Microstructural, electrical, and mechanical characterization of Bi_ 2Cu_(0.1)V_(0.9)O_(5.35) (BICUVOX) ceramics fabricated from co-precipitated precursor powders

摘要

Copper-doped bismuth vanadate (Bi_2Cu_(0.1)V_ (0.9)O_(5.35), BICUVOX) was synthesized by a co-precipitation process which resulted in a homogenous, fine-grained powder with an average particle size of ~0.45 μm. The consolidated BICUVOX powder was sintered at temperatures between 625 and 800 C for 0-8 h in air. The correlation between the thermal processing schedule and the final microstructure were completed for all conditions through stereological analysis of the resultant cross-sectional scanning electron microscope images. From this work, the sintering schedule of 675 C for 1 h resulted in acquiring a BICUVOX ceramic microstructure that displayed ~97 % relative density with an average grain size of ~1.29 μm. This processing condition was ~75-125 C lower than typical sintering temperatures for the same density, and resulted in a final grain size that is ~5-10 μm smaller in size. The four-point conductivity testing of the BICUVOX ceramics in air showed values of ~0.003-0.007 and ~0.07-0.12 S/m at 300 C and 500 C, respectively, depending upon the thermal processing schedule. The average flexure strength of the same BICUVOX membrane was measured using a ring-on-ring configuration, and this measurement showed flexural strengths as high as 159.3 MPa. This strength is ~92 % greater than previously reported values for BICUVOX membranes.