2019 Volume 66 Issue 6 Pages 275-281
In this study, rapid debinding of alumina molded bodies was carried out using superheated steam treatment. The superheated steam treatment was performed with a temperature increase 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 a carbon removal rate of 99.3%. No cracking occurred in sintered bodies obtained by debinding in superheated steam and then firing at 1,600°C in air. However, many large cracks occurred in sintered bodies that had been treated in air under similar temperature conditions. Thus, it was suggested that superheated steam treatment is highly effective for rapid debinding of molded bodies. To understand the debinding behavior under superheated steam, thermal analyses were performed with thermogravimetric and differential scanning calorimetric analysis and gas chromatography in humidified atmospheres. 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 (binder).
