Kinetic formation and thickening of intergranular amorphous films at grain boundaries in barium titanate

Duplex nanocrystalline alloys: Entropic nanostructure stabilization and a case study on W–Cr

“…[12][13][14][15] These generally include segregation of certain atoms at grain boundaries and unusual chemical distributions associated with intergranular or amorphous phases. [16][17][18] Whereas the design of topological characteristics and crystallography of interfaces is a common approach to GB engineering, 7,8,[19][20][21][22][23] the above effects allude to a generalizable chemical approach of GB segregation engineering. [24][25][26][27][28][29][30][31][32][33] The overlap between chemical and topological considerations opens a unique avenue for structural design.…”

High-Temperature Stability and Grain Boundary Complexion Formation in a Nanocrystalline Cu-Zr Alloy

“…Many studies have since reported on the effects of these grain boundary structures on the overall physical and mechanical properties in metals and ceramics, such as the being cause for solid state activated sintering and abnormal grain growth. [29][30][31][32][33][34][35][36][37] Recently, Tang et al 38 introduced the term complexion to differentiate grain boundary "phases" from traditional bulk phases. The main reason for this convention is that complexions depend on their abutting grains and cannot exist as separate entities.…”

Inhibition of abnormal grain growth in BaTiO3 by addition of Al2O3

“…These grains have undergone very limited grain growth and so it is likely that grain boundary wetting has not taken place. Plus, if a liquid phase had wetted the grain boundaries during sintering, it would be expected to remain at the grain boundaries during cooling, as shown in the work of Choi et al 30 Fig. 7 shows SEM micrographs of the samples.…”

“…It is possible that the liquid phase wetted the grain boundaries during sintering and then dewetted during cooling of the samples. Choi et al 30 found similar liquid pockets at triple junctions between matrix grains in TiO 2 -excess BaTiO 3 sintered at 1350 • C. They also found that if grain growth could be suppressed (in their case by pretreatment of the samples in H 2 at 1250 • C), this liquid did not penetrate the grain boundaries even after prolonged sintering at 1350 • C. Moreover, they found that if abnormal grain growth and grain boundary wetting did take place, the liquid phase remained at the grain boundary and did not dewet upon cooling. In the present work, the liquid phase is also found at the triple junctions of matrix grains.…”