反应磁控溅射ZrN/AlON纳米多层膜的晶体生长和超硬效应

采用Zr靶和Al₂O₃靶通过在Ar，N₂混合气氛中进行反应磁控溅射的方法制备了不同AlON调制层厚和不同ZrN调制层厚的两个系列的ZrN/AlON纳米多层膜.利用X射线能量色散谱仪、X射线衍射仪、高分辨透射电子显微镜和微力学探针研究了多层膜的成分、微结构和力学性能.结果表明，在Ar，N₂混合气氛中对Al₂O₃进行溅射的过程中，N原子会部分取代Al₂O₃中的氧原子，形成AlON化合物.在ZrN/AlON纳米多层膜中，由于受到ZrN晶体调制层的模板作用，溅射条件下以非晶态存在的AlON层在其厚度小于0.9nm时被强制晶化并与ZrN层形成共格外延生长；相应地，多层膜的硬度明显提高，最高硬度达到33.0GPa.进一步增加多层膜中AlON调制层的厚度，AlON层形成非晶结构，破坏了多层膜的共格外延生长，导致其硬度逐步降低. 关键词： ZrN/AlON纳米多层膜 外延生长 非晶晶化 力学性能

Crystal growth and superhardness effects of ZrN/AlON nanomultilayers synthesized by reactive magnetron sputtering

Two series of ZrN/AlON nanomultilayers were synthesized by reactively sputtering zirconium and aluminum oxide targets in the gaseous mixture of argon and nitrogen. The thickness of ZrN layers was fixed in one of the series and the thickness of AlON layers in the other. The composition, microstructure and mechanical properties of films were characterized by X-ray energy dispersive spectroscopy, X-ray diffraction, high resolution transmission electron microscopy and nanoindentation. The investigation results indicate that during the process of Al₂O₃ target sputtering in the mixed atmosphere, part of oxygen atoms in Al₂O₃ were replaced by nitrogen atoms, leading to the formation of aluminum oxynitride, AlON. Under the influence of the “template effects” of ZrN layers, the AlON layers that used to exist as amorphous under sputtering conditions were forced to crystallize and grew epitaxially with the ZrN layers when the thickness of AlON was limited to less than 0.9 nm. Correspondingly, the hardness of multilayers was remarkably enhanced to its maximum value of 33.0GPa. A further increase in the thickness of AlON layers led to the crystalline AlON layers transforming into amorphous. The epitaxial growth of multilayers was blocked, accompanied by the decline of hardness.