Study on defect-free debinding green body of ceramic formed by DLP technology

Abstract

Current research into the causes of macro-cracks in the debinding of light-cured ceramic body is predominantly focused on heating rate and holding time. In this paper, we propose a novel approach to analyze the causes of defects in the ceramic body during the debinding process via the interconnected channels formed in the process of the binder discharged from the inside to the outside. The physical and chemical changes, and related reaction products of the binder were analyzed by the TG-FTIR using a specific resin as the binder in the low temperature debinding stage (200–300 °C) and high temperature debinding stage (300–600 °C). Based on the result, a novel approach is proposed to illustrate the process of the formation of interconnected channels and defects. The samples of green bodies debond at different holding time were analyzed by the SEM and μ-CT. The experimental results prove the formation of interconnected channels, and it is found that the holding temperature of 237 °C is favorable for the formation of the channel and the discharge of the gas products. The defect-free samples after low temperature debinding process were debond in the high temperature debinding process at three different holding temperatures of 360 °C, 430 °C, and 550 °C obtained by analyzing the DTG curve and the absorption curve of CO2 in the infrared spectrum, and samples after high temperature debinding process were analyzed by the SEM and μ-CT. The experimental results show that these holding temperatures favor the stable discharge of CO2 and the binder pyrolysis products from the channels, thereby avoiding cracks due to severe gas expansion. The research results in this paper have important reference value for the preparation of defect-free ceramic samples.