Thermal dissolution mechanisms of AlN/CrN hard coating superlattices studied by atom probe tomography and transmission electron microscopy
Thermal dissolution mechanisms of AlN/CrN hard coating superlattices studied by atom probe tomography and transmission electron microscopy
复制标题
DOI：
10.1016/j.actamat.2014.11.004
复制
发表时间：
2015-02
期刊：
影响因子：
9.4
通讯作者：
D. Tytko;P. Choi;D. Raabe
中科院分区：
文献类型：
--
作者：
D. Tytko;P. Choi;D. Raabe
采用射频反应磁控溅射法制备了AlN/CrN超晶格，双层周期为4 nm，具有B1立方晶体结构。研究了涂层在900 °C下的热稳定性以及微观结构和化学组成的变化。AlN层显示出高的化学稳定性，但通过在晶界处夹断而发生溶解。观察到从立方到六方AlN的转变，随后在晶界三重结处粗化。与AlN相反，CrN层显示出差的化学稳定性，并且在保护性氩气气氛中退火时，由于氮损失，它们的组成向Cr 2N转移。然而，即使在建立Cr 2N化学计量后，层的晶体结构仍保持立方。
AlN/CrN superlattices with a B1 cubic crystal structure and a bilayer period of 4 nm were deposited by reactive radiofrequency magnetron sputtering. The coatings were investigated with respect to their thermal stability and changes in microstructure and chemical composition at 900 °C. The AlN layers show high chemical stability but undergo dissolution by pinching off at grain boundaries. A transformation from cubic to hexagonal AlN with subsequent coarsening at grain boundary triple junctions is observed. In contrast to AlN, the CrN layers show poor chemical stability and their compositions are shifted towards Cr2N upon annealing in a protective argon atmosphere due to nitrogen loss. However, even after establishing Cr2N stoichiometry the crystal structure of the layers remains cubic.