Abstract: In this research, rare earth elements were used as adding elements to produce FeNi30 powder catalyst. The composition of thus prepared powder was tested. It was found that, after adding rare earth elements, the oxygen content in catalyst powder decreased from 230*10-6 to 120*10-6 . The deoxidizing and desulfurizing mechanism of the rare earth was analyzed. Diamond synthesizing experiments were carried out separately in three kinds of condition including non-rare earth, adding rare earth into graphite powder and adding rare earth in the form of alloy with catalyst into synthesizing column. By the comparison of experimental data, the authors have got the conclusion that, adding rare earth is beneficial to improve the diamond mixed yield, the proportion of coarse particles, static strength as well as the impact roughness of diamond, and to decrease magnetic susceptibitlity of diamond. The color of the obtained diamond turns from pale yellow to green tendency after adding rare earth elements. The authors also studied the function of vacuum heat treatment for graphite column.

Keywords: rare earth catalyst powder synthesizing diamond