Application of Energy Dispersive X-Ray Diffraction for the Efficient Investigation of Internal Stresses in Thin Films
Application of Energy Dispersive X-Ray Diffraction for the Efficient Investigation of Internal Stresses in Thin Films
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应用能量色散 X 射线衍射有效研究薄膜内应力
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
G. Fritsche
中科院分区：
文献类型：
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作者：
U. Zschenderlein;B. Kämpfe;B. Schultrich;G. Fritsche
内应力对保护性硬涂层的性能非常重要。拉伸应力有利于裂纹的形成和扩展，从而导致断裂和腐蚀。中等压应力会阻碍疲劳。但是，通常对于通过PVD（物理气相沉积）工艺生产的硬涂层，高压缩应力支持分层，以便释放储存的弹性能量。然而，尽管它的相关性，内部应力很少用于工业中硬涂层的优化和质量控制。这种不令人满意的情况是由于缺乏有效的测量方法造成的。薄板的应力可以简单地通过其曲率来测量，其结果不一定代表较厚部件的涂层。传统的X射线衍射法（XRD）是基于角色散法的，需要昂贵的设备，且耗时较长。能量分散技术开辟了新的可能性。它基于多色辐射。通过不同波长（或光子能量）的衍射强度来研究对应于布拉格方程的晶格平面反射的干涉，而不是像常规XRD中那样通过改变布拉格角来研究。因此，整个衍射图案可以在一次拍摄中获得，而无需使用任何测角仪。这允许构造小型和紧凑的测量设备，并将测量时间缩短到几分钟。利用能量色散X射线衍射仪（ED-XRD）对不同工艺参数下的真空电弧沉积氮化钛和氮化铬薄膜进行了分析。与耗时更长的AD-XRD（角度色散X射线衍射）进行了比较，用于残余应力分析。两种方法的结果吻合良好。
Internal stresses are very important for the performance of protective hard coatings. Tensile stresses favour the formation and propagation of cracks, inducing fracture and corrosion. Medium compressive stresses hinder fatigue. But high compressive stresses, typically for hard coatings produced by PVD (physical vapour deposition) processes, support delamination in order to relax the stored elastic energy. However notwithstanding its relevance, the internal stresses are only seldom used for the optimisation and quality control of hard coatings in industry. This unsatisfying situation is caused by the deficit in efficient measuring methods. The results of thin sheets, where the stresses can be simply measured by their curvature, are not necessarily representative for the coating of thicker parts. The conventional XRD (X-ray Diffraction), based on angle-dispersive evaluation needs expensive devices and is rather time consuming. The energy-dispersive technique opens new possibilities. It is based on polychromatic radiation. The interference of the lattice plane reflections corresponding to the Bragg-equation is investigated by the diffraction intensity of the different wavelength (or photon energies), not by varying the Bragg-angle as in conventional XRD. Hence, the whole diffraction pattern can be obtained in one shoot without the use of any goniometer. This allows the construction of small and compact measuring devices and the reduction of measuring time to a few minutes. The capability of the ED-XRD (Energy Dispersive X-ray Diffraction) is demonstrated for titanium nitride and chromium nitride films deposited by cathodic vacuum arc with varying parameters. Comparisons were made with the much more time-consuming AD-XRD (Angle Dispersive X-ray Diffraction) for residual stress analysis. The results of both methods are in good agreement.