Publication Date:
2012-05-03
Description:
Barium titanate-20wt% cobalt ferrite ( BaTiO 3 -20wt% CoFe 2 O 4 ) nanocomposites were sintered from nanocrystalline BaTiO 3 and CoFe 2 O 4 powders using spark plasma sintering (SPS) and pressureless sintering (PS) techniques. Using SPS, dense polycrystalline composites were obtained at a sintering temperature as low as 860°C and a time of 5 min whereas PS required a higher sintering temperature (1150°C) and time (120 min) to obtain similarly dense composites. Microstructural analysis of the composites showed that both the techniques retained nanocrystalline grain sizes after sintering. High resolution X-ray diffraction measurements revealed that the BaTiO 3 -20wt% CoFe 2 O 4 composites sintered by the SPS technique did not exhibit formation of any new phase(s) due to reaction between the BaTiO 3 and CoFe 2 O 4 phases during sintering. However, the PS technique resulted in the formation of additional phases (other than the BaTiO 3 and CoFe 2 O 4 phases) in the composites. While the composites synthesized by SPS were of superior phase-purity, evidence of Fe diffusion from the spinel to the perovskite phase was found from X-ray diffraction and permittivity measurements.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Permalink