Fabrication and Microstructure Evaluation of Oxide and Carbide Ceramic Coatings onto Heterogeneous Substrates by Solid-Vapor Reaction
Silicon carbide (SiC) and alumina (Al2O3) have been synthesized on graphite and silica (SiO2) substrates, respectively, using a solid-vapor reaction (SVR). SiC and Al2O3 layers are synthesized on each substrate by reacting between SiO vapor and substrate (SiO (vapor) + 2 C (from graphite)), and between AlO vapor and substrate (2AlO (vapor) + 1/2O2 (from SiO2)). Both reaction processes were performed at 1400 °C for 9 hour at a heating rate of 5 °C/min under an Ar/H2 (160:40) flow of 200 sccm (ml/min). The pack composition for each case was adjusted with 1:1 mole ratio, which was used as precursors of the AlO and SiO vapors. The synthesized SiC layer consists of α-SiC and β-SiC, and its thickness is affected by the porosity of graphite. The Al2O3 top layer synthesized on SiO2 substrate is coarse and relatively porous, resulting in some defects.
Deliang Zhang, Kim Pickering, Brian Gabbitas, Peng Cao, Alan Langdon, Rob Torrens and Johan Verbeek
J. H. Kang et al., "Fabrication and Microstructure Evaluation of Oxide and Carbide Ceramic Coatings onto Heterogeneous Substrates by Solid-Vapor Reaction", Advanced Materials Research, Vols. 29-30, pp. 219-222, 2007