Investigation of the Quartz Distribution in Electro-Porcelain Materials

Analysis of the microstructure of electro-porcelain is important to better understand its influence on mechanical, electrical and aging behavior. The microstructures of two electro-porcelain materials with low and high quartz contents were analyzed with respect to the distribution of quartz. Using an adequate evaluation of EDS (energy dispersive spectroscopy) mapping data, a reproducible analysis of the size distribution and quantity of quartz was achieved. The method allows the analysis of large areas (12.5 mm2). Therefore, the probability of occurrence for a few large quartz grains could be determined. Independent of the overall amount of quartz in the materials, a wide distribution of the grain size was observed. The size of the large detected quartz grains in both materials was very similar. Around the large quartz particles, microcrack systems with lengths of several 100 µm were observed. They are linearly correlated with the equivalent circle diameter of the quartz grains. The evaluation of the cracks allowed us to determine the critical size below which no cracks around the quartz particles are formed. This size is approximately 10 µm.