TITLE:
Structural and Mechanical Properties of Alumina-Zirconia (ZTA) Composites with Unstabilized Zirconia Modulation
AUTHORS:
Md. Abdul Gafur, Md. Al-Amin, Md. Saifur Rahman Sarker, Md. Zahangir Alam
KEYWORDS:
Zirconia Toughened Alumina (ZTA), Mechanical Properties, Toughening, XRD, SEM, Grain Size
JOURNAL NAME:
Materials Sciences and Applications,
Vol.12 No.11,
November
25,
2021
ABSTRACT: Zirconia toughened alumina (ZTA) ceramics are very promising materials for structural and biomedical applications due to their high hardness, fracture toughness, strength, corrosion and abrasion resistance and excellent biocompatibility. The effect of unstabilized ZrO2 on the density, fracture toughness, microhardness, flexural strength and microstructure of some Zirconia-toughened alumina (ZTA) samples was investigated in this work. The volume percentage of unstabilized ZrO2 was varied from 0% - 20% whereas sintering time and sintering temperature were kept constant at 2 hours and 1580°C. The samples were fabricated from nanometer-sized (α-Al2O3: 150 nm, monoclinic ZrO2: 30 - 60 nm) powder raw materials by the conventional mechanical mixing process. Using a small amount of sintering aid (0.2 wt% MgO) almost 99.2% of theoretical density, 8.54 MPam? fracture toughness, 17.35 GPa Vickers microhardness and 495.67 MPa flexural strength were found. It was observed that the maximum flexural strength and fracture toughness was obtained for 10 vol% monoclinic ZrO2 but maximum Vickers microhardness was achieved for 5 vol% ZrO2 although the maximum density was found for 20 vol% ZrO2. It is assumed that this was happened due to addition of denser component, phase transformation of monoclinic ZrO2 and the changes of grain size of α-Al2O3 and ZrO2.