Drying Behavior of a Slip Cast Body Using a Microwave Heating
Abstract:To reduce the drying period a significant enhancement of manufacturing speed and improvement of productivity of ceramic fabrication were needed. The evaporation and transport of water were the keys to drying and controlling the kinetics of drying, which subsequently affects the properties of green bodies. This research was conducted to investigate the effects of rapid drying of ZnO slip cast bodies by microwave drying and compared with those dried by conventional drying techniques. From these results, the extent of warpage of a dried body was smaller in microwave drying than in other conventional drying methods. Furthermore, the number and size of pores were smaller for this drying technique than for other drying methods after sintering. Microwave heating was tentatively considered as a small difference in the water content between the inside and the outside of the green body, because the free and bound waters with NH4+ salt of polyacrylic acid in a green body were selectively heated compared with ZnO powder, and evaporation and diffusion of water was done efficiently from the inside of the green body under microwave drying. Microwave drying has merits in terms of both the rapid drying and structural uniformity of dried bodies. It not only reduces drying period, but also improves the characteristics of green and sintered bodies.
Document Type: Research Article
Affiliations: National Institute of Advanced Industrial Science and Technology (AIST), Shimoshidami, Moriyama, Nagoya 463-8560, Japan
Publication date: July 1, 2008