Armour plate

Patent metadata

Field	Value
Publication number	US-2019234712-A1
Application number	US-201716316821-A
Country	US
Kind code	A1
Filing date	Jul 7, 2017
Priority date	Jul 11, 2016
Publication date	Aug 1, 2019
Grant date	—

Abstract

Antiballistic armour plate includes a ceramic body including a hard material, provided, on its inner face, with a back energy-dissipating coating. The ceramic body is monolithic. The constituent material of the ceramic body includes grains of ceramic material having a Vickers hardness that is higher than 15 GPa, and a matrix binding the grains, the matrix including a silicon nitride phase and/or a silicon oxynitride phase, the matrix representing between 5 and 40% by weight of the constituent material of the ceramic body. The maximum equivalent diameter of the grains of ceramic material is smaller than or equal to 800 micrometres. The constituent material of the ceramic body has an open porosity that is higher than 5% and lower than 14%. The metallic silicon content in the material, expressed per mm of thickness of the body, is lower than 0.5% by weight.

First claim

1 . 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 cm 2 , a thickness that is greater than 12 mm and a bulk density that is lower than 3.5 g/cm 3 ; 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 comprising or consisting of a silicon nitride phase and/or a silicon oxynitride phase, said matrix representing between 5 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%; the metallic silicon content in said material, expressed per mm of thickness of said body, is lower than 0.5% by weight.

2 . The armor plate as claimed in claim 1 , wherein the constituent grains of the ceramic material consist essentially of SiC.

3 . The armor plate as claimed in claim 1 , wherein the metallic silicon is present in said constituent material of the ceramic body along a concentration gradient from the outer edges to the core of said body, in the direction of its thickness.

4 . The armor plate as claimed in claim 1 , which has a mass-to-area ratio, measured in kg/m 2 , that is higher than 60.

5 . The armor plate as claimed in claim 1 , wherein a total sum of rare-earth elements in the constituent material of the ceramic body is lower than 0.05% by weight.

6 . The armor plate as claimed in claim 1 , wherein the maximum equivalent diameter of the grains in said constituent material of the ceramic body is comprised between 10 micrometers and 500 micrometers.

7 . The armor plate as claimed in claim 1 , wherein the constituent material of the ceramic body contains no elements from the group of the rare-earth elements.

8 . The armor plate as claimed in claim 1 , wherein a mean equivalent diameter of the constituent grains of the ceramic material is larger than 5 micrometers and smaller than 300 micrometers.

9 . The armor plate as claimed in claim 1 , wherein the metallic silicon content of the constituent material of the ceramic body is lower than 10% by weight.

10 . The armor plate as claimed in claim 1 , wherein a nitrogen content in the constituent material of the ceramic body is higher than 4% by weight.

11 . The armor plate as claimed in claim 1 , wherein the binding matrix essentially consists of silicon nitride Si 3 N 4 and/or silicon oxynitride Si 2 ON 2 .

12 . The armor plate as claimed in claim 1 , wherein the constituent material of the back coating is chosen from the polyethenes PE, glass or carbon fibers, aramids, metals, or steel.

13 . The armor plate as claimed in claim 1 , wherein the ceramic body-back coating assembly is surrounded by an envelope of a confining material.

14 . The armor plate as claimed in claim 13 , wherein the constituent material of the envelope is chosen from the polyethenes PE, glass or carbon fibers, aramids, metals or steel.

15 . A monolithic ceramic body in the form of a plate and having an area that is larger than 150 cm 2 and a thickness that is greater than 12 mm, and a bulk density that is lower than 3.5 g/cm 3 , consisting of a material comprising:
grains of ceramic material having a Vickers hardness that is higher than 15 GPa, a maximum equivalent diameter of said grains being smaller than or equal to 500 micrometers; and a matrix binding said grains, said matrix comprising or consisting of a silicon nitride and/or silicon oxynitride phase, said matrix representing between 5 and 40% by weight of said constituent material of the ceramic body;
said ceramic material having an open porosity that is higher than 5% and lower than 14% and a metallic silicon content in said material, expressed per mm of thickness of said body, that is lower than 0.5% by weight.

16 . The armor plate as claimed in claim 1 , wherein the back energy-dissipating coating consists of a material having a hardness that is lower than that of the constituent material of the ceramic body.

17 . The armor plate as claimed in claim 2 , wherein the SiC is in the alpha form.

18 . The armor plate as claimed in claim 4 , wherein the mass-to-area ratio, measured in kg/m 2 , is lower than 200.

19 . The armor plate as claimed in claim 7 , wherein the constituent material of the ceramic body contains no yttrium and/or no lanthanum.

20 . The armor plate as claimed in claim 7 , wherein the constituent material of the ceramic body contains no elements from the group of the actinides.

21 . The armor plate as claimed in claim 11 , wherein the binding matrix essentially consists of silicon nitride Si 3 N 4 .

22 . The armor plate as claimed in claim 12 , wherein the polyethenes PE are ultra-high-molecular-weight polyethenes (UHMPEs).

23 . The armor plate as claimed in claim 12 , wherein the metals are aluminum, titanium or their alloys.

24 . The armor plate as claimed in claim 14 , wherein the constituent material of the envelope is chosen from ultra-high-molecular-weight polyethenes (UHMPEs).

25 . The armor plate as claimed in claim 14 , wherein the metal is aluminum.

26 . The monolithic ceramic body as claimed in claim 15 , wherein the ceramic material is metal carbide or boride.

27 . The monolithic ceramic body as claimed in claim 15 , wherein the ceramic material is silicon or boron carbide or a mixture of these two carbides.

Assignees

• Saint Gobain Ct Recherches

Inventors

• Moeller Malte
• Rossiquet Gilles

Classifications

• C04B2235/3821

  Boron carbides · CPC title

• C04B2235/3873

  Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride · CPC title

• C04B2235/5436

  micrometer sized, i.e. from 1 to 100 micron · CPC title

• C04B35/6316

  Binders based on silicon compounds · CPC title

• C04B2235/6027

  Slip casting · CPC title