Shock compression of magnesium silicon nitride

Magnesium silicon nitride is a ternary nitride compound with an orthorhombic, distorted wurtize structure at ambient condition. There is no study on this material at high pressures, but a recent theoretical work predicts phase transitions at $\sim $17 GPa. We have determined Hugoniot for magnesium silicon nitride ceramics up to 150 GPa and performed recovery experiments up to $\sim $50 GPa. The Hugoniot measurement indicates HEL of 15-17 GPa and a compression curve with no clear phase transition. The compression curve, however, showed a gradual deviation from the compression curve calculated for the low-pressure phase with increasing pressure. If this is the case, there would be a sluggish phase transition at high pressure. We carried out a series of recovery shots on the powders mixed with copper, but the results indicated no additional phase. We compared the results with the theoretical prediction.