Lee Jang-Hyeong, Park Sae-Heum, Cho Tae-Sik
Department of Nano Materials Science and Engineering, Kyungpook National University, Sangju, 37224, Korea.
Daegu & Gyeongbuk Branch, Korea Conformity Laboratories, Daegu, 42994, Korea.
J Nanosci Nanotechnol. 2020 Jan 1;20(1):415-419. doi: 10.1166/jnn.2020.17265.
We have studied the solid-phase sintering behaviors of Au nanopowders with different particle sizes using real-time synchrotron X-ray scattering and field-emission scanning electron microscopy (FESEM) experiments in air. Au powders with large particle size of 173 nm at room temperature showed a defect-free crystal domain size of 47 nm. Most of these powders showed multiple grains within the particle. Solid-phase sintering typically occurred via surface diffusion of Au atoms near the surface of powders at temperatures above 300 °C, Au nanopowders with small particle size of 50 nm at room temperature showed a crystal domain size of 43 nm. Most of these powders showed a single grain inside the particle. Solid-phase sintering occurred simultaneously with volume diffusion of Au atoms near the grain boundary inside powders at temperatures above 250 °C and surface diffusion near the surface of powders at temperatures above 300 °C. Our study revealed that the solid-phase sintering behaviors of Au nanopowders began at temperatures over 250 °C, which is much lower than the melting temperature of 1064 °C. The thermal analysis results were consistent with the results of real-time synchrotron X-ray scattering and FE-SEM.
我们利用实时同步加速器X射线散射和场发射扫描电子显微镜（FESEM）实验，在空气中研究了不同粒径的金纳米粉末的固相烧结行为。室温下粒径为173nm的大金粉显示出无缺陷的晶畴尺寸为47nm。这些粉末中的大多数在颗粒内显示出多个晶粒。固相烧结通常在300℃以上的温度下通过粉末表面附近金原子的表面扩散发生，室温下粒径为50nm的小金纳米粉末显示出晶畴尺寸为43nm。这些粉末中的大多数在颗粒内部显示出单个晶粒。固相烧结在250℃以上的温度下与粉末内部晶界附近金原子的体积扩散以及300℃以上的温度下粉末表面附近的表面扩散同时发生。我们的研究表明，金纳米粉末的固相烧结行为在250℃以上的温度开始，这远低于1064℃的熔点。热分析结果与实时同步加速器X射线散射和FE-SEM的结果一致。
