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High current characterization of SnO2-based varistors have been carried out and the results obtained have been compared with those ZnO-based commercial surge arresters. It is shown that for a high temperature sintering (1350 °C), the leakage current, breakdown voltage and the saturation at high current density are similar between both types of surge arresters. The paper shows, for the first time, that the high breakdown voltage observed with tin dioxide cannot be easily maintained since the saturation of the ceramics is reached for current densities of several amperes per square centimetre. [ABSTRACT FROM AUTHOR]

The processing of yttria-stabilised zirconia (Y-ZrO2)-based ceramic nanocomposites by means of pulsed electric current sintering (PECS) is described. A nanometer-sized electrically conductive secondary TiCN phase was added to the insulating zirconia matrix in order to make the composite electrically conductive. The paper focuses on the importance of processing conditions and highlights the benefits of the PECS method as compared to more traditional hot pressing. The mechanical and microstructural properties of the ZrO2–TiCN composites have been determined, and the benefits of using an electrical current to densify these composites were explained in terms of the evolution of the electrical properties of the densifying powder compact. [ABSTRACT FROM AUTHOR]

The reliability of a ceramic structure or device is closely related to its faults, such as structural defects and cracks. Here, we show that cracking in piezoelectric semi-conductive ceramics (PSCs) can be restrained with the application of an electric current. Due to the crack-generated flexoelectricity, piezoelectric polarization charges that generate and gather on the front of a crack result in a strong thermoelectric effect. The phase transition and plastic deformation happened near a crack tip can hinder the propagation of the crack and even lead to its partial closure. These new findings are instructive to study the crack control and the design of PSC devices with damage tolerance. [ABSTRACT FROM AUTHOR]

The use of electric current to activate the consolidation and reaction-sintering of materials is reviewed with special emphasis of the spark plasma sintering method. The method has been used extensively over the past decade with results showing clear benefits over conventional methods. The review critically examines the important features of this method and their individual roles in the observed enhancement of the consolidation process and the properties of the resulting materials. [ABSTRACT FROM AUTHOR]