Armour plate

An antiballistic armor plate including a ceramic body consisting of a hard material, provided, on its inner face, with a back energy-dissipating coating, wherein:

• said ceramic body is monolithic and has an area that is larger than 150 cm2, a thickness that is greater than 12 mm and a bulk density that is lower than 3.5 g/cm3;
• the constituent material of the ceramic body comprises grains of ceramic material having a Vickers hardness that is higher than 15 GPa, and a matrix binding said grains, said matrix consisting of one or more phases selected from the group consisting of a silicon nitride phase, a SiMON phase, where M is a metal chosen from Ca, Mg, Sr and Ba, and a silicon oxynitride (Si2ON2) phase, said matrix representing between 15 and 40% by weight of said constituent material of the ceramic body;
• a maximum equivalent diameter of said grains of ceramic material is smaller than or equal to 800 micrometers;
• said constituent material of the ceramic body has an open porosity that is higher than 5% and lower than 14%;
• a metallic silicon content in said material, expressed per mm of thickness of said body, is lower than 0.5% by weight.