Effect of PbO on the Kinetics of {001} Pb(Mg1/3Nb2/3)O3–35 mol% PbTiO3 Single Crystals Grown into Fully Dense Matrices.

The influence of excess PbO on Pb(Mg1/3Nb2/3)O3–35mol% PbTiO3 {001} single crystal growth by seeded polycrystal conversion (SPC) was studied in the range of 0–10 vol% PbO. As in previous studies, additions of PbO increased the boundary mobility significantly, thus facilitating single crystal growth via SPC. Unlike previous studies, single crystals were grown into pore-free matrices, resulting in different crystal growth kinetics (signifying interface reaction controlled as opposed to diffusion controlled). Porosity was shown to decrease single crystal growth rates by a factor of 2. Additionally, it was found that single crystal and matrix grain growth rates are optimized at 1.5 vol% PbO, as opposed to previous work, which showed that 3 vol% PbO was fastest. Increasing PbO content beyond 1.5 vol% results in growth that is independent of liquid fraction for all annealing times. In addition, the matrix grains were faceted and the growth best-fit parabolic kinetics so interface reaction control was deemed the most likely growth mechanism. [ABSTRACT FROM AUTHOR]