Effect of sintering technique on mechanical property and chemical durability of Ce0.5Pr0.5PO4 ceramics

New insights into phosphate based materials for the immobilisation of actinides

“…The dissolution rate varied between ~10 −3 g · m −2 · day −1 at pH 3 and ~10 −7 g · m −2 · day −1 at pH 7 with no significant change when increasing the temperature from 90°C to 200°C and no significant influence of the fabrication method i.e. either using conventional sintering or hot-pressing [143,148]. Brandt et al [53] investigated the dissolution behaviour of La 1−x Eu x PO 4 solid solutions in dynamic dissolution experiments at pH 2 and 90°C.…”

“…The densification processes for the preparation of dense pellets were thoroughly investigated for phosphate matrices. It is a crucial part of the waste form fabrication process, since the morphology of the precursor [82], the sintering method [143] and the sintering protocol [144] govern the final microstructure and porosity of the waste form. Monazite pellets with a relative density exceeding 95 % can be prepared by sintering using a typical temperature range of 1350-1500°C [45,145,146].…”

“…Sintering at higher temperature was observed to result in the decomposition of the phosphate group [147]. Hot-pressing methods allow for lowering the sintering temperature by about 250-300°C at 30 MPa, yielding pellets with 98 % relative density [143,[148][149][150][151][152]. Du et al [153][154][155] achieved the same density (98 %) of La-monazite after 3 min of sintering at 1350°C (heating rate 100°C · min −1 ) at a pressure of 40 MPa using Spark Plasma Sintering (SPS).…”