Correlative Microscopy and Energy Dispersive X-ray Spectroscopy for Comprehensive Surface Characterization Before and After Laser Treatment of Tungsten Carbide-Cobalt Material

Abstract

Comprehensive correlative characterization of material surfaces is essential for understanding how certain treatments, such as laser treatments, can modify their properties and overall performance. This study employs a multi-modal correlative microscopy approach, combining Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Optical Microscopy (OM), Focus-Variation Optical Microscopy (F-V OM) and Atomic Force Microscopy (AFM) to characterize laser-textured Tungsten Carbide-Cobalt (WC-Co) surfaces. The characterization was carried out on the same area before and after pulsed laser treatment at ambient atmosphere. The experiments revealed the persistence of surface defects, presumably caused by Wire Electrical Discharge Machining (WEDM) during sample preparation, which were further accentuated by the subsequent laser treatment. In addition, significant and non-uniform surface oxidation was observed, with elevated levels on specific flanks of laser-ablated grooves. This analysis demonstrated that spatial property decoupling is key, as the maximum topographic height, nearing 7 μm height from the lowest surface point, did not spatially coincide with the extremes of the chemical composition or total deformation curves. Specifically, point analysis showed that oxygen concentrations varied sharply, reaching 29.02 atomic oxygen percentage on high-deformation zones, contrasting with 21.18 at.% O found at adjacent low-deformation zones. Finally, the relationship among topography, chemical composition and nanomechanical properties was demonstrated, and the value of applying multi-modal correlative microscopy for understanding laser-material interactions was underscored. The insights gained highlight the potential of the methodology for optimizing laser parameters to achieve targeted surface functionalities.