Nanostructured SiC by chemical vapor deposition and nanoparticle impaction

摘要: SiC nanostructured coatings were deposited using a novel synthesis process combining chemical vapor deposition (CVD) with nanoparticle impaction. Indentation moduli (∼370 GPa) similar to and hardnesses (∼39 exceeded the best commercially grown CVD films. Furthermore, film fracture toughness (∼ 6 MPa m 1/2 ) showed significant improvement reported values in literature. The nanoparticles synthesized by injecting reactants into thermal plasma that undergoes rapid expansion through converging nozzle, resulting gas-phase nucleation. This purposefully runs counter design criteria for CVD, where reactant concentration is kept low avoid nucleation disordering of growth. By limiting residence time, average particle size can be under 20 nm. However, these films suffer greatly from porosity. In present paper, an increase substrate temperature used enhance amount growth due deposition. Particle formation was confirmed in-situ distribution measurements. relative contributions investigated observation preferred orientation microstructural characteristics. addition, improvements hardness are presented explained terms observed structural changes.