Laser carbonitriding of alumina surface

Laser carbonitriding of alumina surfaces is examined. Temperature and stress fields developed during the laser heating of the substrate surface are predicted using the finite element method in line with the experimental conditions. The formation of Al(C, N) and AlN compounds in the surface region of irradiated workpiece is examined using X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD). The microstructural and morphological changes in the laser irradiated region are examined using Scanning Electron Microscope (SEM). The microhardness of the resulting surface is measured and compared with the base material hardness. It is found that high temperature gradient is developed in the irradiated region, which in turn, results in high residual stress levels in this region. XPS and XRD data reveal the presence of Al (C, N) and AlN compounds in the surface region. The microhardness in the surface region of the laser treated workpiece increases significantly.

Research highlights
► The laser controlled melting of alumina ceramics improves the surface properties through homogenizing the microstructure in the surface region, transformation of metastable γ-phase into equilibrium α-phase, and other chemical transformations including nitriding.
► In the present study, laser carbonitriding of alumina surfaces is examined.
► Temperature and stress fields developed during the laser heating of the substrate surface are predicted using the finite element method in line with the experimental conditions.
► The formation of Al(C, N) and AlN compounds in the surface region of irradiated workpiece is examined using X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD).
► The microstructural and morphological changes in the laser irradiated region are examined using Scanning Electron Microscope (SEM).