Three kinds of sintering aids, LiBiO
2, CuBi
2O
4 and LiBO
2, were selected as sintering aids for the low temperature sintering of (Li
0.04K
0.52Na
0.44)(Nb
0.84Ta
0.1Sb
0.06)O
3 (LF4) ceramics and the effects of these compounds on the sintering behavior of the LF4 ceramics was investigated. The addition of LiBiO
2 decreased the sintering temperature of LF4 about 100°C but the effect was limited and the broadening of XRD peaks due to the degradation of crystallinity was observed. The CuBi
2O
4 was also effective to decrease the sintering temperature of LF4 ceramics but a secondary phase was formed when a large amount of CuBi
2O
4 was added. The addition of a small amount of LiBO
2 was very effective to decrease the sintering temperature of LF4 ceramics. By optimizing the sintering conditions, ceramics with the relative density of 95% were obtained at 950°C which was lower than the melting point of Ag. Li ions in LiBO
2 were incorporated into the LF4 lattices, giving rise to the degradation of piezoelectric properties through the change of crystalline phase. The addition of excess Na with LiBO
2 restricted the incorporation of Li ions into the lattice. Ceramics sintered at 950°C showed the relative permittivity of 738 and the
d33 constant of 138 pC/N at room temperature.
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