NEW ROUTE FOR THE SYNTHESIS OF BORON-RICH RARE-EARTH BORIDE NDB6 UNDER HIGH-PRESSURE AND HIGH-TEMPERATURE

The boron-rich rare-earth boride NdB6, which is a pure phase without t he intergrowth of other phases, has been obtained for the first time b y the reduction of rare-earth oxide with elemental boron under the ext reme conditions of high pressure and high temperature. The synthesis c an be carried out in air from the beginning to the end without the pro tection of inert gas, and the synthesis can be completed rapidly. The residual rare-earth oxide and the elemental rare-earth metal produced in the process of synthesis can be easily removed by leaching them in HCl.