Abstract
A high-performance CaO-based integral ceramic mould was fabricated for investment casting by stereolithography (SLA) and non-aqueous gelcasting. The rheology of tert-butyl alcohol (TBA)-based CaO slurries and the effect of gelation parameters on the gelation time and strength of the green body were investigated to obtain a high-quality green body of the CaO-based integral ceramic mould. Then the pre-sintering and sintering processes were optimized to avoid cracks, reduce the sintering shrinkage, and improve the strength of CaO-based ceramic mould. The results showed that the CaO-based slurry with 56 vol % solid loading and 3 wt % dispersant content exhibited high stability and good flowability. The optimized gelation parameters were determined to be a monomer content of 20 wt %, a ratio of crosslinker to monomer of 0.06, an initiator content of 1 wt % and a gelation temperature of 40 °C. A reasonable sintering regime was identified to avoid cracks and guarantee a low shrinkage of 0.6%, a room temperature bending strength of 14.12 MPa and a high temperature (1200 °C) strength of 8.22 MPa. The CaO-based integral ceramic mould fabricated in this study has many advantages including excellent thermal stability, reaction-resistance to molten active alloys, ease of dissolution, and enhanced efficiency and economy in comparison to SiO2 or Al2O3 ceramic moulds.
Highlights
Ceramic moulds are the most critical component in investment casting processes for the fabrication of castings with complex structures and internal cavities [1]
Rheology of CaO Slurries is crucial for fabricating ceramic parts with complex architectures, low shrinkage, and high strength
The low-toxicity DMAA-MBAM gel system was successfully employed to fabricate the CaO-based integral ceramic mould with tert-butyl alcohol (TBA) solvent, which can effectively negate the hydrolysis of calcia in the preparation process
Summary
Ceramic moulds are the most critical component in investment casting processes for the fabrication of castings with complex structures and internal cavities [1]. Ceramic moulds are usually made of fused silica or alumina due to their excellent properties, such as low density, good strength, high-temperature resistance, and thermal shock resistance [2,3,4]. Fused silica or alumina-based cores are not suitable for the investment casting of active alloy components, such as Ti, TiAl, or magnesium alloys, due to the interaction between the molten metal and SiO2 or Al2 O3 , which results in a poor surface finish of the castings [5]. The cost is increased sharply due to the high price of
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
