Hexoloy might have a name that seems like it’s been ripped straight out of a science fiction novel but it’s a real substance with plenty of applications in the real world. In the ceramic materials industry, it’s especially useful as a high-performance, highly durable material.
To understand what Hexoloy is it’s best to first have a fundamental knowledge of the process known as “sintering”. Sintering is a process that can happen naturally (think of crystals and other minerals that are created over millennia due to high heat and high pressure of the subterranean Earth) but it can also be replicated in manufacturing. There is another pressureless sintered version of Hexoloy, which shares the same qualities.
Using high heat and high pressure, a powdered material is pressed into a solid substance without first liquefying it (melting it). In the case of sintered alpha Hexoloy, the powdered material is alpha silicon carbide powder (Hexoloy SiC). Hexoloy is a registered substance, patented by the Pittsburgh-based Carborundum Corporation in 1979.
Hexoloy has many uses in manufacturing and chemical processing because it's a highly durable material that can withstand high heat and perform over and over again even in these extreme environments.
The material is ideal for applications involving extremely high-temperature liquid and gasses, as a means of sealing high-pressure and high-heat mechanisms, and in high-temperature kilns and furnaces. Hexoloy performs well in these scenarios because it will not melt or become brittle under these extreme temperatures.
The ceramics industry is well-versed in the clear advantages of using Hexoloy. Let’s break them down.
You may know that the diamond is the hardest material found on Earth. Hexoloy comes in as a close second on the hardness scale, making it the second hardest high-performance materials in the world and much harder than tungsten carbide, another industry standard. It measures 2800 kg/mm2 at room temperature. Diamonds come in at just under 3 times that, which tells you how incredibly hard diamonds are!
Durability is incredibly important in the high-temperature production process. Hexoloy maintains its structure at temperatures exceeding 3,000F. It can also withstand pressure up to 55,000 psi.
As strong as the material is, you’d think Hexoloy would be a heavy material. However, it weighs less than half than most metal allows. Hexoloy is 40% lighter than the much more brittle steel and weighs about the same as aluminum, which is much weaker.
With a density of 3.10 g/cm3 minimum Hexoloy is one of the densest materials used for its multitude of applications.
Due to its high hardness and density, Hexoloy is resistant to wear and tear in the form of abrasion and sliding wear.
There are 5 grades of Hexoloy as categorized by the multinational manufacturing corporation Saint-Gobain. Each grade has its own specific densities, resistances, and grain structures.
Great for: Applications that require excellent wear and chemical resistance.
Great for: High-stress loads and high rotational speeds due to its reduced miro-porosity.
Great for: Applications that require corrosion and extreme temperature resistance (up to 1,900C). Resistant to thermal shock.
Great for: Sliding contact applications due to the ability of the SP's pores to act as reservoirs for fluid lubricants.
Great for: Applications that require high thermal conductivity as well as the usual hardness, corrosion resistance, and stability.