fig3
Figure 3. (A) Schematic illustration of grain boundary phase transformation. (B) ECCI images after heat treatment at different temperatures (the secondary phase indicated with RED). (C) The secondary phase area of the grain boundary after heat treatment at different temperatures. (D) The change in the d33 after heat treatment at different temperatures, and (E) the thermal depolarization behavior for the WCBN, WCBN-900HT, WCBN-950HT, and WCBN-1000HT ceramics.
