A parametric study of conventional and high-speed microwave sintering of robocast porcelain

Abstract

The combination of three-dimensional (3D) printing technologies and microwave (MW) sintering offers new perspectives for minimizing material, energy and time waste. This study aimed at conducting a parametric study on the sintering of robocast porcelain by conventional and MW heating in a multimode cavity (2.45 GHz, 3 kW). The effect of heating rate, dwell temperature and dwell duration on sample density, shrinkage and microstructure was investigated on small pellets. With conventional heating, a good densification was achieved with a 2 h dwell at 1250 °C, independent of heating rate (1–20 °C/min). A similar density was reached using microwave hybrid heating at a much higher heating rate (100 °C/min), shorter dwell (30 min) and slightly higher sintering temperature (1300 °C). Without susceptor, a longer pre-heating step was required to initiate the sample heating, thus extending the heat treatment duration. This study provides seeding data for the development of greener processes for aluminosilicate ceramic manufacturing.

Keywords

• Clay 3D printer
• Direct ink writing
• Robocasting
• Microwave hybrid heating
• Porcelain