Microstructure Of Porcelain Insulators And Its Effect On The Mechanical Properties

As an essential component of electric equipments, the porcelain insulator has an important application in the ultra-high-voltage power distribution and transformation project and railway electrification system. How to improve mechanical properties and reliability of porcelain insulators will become a major problem in the future. In this paper, through microstructure investigation about composition morphology?size?distribution and type? content of phase by Scanning Electron Microscope?X-ray diffraction analysis and ceramography, how the mechanical properties changed can be reasonably explained and there maybe possible ways to improve the mechanical properties quality as well as stability of porcelain insulator materials. It's came to several conclusions:(1)Comparative bending strength and dispersion study of siliceous porcelain and alumina porcelain found that the bending strength was gradually reduced as the dispersion increases in turn along with the frequency of firing. After re-firing, the secondary mullite grew up in a certain degree but there was no unusually crystals development phenomenon. Mullite-quartz crystals partly dissolved and the content of amorphous phase decreased 44.72% and microcracks gathered and grew up in siliceous porcelain,.However, corundum-mullite content almost the same in alumina porcelain with significant cracks.(2)With 2wt% ZnO?TiO2?ZrSiO4 additives separately in siliceous porcelain, the content of amorphous phase decreased above 50% and the secondary mullite grew up well, thus the bending strength increased 10%?25% with sintered density improved and the open porosity decreased almost 50% at the same time. The density and homogeneity of the overall microstructure has improved.(3) When porcelain insulators sintering, temperature distribution of the body is always lagging behind the kiln; There was temperature difference between body center outer edge and kiln that gradually increased through the heating process. In the stage of the heat preservation temperature difference narrowed. Through analysis of failure samples, simulation of the electric porcelain sintering process was carried out by ANSYS software, by means of prolonging soaking time or raising the temperature. The results indicated that by means of prolonging soaking time or raising the temperature was conducive to the density and homogeneity of the overall microstructure. The secondary needle-like mullite grew up obviously as well in body center location.