Table 3.

Comparison of mechanical properties of silicon nitride.

Additives	Sintering Method	Sintering Temperature/°C	Holding Time/min	Relative Density/%	Hardness/GPa	Fracture Toughness/MPa·m1/2
5 wt% Y2O3 + 5 wt% MgO + 2 wt% Al2O3 [3]	Microwave	1700	10	98.52	14.92	6.44
3 wt% MgO + 1.5 wt% Al2O3 + 3.5 wt% SiO2 [29]	Pressureless	1780	180	99.70	14.20	6.40
5 wt% MgSiN2 + 3 wt% Y2O3 + 1 wt% CeO2 [13]	Spark plasma	1650	6	99.40	16.53	6.89
10 wt% LiYO2 + 5 wt% ZrO2 [30]	Microwave	1600	15	93.00	13.00	6.10