Microstructure and electrical conductivity of Ce0.85Y0.15O1.925-Al2O3 composite ceramics

The polycrystalline Ce 0.85 Y 0.15 O 1.925 (YDC)-xmol%Al 2 O 3 (x=0, 5, 10, 20, 30) composite ceramic was sintered and prepared at 1300  ° C for 10 h in the air atmosphere to investigate the effects of the YDC/Al 2 O 3 heterogeneous interface on its electrical conduction properties. The main phase of YDC exists in all samples, and the second phase of Al 2 O 3 starts to appear in the XRD patterns when its content is beyond the solid solubility limit in YDC. No severe reaction between YDC and Al 2 O 3 occurs in the composite samples at 1300  ° C. The average grain size of the composite ceramics decreases from 510 nm to 330 nm with the rise in Al 2 O 3 content from 0 to 30%. The specific grain boundary electrical conductivity of YDC-xAl 2 O 3 samples decreases with the Al 2 O 3 content from 0 to 20% and then begins to increase when the Al 2 O 3 content rises from 20% to 30%. The YDC-30%Al 2 O 3 sample shows a higher specific grain boundary conductivity than YDC-20%Al 2 O 3 , which mainly originates from the higher volumetric fraction of YDC/Al 2 O 3 heterogeneous interface in YDC-30% Al 2 O 3 as well as the higher oxygen ion mobility in YDC/Al 2 O 3 heterogeneous interface region.