Characterization of carbonized magnesium formed in a low energy plasma focus device

Carbon-ion deposition on magnesium substrate was performed using a low energy Mather-type plasma focus device. Deposition process was carried out at 0, 15, 30 and 45° angular position with respect to the device anode axis. X-ray diffraction (XRD) confirmed presence of Mg2C3, Mg (OH)2 and graphite crystals on the produced films. Field emission scanning electron microscope (FE-SEM) coupled to elemental mapping analysis from surface and cross section of the samples was performed. The analysis showed the formation of a multi-layer thin film, in which carbon nano particles (CNPs) covered the composite layer. The CNPs were formed by graphite crystals while the composite layer formed by combination of Mg2C3 and Mg (OH)2 crystals. The band gap energy of indirect transition (⁓1.75 eV) of Mg2C3 was extracted from optical measurements of UV–Visible spectrum. XRD and Raman spectroscopy were used to investigate the graphite crystal structure of CNPs at each deposition angle. The study indicates that the graphite crystal structure of the samples is consisted of nano-crystalline and reduced nano-crystalline graphite structures. X-ray photoelectron spectroscopy (XPS) was used to characterize the elemental composition of the surface structure. The presence of Mg2C3 and Mg (OH)2 in composite layer, nano-crystalline, and reduced nano-crystalline graphite in CNPs was identified by high resolution transmission electron microscopy (HR-TEM). Potentio-dynamic polarization test was used to analyze the corrosion resistance of the prepared thin films with respect to un-deposited substrate. The findings indicate that the thickness and the size of Mg2C3 crystals have direct effect on corrosion resistance parameters. •Carbon-ion deposition on magnesium substrate by a low energy plasma focus device.•Effects of substrate angular position on characteristics of coated layers.•Formation of Mg2C3, Mg(OH)2 and graphite crystals on the produced films.•Formation of a multi-layer thin film covered by carbon nano particles.