Lanthanide (Nd, Gd) compounds with garnet and monazite structures. Powders synthesis by “wet” chemistry to sintering ceramics by Spark Plasma Sintering

Abstract Complex oxide Y 2.5 Nd 0.5 Al 5 O 12 with garnet structure and phosphates NdPO 4 and GdPO 4 with monazite structure were obtained by using precipitation methods. Ceramics Y 2.5 Nd 0.5 Al 5 O 12 and NdPO 4 were processed by Spark Plasma Sintering (SPS). Relative density more 98%, sintering time did not exceed 8 min, sintering temperature 1330–1390 °C. Leaching rates of elements from ceramics were 10 −6 –10 −7 g/(cm 2 d). The process of ceramics sintering has two-stage character: the first step of sintering-compaction process is related to the plastic flow of the material, the second step–to the process of grain boundary diffusion and grain growth.