氮化物硬質薄膜擁有良好的機械性質、抗氧化性及耐磨耗等特性，近年來被廣泛應用於工業領域。然隨著科技的日新月異，對於硬質塗層的需求日漸嚴苛，除了需具備高硬度外，韌性逐漸成為硬質薄膜的要求，而要鍍製出高硬度且具備優異韌性的保護性硬膜著實屬一大挑戰。
多層膜為利用兩種不同材料鍍製出具有週期性的結構，其中材料與材料間之介面可分散掉裂縫向下延伸的能量，以良好的保護基板材料。此外，多層膜的結構也比單層膜擁有較高的韌性。藉由特定的材料選擇，可觀察到磊晶生長的多層薄膜，並在調變雙層週期比例會有相變化的發生，而呈現不一樣的薄膜性質。
本研究系利用真空磁控濺鍍之手法，製備不同雙層週期比例之氮化鋯鈦/氮化鈮多層薄膜，控制氮化鋯鈦之於氮化鈮比例介於2.7-0.4，觀察與氮化鈮的相變化如何影響薄膜之磊晶生長。再藉由奈米壓痕測試驗證因介面引入而得到的結構強化效果，並揭示出其中最適當的週期比例。在奈米尺度下的磨耗測試，觀察介面如何分散外界壓力表現出最佳的抗磨耗性質。於本研究中結果顯示，由於氮化鋯鈦/氮化鈮相近的晶格常數與楊氏係數，多層膜的硬度強化並不明顯，然多層膜之韌性則優異於單層氮化鋯鈦(K_c=3.22 MPa√m)及單層氮化鈮(K_c=2.70 MPa√m)。此外在奈米刮痕試驗中，刮痕過程中的曲線可觀察到階梯狀的形貌，象徵應力在遇到介面後被分散而達到保護基板的作用，而氮化鈮的相轉變則弱化薄膜的抗磨耗性質，主要係由於此相轉變破壞了原有的薄膜磊晶生長。

Protective hard thin films have drawn extensive attention in modern industry under extreme condition. The design of high hardness and excellent toughness is great significant for expanding the application of transition nitride coatings. In this regard, epitaxial stabilization superlattices have been proposed as a potential candidate. The ZrTiN/NbN system was designed owing to the similar crystal structure and lattice parameter. Thus, the relationship between epitaxial grain growth and thickness of sub-layer were clearly studied. In this work, all coatings were deposited via RF magnetron sputtering. Superlattices with four different thickness ratio of individual layers were designed while bilayer period was fixed at 8 nm. The microstructure and tribological performance of superlattices were investigated by the characterization of chemical composition, crystal structure, and mechanical properties.
It has been found that metastable cubic NbN transforms to the stable hexagonal structure with the NbN component layer thicker than 3 nm, since NbN possesses higher valence electron concentration (VEC). HRTEM images revealed that the existence of h-NBN resulted in the loss of coherent growth, thereby showing the polycrystalline structure in SAED. The superlattices demonstrated no radical cracks after indentation. It is obvious that superlattices possessed stronger crack resistance than ZrTiN (K_c=3.22 MPa√m) and NbN (K_c=2.70 MPa√m) monolithic films.
Superlattices exhibited the staircase deformation during scratching. It was argued that the wear volume of superlattices was remarkably lower than monolayers, however, the formation of h-NbN was the reason deteriorating the wear resistance of the coatings. To sum up, epitaxial ZrTiN/c-NbN superlattices exhibited not only excellent mechanical behavior but also favorable tribological performance.

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