Liang Nan-Nan, Park Sae-Heum, Cho Tae-Sik
Department of Nano Materials Science and Engineering, Kyungpook National University, Sangju, 37224, Korea.
J Nanosci Nanotechnol. 2021 Mar 1;21(3):1784-1788. doi: 10.1166/jnn.2021.18941.
We have studied the oxidation behaviors of aluminum (Al) nanopowders with different particle sizes using a real-time synchrotron X-ray scattering during annealing in air. The Al nanopowders with small particle size of 78 nm at room temperature (RT) were a single crystal. The surface of the nanopowders was first oxidized to amorphous Al oxide near 450 °C, and then crystallized to γ-Al₂O₃ phase at 550 °C. The inside of the nanopowders existed as crystal Al phase at 680 °C, high compared to the melting temperature of Al bulk, 660 °C. In contrast, the Al nanopowders with large particle size of 816 nm at RT have multi grains inside a particle. The surface and grain boundary of the powders were first oxidized to amorphous Al oxide near 470 °C, and then crystallized to γ-Al₂O₃ phase at 550 °C. The inside of the powders existed as amorphous Al phase at 620 °C, melted at 656 °C, and then oxidized gradually above 656 °C.
我们利用实时同步加速器X射线散射技术，研究了不同粒径的铝（Al）纳米粉末在空气中退火时的氧化行为。室温（RT）下粒径为78 nm的小粒径Al纳米粉末为单晶。纳米粉末的表面首先在450℃左右被氧化成非晶态氧化铝，然后在550℃结晶成γ-Al₂O₃相。纳米粉末内部在680℃时以晶体Al相存在，这一温度高于块状Al的熔点660℃。相比之下，室温下粒径为816 nm的大粒径Al纳米粉末在颗粒内部有多个晶粒。粉末的表面和晶界首先在470℃左右被氧化成非晶态氧化铝，然后在550℃结晶成γ-Al₂O₃相。粉末内部在620℃时以非晶态Al相存在，在656℃熔化，然后在656℃以上逐渐被氧化。
