Abstract: Skeletal form of KNbO3 crystals growing in Li2B4O7 solvent was in-situ observed at 900℃ and it was found that shallow depression started to develop on the surface of KNbO3 crystals when the crystal size exceeded several micron, typically 7 micron. Based on the quantitative criterion derived by Chernov, the estimated critical size of KNbO3 crystals was 1 micron, which was consistent with the experimental measurement. The kinetic coefficients, kcorner and kcr, in the criterion were experimentally obtained in the diffusive-convective and diffusive-advective flow states respectively.

Key words: Morphology instability, KNbO3, In-situ observation, Electron microprobe analyses