A possible power output estimation based on material constants in piezoelectric vibration-based generators is proposed. A modified equivalent circuit model of the generator was built and was validated by the measurement results in the generator fabricated using potassium sodium niobate-based and lead zirconate titanate (PZT) ceramics. Subsequently, generators with the same structure using other PZT-based and bismuth-layered structure ferroelectrics ceramics were fabricated and tested. The power outputs of these generators were expressed as a linear functions of the term composed of electromechanical coupling coefficients k(sys)(2) and mechanical quality factors Q*(m) of the generator. The relationship between device constants (k(sys)(2) and Q*(m)) and material constants (k(31)(2) and Q(m)) was clarified. Estimation of the power output using material constants is demonstrated and the appropriate piezoelectric material for the generator is suggested.
To understand the controlling factor of film thickness in aerosol deposition method (ADM), the deposition apparatus was improved at first and the effect of pretreatment of raw barium titanate powder was studied. A developed aerosol generator where the carrier gas was separated from the aerosol generating gas was effective to avoid the agglomeration of powders during the deposition. Two dimensional scanning of the substrate decreased the film-thickness distribution caused by the imhomogeneity of deposition rate in a line-type nozzle. Effect of pretreatments of raw powders, including sieving, drying, planetary ball milling and heating was examined, respectively. There was an optimum rotational velocity of planetary milling to increase the film thickness, indicating that adequate agglomeration of raw powders enhance the film deposition. The film thickness decreased as the heating temperature increased. The heating strengthened the agglomeration of raw powders which restricted the film deposition because the kinetic energy of particles in the aerosol was consumed to break the agglomerations rather than making film. Weakly agglomerated powders with optimum size enhanced the film thickness in ADM.
In the aerosol deposition method (ADM), we investigated an influence of pre-treatments for barium titanate powders as raw material on the deposition rate of thick films. By sieving and drying the powder, deposition rate of the films fabricated by ADM was effectively enhanced. On the other hand, heating the powders at 400-800°C, the resulting powders caused low deposition rate of the films. When a planetary milling was performed prior to charge aerosol chamber, the deposition rate of the films was four times higher than that in deposition using the powder without milling. By changing the milling rotation rate, we control size of agglomerated particles consisting of powders, which results in the control of deposition rate of the films.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.