In this study,magnesium oxide(MgO)doped by cobalt(Co)was prepared as pressure-transmitting medium,by solid reaction process.The starting material is a pre-compressed mixture of MgO and cobalt oxide(CoO),which was mixed for 8 hand compressed at 200 MPa,and then treated at 1 200℃.The as-prepared samples were characterized by X-ray diffraction,scanning electron microscopy,and thermogravimetric analysis.The results demonstrate that during the sintering process,the reaction between MgO and CoO was completed and ...