Material         Hardness(HRC)

ZrO2             90

Al2O3            88-90

Si3N4            90-95

SiC               90-92

AlN               90-92

Industrial ceramics come in a variety of types, and from the table, it's evident that Silicon nitride ceramics are the hardest among them. However, due to the expensive raw materials and challenging processing, zirconia and silicon carbide are more widely used in the market. But in cost-sensitive scenarios alumina is the most economical choice. While Silicon nitride ceramic has certain advantages in rapid temperature changes, it is the ony ceramic that can stand big thermal shock . Choosing the appropriate industrial ceramic depends on specific application needs, performance requirements, and cost considerations.