Kato Takahiro, Sugawara Katsuyasu
Faculty of Engineering Science, Akita University, 1-1 Tegata Gakuen-machi, Akita City, Akita Prefecture 010-8502, Japan.
ACS Omega. 2019 Sep 5;4(12):14714-14720. doi: 10.1021/acsomega.9b01140. eCollection 2019 Sep 17.
Aluminum nitride (AlN) is highly insulating and has a high thermal conductivity. AlN also has the advantages of being nontoxic and chemically stable. Therefore, it is a suitable sealing material for electric devices. Previous studies have shown that the addition of NHCl has a large influence on the formation of AlN and can effectively be used in its low-temperature synthesis without the use of special equipment. However, it has not been clarified whether NHCl simply promotes the reaction between Al and nitrogen or directly contributes to the nitridation reaction. In this study, which was part of a series of studies on the development of low-temperature synthesis methods for AlN, the nitridation behaviors of Al in Al-N, Al-NHCl-N, and Al-NHCl-He systems were determined, and the effects of the heating temperature and amount of NHCl on the nitridation behavior were examined in detail. When NHCl was added, AlN began to form at 600 °C, a formation temperature that was approximately 200 °C lower than that when only Al powder was heated under a nitrogen stream. The fact that the formation of AlN was also observed when the NHCl-added Al powder was heated under a helium gas stream confirmed that nitrogen derived from NHCl contributed to the formation of the AlN. Furthermore, based on the experimental results, the reaction mechanism was clarified, and the kinetic parameters for the nitridation of Al were determined.
氮化铝（AlN）具有高度绝缘性且热导率高。AlN还具有无毒且化学稳定的优点。因此，它是一种适用于电子器件的密封材料。先前的研究表明，添加氯化铵（NH₄Cl）对AlN的形成有很大影响，并且无需使用特殊设备就能有效地用于其低温合成。然而，尚未明确NH₄Cl是仅仅促进了Al与氮之间的反应还是直接促成了氮化反应。在本研究中，作为AlN低温合成方法开发系列研究的一部分，测定了Al在Al-N、Al-NH₄Cl-N和Al-NH₄Cl-He体系中的氮化行为，并详细研究了加热温度和NH₄Cl用量对氮化行为的影响。添加NH₄Cl时，AlN在600℃开始形成，该形成温度比仅在氮气流下加热铝粉时的温度低约200℃。当在氦气流下加热添加NH₄Cl的铝粉时也观察到AlN的形成，这一事实证实了源自NH₄Cl的氮促成了AlN的形成。此外，基于实验结果，阐明了反应机理，并确定了Al氮化的动力学参数。
