Super Hard Ceramics – They don’t get much tougher

Published on Apr 6, 2021 | Last updated May 31, 2022

In the world of advanced ceramics, there are two materials which are only surpassed by diamond and cubic boron nitride in terms of hardness – and both are used by Precision Ceramics as a base material for a wide range of technical components in an equally wide field of applications.

In terms of toughness, there’s not much to choose between them but each has its own specific advantages in terms of properties and application.

Boron Carbide (B4C) is currently the hardest material produced in tonnage quantities and is the third hardest material known to man after diamond and cubic boron nitride.

Not far behind it in the hardness stakes comes silicon carbide (SiC), more commonly known as carborundum, steeped in history since it was first mass-produced in 1893 and probably the most common of all industrial abrasives.

Boron Carbide (B4C)

The extreme hardness of boron carbide provides excellent wear and abrasion resistance and consequently it is a perfect base material for the manufacture of nozzles for slurry pumping, grit blasting and in water jet cutters.

In combination with other materials, boron carbide also finds extensive use in ballistic armour (including body and personnel armour) where its combination of high hardness, high elastic modulus, and low density gives the material an exceptionally high specific stopping power to defeat high velocity projectiles.

Other applications include ceramic tooling dies, precision tool parts, Jigs and other high wear applications.

Silicon Carbide (SiC)

The technical properties of silicon carbide are remarkably similar to those of diamond. It is one of the lightest, hardest and strongest technical ceramic materials and has exceptional thermal conductivity, chemical resistance and low thermal expansion.

Silicon carbide is an excellent material to use when physical wear is an important consideration because it provides good erosion and abrasive resistance making it particularly suitable for such applications as spray nozzles, shot blast nozzles and cyclone components.

Not so long ago, silicon carbide was the chosen material to line the brakes of the most advanced, jaw-dropping cars the world has ever seen, the  McLaren P1 for example:

DuraShock & DuraWear

Precision ceramics has also developed a range of other materials to add to our collection of ultra-hard materials.

Durawear, a Hybrid combining the benefits of Boron Carbide (B4C) and Silicon Carbide (SiC) this material evolved to retain the incredible hardness of both materials without some of the constraints of either. This Hybrid offers the benefit of a high melting point, combined with good thermal shock and is chemically inert.

Durashock, a hybrid also combining B4c and SiC but focused on ballistic applications, where  this light but incredibly hard material can withstand some of the latest threat’s whist being much easier to produce than pure Hot pressed  Boron Carbide

Ceramalloy Ultra Hard, a Zirconia toughened Alumina (ZTA), an oxide ceramic, this material combines high hardness, with good fracture toughness and good bending strength. The material. Is also Hipped (Hot Iso Pressed) this process applies extreme pressure and temperature at the same time further enhancing the material and gives excellent consistency.

Our in-house Hipping process has been utilised with many of our ultra-hard and ultra-tough materials to take materials to another level.

It’s tough at the top…

… and to be at the top you have to be tough. That’s why these materials sit tall on the shelves of the Precision Ceramics raw materials stores. And that’s why they continue to provide the very highest level of quality and service to PC customers worldwide in a wide field of component applications.

Further detailed technical and applications information and downloadable data sheets are available for all our materials from the Precision Ceramics website.

The below data table compares the Hardness and Fracture Toughness (with indicative values) of the 4 materials mentioned:

Compound
Boron Carbide
Silicon Carbide
Boron Carbide-Silicon Carbide (DuraWear)
Boron Carbide-Silicon Carbide (DuraShock)
Zirconia Toughened Alumina (CeramAlloy)
ID
B4C
SiC
B4C / SiC Composite
B4C / SiC Composite
ZTA
Hardness
35 HV0.5 [GPa]
25 HV0.5 [GPa]
31 HV0.5 [GPa]
28 HV0.5 [GPa]
16 HV0.5 [GPa]
Fracture Toughness
2 KIC [MPa/m2]
3.5 KIC [MPa/m2]
3.4 KIC [MPa/m2]
4 KIC [MPa/m2]
7 KIC [MPa/m2]

Interested in finding out more and if any of our materials are the right fit for your application? Please don’t hesitate to get in touch.

Related topics:

Hardness

Hardness

One of the most valuable characteristics of advanced ceramics in high-performance applications is their extreme hardness. Hard ceramic materials are used for a wide range of applications in diverse fields and applications such as cutting tools for milling and grinding.

Fracture Toughness

Fracture Toughness

The ability to resist fracture is a mechanical property of materials known as fracture toughness. For advanced ceramics it uses a critical stress intensity factor known as KIC where the fracture normally occurs at the crack terminations.

Boron-Silicon Carbide DuraShock Material Brand

Boron-Silicon Carbide

DuraShock™

DuraShock is a Boron-Silicon Carbide ceramic composite, developed to give the very best combination of high ballistic performance and weight saving considerations.

CeramAlloy ZTA Material Brand

Zirconia Toughened Alumina

CeramAlloy™

Zirconia Toughened Alumina (ZTA) is a high performance ceramic composite and a unique ceramic material by way of exhibiting a combination of high hardness, strength, wear and corrosion resistance.

Frequently Asked Questions

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    What is Silicon Carbide used for?

    Silicon Carbide has properties remarkably similar to those of diamond – it is one of the lightest, hardest, and strongest technical ceramic materials and has exceptional thermal conductivity, resistance to acids, and low thermal expansion. Silicon Carbide is an excellent material to use when physical wear is an important consideration because it exhibits good erosion and abrasive resistance, making it useful in a variety of applications including the following:

    • Valve seats
    • Sliding bearings
    • Mechanical seals
    • Plungers
    • Seal rings (water ring pumps)
    • Wear parts (thread guides)
    • Kiln furniture crucibles
    • Burners
    • Blast nozzles
    • Heat exchangers
  • image/svg+xmlimage/svg+xml
    What is Boron Carbide used for?

    The combination of low specific weight, high hardness and reasonable toughness makes it a suitable material for body and vehicle armor. Boron carbide is also extensively used as control rods, shielding materials and as neutron detectors in nuclear reactors due to its ability to absorb neutrons without forming long lived radionuclide. As it is a p-type semiconductor, boron carbide can be a suitable candidate material for electronic devices that can be operated at high temperatures. Boron Carbide is also an excellent p-type thermoelectric material. Some typical applications of boron carbide include:

    • Sand blasting nozzles
    • Ball & roller bearings
    • Seals
    • Wire drawing dies
    • Body armour
  • image/svg+xmlimage/svg+xml
    Steel vs ceramic armor, what are the benefits?

    There are differing factors when comparing steel and ceramic body armor. Below is a list of some of the benefits and draw backs of ceramic armor in comparison to steel:

    BENEFITS

    • Lightweight – ceramic plates weigh considerably less than steel and in some cases the weight can be halved
    • Ceramic armor protects against high-caliber weapons whereas as steel is vulnerable (NIJ Lever 4 AP M2 or similar)
    • Increased flexibility of ceramic armor which increases effectiveness in combat situations
    • Ceramic armor is more stable than steel meaning its easy to store without worrying about armor degradation
    • Steel armor tends to cause ricochet and is shrapnel prone both of which is not found with ceramic armor

    DRAW BACKS

    • In most cases after cermic armor has suffered an impact it cannot be used again and is more brittle than steel
    • Steel has a longer lifespan when compared to ceramic armor
    • Steel armor is usually cheaper
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    What is the difference between DuraShock™ and other ceramic armor?

    DuraShock™ is a ceramic ceramic composite between BoronCarbide and Silicon Carbide.

    Both Boron Carbide and Silicon Carbide are excellent armour materials in their own rights , each with advantages and disadvantages. For example Boron Carbide is very light and provides a very good level of protection but its brittle and very expensive to manufacture. Silicon Carbide is more economical to produce but it’s heavier and its performance is less than that of Boron Carbide. DuraShock™ effectively combines the advantages of both while minimising the disadvantages. With DuraShock™ the performance is comparable to that of Boron Carbide for a price more indicative of Silicon Carbide.

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    What is DuraShock™ ceramic armor made of?

    DuraShock™ is a Boron Carbide/Silicon Carbide ceramic composite, developed to give the very best combination of high ballistic performance with weight saving considerations while maintaining a reasonable cost. It’s a material developed and sold by Precision Ceramics.

  • image/svg+xmlimage/svg+xml
    Why is ceramic used in body armor?

    The combination of low specific weight, high hardness and reasonable toughness makes it a great material for body and vehicle armor. The weight reduction achieved with lightweight ceramics like DuraShock™ vs. steel or heavier ceramics is substantial and allows the vehicle to take on more cargo or ammunition. For these reasons it is a popular alternative to steel armor and offers extra comfort and flexibility in body armor allowing the wearer to move more freely.

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