Elaboration of Alumina-Zirconia Composites: Role of the Zirconia Content on the Microstructure and Mechanical Properties

Abstract

Alumina-zirconia (AZ) composites are attractive structural materials, which combine the high hardness and Young’s modulus of the alumina matrix with additional toughening effects, due to the zirconia dispersion. In this study, AZ composites containing different amounts of zirconia (in the range 5–20 vol %) were prepared by a wet chemical method, consisting on the surface coating of alumina powders by mixing them with zirconium salt aqueous solutions. After spray-drying, powders were calcined at 600 °C for 1 h. Green bodies were then prepared by two methods: uniaxial pressing of spray-dried granules and slip casting of slurries, obtained by re-dispersing the spray dried granulates. After pressureless sintering at 1500 °C for 1 h, the slip cast samples gave rise to fully dense materials, characterized by a quite homogeneous distribution of ZrO2 grains in the alumina matrix. The microstructure, phase composition, tetragonal to monoclinic transformation behavior and mechanical properties were investigated and are here discussed as a function of the ZrO2 content. The material containing 10 vol % ZrO2 presented a relevant hardness and exhibited the maximum value of KI0, mainly imputable to the t → m transformation at the crack tip.

Kesan Suhu Pensinteran terhadap Sifat Mekanik dan Mikrostruktur Alumina- Zirkonia yang Difabrikasi dengan Kaedah Pengacuan Suntikan Seramik

“…Menurut Naglieri et al (2013) peningkatan nilai keliatan patah juga dapat dijelaskan dengan kehadiran fasa monoklinik. Rajah 7 menunjukkan kehadiran fasa tetragonal dan monoklinik masing-masing mengikut bentuk spektrum 00-060-0505 dan 00-037-1484 berdasarkan kepada analisis pembelauan sinar-X (XRD) yang dilakukan ke atas sampel yang disinter pada suhu 1650°C.…”

“…Nilai keliatan patah yang diperoleh dalam kajian ini adalah setara dengan kajian terdahulu iaitu di antara 3.70 hingga 4.20 MPa.m 1/2 . Walaupun kajian terdahulu menggunakan proses pembuatan yang berbeza iaitu kaedah padatan serbuk dan teknik penuangan buburan namun komposisi bahan dan parameter pensinteran yang digunakan adalah hampir sama (Azhar et al 2010;Naglieri et al 2013;Oungkulsolmongkol et al 2010). Ini kerana nilai keliatan patah amat bergantung kepada suhu pensinteran, komposisi bahan dan mikrostruktur.…”

Relationship between residual stresses and mechanical behavior in ceramic composites

“…As one of the most popular alumina-zirconia materials, the alumina (α-Al 2 O 3 )/Y-TZP (tetragonal zirconia polycrystalline stabilized with 3 mol.% Y 2 O 3 ) exhibit desirable performance, e.g. high strength and toughness as well as excellent biocompatibility, wear resistance, high chemical and corrosion resistance, and it is regarded as a strong candidate for structural and biomedical applications [1,2]. Great interest is put on the possible reinforcing mechanisms as well as the influential factors, which can be closely associated to the processing route, as well as the addition of the appropriate zirconia content.…”

“…The materials to be studied were prepared using high-purity α-Al 2 Table 3.1. In addition, XRD analysis of the raw powders was conducted by the materials supplier in previous work [128].…”

“…Alumina-based ceramic composites are considered as a candidate material for certain structural applications, such as thermal insulation barriers in motors and turbines, cutting tools, high temperature filtering and biomedical application [1,2], because of their excellent resistance to wear, high hardness, resistance to corrosion, chemical stability behavior, good mechanical properties at high temperatures and relatively cheap technology of production. The primary disadvantage of ceramic materials is their inherent brittle nature.…”