Comparative Study of Two Methods of Drying an Electro-Porcelain Paste

Abstract

A comparative analysis between two methods of drying ceramics (microwave and conventional) was done based on the results of the Bigot curves of an electro-porcelain paste used as an insulator element in high-voltage circuits. The study was conducted on ceramic bars molded at 300, 600, and 900 kPa and, as expected, it was found that the higher the pressure, the lower the shrinkage and the smoother moisture profiles.

The microwave technique proved to be a much more efficient method of drying ceramics because the results were always better: the volumetric shrinkage was lower (less defects), it required half the time to dry an object (less pollution and costs), and it produced a more uniformly dried piece (the residual moisture content was better distributed throughout the object). Additionally, the mechanical properties of microwave-dried bars were 20% better and the dielectric strength intensity was slightly higher than that of conventionally dried samples.

Keywords:

• Bigot curves
• Drying
• Moisture profiles
• Porosity
• Processing

ACKNOWLEDGMENTS

This work was partially supported by the Darwin Project 20101008126 of the Universidad Nacional de Colombia, Medellín campus. Isabel Cristina Salinas kindly helped with the English translation.