Estimation of Internal Gas Pressure during Binder Burnout via Centrifugal Firing

Internal gas pressure in layered green sheets during binder burnout has been focused on in terms of heating rate. Microstructure observation revealed that the defect arose at the temperature where the decomposition rate of binder reached maximum, and severe defects formed at high heating rate. These results suggest that the defect formation originated in the decomposed gas passing through the finely porous structure, i.e. internal gas pressure. Thus the external compressive pressure upon green bodies should suppress the defect formation, which was demonstrated by the pressure generated via centrifugal force. Then the pressure balance between the internal gas pressure and a green strength assisted by centrifugal force was analyzed based on gas flow kinetics, which revealed the quantitative aspects of internal gas pressure as a function of a heating rate and the size of green body.