Preparation of “NaREF4” phases from the sodium nitrate melt

Synthesis of NaYF4:Yb, Er up-conversion luminophore from nitrate flux

“…However, microcrystals that are approximately characterized by these simple habit forms have a huge number of rough defects and are splices of smaller crystals. These results are similar to what we previously observed in the synthesis of NaRF 4 phases [45].…”

“…The method is characterized by simple hardware design, high performance, environmental friendliness and low cost. We have shown [45] that in this way it is easy to obtain powders of equilibrium hexagonal phases formed in systems of sodium fluoride with REE fluorides RF 3 (R = Pr-Lu,Y).…”

Low‐temperature phase formation in the SrF2–LaF3 system

“…The method of co‐precipitation from aqueous solutions was used as an auxiliary synthesis method for obtaining single‐phase samples of solid solutions 42 . An aqueous solution of nitrates (0.08 mol/L) was added dropwise at a rate of 4 mL/min to a solution of hydrofluoric acid (5 mol/L, 10‐fold excess) placed in a polypropylene reactor, under constant magnetic stirring.…”

“…Promising for the synthesis of fluoride systems is nitrate fluxes, namely melts of alkali metal nitrates, primarily sodium nitrate. [40][41][42][43] NaNO 3 melts at 308°C, stable up to 500° C. The melting point can be lowered by adding potassium or lithium nitrates. [44][45][46] The purpose of this work is to study the low-temperature phase formation in the SrF 2 -LaF 3 system using a nitrate flux, to find out the limits of the stability of the non-stoichiometric phases.…”

“…The flux has to satisfy a number of requirements, 40 including the solubility of the flux components in the test substance must be negligible. Promising for the synthesis of fluoride systems is nitrate fluxes, namely melts of alkali metal nitrates, primarily sodium nitrate 40‐43 . NaNO 3 melts at 308°C, stable up to 500° C. The melting point can be lowered by adding potassium or lithium nitrates 44‐46 …”