Date of Award

8-2024

Document Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Materials Science and Engineering

Committee Chair/Advisor

Dr.Luiz Jacobsohn

Committee Member

Dr.Fei Peng

Committee Member

Dr.Jianhua Tong

Abstract

Magnesium aluminate spinel solid state solutions were prepared via the coprecipitation method and calcined in air at 900 °C for 2 h. The manipulation of magnesium aluminate spinel’s microstructure through the formation of solid state solutions with zinc and gadolinium substituting for magnesium was investigated. X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR) confirmed the formation of a single cubic crystalline phase. The luminescence properties were investigated by radioluminescence (RL) under X-ray excitation and thermoluminescence (TL) measurements. In the case of zinc, all concentrations of the solid state solutions showed similar luminescence with bands at 400 nm, 550-650 nm, and 690-712 nm and exhibited a broad TL glow peak at about 100 °C. In the gadolinium case, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) revealed a uniform distribution of gadolinium within the grains with further X-ray photoelectron spectroscopy (XPS) measurements supporting this. RL measurements showed a narrow band attributed to Gd3+, in addition to the luminescence bands of the host, and identified the solid state solution with 7.5% Gd having the maximum emission intensity of this UV band. Gd3+emission was also investigated at high temperatures and showed a good thermal stability event at 300 °C. TL fading measurements of the solid state solutions showed high losses that hinder practical applications.

Author ORCID Identifier

0009-0009-6155-7906

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