Silicon Carbide (SiC) is a dark-grey ceramic material that has been one of the biggest advancements in body armor weight reduction. Silicon Carbide is currently dominating the market in terms of it's cost-to-benefit ratio and the availability to the civilian body armor market is growing quickly.
SiC Technical Data
(These will vary slightly depending on which SiC variant is used, but generally this data range works for almost all SiC)
Hardness: 2200-2800 HV1
Fracture toughness: 3 – 4 MPa*m1/2
Compressive strength: 3500-4900 MPa
Melting point: Degrades at 2830°C ± 30°C
A short history on Silicon Carbide
The creation of Silicon Carbide was accidental. In 1891 Edward Goodrich Acheson was doing experiments on synthesizing diamonds in an electric arc furnace and after heating up a mixture of clay and coke to very high temperatures some blue crystals formed on the furnaces carbon electrode. At the time, Acheson assumed it was caused by a reaction with the clay and the carbon, so the substance was named Carborundum. We know now that, that name is incorrect and the real name is Silicon Carbide. However the name "Carborundum" stuck. I keep a small SiC "Carborundum" rock at my office window! Some pieces of this natural forming rock are very pretty. It's also found in Moissanite but on the commercial market, "Carborundum" is the term you'll want to search.
The "Acheson" Process - a step towards commercial SiC.
The Acheson process was one the first methods to producing an industrial amount of Silicon Carbide. Essentially the Acheson process involves heating Silica sand and coke in an electric furnace to upwards of 2600 degrees Celsius. This heating creates it own endothermic reaction which helps it reach such high temperatures. However, by utilizing this reaction process, you emit a lot of CO and CO2. Doing this is frowned upon in wake of the global climate crisis, so almost all Silicon Carbide is made in China. Infact over 90% of the global SiC supply comes from China.SiC and China
If you're a manufacturer and sourcing SiC, you'll quickly realize the options for US made SiC is limited. Let's set aside our political opinions towards the country for a moment and discuss the situation. Many body armor opinions will lead you to believe that everything made in China, is made crudely using unsafe and unreliable methods. They'll lead you to believe that they cut corners with zero regard for anyone. While there are certainly examples of bad manufactures in China, there are examples of bad manufacturers anywhere we look. It won't take you long to find US armor companies that engage in extremely irresponsible practices!
My point is, who you buy your armor and materials from is important, regardless of nationality. China produces the most SiC in the world. They make over 90% of the global SiC supply. It would be insane to believe that every single manufacturer of it, in China, is bad. I wanted to touch on this, because we work with Militech, an ISO Certified Chinese armor manufacturer, and sometimes the accusations we hear are absurd. It's one thing to avoid it because of political differences, it's another to flat out make up false truths. Of course, these are my opinions based on my years of experience (and NIJ tests) but, I urge you to continue your research and make your own opinions. If you decide to buy foreign armor due to ITAR or budget reasons, I urge you to seek out Militech, as they are the leading professionals. Buying directly from us or Militech will save you a lot of headaches too!
We are working with Militech to continue leveraging their advantage of their widely available SiC and pushing for more SiC products! We have a few available now and they some of the best armor options for their cost. SiC is my personal favorite armor material and it's the direction I am pushing for.
SiC's Unique Ability to Outshine Other Ceramics
So what makes SiC so cool? Silicon Carbide is extremely predictable compared to other armor materials. More specifically, it's more predictable against Tungsten Carbide. Tungsten Carbide is used in the armor piercing ammo that the NIJ labs use to test body armor. This is because SiC is harder than Tungsten Carbide, whereas materials like Alumina Ceramic. Let's dive into the main materials used to make body armor and discuss the issues of each of them.
Alumina Ceramic - This is the most common material used to make body armor. It's a great ceramic and is widely available. However, it is heavy and you must over-build the ceramic strikeface to make up for it's lack of hardness when being tested against tungsten carbide. This leads to thick and heavy plates. It is cheap however and it is absolutely dominating the civilian body armor market. It's just not the most efficient.
Boron Carbide - Boron Carbide is used in very high-end armor. It's lighter than SiC, but just barely. Typically the weight reduction of Boron Carbide is less than a pound and it cost 5x as much, if not more. This is because the crystalline structure of Boron Carbide is susceptible to breaking down at high pressures. So it also needs overbuilt like Alumina Ceramic.
Steel - Although I am discussing ceramics we must also discuss steel and it's weaknesses. The circulating theory on steel is that "speed kills armor" and while somewhat true, in the case of steel it is not. An M193 lead core projectile traveling in excess of 3000fps will punch through steel whereas M855 traveling at the same speed will not. Why is that? It's all about the physics that occur when a bullet hits steel. In the case of M193, it is able to "plug" through the armor because upon impact the lead core of the bullet practically turns to liquid, all of the projectile's energy is placed into a very small surface area. This allows the lead to push through out the back of the armor and catastrophically fail. Whereas M855, the steel core is decelerated quickly and leads to the bullet to explode/splash on contact with the steel armor. Steel is incredibly heavy, especially with build-up coats. It is cheap though!
So knowing these things, and how efficient the ceramic is, it's clear to us why we are choosing to push for more SiC armor.
SiC and it's Many Variants
100% pure SiC is actually colorless and transparent. SiC variants used in body armor are generally 98% pure, with a small percentage of sintering aides added to the process when making it. It does not take much to turn the SiC ceramic black. Most SiC on the market is mixed with a 1% ratio of Carbon and Boron. Both provide their own advantages to the manufacturing process.
While some body armor retailers like to exaggerate the variables in SiC, there are few instances where SiC, used for body armor purposes, strays from this molecular make-up. There is no reason to believe that one company's body armor SiC is vastly different from another's, to the point that one will lead in catastrophic failure. Additionally, any SiC manufactured for body armor purposes is done so with specific intentions and uses specific mixtures in the manufacturing process.
For example, SiC produced with 1% Boron and Carbon are oftentimes called "ABC-SiC", "Hexoloy SA" or "SiC-I" and is sold by different manufacturers. There are companies creating SiC variants with much larger mixtures such as 70% SiC and 30% Boron Carbide, or even 50% SiC and 50% Boron Carbide, but they create these variants specifically for use in body armor. Though, the hardness, density and such will be variable.
SiC is used in the power, automotive, abrasives, jewelry, fuel and the armor industry.
You would not approach these SiC manufacturers and say, "Please give me the SiC variants you use to make automotive parts, I want to use them on armor." Any reputable armor manufacture will approach the SiC manufactures with the intention of making Body Armor and order the proper blend for this purpose.
Our SiC Products!
Militech Level III++ SiC Multicurve Plates
Weight per plate (Medium): 4.2lbs.
Cost per plate (Medium): $200
These Silicon Carbide Plates are my go-to. They're about 4lbs a plate, tiled, multi-curve and capable of stopping M855A1! Using the same successful hexagon tiles Militech has used in the the Alumina Ceramic III+ plates, Militech has created a III++ Silicon Carbide plate that is 2 pounds lighter for the same protection. The multi-curve design allows you to move more freely compared to regular single-curve plates.
These feature full edge-to-edge protection and a pressed backers! This helps mitigate backface deformation and ensures the overall integrity of the armor.
There are no US made level III+ tiled SiC plates, at this weight, that I am aware of. UARM, a Ukrainian based manufacturer, is the only comparable option with their "SA3S" model. They are about $400 per plate. It likely they are using Chinese made SiC for their armor, because that is where the global supply of SiC is made.
Militech Black Label Level IV Silicon Carbide Monolithic Plates
Weight per plate (Medium): 6.55lbs.
Cost per plate (Medium): $320
Militech Black Label Level IV SiC plates are Militech's top of the line Level IV option. These feature a Monolithic Silicon Carbide ceramic core, strengthened with a Carbon Fiber laminate later. They utilize a pressed UHMWPE backer and create a wonderful lightweight and multi-hit capable plate.
The cost this plate cannot be beat! USA made SiC level IV plates around 6lbs per plate sell for no less than $1,000 per plate. This is due to the widespread inability to obtain USA made SiC cheaply.