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目的：研究划痕法测试参数对临界失效载荷的影响,以便更准确地测定硬质薄膜的结合强度。方法采用磁控溅射技术在304不锈钢和Si片上制备氮化钛( TiN )薄膜。采用扫描电镜观察薄膜的截面形貌和厚度,采用纳米压入法测试薄膜的硬度,采用划痕法测试薄膜的结合强度,研究不同划痕长度、划动速率和加载速率对临界载荷的影响。结果所制备TiN薄膜致密,厚度约2μm,纳米压入硬度约2300HV,TiN/304不锈钢体系为硬膜软基体。相同加载载荷(10 N)和划动行程(3 mm)条件下,增加划动速率(1~3 mm/min),导致首次声发射信号延迟；相同加载载荷(10 N)和划动速率(3 mm/min)条件下,随着划动行程的增加(3~9 mm),第三、四类失效模式逐渐减弱。结论采用划痕法测定结合强度时,应该以划痕形貌同时出现第一到第四模式时判断失效,并且对应典型声发射信号为参考；合理的测试参数范围,可重复出现临界载荷值。制备的TiN薄膜声发射信号存在共同的临界特征值4.9 N,结合划痕形貌特征,判定其结合强度值为4.9 N。

Objective In order to determine precise adhesion strength of hard film, the effects of parameters of scratch test on the critical failure load were studied and discussed. Methods Titanium Nitride ( TiN) film was deposited on 304 stainless steel plates and Si wafer by magnetron sputtering. The cross-section morphology and thickness of TiN film were observed by Scanning E-lectric Microscopy ( SEM) , the hardness was evaluated by nano-indentation method, the adhesion strength was studied by scratch tester, and the influences of slide length, slide speed and loading rate on the critical load were analyzed. Results As-deposited TiN film possessed dense morphology with a thickness of about 2 μm. The hardness of TiN film was about 2300HV and the TiN/304 stainless steel system was hard film and soft substrate. The increase of slide speed (1~3 mm/min) resulted in the first acoustic e-mission (AE) signal delay under the same load (10 N) and slide length (3 mm) conditions, the increase of slide length (3~9 mm) resulted in the gradual weakening of III and IV failure mode under the same load (10 N) and slide speed(3 mm/min) condi-tions. Conclusion In order to evaluate ideal adhesion strength, I to IV failure mode appearance should be observed in single scratch path with specific AE signal. Critical load repeated itself within proper range of testing parameters. Position 4. 9 N AE sig-nal appeared during several tests under different setting parameters, in combination with the scratch morphology, it clarified that the adhesion strength of as-deposited TiN film was 4. 9 N.