Interdiffusion between perovskites BaTiO3 and SrTiO3 diffusion couple was

studied by determining the crystalline phases and analyzing the microchemistry

and microstructure of undoped BaTiO3–SrTiO3 stacks sintered at 1250C in air. The

Kirkendall effect manifested by: (1) an inter-diffusion zone containing

(Ba1−xSrx)TiO3 and (Sr1−xBax)TiO3 solid solutions, (2) the migration of the initial

BaTiO3–SrTiO3 interface, and (3) the Kirkendall porosity was observed. The interdiffused

regions on both sides of the initial interface contain grains exhibiting the

characteristic core–shell structure with distinctive solute contents between core and

shell. TiO2-rich polytitanates, notably Ba4Ti13O30 and Ba6Ti17O40 containing a

minor amount of Sr from inter-diffusion, were detected at the BaTiO3 side near the

initial BaTiO3–SrTiO3 interface. An analogy between the BaTiO3–SrTiO3 diffusion

couple and Kirkendall's original α-brass-Cu couple was presented.

Kirkendall Porosity in Barium Titanate–Strontium Titanate Diffusion Couple.

C.Y.Siao, H.W.Lee, H.Y.Lu: Ceramics International, 2009, 35[7], 51-2958