Abstract The development of low-cost high quality surface finishing methods for silicon carbide (SiC) is an arduous task. Nowadays, the SiC mirrors manufacture involves extensive, complex, and costly finishing processes carried out on highly expensive ultra-precise machines. In this work, a cost-effective surface finishing method has been successfully developed, using conventional machines for the optical finishing of SiC. The results showed that the combination of ductile grinding and polishing in conventional low-cost machines allowed to obtain high-quality surface finish on SiC substrates with low roughness (4 - 10 nm Ra ) and optical figure in the range λ / 4 - λ / 8, at a reduced 32 hours total processing time.

The thermal decomposition of silicon carbide (SiC), with the subsequent formation of graphene, can be achieved by heating treatment. Several heating processes have been applied for this purpose by using SiC, either in form of powder particles or monocrystalline substrate. In this work, instead of using an expensive commercially available SiC wafer, a polycrystalline SiC substrate was obtained, based on powder metallurgy process, in order to explore the synthesis of graphene layers on its surface by using a CO2 laser beam as heating source. Different levels of energy density (fluence) were applied and Raman spectroscopy analyses demonstrated that graphene layers were formed on the polycrystalline SiC surface. The ratio of the integrated intensity of the D and G bands, and the crystallite size were calculated. The FWHM of the 2D band peaks are in excellent agreement with the range of values found in the literature. The samples irradiated with energy density of 138.4 J/cm2 presented lower concentration of defects and higher crystallite size, while the lowest FWHM was obtained for energy density of 188 J/cm2. The process occurred at room conditions and no gas flow was used. The results reveal a simple and cost-effective alternative for synthesis of graphene-based structures on SiC.