High-performance (K,Na)NbO_(3)-based multilayer piezoelectric ceramic actuators with nickel inner electrodes

Multilayer ceramic actuator(MLCA)has been widely employed in actuators due to the large cumulative displacement under the low driving voltage.In this work,the MLCA devices consisting of a lead-free MnCO_(3-)and CuO-doped 0.96(K_(0.48)Na_(0.52))(Nb_(0.96)Ta_(0.04))O_(3)-0.04CaZrO_(3) piezoelectric ceramics and a base nickel(Ni)metal inner electrode were well co-fired by the two-step sintering process in a reducing atmosphere.The ceramic layer/electrode interface is well-integrated and clearly continuous without distinct interdiffusion and chemical reaction,which is beneficial to the electrical reliability of the MLCA.As a result,the MLCA laminated with nine active ceramic layers obtains an ultrahigh piezoelectric coefficient d_(33) of 3157 pC/N,about 9 times than bulk ceramics.The 0.5 mm-thick MLCA composed of a series of~50μm-thick ceramic layers and~3μm-thick Ni electrodes reaches a high 1.8μm displacement under the low applied voltage of 200 V(the same displacement requires a voltage as high as 3700 V for~1 mm-thick bulk ceramics).The excellent electrical performance and low-cost base electrode reveal that the(K,Na)NbO_(3)(KNN)-based MLCAs are promising lead-free candidate for actuator application.

Effect of Au film pre-deposited at different durations as inner electrode on the electrical properties and interface microstructures of Na_2O-PbO-Nb_2O_5-SiO_2 multi-layer glass-ceramic capacitors

To further study the effect of sputtered Au film as transition electrode layer on the electrical properties and interface microstructures of Na20-PbO-Nb2O5-SiO2 multilayer glass-ceramic capacitors, Au films pre-deposited at different time were prepared by DC magnetron sputtering. Compared with the single paste electrode structure, samples with Au films pre-deposited from 6 to 18 min have the consistent perfor- mance to effectively improve the electrical properties of the capacitors, resulting in the doubled breakdown strength, an increase of equivalent capacitance by 22% and a decrease of leakage current by an order of magnitude. SEM observations indicate that the Au films with deposition time from 6 to 18 min would all help the formation of a dense electrode/dielectric interface and inhibit the diffusion of Ag. The results reveal that Au film pre-deposited for 6 min as inner electrode was sufficient to improve the interface microstructure and therefore to inhibit the Ag diffusion and enhance the overall performance of the multi-layer glass-ceramic capacitors.

A comparative study of liquid and solid inner contact roxatidine acetate ion-selective electrode membranes

A comparative study was conducted using two designs of a roxatidine acetate （ROX）-selective electrode; a conventional liquid inner contact called electrode A and a graphite-coated solid contact called electrode 13. The fabrication of electrodes was based on roxatidine-tetraphenylborate （ROX-TPB） as an ion-association complex in a PVC matrix using different plasticizers. Electrode A has a linear dynamic range of 2.2 ×10^-5 mol/L to 1.0 ×10^-2 mol/L, with a Nernstian slope of 54.7 mV/decade and a detection limit of 1.4 ×10^-6 mol/L. Electrode B shows linearity over the concentration range of 1.0×10^-6 mol/L to 1.0×10^-2 tool/L, with a Nernstian slope of 51.2 mV/decade and a limit of detection of 1.1×10^7 mol/L which is remarkably improved as a result of diminishing ion fluxes in this solid contact, ion-selective electrode. The proposed sensors display useful analytical characteristics for the determination of ROX in bulk powder and its pharmaceutical formulation. The present electrodes show clear discrimination of ROX from several inorganic, organic ions, sugars, some common drug excipients and the degradation product （3-[3-（1-piperidinyl methyl） phenoxy] propyl amine） of ROX. Furthermore, the proposed electrodes were utilized for the determination of ROX in human plasma, where electrode B covers drug Cmax which indicated its applicability to pharmacokinetic, bioavailability and bioequivalent studies. The results obtained by the proposed electrodes were statistically analyzed and compared with those obtained by a reported HPLC method. No significant difference for either accuracy or precision was observed.