By the solid state reaction route, (Ba_0.85Ca_0.15-x Ce_x) (Zr_0.1T_i0.9) O₃ (BCCeZT) lead-free piezoelectric ceramics were prepared. The powder was processed at 1250 ºC for 2 h, and compacted green bodies were then sintered at various sintering temperatures. X-ray diffraction analysis and Raman spectra confirmed the rhombohedral-tetragonal phase coexistence of x = 0 - 0.00131. Addition of CeO₂ facilitated development of grain sizes greater than 10 μm at low sintering temperatures. The effects of grain size on the ferroelectric and piezoelectric properties were studied systematically and it was found that a ~ (10 - 12) μm grain size is critical for the processing of high - performance lead-free BCCeZT ceramics. CeO₂ substitution at the A site may bring down the sintering temperature by about 200 °C without significant loss of properties. The best properties were obtained for x = 0.00131 at a low sintering temperature of 1350°C for 4 hours exhibiting d₃₃ = 501±10 pC/N, k_p = 38.5±1.92 %, P_r = 12.19 μC/cm², T_C = 108.1°C and a large strain of 0.14%. These results show that BCCeZT ceramics could be promising candidates for the fabrication of lead-free devices.

The present work presents a strategy to stabilize amorphous anodic self-organized TiO₂ nanotube layers against morphological changes and crystallization upon extensive water soaking. The growth of needle-like nanoparticles was observed on the outer and inner walls of amorphous nanotube layers after extensive water soakings, in line with the literature on water annealing. In contrary, when TiO₂ nanotube layers uniformly coated by thin TiO₂ using atomic layer deposition (ALD) were soaked in water, the growth rates of needle-like nanoparticles were substantially reduced. We investigated the soaking effects of ALD TiO₂ coatings with different thicknesses and deposition temperatures. Sufficiently thick TiO₂ coatings (≈8.4 nm) deposited at different ALD process temperatures efficiently hamper the reactions between water and F⁻ ions, maintain the amorphous state, and preserve the original tubular morphology. This work demonstrates the possibility of having robust amorphous 1D TiO₂ nanotube layers that are very stable in water. This is very practical for diverse biomedical applications that are accompanied by extensive contact with an aqueous environment.