Research on thermal debinding of powder injection moulded SiC parts in air atmosphere

Thermal debinding of injection moulded SiC parts is usually performed in an inert atmosphere orvacuum, which increases the production cycle and costs. The present study examines the thermal debinding of SiC green parts in air atmosphere. No obvious defects were found for debound parts under 500°C. Binders were easier to remove in air because of the continuous oxygen supply. Subsequent pre-sintering was performed at different temperatures (550, 650, 750, 850, 950uC). Cracking was only found in samples pre-sintered at 950°C, which is a result of the volume expansion induced by oxidation. The oxidation decreases the pores and enhances the contact area of SiC powders. Sufficient strength for transport could be obtained by pre-sintering samples in air atmosphere at low temperature. So, thermal debinding in air atmosphere at a suitable temperature could reduce the requirement of debinding for heating equipment, decrease production costs and increase the efficiency ofdebinding for SiC parts.