Enhancing the quartz-clay-feldspar system by nano-Al2O3 addition for electrical insulators: From laboratory to prototype scale

Nanotechnology applications have been increasing in the last years, offering innovative nanomaterials with enhanced characteristics and performance compared to conventional materials. In this work, a nanotechnology concept is proposed to improve the properties of a quartz-clay-feldspar ceramic system. The application target is in the electrical industry as an outdoor insulator. Experimental compositions were obtained by incorporating nano-alumina (nano-Al2O3) in siliceous porcelain to study their influence on the microstructure, physical, mechanical, and electrical properties. Industrial grade raw materials with a typical particle size distribution were used to prepare siliceous porcelain mixtures. Nano-sized alumina powder was added to the raw materials and then mixed to obtain good dispersion and high homogeneity. Specimens were prepared by uniaxial pressed and plastic extrusion processes for laboratory and prototype scale respectively and then were dried and fired, reaching a maximum temperature of 1250 °C. According to the SEM and XRD analysis, it was observed that alumina nanoparticles promote a mechanical strengthening mechanism in the ceramic body, mainly due to the increment of mullite. It was also found that dispersed nano-Al2O3 reinforces the glassy matrix providing a strong barrier that causes the crack deflection when loading. Nanostructured ceramic formulations exhibit higher flexural strength and superior breakdown voltage than conventional porcelain. The results include in this work strengthen the knowledge of nanotechnology concepts to develop advanced electrical porcelain systems.