Phase Transition of CuAl2O4 to CuAlO2 at High Temperature Investigated by Positron Annihilation Lifetime Spectroscopy Article Swipe
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· 2025
· Open Access
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· DOI: https://doi.org/10.1088/1742-6596/3029/1/012019
· OA: W4411277326
Phase transition of CuAl 2 O 4 to CuAlO 2 during the sintering process of Al 2 O 3 /CuO nanoceramics at high temperatures (973 - 1373 K) were investigated by positron annihilation lifetime spectroscopy (PALS), X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD results showed that the CuAl 2 O 4 phase was first synthesized at 973 K and then decomposed into CuAlO 2 at 1373 K during the sintering process of Al 2 O 3 /CuO. SEM revealed that a lot of agglomerated small particles were formed at 1273 K, exhibiting octahedral structure features of CuAl 2 O 4 crystals, but transformed into a distinct layered structure of CuAlO 2 crystals after phase transition occurred at 1373 K. PALS found that positron lifetime parameters exhibited a decreasing trend throughout the entire process with increasing sintering temperature, indicating a decrease of both small vacancy-sized and vacancy cluster-sized defects, and a significant decrease occurred during the transition from CuAl 2 O 4 at 1273 K to CuAlO 2 at 1373 K. These findings align with the results obtained from XRD and SEM analyses.
