Model for Vickers microhardness prediction applied to SnO2 and TiO2 in the normal and high pressure phases

The Vickers microhardness of TiO2 is calculated using elastic properties obtained by first principles calculations combined with Discrete Elements Method (DEM). The calculation is carried out in rutile and cotunnite phases. It was found that rutile phase, has a microhardness of 8.6 GPa and 12.8 GPa for the failure and fracture modes in agreement with experimental results range. In cotunnite phase the hardness for failure and fracture mode are 24.1 and 24.4 GPa, close to 26 GPa, applying Simunek model. To give insight to this methodology, the calculation is extended to SnO2 in the normal phase. The microhardness value obtained in the failure mode is 2.67 GPa. The method developed here, to obtain the Vickers microhardness, could be applied to a systematic study of tailoring materials. Since hardness is related to elastic shear properties, our results can be used as an assessment of the material properties as solid lubricating at first order.