Improved piezoelectric properties of (KxNa1−x)0.94Li0.06NbO3 lead-free ceramics fabricated by combining two-step sintering

Influence of K/Na ratio on phase structure and electrical properties of 0.96 (K x Na1−x ) NbO3-0.04 (Bi0.5Na0.5) ZrO3 lead-free ceramics

“…As the K/Na ratio changes, the T C increases with the increase of x and then drops with further increase of x, and all its values are at 329~339°C. Similar phenomenon has been observed in the (K x Na 1−x ) 0.94 Li 0.06 NbO 3 lead-free ceramics [35]. In addition, the K/Na ratio also affects both T R−O and T O −T of the ceramics, that is, both T R−O and T O−T firstly drop and then rise with increasing x.…”

“…Figure 12 gives the piezoelectric constant d 33 and the electromechanical coupling coefficients k p of the Meanwhile, the k p shows a different tendency to that of d 33 , and a maximum k p value is observed in the ceramic with x=0.45. In the present work, the d 33 is higher than those reported results of KNN -based ceramics with different K/Na ratios [35,40], as shown in Table 1. We discussed the relationship between Na/K ratio The inset is P r and E C vs. K/Na ratio and enhanced piezoelectricity of this material system, and the underlying physical mechanisms are listed below: the phase structure has been modified by changing the K/Na [17][18][19][20], and then different piezoelectric properties could be observed.…”

“…In addition, the K/Na ratio also affects both T R−O and T O −T of the ceramics, that is, both T R−O and T O−T firstly drop and then rise with increasing x. The influence of K/Na ratio on their T C , T O−T , and T R−O should be attributed to the K and Na content [35,36] and grain size [36,37]. As a result, the K/Na ratio dependence of T C , T R−O , and T O−T could be clearly shown by establishing the phase diagram.…”

Two-Step Sintering of Ceramics

“…So far TSS is applied for 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) [ [25] (K x Na 1−x ) NbO 3 (KNN) ceramic [12,[55][56][57], SiC [58][59][60] and Si3N4 [2] and used for several applications. This section outlined the changes in properties of various ceramics sintered using different TSS profiles.…”

“…Alkaline-based niobate (KNN) ceramics are successfully sintered by using TSS, and they exhibited excellent dielectric [12,55,73], ferroelectric [12,55,56,73] and piezoelectric properties [12,21,55,56]. Furthermore (K 0.4425 Na 0.…”