Tuning mechanical and corrosion performance of SiOC glass coatings prepared by thermal MOCVD

In this study, silicon oxycarbide (SiOC) glass coatings were successfully deposited by thermal metal organic chemical vapor deposition (MOCVD). The composition, chemical bonding and mechanical properties of the prepared SiOC glass coatings were studied using X-ray photoelectron spectroscopy (XPS) and nano indentation techniques. The surface morphologies of SiOC coatings were characterized by field emission scanning electron microscopy (FESEM) before and after etching with HF acid for prolong time. The results showed that the percentage of Si-C bonds in SiOC glass coatings increases with increasing the content of HMDS in liquid precursors mixture. Raman spectroscopy results revealed the presence of amorphous carbon (with high content of sp3 bonds) in the prepared SiOC coatings. Consequently, the hardness and modulus of SiOC glass coatings increased from 8.99 GPa and 82.6 GPa to 17.93 GPa and 195.6 GPa, respectively. Further, the prepared SiOC glass coatings exhibited excellent corrosion resistance against HF acid.