Seeding effect: impact and consequences on the characteristics of sol-gel derived α-Al₂O₃

Abstract

Alumina (α-Al₂O₃) -an advanced ceramic with high mechanical strength, chemical stability and biocompatibility- can be effectively produced via the sol-gel technique. Seeding approach can be an alternative way to further improve the properties of sol-gel derived α-Al₂O₃ by promoting nucleation and growth. This work concentrates on the chemical/physical, microstructural, and mechanical characteristics of the sol-gel derived and seeded α-Al₂O₃ powders, and pellets. Seeding was applied by using commercial α-Al₂O₃ powders with wt.0%, 3%, 6%, and 10% of the precursor. As the seeding agent amount increased, bulk density values of the pellets also increased. However, the highest bulk density increase was observed for the samples heat treated at 1300 °C. Likewise, the compression strength enhanced but the best results were determined for the samples heat treated at 1300 °C. As the heat treatment temperature increased, heterogeneous grain growth occurred depending on the formation of large pores, and this situation reduced the compression strength.

Keywords:

• Sol-gel process
• porosity
• mechanical properties
• Al₂O₃
• seeding

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Scientific Research Project Coordination Unit of Istanbul University-Cerrahpasa under Grant [numbers 37881, FYL-2016-21009, and BYP-2018-28135].