Surface morphology study of some Cu–Ni reference alloys using laser induced breakdown spectroscopy

• Surface LIBS scanning was performed for Cu–Ni reference alloy samples.
• LIBS system was based on a 2nd harmonic Nd:YAG laser and a focusing lens (f = 7 cm).
• LIBS results were compared with SEM imaging and EDS chemical analysis.
• Surface homogeneity and heterogeneity have been differentiated successfully.
• LIBS is a sensitive analytical tool in surface metallurgical study.

In the present work a detailed study of the surface morphology of purposely-prepared Cu–Ni reference alloys has been performed. These alloys have been prepared via tailored casting methods in order to have samples with same chemical composition and different local chemical enrichments of both metals. A micro-LIBS system for surface spatial scanning was set up based on a second harmonic Nd:YAG laser at 532 nm and using a focusing lens of focal length 7 cm to disclose the local chemical composition variation. Surface morphological scanning was performed for some of the binary Cu–Ni reference alloys to differentiate between chemically homogeneous and heterogeneous alloys. LIBS results were compared with the information of the Scanning Electron Microscope coupled with Energy Dispersive X-ray (SEMEDS) investigation carried out to provide surface local large-area chemical analysis via EDS technique. It has been proved that LIBS is a simple, sensitive and direct technique in the determination of homogeneity or heterogeneity of the sample's surface. The LIBS results have been shown to be more sensitive and accurate in the heterogeneity determination than other used conventional analytical techniques.