Sintering and properties of lead-free (K,Na,Li)(Nb,Ta,Sb)O3 ceramics

✍ Scribed by F. Rubio-Marcos; P. Ochoa; J.F. Fernandez

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 887 KB
• Volume: 27
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.02.110

✦ Synopsis

Two different stoichiometric (K 0.44 Na 0.52 Li 0.04 )(Nb 0.86 Ta 0.10 Sb 0.04 )O 3 and non-stoichiometric (K 0.38 Na 0.52 Li 0.04 )(Nb 0.86 Ta 0.10 Sb 0.04 ) O 2.97 compositions were prepared by the conventional mixed oxide and carbonate route. Low temperature synthesis process at 700 • C for 2 h, and further attrition milling process resulted in agglomerated powder of 500 nm of primary particles in the range of 50-70 nm. The ceramics sintered at 1125 • C showed the highest densification that decreased for higher sintering temperatures. Non-stoichiometric composition densification process was assisted through the presence of a liquid phase that promotes grain growth and the appearance of a secondary ferroelectric phase with tungsten-bronze type structure. The samples showed a relaxor type behaviour that diminished because of the compositional homogeneity improvement of the liquid phase in the non-stoichiometric samples. The higher piezoelectric properties were obtained for the samples with high ferroelectric type dielectric constant versus temperature behaviour. In the non-stoichiometric samples piezoelectric constant d 33 values reach ∼200 pC/N.