heating process may be attributed to the discharge of lattice distortion energy.The lattice distortion increased with grinding time up to 200 hours, but after 200 hours it increased little. Such lattice distortion diminished or disappeared easily by heating at 200°C, and gradually diminished even at room temperature after a long time.On the other hand, the crystallite size increased gradually by heating above 200°C and rapidly above 700°C.