RESUMO
A tetragonal (Ba,Ca)(Zr,Ti)O3 (BCZT) single crystal was grown by a flux method, and the piezoelectric coefficient ( d33) was characterized. The piezoelectric response was proved to be associated with polarization extension, which was successfully used to explain the variation in d33*. From the intrinsic aspect, the compositional effect on Landau free-energy profiles was discussed, showing an "extender" nature of the as-grown crystal and the increasing tendency of structural instability toward the morphotropic phase boundary. From the extrinsic aspect, the evolution of domain structure under various external fields (electric and temperature) was studied, revealing that the fine-domain structure of the as-grown BCZT single crystal was stable to E-field and temperature. The results manifest possibilities of further improving the piezoelectric property of the BCZT single crystal, which requires optimization of the crystal growth technique in future work.
RESUMO
SiC nanoparticles were successfully fabricated by a high energy ball milling method, so that can be used in the printed electronics to make SiC thin film patterns. Here we utilized the waste of Si sludge for making the SiC nanoparticles. In order to achieve uniform thin film from the nanoparticle ink, fine sized SiC nanoparticles less than 100 nm has to be uniformly dispersed. In this study, we employed the ultra apex milling (UAM) system for particle comminution and dispersion. We investigated the effects of milling parameters, e.g., size of ZrO2 bead and milling time. The size of the SiC particles reached about 103 nm after 4 hours of UAM, when the ZrO2 beads of 50 microm were used. Then SiC ink was formulated with organic solvents and a dispersing agent. A specially designed pattern was printed by an ink-jet printer for evaluating the feasibility of the SiC nanoparticle inks.
RESUMO
Here we tried to show the possibility of mechanical milling method for fabrication of SiC nanoparticles and ink-jet printing method to make SiC patterns for use as several applications, e.g., micro hotplates. Planetary milling was employed to fabricate the nano-scale SiC particles from coarse powders. After 100 hours of milling, the size of the SiC particles decreased to about 100 nm, which was sufficient for the formulation of ink for ink-jet printing. The SiC particles were dispersed in an ink system consisted of ethylene glycol and ethanol with a small amount of additives. The ink with SiC nanoparticles could be successfully printed on an alumina substrate by the ink-jet printing method.
