Development of Rapid Debinding Process and Debinding Behavior for Zirconia Molded Bodies Using Superheated Steam

Abstract

In this study, the rapid debinding of zirconia molded bodies was carried out using a superheated steam treatment. The superheated steam treatment was performed with the heating rate of 10°C/min to a holding temperature range of 500°C to 800°C. The molded body after superheated steam treatment to 800°C resulted in the residual carbon content of 0.3%. No cracking occurred in sintered bodies obtained by debinding in the superheated steam and then firing at 1500°C in air, although many large cracks occurred in sintered bodies that had been treated in air or nitrogen under similar temperature conditions. To understand the debinding behavior under the superheated steam, thermal analyses were performed with thermogravimetric. These results suggested that the debinding in superheated steam suppressed thermal runaway and the generation of pyrolysis gas caused by the chain of exothermic reactions derived from the oxidation of the forming aid. Thus, it was suggested that superheated steam treatment is highly effective for rapid debinding of molded bodies.