脉冲偏压对贫铀表面磁控溅射CrN_x薄膜结构与性能的影响

为改善金属铀基体的抗腐蚀性能,采用非平衡磁控溅射离子镀技术在不同偏压下于金属铀表面制备CrNx薄膜。采用SEM和AFM研究了薄膜形貌和表面粗糙度,采用X射线光电子能谱研究了薄膜表面的元素分布及化学价态。试验结果表明,采用磁控溅射在较低脉冲偏压下沉积的CrNx薄膜晶粒较细小,偏压越高,表面粗糙度越大。生成的薄膜为Cr+CrN+Cr2N混合结构,并含有少量的Cr2O3,随着偏压的升高,金属态Cr的含量减少,而铬的氮化物的含量增加,所制备薄膜的自然腐蚀电位升高,腐蚀电流密度减小。偏压为-800 V时,所制备的薄膜具有较好的抗腐蚀性能。

Effect of pulse bias voltage on microstructure and properties of CrN_x film prepared by magnetron sputtering on uranium

CrNx film was prepared on surface of uranium by unbalanced magnetron sputtering at different pulse bias voltages to improve its corrosion resistance.Surface and cross-section morphology of the CrNx film were observed by scanning electron microscope.Roughness of the film was examined by atomic force microscope(AFM).X-ray photoelectron spectroscopy(XPS) was used to characterize the chemical state and distribution profiles of Cr,N and O elements.The results show that CrNx film prepared at lower pulse bias voltage has fine grain and high density.The higher the bias voltage,the bigger the size of grain and the more the surface roughness.The phase composition of CrNx films is composed of Cr,CrN,Cr2N and a small quantity of Cr2O3.With the increasing of bias voltage,the content of metal state Cr decreases,while the content of chromium nitride increases.When the bias voltage is-800 V,the corrosion potential increases dramatically and the corrosion current density decreases.It is indicated that the CrN film prepared by unbalanced magnetron sputtering at-800V bias voltage effectively improves the corrosion resistance of uranium substrate.