Abstract
The aim of this study was to evaluate the effect of an 11.6Li2O-16.8ZrO2-68.2SiO2-3.4Al2O3 (LZSA) glass ceramic on the grain growth of alumina obtained by pressureless sintering. Three contents of the LZSA glass ceramic (7, 15, and 21 vol%; mean particle size of 1.52 µm) and three types of alumina (mean particle sizes of 0.5, 1.7, and 2.8 µm) were used. The powder compositions were formed by cold pressing. The samples (5 mm × 5 mm × 13 mm) were sintered in an optical dilatometer. The grain size and morphology were evaluated by scanning electron microscopy. The results show that elongated alumina particles were obtained for the investigated composites compared with pure alumina because of the LZSA addition. The grain growth of alumina was less pronounced at higher LZSA contents. High relative densities were obtained for higher LZSA contents at lower temperatures and holding times compared with pure alumina.
Highlights
Grain-refining processes have recently attracted considerable attention[1,2] because they significantly affect the final properties of the material
The main objective of adding the LZSA glass ceramic to alumina was to densify it at lower temperatures and holding times in order to suppress the grain growth
According to a previous work[21], the use of LZSA helps alumina to densify by liquid phase sintering (LPS)
Summary
Grain-refining processes have recently attracted considerable attention[1,2] because they significantly affect the final properties of the material. For example, help to increase densification but form a vitreous, fragile phase during cooling, reducing the fracture toughness and, in most cases, the wear resistance To overcome this limitation of ordinary glasses, glass ceramics can be used, as the parent glass can act as a very low-viscosity liquid phase with a high wettability, densifying the alumina at lower sintering temperatures and suppressing grain growth of alumina. Li2O-ZrO2-SiO2-Al2O3 (LZSA) glass ceramics achieve maximum densification at low temperatures (800-850 oC)[17,18] and crystallize to form mostly β-spodumeness (solid solution, Li2O.Al2O3.4-10SiO2) and zirconium silicate (ZrSiO4) as crystalline phases[19,20] Their low coefficient of thermal expansion (CTE) compared with alumina can create compressive stresses in the glass ceramic/alumina interface, strengthening the obtained composite and improving mechanical properties such as the wear resistance[21]. Part I of this work aims to demonstrate the effect of an LZSA glass ceramic on the grain growth of alumina
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
