Microwave vs conventional porcelain firing: Macroscopic properties

摘要

This paper provides an overview of the macroscopic properties of porcelain tableware fired in a microwave furnace with six magnetrons (each with a nominal power of 900 W) operating at the frequency of 2.45 GHz. The dependence of firing temperature on physical properties such as shrinkage, water absorption, apparent porosity, bulk density, and impact resistance was analyzed. Emphasis is on the differences in the macroscopic properties of microwave and conventionally (gas and electric) fired porcelain. Batches were fired from room temperature up to above the optimum firing temperature (1380 degrees C). Results show similar macroscopic properties for both firing methods, microwave heating required lower firing temperatures (between 1300 degrees C and 1350 degrees C), and shorter processing times (about 70 minutes). The main differences between microwave and electric firing methods occur in a temperature band of 300 degrees C above the porcelain eutectic temperature (close to 1000 degrees C).