STUDY OF EVOLUTION OF PORE STRUCTURE DURING WATER LEACHING USING PEG-PMMA BINDER SYSTEM

摘要

The debinding process using solvent extraction has been broadly accepted in Metal Injection Molding (MIM) industry due to its capability to shorten the total debinding cycle. This paper attempts to investigate the effect of solvent temperature at different lengths of time on rate of binder removal and morphology of evolution of pore structure on green parts. The binder consisted of PMMA and PEG system and the powder was 316L stainless steel. The PEG component of the binder is readily soluble in water, so that after leaching, a network of open pores is provided to facilitate the extraction of the PMMA by pyrolisis. This has been shown to lead to a reduction in overall debinding time. The SEM images showed that the progression of binder extraction started from the surface and toward the center of the green parts. As the debinding continued, the pores grew and were widely distributed in size.