【摘要】 Ta(ⅤB族)、Hf(ⅣB族)、W(ⅥB族)等过渡族金属合金受其晶体结构(BCC)的影响，导致耐磨性受限。氮掺杂可形成固溶体及氮化物强化相，显著提升硬度和抗磨损能力。采用磁控溅射沉积技术成功制备出Ta-Hf-W体系合金及其氮化物薄膜。系统探讨四种氮气流率(R_N=0、10、20、30%)对Ta-Hf-W(-N)薄膜结构与性能的调控规律，揭示氮掺杂与机械性能和摩擦磨损性能的关联机制。结合XRD的晶体结构分析、SEM与TEM的微观形貌观察、AFM的表面三维形貌等表征手段，系统分析薄膜微观结构特征，同时使用纳米压痕仪进行机械性能测试，并基于摩擦磨损试验平台完成表面摩擦学行为评估，构建了材料组成、微观结构、性能测试的完整研究体系，筛选优质薄膜。采用白光干涉仪和扫描电子显微镜对磨损部分进行测试，结合磨损形貌以及组织结构分析耐磨内因。研究表明适当的氮气流量能够显著提高薄膜的硬度和摩擦磨损性能，而过高的氮气流量则可能导致薄膜性能下降，影响其长期稳定性。在氮气流率R_N=20%时，制备的氮化物薄膜表现出最高的硬度和弹性模量，分别为36.2 GPa和357.2 GPa，同时表面粗糙度达到最低值1.85 Ra。此外，耐磨性能也在该条件下达到最优，相同磨损条件下相比Ta-Hf-W合金薄膜磨损率降低2/3。更多还原

【Abstract】 The development of advanced wear-resistant coatings is of paramount importance for enhancing the service life and reliability of mechanical components in demanding aerospace and precision engineering applications. Transition metal alloys based on refractory elements like Ta(Group VB), Hf(Group IVB), and W(Group VIB) are promising candidates due to their inherent high strength and stability. However, their wear resistance is often intrinsically limited by the propensity for plastic deformation and adhesive wear associated with their body-centered cubic(BCC) crystal structure. Nitrogen doping is widely recognized as an effective strategy for performance enhancement, capable of forming interstitial solid solutions and hard nitride phases, which significantly improve hardness and resistance to wear. While the individual binary nitrides of Ta, Hf, and W are well-studied, the systematic investigation of their multi-principal element alloy nitride system, specifically Ta-Hf-W-N, remains largely unexplored. The relationship between nitrogen content, evolving microstructure, and the resulting tribological properties in this novel system is not yet established, presenting a significant knowledge gap.This study is designed to comprehensively address this gap by fabricating and characterizing a series of Ta-Hf-W(-N) films with precisely controlled nitrogen content. The primary objective is to elucidate the correlation between nitrogen doping, microstructural evolution, mechanical properties, and tribological performance. The Ta-Hf-W-N films are synthesized using a direct current magnetron sputtering system, with high-purity argon and nitrogen gases serving as the working and reactive atmospheres, respectively. A critical aspect of the experimental design involves the systematic gradient control of the nitrogen flow rate, specifically at values of R_N = 0%, 10%, 20%, and 30%, to precisely tune the chemical composition and phase formation within the films. A multi-faceted characterization approach is employed to construct a complete picture of the structure-property relationships. The phase composition and crystal structure are determined by X-ray diffraction(XRD). The surface morphology, cross-sectional microstructure, and coating thickness are meticulously examined using scanning electron microscopy(SEM) and atomic force microscopy(AFM), the latter providing quantitative data on surface roughness. The mechanical properties, including nanohardness(H) and elastic modulus(E), are accurately measured using a nanoindentation tester. The tribological behavior, namely the coefficient of friction and wear rate, is evaluated under dry sliding conditions using a ball-on-disk tribometer. Subsequent wear track analysis is conducted using white light interferometry to determine wear volume and SEM to observe wear mechanisms and surface damage. The results demonstrate a non-monotonic dependence of the film properties on the nitrogen flow rate, revealing a distinct optimum. The film synthesized at R_N = 20% exhibits the most superior combination of properties. It possesses the highest nanohardness of 36.2 GPa and elastic modulus of 357.2 GPa, attributable to a dense, fine-columnar microstructure and effective solid solution strengthening. Concurrently, this film achieves the lowest surface roughness(1.85 nm Ra), which is crucial for friction reduction. In tribological tests, this optimal film outperforms all others, showing a stable friction coefficient and a wear rate that is reduced by two-thirds compared to the un-doped Ta-Hf-W alloy film(R_N = 0%). Analysis of its wear mechanism identifies a mild, self-renewing cycle of oxidative wear coupled with minimal abrasive grooving. In contrast, deviations from this optimal nitrogen content lead to performance degradation. An insufficient nitrogen flow(R_N= 10%) results in a relatively softer film with a thicker amorphous base layer and less pronounced strengthening. Conversely, an excessive nitrogen flow(R_N = 30%) induces microstructural coarsening, increased surface roughness, and a potential rise in brittleness, which collectively elevate the friction coefficient and accelerate material removal. The fundamental innovation of this work lies in the systematic gradient investigation that successfully establishes the intricate linkages between nitrogen content, the transition from amorphous-to-columnar growth morphology, and the resulting mechanical and tribological responses within the novel Ta-Hf-W-N system. It is conclusively demonstrated that precise control of nitrogen incorporation is the key to unlocking the high-performance potential of this material system. The findings provide robust theoretical guidance and a reliable technical pathway for developing next-generation, high-performance wear-resistant coatings for critical applications in spacecraft and other advanced engineering systems.更多还原