Cluster Formation in Liquid Lithium Niobate A Small Angle X-ray Scattering Investigation

Abstract

Structural analysis of the clustering phenomenon in the LiNb0 3 melt was carried out by means of small-angle X-ray scattering using synchrotron radiation in the range of momentum transfer 0.2 nm -1 <£< 14.0 nm -1 . Microclusters were present in the melt throughout the entire explored temperature-domain from 1673 K to 1513 K which includes undercooling (melting point T m = 1526 K). The radius of gyration, size, shape and distance of particles were determined. Chains of few Nb0 6 octahedra and small blocks constituted by two layers of four corner-shared octahedra, interlocked by a lithium atom, could be good models for the microclusters in a large temperature-domain. By lowering the temperature, the particle size increased. Below 1553 K, probable macroclusters would be correlated to the rapid increase of the viscosity. Using the viscosity data and previously published and the present SAXS results, it was possible to evaluate the volume of the clusters. Near the freezing point about a quarter of the volume would be occupied by clusters.

Bismuth sodium titanate lead‐free piezoelectric coatings by thermal spray process

“…Compared with the cool melt process in furnace, thermal spray process is much faster and the volatilization is much lesser, although the mechanism of crystallization has similarity. Some studies on melting and crystal growth behavior of LiNbO 3 and KNbO 3 perovskite single crystals show [BO 6 ] oxygen octahedron, which is the basic unit of perovskite structure are still present in the melt close to the crystal‐melt interfaces, or at the temperature right above the melting point . During the thermal spray process, feedstock is heated to molten/semimolten state, which is similar to the condition of crystal‐melt interfaces.…”