Molecular simulation of high-velocity deposition of titanium dioxide nanoparticles on titanium

The aerosol deposition method (AD) has recently attracted attention as a new room temperature coating technique for titanium dioxide (TiO2) and other ceramic particles deposition. This low-temperature process offers a considerable advantage to conventional ceramic coating methods. However, utilizing this technique requires optimizing critical material and process parameters by fully understanding the underlying physical processes involved in the formation and bonding of the ceramic films. Here molecular dynamics simulations with sophisticated potentials are used to simulate the impact of titania (TiO2) nanoparticles on a titanium (Ti) substrate. We have calculated temperature and mechanical stresses for practical deposition velocities. The deformation analysis of TiO2 nanoparticle reveals this ceramic nanoparticle has an unusual elastic-plastic deformation. We demonstrate that the deformation takes place at extraordinarily high strain rates in the order of 1010 s−1 and the temperature rises for a femtosecond-long duration to values up to 1387 K. The high energy impact leads to debonding of oxygen atoms from titania and bonding with Ti atoms in the substrate. Titanium atoms from TiO2, are also shown to make bonds with Ti atoms in the substrate, revealing the bonding mechanism of titania with titanium at the atomic scale.