Effect of carbon on microstructure and interfaces of NiC/Ti multilayers for neutron applications. (September 2018)

• Record Type: Journal Article
• Authors: Jiao, Hongfei; Yu, Changyang; Zhang, Zhong; Li, Wenbin; Huang, Qiushi; Chen, Hong; Wang, Zhanshan
• Is Part Of: Vacuum. Volume 155(2018)
• Page Start: 49
• Page End: 54
• Publication Date: 2018-09
• Subjects: Neutron multilayer -- Magnetron sputtering -- Crystallization -- Diffusion; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2018.05.043
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: NiC/Ti and Ni/Ti multilayer samples were fabricated by direct-current (DC) magnetron sputtering technique for investigating the effects of C atoms on their microstructure, interfaces and composition. Both multilayers consist of 10-nm-thickness Ti layers and 8.5-nm-thickness Ni or NiC layers, respectively. Grazing incidence X-ray reflectivity (GIXR) was performed to characterize the layer thicknesses and interfaces of multilayers. X-ray diffraction (XRD) was utilized to characterize their crystallizations. The layer morphology of these multilayers was investigated by transmission electron microscopy (TEM), and the depth distributions of Ni, Ti and C in both multilayers were studied through energy dispersive X-ray (EDX). Finally, depth profile X-ray photoelectron spectroscopy (XPS) was used to study the chemical state of Ni, Ti, and C. The experimental results present that crystallizations of the NiC/Ti multilayer were suppressed for not only Ni layers but also for Ti layers so that its interfaces were smoother than those of the Ni/Ti multilayer. In the NiC/Ti multilayer, a high concentration of carbon at the interfaces and the existence of carbon in the Ti layers were found. These phenomena could be explained by the compound formation and resputtering effect. Highlights: Crystallization of Ni and Ti was suppressed in NiC/Ti film as compared to Ni/Ti. The interfaces of the NiC/Ti film were smoother than those of the Ni/Ti film. For the NiC/Ti film, carbon enriched at interfaces and also existed in Ti layers. Compound formation of TiC was found in NiC/Ti film.