Monolithic Ceramic Armor Plate with Silicon Nitride Matrix
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Solution Overview
Problem
Current armor technologies face challenges in achieving multi-impact resistance with low mass density, particularly for large ceramic shielding surfaces, as they tend to fragment after initial shots and are heavy, making them unsuitable for vehicles and installations without excessive weight.
Innovation Solution
A monolithic ceramic armor plate with a surface area greater than 150 cm², thickness greater than 12 mm, and apparent density less than 3.5 g/cm³, featuring grains of ceramic material with Vickers hardness greater than 15 GPa, a silicon nitride or silicon oxynitride matrix, and a rear energy dissipation coating, optimized for low porosity and silicon content, to enhance ballistic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monolithic ceramic armor plates are used to reduce assembly complexity and improve multi-impact resistance, then reliability is improved, but manufacturing precision becomes more difficult to maintain due to the large surface area requiring uniform density and grain structure throughout the entire plate
Solution Approach 1:
The invention segments the monolithic ceramic plate into distinct functional zones: a first zone with coarser grains (5-500 μm) providing bulk structural support and shock absorption, and a second zone with finer grains (2-20 μm) providing surface hardness and projectile resistance. This segmentation allows each zone to be optimized for its specific function while maintaining manufacturability of the overall large-area plate.
Solution Approach 2:
The invention applies local quality by creating different grain size distributions in different regions of the ceramic plate. The coarser-grained first zone occupies the majority of the plate thickness and provides ductility and energy absorption, while the finer-grained second zone at the impact surface provides hardness and resistance to projectile penetration. This local differentiation resolves the contradiction between achieving uniform properties throughout and optimizing for specific functional requirements.
2Strength
If ceramic armor plates with high hardness are used to resist projectile impact, then strength is improved, but the material becomes more brittle and fragments more easily after initial impact, reducing reliability for successive shots
Solution Approach 1:
The invention creates a gradient structure where the second zone at the impact surface has finer grains providing high hardness for projectile resistance, while the first zone in the bulk has coarser grains providing ductility and toughness to prevent catastrophic fragmentation. This local differentiation of grain size allows the plate to simultaneously achieve high surface hardness and bulk resistance to fragmentation.
Solution Approach 2:
The invention creates a composite ceramic structure with two distinct grain size zones within the same material system. The coarser-grained first zone acts as a ductile matrix that absorbs impact energy and prevents crack propagation, while the finer-grained second zone acts as a hard surface layer that resists projectile penetration. This composite grain structure resolves the contradiction between hardness and fragmentation resistance.
3Ease of manufacture
If mosaic assembly of smaller ceramic pieces is used to achieve required surface area, then manufacturing flexibility is improved, but the number of parts and assembly complexity increase, worsening device complexity
Solution Approach 1:
The invention merges multiple smaller ceramic elements into a single monolithic plate structure, eliminating the need for assembly joints and multiple components. The entire large-area plate (greater than 150 cm²) is produced as one continuous piece with controlled grain structure, thereby reducing device complexity while maintaining the required surface area for armor applications.
Solution Approach 2:
The monolithic ceramic plate design serves multiple functions simultaneously: it provides the required large surface area for armor coverage, maintains structural integrity as a single piece, achieves the desired grain structure for ballistic performance, and eliminates assembly complexity. This universal design approach resolves the contradiction between manufacturing flexibility and device complexity.
4Strength
If conventional ceramic materials are used to achieve required hardness, then strength is improved, but the mass-to-surface ratio becomes excessive, increasing the weight of armored vehicles and reducing mobility
Solution Approach 1:
The invention changes the microstructural parameters of the ceramic material by controlling grain size distribution, with the first zone having grains of 5-500 μm and the second zone having grains of 2-20 μm. This parameter optimization allows achieving the required hardness for projectile resistance while controlling the overall density and mass-to-surface ratio of the armor plate, thereby reducing vehicle weight compared to conventional ceramic armors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides improved resistance to fragmentation and perforation from successive armor-piercing projectiles while maintaining a low mass-to-surface ratio, equivalent to steel-based plates but with reduced weight, adhering to STANAG 4569 and AEP 55 standards for protection levels 4 and 5.
Implementation Method 1
a matrix binding said grains, said matrix essentially consisting of a silicon nitride phase and/or a silicon oxynitride phase
Implementation Method 2
provided on its inner face with a rear energy dissipation coating, preferably made of a material of lower hardness than that of the material constituting the ceramic body
Implementation Method 3
grains of ceramic material with a Vickers hardness greater than 15 GPa
Data Source
AI summary
Antiballistic armour plate including a ceramic body consisting of a hard material, provided, on its inner face, with a back energy-dissipating coating, preferably consisting of a material having a hardness that is lower than that of the constituent material of the ceramic body, said plate being characterized in that: - 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 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; - the maximum equivalent diameter of said grains of ceramic material is smaller than or equal to 800 micrometres; - said constituent material of the ceramic body having 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.