Effect of the Binder on Properties of Molten Core and Co-Debinding Behavior in Silica-Based Ceramics

Abstract

The effects of molecular weight of the binder on the properties of molten cores were studied The results showed that the filling parameter had an inverse correlation to molecular weight and was consistent with the Market-Houwink Equation. The surface roughness of the cavity surface deteriorated from 2.468 μm to 11.998 μm as the molecular weight of the binder climbed from 2000 to 6000 due to the presence of residual carbon, which was confirmed by SEM and EDS results. At the debinding stage, the pores that occurred in the ceramic core, were insufficient for the liquid PEG binder to flow out, some of the liquid binder moved to the fringe side. More pores formed as the temperature increased and the rest of the binder flowed out through this channel to flow to the filler. Some of the higher molecular weight PEG binder remained as it could not flow away completely and became residual carbon in the cavity surface.