Structural, optical tuning, and mechanical behavior of zirconia toughened alumina through europium substitutions

Abstract

The structural and optical features of zirconia toughened alumina (ZTA) due to the assorted range of Eu 3+ substitutions are demonstrated. The characterization studies affirm the pivotal role of Eu 3+ on the improved structural stability of ZTA and associated tetragonal zirconia (t-ZrO 2 ) ! cubic zirconia (c-ZrO 2 ) transformation. Eu 3+ prefers accommodation at the lattice sites of ZrO 2 and their gradual accumulation induces t-! c-ZrO 2 transition. Beyond the substitution limit, Eu 3+ reacts with Al 2 O 3 to form EuAlO 3 . Optical studies validate typical Eu 3+ emissions, and further, the emission spectrum also predicts the symmetry of Eu 3+ coordination at the ZrO 2 lattice. Uniform distribution of ZrO 2 and Al 2 O 3 grains throughout the microstructures are evident from the morphological analysis. Further, the influence of Eu 3+ on the enhanced mechanical stability of ZTA is ensured from indentation technique.

Combined Occupancy of Gadolinium at the Lattice Sites of β‐Ca3(PO4)2 and t‐ZrO2 Crystal Structures

“…In particular, the stabilization capacity of Y 3+ (1.019 Å) in ZrO 2 has been documented extensively in previous reports that ensured the stabilization of tetragonal ZrO 2 polymorph with Y 3+ content in the range of 3–8 mol‐%, while its cubic polymorph is retained beyond 8 mol‐% , . In a similar manner, the effects of rare earth elements on the stabilization capacity of ZrO 2 polymorphs have been documented , , . 10 mol‐% of individual substitution of different rare earths such as Yb 3+ (0.985 Å), Dy 3+ (1.027 Å), Tb 3+ (1.040 Å), Gd 3+ (1.053 Å), Eu 3+ (1.066 Å) and Nd 3+ (1.109 Å) ensured t ‐ZrO 2 stabilization until 1500 °C.…”

Synthesis, characterization, mechanical and magnetic characteristics of Gd3+/PO43− substituted zircon for application in hard tissue replacements

“…Nevertheless, the gradual water mediated phase transformation t‐ZrO 2 (P42/nmc) → m‐ZrO 2 (P21/c) leads to implant failure and restricts the long term applications of ZrO 2 in vivo. Zirconia toughened alumina (ZTA) proposed as an alternative to t ‐ZrO 2 also encounter with similar shortcomings, especially the ZrO 2 component of ZTA experience t ‐ → m ‐ZrO 2 transformation during in vivo implantation 1,2 . Among the available alternatives, zircon (ZrSiO 4 ), a combination ZrO 2 and SiO 2 that possesses the prominent features of high refractive index, hardness, low thermal expansion coefficient and high melting point is considered a better choice 3 .…”

Epitaxial Core/Shell Nanocrystals of (Europium-Doped) zirconia and hafnia

“…28,[50][51][52] This indicates that the Eu ions remain located in the core during the shelling, since the presence of Eu ions in the shell would suppress the ZrO2 defect emission (either by preventing the defect to form or by energy transfer to Eu). [53][54][55] Therefore, the overall emission spectrum of the core/shells contains emission from Eu 3+ in the core and defect emission from the shells. This also explains the drastic increase in the lifetime of the core/shell particles, since the Eu 3+ ions are now in a perfect environment far from the outside.…”