Grain growth in nanocomposite Ti-B-N films during deposition: The effect of amorphous phase precipitation

Experimental investigations by high-resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction show that during sputter-deposition of Ti-B-N films amorphous materials, e.g., TiB₂ and BN, are found to precipitate at the grain boundaries, resulting in a decrease in grain size when the boron concentration or the amount of amorphous phase increases. To understand these experimental observations, we have used Monte Carlo simulations to investigate the effect of the amorphous phase precipitation on grain growth during film deposition. Our simulations demonstrate that the precipitation of amorphous phase at the grain boundaries can lower the grain growth exponent and thus leads to a low grain growth rate, particularly in the case of large amounts of amorphous phase. As a result, an exponential decay in grain size with the amount of amorphous phase can be observed in our simulations, which is in reasonably good agreement with the experimental results. © 2006 Materials Research Society.