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A large quantity of ultrafine tetragonal barium titanate (BaTiO3) nanoparticles is directly synthesized at room temperature. The crystalline form and grain size are checked by both X-ray diffraction and transmission electron microscopy. The results revealed that the perovskite nanoparticles as fine as 7 nm have been synthesized. The phase transition of the as-prepared nanoparticles is investigated by the temperature-dependent Raman spectrum and shows the similar tendency to that of bulk BaTiO3 materials. It is confirmed that the nanoparticles have tetragonal phase at room temperature.

Here we report a very simple method to convert conventional CuO powders to nanoparticle interlinked microsphere cages by solution method. CuO is dissolved into aqueous ammonia, and the solution is diluted by alcohol and dip coating onto a glass substrate. Drying at 80°C, the nanostructures with bunchy nanoparticles of Cu(OH) 2 can be formed. After the substrate immerges into the solution and we vaporize the solution, hollow microspheres can be formed onto the substrate. There are three phases in the as-prepared samples, monoclinic tenorite CuO, orthorhombic Cu(OH) 2 , and monoclinic carbonatodiamminecopper(II) (Cu(NH 3 ) 2 CO 3 ). After annealing at 150°C, the products convert to CuO completely. At annealing temperature above 350°C, the hollow microspheres became nanoparticle interlinked cages.

The effect of silver doping on the DC‐voltage resistance failure of lead‐based relaxor ferroelectrics was investigated via temperature‐humidity‐bias (THB) testing, scanning electron microscopy, X‐ray diffraction spectroscopy, and electrical measurements. The failure rate of silver‐doped specimens was found to increase significantly with the doping level during the THB test. However, some degraded specimens can partially recover their electrical properties after a few days of storing in natural conditions. X‐ray diffraction analysis showed that silver could be incorporated into the perovskite lattice in the range of silver contents studied. The presence of an inner‐bias field in the degraded ceramics was first demonstrated through hysteresis property measurement. Based on these results, it was inferred that the accumulation of oxygen vacancies under DC‐voltage should be responsible for the inner‐bias field, which consequently resulted in the increase of electronic defects in the ceramics.