Archives of Metallurgy and Materials

Abstract

The paper presents the technology and basic properties of three compositions of lead-free ceramics: (i) (K 0.44 Na 0.52 Li 0.04 ) NbO 3 , (ii) (K 0.44 Na 0.52 Li 0.04 )NbO 3 +0.5%mol Nd 2 O 3 and (iii) (K 0.44 Na 0.52 Li 0.04 )NbO 3 +0.5%mol Pr 2 O 3 . Powders of the designed compositions based on KNLN were obtained with the classic ceramic technology, as a result of solid phase synthesis, from a mixture of simple oxides and carbonates. The synthesis of ceramic powders was carried out at T s = 900°C for t s = 4 h, while compaction by free sintering at T sint = 1100°C for t sint = 2 h.XRD studies have shown that doping with praseodymium and neodymium promotes the formation of the tetragonal phase in the base composition (K 0.44 Na 0.52 Li 0.04 )NbO 3 at lower temperatures. On the other hand, microstructural tests have shown that the admixture of neodymium and praseodymium improves the sinterability of ceramic samples during the technological process; however, the ceramic samples still exhibit high porosity.