Abnormal grain growth in undoped strontium and barium titanate

Linking Grain Boundaries and Grain Growth in Ceramics

“…Therefore the GB energy is a function of the orientation of the GB plane relative to both adjacent grains and only indirectly linked to the misorientation of the grains. The high frequency of 100 parallel GB planes in material sintered at 1 425 8C [13] had been explained with the highly anisotropic surface energy of SrTiO 3 crystals, leading to a minimum in GB energy if the GB plane is parallel to 100 in one of the grains, the plane with the lowest surface energy. The temperature dependence of the surface energy g may be described by…”

“…[18] After these energetical arguments for the existence of different types of grain boundaries a link to the effective mobilities of the grain boundaries has to be established. It has been shown that the 100 parallel facets in the high temperature range exhibit a higher mobility than the average grain boundaries [13] possibly due to the high number of Ti and O vacancies at such grain boundaries. [19] This is in agreement with the findings of Sursaeva et al [20] that a facetted boundary can move faster than a curved boundary.…”

“…For comparison with the results from the high temperature sintered ceramics [13] , eight grains were aligned with the 100 direction of the crystal parallel to the electron-beam direction ( Figure 3) which gives approximately 50 GBs to neighboring grains with different misorientations and GB-planes. Additionally four grains were aligned with the 110 or 112 directions parallel to the electron beam (Figure 4).…”

“…In order to understand this interesting phenomenon, we analyzed the grain boundaries formed during grain growth in the low temperature regime (1 300 8C) and compared them with previously published data of the GB morphology taken from samples processed at 1 425 8C. [13] In the high temperature regime a high fraction of the GBs is parallel to a 100-type plane of one of the adjacent grains. The microstructure is dominated by these facets, as shown in Fig.…”

Growth of single crystalline seeds into polycrystalline strontium titanate: Anisotropy of the mobility, intrinsic drag effects and kinetic shape of grain boundaries

“…In this paper we present a suite of measurements and combined analyses of grain growth of large, oriented single crystals into polycrystals which are themselves undergoing grain growth, to provide additional insights into the origins of growth rate transitions in strontium titanate [17][18][19][20][21]. The initial orientation of the interface between the single crystal and the polycrystal can be set by polishing the single crystal at a particular orientation before joining and the polycrystalline matrix provides the driving force for growth of the single crystal at any point in time at temperature.…”