Synthesis of nanocrystalline lanthanum phosphate for low temperature densification to monazite ceramics

Microwave Dielectric Properties of LaPO$lt;inf$gt;4$lt;/inf$gt; Ceramics Synthesized by a Hydrothermal Method

“…As can be seen, the relative densities of H-LaPO 4 ceramics increased to a maximum of 97.1% at 1300℃ and thereafter it decreased with increasing sintering temperature. This sintering temperature was very close to the LaPO 4 prepared by a precipitation method [30] . The relative densities of SSR-LaPO 4 ceramics slightly decreased from 95.8% at 1300 ℃ to 92.1% at 1460℃ with increasing sintering temperature.…”

Thermal evolution, second phases, and sintering behavior of LaPO4·nH2O nanorods prepared by two different chemical synthesis routes

“…The hydration of the LaPO 4 crystal is due to zeolitic water present in the channel-type structure. Different temperature values are given in the revised literature for the dehydration phenomena of the rhabdophane-type LaPO 4 •nH 2 O depending on the synthesis method employed [13,14,18,[38][39][40][41][42][43][44]. A 17% TGA weight loss and a sharp endothermic peak centered at $ 325 1C can be attributed to NO 2 emission, intermediate compound in the combustion reactions, which gives rise to the N 2 and O 2 gases [45].…”

“…Another endothermic peak at $ 490 1C can be attributed to rhabdophane to monazite phase transition, according to the XRD analysis (see below). There must be taken into account the shift of the temperatures for the different events between the DTA-TG and XRD results since the powders were calcined at each temperature for 12 h. The position of the exothermic peak corresponding to the hexagonal-monoclinic transition is observed at different temperatures from 375-900 1C [13,14,18,[38][39][40][41][42][43][44] also depending on the synthesis method employed. The broad exothermic peak centered at $ 900 1C can be assigned to further crystallization of the monazite phase, accompanied by the combustion of the organic material, i.e., thermal decomposition products of the urea, both elimination and nitrates decomposition, etc.…”

Crystal chemistry of the monazite structure

“…94 Within this application, particular studies are dedicated to the fabrication processes [95][96][97][98][99][100][101][102][103][104] or to the sintering of monazite compounds loaded with actinides or actinide surrogates. [105][106][107][108][109][110] In these applications, the elementary incorporation in the structure is the key factor driving the material properties. The understanding and forecasting of elementary substitution in the monazite structure is of major interest to obtain designed materials.…”