Rapid synthesis of A2(MoO4)3 (A = Y3+ and La3+)with a CO2 laser

Abstract Negative thermal expansion material of yttrium molybdate and positive thermal expansion material of lanthanum molybdate have been successfully synthesized by rapid solidification with a CO 2 laser. Both materials were solidified in densely packed blocks with smooth surface and glazing color. They have similar microstructures consisting of nano-particles or nano-dendrites with grain sizes around 20–30 nm. Raman spectroscopic and XRD analyses reveal that lanthanum molybdate crystallized in a high temperature phase of tetrahedral La 2 Mo 3 O 12 , whereas yttrium molybdate crystallized in an orthorhombic Y 2 Mo 3 O 12 . This synthetic route is a very rapid process with which a sample can be synthesized within a few seconds and holds prospect for the synthesis of other rare earth molybdates and tungstates.