In the world of technical ceramics, there are two materials which are only surpassed by diamond 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, for instance, 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, 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.
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.
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:
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 B4c Boron Carbide and SIC Silicon Carbide 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, this ZTA (Zirconia toughened Aluminia) is 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:
|Boron Carbide||B4C||35 HV0.5 [GPa]||2 KIC [MPa/m2]|
|Silicon Carbide||SiC||25 HV0.5 [GPa]||3.5 KIC [MPa/m2]|
|Boron Carbide-Silicon Carbide (DuraWear)||B4C / SiC Composite||31 HV0.5 [GPa]||3.4 KIC [MPa/m2]|
|Zirconia Toughened Alumina (CeramAlloy)||ZTA||16 HV0.5 [GPa]||7 KIC [MPa/m2]|
To see the full range of materials offered at Precision Ceramics – Click Here!
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FAQ’s on Hard Ceramics:
How hard is ceramic?
The top 5 hardest materials on earth are all ceramics , with diamond only ranking third on the list . The most common element being Aluminia or AL2O3 which is used extensively in pumps, wear parts and ballistic armour and this only ranks 10th of the top 10.
What is the hardest ceramic?
The hardest ceramic on earth is Wurtzite Boron Nitride , created in volcanic eruptions under intense heat and pressure this rare material is more complex than diamond and 80% harder.
What is the strongest Ceramic?
Ceramics don’t make the top 4 strongest materials , the strongest Ceramic in 5th place is Lonsdaleite, created during the impact or carbon rich meteorites , a pure piece of Lonsdaleite would be stronger and 58% harder than diamond , but these are often found with impurities significantly reducing their theoretical strength.
When are ceramics with high strength useful?
Ceramics are strongest in compression and typically their compressive strength is 10 times its tensile strength. Impurities and flaws within the ceramics don’t tend to be adversely affected under pressure whereas tensile loading tends to cause the defects to propagate.