Fujii Satoshi, Suzuki Eiichi, Inazu Naomi, Tsubaki Shuntaro, Fukushima Jun, Takizawa Hirotsugu, Wada Yuji
Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookyama, Meguro-ku, Tokyo, 152-8550, Japan.
Department of Information and Communication System Engineering, National Institute of Technology, Okinawa College, 980 Henoko, Nago-shi, Okinawa, 905-2192, Japan.
Sci Rep. 2020 Feb 14;10(1):2689. doi: 10.1038/s41598-020-59664-2.
Scandium is being explored as an alloying element for aluminium alloys, which are gaining importance as high-performance lightweight structural alloys in the transportation industry. Sc-rich ScAlN thin films show strong piezoelectricity and can be fabricated on a hard substrate for use as wideband surface acoustic wave filters in next-generation wireless mobile communication systems. However, the use of ScAlN thin films in microelectromechanical system devices is limited by the high cost of metallic Sc, which is due to the difficulty in smelting of this material. Here, we propose a novel microwave irradiation process for producing Al-Sc alloys, with Mg ions as a reducing agent. Although scandium oxide is thermodynamically stable, intermetallic AlSc is obtained in high yield (69.8%) via a low-temperature (660 °C) reduction reaction under microwave irradiation. Optical spectroscopy results and thermodynamic considerations suggest a non-thermal equilibrium reaction with the univalent magnesium ions excited by microwave irradiation.
钪正被作为铝合金的一种合金化元素进行探索，铝合金作为高性能轻质结构合金在交通运输行业正变得越来越重要。富含钪的ScAlN薄膜显示出很强的压电性，并且可以在硬质衬底上制造，用作下一代无线移动通信系统中的宽带表面声波滤波器。然而，ScAlN薄膜在微机电系统器件中的应用受到金属钪高成本的限制，这是由于这种材料熔炼困难所致。在此，我们提出一种以镁离子作为还原剂生产Al-Sc合金的新型微波辐照工艺。尽管氧化钪在热力学上是稳定的，但通过微波辐照下的低温（660 °C）还原反应可高产率（69.8%）地获得金属间化合物AlSc。光谱学结果和热力学考量表明这是一个与被微波辐照激发的单价镁离子发生的非热平衡反应。
