Improvement of ceramic core strength by combining 3D printing technology and an organic-inorganic conversion process using dual polymers. Issue 12 (15th June 2021)

• Record Type: Journal Article
• Authors: Choi, Hyun-Hee; Kim, Eun-Hee; Kim, Bong-Gu; Yang, SeungCheol; Jung, Yeon-Gil
• Is Part Of: Ceramics international. Volume 47:Issue 12(2021)
• Page Start: 17644
• Page End: 17651
• Publication Date: 2021-06-15
• Subjects: Dual polymer -- Organic-inorganic conversion process -- Inorganic binder -- 3D printing -- Ceramic core; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.03.083
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Ceramic cores are essential for manufacturing hollow mechanical parts, such as impellers and blades, in the casting process. High temperature heat treatment, which causes dimensional deformation and breakage, is required to reveal the effective strength of ceramic cores. Therefore, in this study, a new 3D printing-based process, combined with an organic-inorganic binder conversion process, is proposed to fabricate a ceramic core with high dimensional stability using dual polymers with different chemical properties. The ceramic core was prepared using an extrusion-type 3D printer with a slurry prepared by mixing a starting powder with hydrophilic and hydrophobic polymers. The extruded samples molded from the heterogeneous polymers were immersed in water at 60 °C for 3 min to remove the hydrophilic polymer to create space for impregnating an inorganic binder. The core samples were then dipped in an inorganic binder solution composed of tetraethyl orthosilicate and sodium methoxide and then dried at 80 °C for 1h, followed by a heat treatment at 1000 °C for 1h. Using dual polymers, the amount of inorganic binder coating converted into the glass phase during heat treatment was increased, which resulted in improved core strength. These results confirm that the dual polymer can be used to manufacture ceramic cores with excellent dimensional stability and firing strength through 3D printing combined with the organic-inorganic binder conversion process. Graphical abstract: Image 1 Highlights: Core strength was increased using a dual polymer consisting of PVA and PS. The miscibility of chains increased with the molarity of the polymer solution. The coating amount of the inorganic binder increased with PVA. Core stability was maintained, even if the organic binder was removed.