Effective infiltration with polyethyleneimine-grafted colloidal alumina particles for silica-based ceramic cores

Abstract

Amine-functionalized alumina colloidal particles were prepared using polyethyleneimine (PEI) for enhancing the infiltration process of silica based ceramic core. The surface properties of PEI-grafted alumina particles were adjusted to improve their dispersion behavior in aqueous suspension, and the surface charge was adjusted to enhance their adsorption behavior, in neutral pH atmosphere, via an electrostatic repulsion force with a fused silica matrix containing an implied strong negative charge. The characteristics of the surface-modified particles were optimized as shown by the CH stretching vibration and NH bending vibration from FT-IR spectra, and the surface charge alternated from ¹3 to 45 mV. As a result, the dispersion behavior in aqueous solvent was advanced as indicated by the decrease of the polydispersity index, decrease of the average size from 178 to 58 nm, and sharpness of the particle size distribution parabola. These improvements greatly contributed to the acceleration of the infiltration time and efficiency (up to 30 min). Consequently, the promptly infiltrated specimens improved the flexural strength from 3.2 to 10.2 MPa and reduced the linear shrinkage rate from 1.91 to 1.05% as well.

Influence of Al2O3 content on mechanical properties of silica-based ceramic cores prepared by stereolithography

“…Furthermore, Al 2 O 3 has a fairly high flexural strength of 472 MPa [28] and thus contributes to enhancing the flexural strength of silica ceramics. Al 2 O 3 can be also very helpful in reducing the shrinkage of silica ceramics by promoting the crystallization of the fused silica [29]. Therefore, the Al 2 O 3 is promising to be regarded as a powerful reinforcement in silica ceramic cores.…”

Influence of Al2O3 Content on Mechanical Properties of Silica-based Ceramic Cores Prepared by Stereolithography

“…Furthermore, Al2O3 has a fairly high flexural strength of 472 MPa [28] and thus contributes to enhancing the flexural strength of silica ceramics. Al2O3 can be also very helpful to reduce the shrinkage of silica ceramics by promoting the the crystallization of the fused silica [29]. Therefore, the Al2O3 is promising to be regarded as a powerful reinforcement in silica ceramic cores.…”