Design of hard coating architecture for the optimization of erosion resistance

The architecture of erosion-resistant coatings is usually established empirically and their performance is evaluated experimentally through the measurement of minimum erosion loss. This makes it difficult to optimize the coating structure without a detailed knowledge of the damage mechanisms and the governing erosion parameters. In this context, the present work focuses on the use of advanced finite element (FE) methods to study the erosion mechanisms and to predict the coating behaviour in simulated erosion conditions. The calculation variables include impact velocity, particle size and the mechanical properties of both the target and the impacting particle. Specifically, we investigate the impact response of coatings fabricated by physical vapour deposition and plasma enhanced chemical vapour deposition. This includes single and multilayer TiN and nanocomposite nc-TiN/a-SiN1.3 and nc-TiCN/a-SiCN systems on titanium alloy and stainless steel substrates. In particular, we correlate the thickness and the coating macroscopic properties, such as hardness, Young's modulus, and toughness with the erosion resistance. We demonstrate that the FE design of the coating architecture, combined with the tailored mechanical properties of individual components of the coating systems, opens new opportunities as a predictive tool for high-performance erosion coatings.