Abstract
	Because of Lead-based piezoceramic`s environmental issues associated with lead, the development of lead-free piezoceramics has attracted much attention recently. Among various candidates for lead-free piezoelectric materials. ceramics based on potassium sodium niobate (Na0.5K0.5)NbO3, abbreviated as KNN), which are the most promising candidates, because of its moderate piezoelectric and ferroelectric properties as well as its better environmental compatibility. (Na0.5K0.5)NbO3 based piezoelectric ceramics has a perovskite structure. The room temperature phase of AgNbO3 also belongs to the perovskite family and is it closely related to the room-temperature phase (Na0.5K0.5)NbO3. Influence of AgNbO3 (abbreviated as AN) addition into (Na0.5K0.5)NbO3 with different content ((Na0.5K0.5)NbO3, 0.875(Na0.5K0.5)NbO3-0.125AgNbO3, 0.750(Na0.5K0.5)NbO3-0.250AgNbO3) on microstructure and mechanical properties was investigated. Furthermore, in the case of 0.875(Na0.5K0.5)NbO3 - 0.125AgNbO3 influence of 5.5 mol.%LiSbO3 was estimated. It was found that addition of AgNbO3 into (Na0.5K0.5)NbO3 improved the mechanical properties such as microhardness at 10N (from 1.802 ± 0.82GPa to 2.449 ± 0.41 GPa), macrohardness at 50N (from 1.051± 0.37 GPa to 1.550 ± 0.09 GPa), fracture toughness (from 1.445 ± 0.04 MPa.m1/2 to 1.521 ± 0.17 MPa.m1/2) and strength (from 60.127 ± 0.28 MPa to 90.927 ± 0.37 MPa). Addition of the LiSbO3 into 0.875 (Na0.5K0.5)NbO3  - 0.125AgNbO3 has a significantly possitive influence on microhardness values (from 1.717 ± 0.24GPa to 2.495 ± 0.79 GPa) and on macrohardness values (from 1.550 ± 0.09 GPa to 2.413 ± 0.29 GPa), no significantly influence on fracture toughness was observed, but porosity was significantly increased and strength was decreased (from 72.583 ± 0.59 MPa to 71.702 ± 0.52 MPa).