Abstract
Scanning electron microscopy shows that the microstructure, in particular the overall grain size, of chemical vapor deposited silicon carbide coatings depends on the deposition temperature. So far, the influence of the microstructure on the mechanical properties of such coatings is not well described in literature. To investigate the influence of the deposition temperature on the mechanical properties of the coating, nanoindentation is used in this work. Since the measurement results of nanoindentation can be affected by the substrate material, the contribution of the substrate material is taken into account utilizing a finite element model. The model is then employed to generate information about elastic and plastic properties of the coating by inverse simulation. To evaluate the fracture toughness of the coating, the generated material model is used in a cohesive-zone based formulation of the fracture process during indentation at higher loads. The results of this model allow determining the fracture toughness of silicon carbide coatings deposited at different temperatures.
Highlights
A broad range of mechanical properties is reported for silicon carbide (SiC) in the literature
For thin coatings, measured in a cross-sectional setup, it can be shown that the elastic modulus determined by the Oliver & Pharr method decreases, which is a result of neglecting the nature of the indentation periphery
Silicon carbide coatings were deposited on a graphite substrate by chemical vapor deposition, at different deposition temperatures leading to different microstructure of the coating
Summary
A broad range of mechanical properties is reported for silicon carbide (SiC) in the literature. For chemical vapor deposited (CVD) SiC coatings the Young’s modulus values range from around 330 GPa [1] up to approximately 480 GPa [2]. Reasons for this broad range in the reported data can result from different measurement methods, experimental errors, or from different production processes of the coatings and, differences in their microstructure. If the standardized Oliver and Phar method [7] for bulk materials is used, the measurement of the elastic modulus can be affected by the respective substrate. In addition to elastic properties, which are evaluated by the Oliver and Phar method, this allows us to generate information about the plastic deformation of the coating. The generated elastic plastic material model is used in further simulations to evaluate the fracture toughness of the coatings
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
